1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux I2C core
4  *
5  * Copyright (C) 1995-99 Simon G. Vogl
6  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
9  *
10  * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11  */
12 
13 #define pr_fmt(fmt) "i2c-core: " fmt
14 
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/delay.h>
20 #include <linux/err.h>
21 #include <linux/errno.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/idr.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/irqflags.h>
29 #include <linux/jump_label.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/mutex.h>
33 #include <linux/of_device.h>
34 #include <linux/of.h>
35 #include <linux/of_irq.h>
36 #include <linux/pinctrl/consumer.h>
37 #include <linux/pinctrl/devinfo.h>
38 #include <linux/pm_domain.h>
39 #include <linux/pm_runtime.h>
40 #include <linux/pm_wakeirq.h>
41 #include <linux/property.h>
42 #include <linux/rwsem.h>
43 #include <linux/slab.h>
44 
45 #include "i2c-core.h"
46 
47 #define CREATE_TRACE_POINTS
48 #include <trace/events/i2c.h>
49 
50 #define I2C_ADDR_OFFSET_TEN_BIT	0xa000
51 #define I2C_ADDR_OFFSET_SLAVE	0x1000
52 
53 #define I2C_ADDR_7BITS_MAX	0x77
54 #define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)
55 
56 #define I2C_ADDR_DEVICE_ID	0x7c
57 
58 /*
59  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
60  * deletion of detected devices are serialized
61  */
62 static DEFINE_MUTEX(core_lock);
63 static DEFINE_IDR(i2c_adapter_idr);
64 
65 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
66 
67 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
68 static bool is_registered;
69 
i2c_transfer_trace_reg(void)70 int i2c_transfer_trace_reg(void)
71 {
72 	static_branch_inc(&i2c_trace_msg_key);
73 	return 0;
74 }
75 
i2c_transfer_trace_unreg(void)76 void i2c_transfer_trace_unreg(void)
77 {
78 	static_branch_dec(&i2c_trace_msg_key);
79 }
80 
i2c_freq_mode_string(u32 bus_freq_hz)81 const char *i2c_freq_mode_string(u32 bus_freq_hz)
82 {
83 	switch (bus_freq_hz) {
84 	case I2C_MAX_STANDARD_MODE_FREQ:
85 		return "Standard Mode (100 kHz)";
86 	case I2C_MAX_FAST_MODE_FREQ:
87 		return "Fast Mode (400 kHz)";
88 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
89 		return "Fast Mode Plus (1.0 MHz)";
90 	case I2C_MAX_TURBO_MODE_FREQ:
91 		return "Turbo Mode (1.4 MHz)";
92 	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
93 		return "High Speed Mode (3.4 MHz)";
94 	case I2C_MAX_ULTRA_FAST_MODE_FREQ:
95 		return "Ultra Fast Mode (5.0 MHz)";
96 	default:
97 		return "Unknown Mode";
98 	}
99 }
100 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
101 
i2c_match_id(const struct i2c_device_id * id,const struct i2c_client * client)102 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
103 						const struct i2c_client *client)
104 {
105 	if (!(id && client))
106 		return NULL;
107 
108 	while (id->name[0]) {
109 		if (strcmp(client->name, id->name) == 0)
110 			return id;
111 		id++;
112 	}
113 	return NULL;
114 }
115 EXPORT_SYMBOL_GPL(i2c_match_id);
116 
i2c_get_match_data(const struct i2c_client * client)117 const void *i2c_get_match_data(const struct i2c_client *client)
118 {
119 	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
120 	const struct i2c_device_id *match;
121 	const void *data;
122 
123 	data = device_get_match_data(&client->dev);
124 	if (!data) {
125 		match = i2c_match_id(driver->id_table, client);
126 		if (!match)
127 			return NULL;
128 
129 		data = (const void *)match->driver_data;
130 	}
131 
132 	return data;
133 }
134 EXPORT_SYMBOL(i2c_get_match_data);
135 
i2c_device_match(struct device * dev,struct device_driver * drv)136 static int i2c_device_match(struct device *dev, struct device_driver *drv)
137 {
138 	struct i2c_client	*client = i2c_verify_client(dev);
139 	struct i2c_driver	*driver;
140 
141 
142 	/* Attempt an OF style match */
143 	if (i2c_of_match_device(drv->of_match_table, client))
144 		return 1;
145 
146 	/* Then ACPI style match */
147 	if (acpi_driver_match_device(dev, drv))
148 		return 1;
149 
150 	driver = to_i2c_driver(drv);
151 
152 	/* Finally an I2C match */
153 	if (i2c_match_id(driver->id_table, client))
154 		return 1;
155 
156 	return 0;
157 }
158 
i2c_device_uevent(const struct device * dev,struct kobj_uevent_env * env)159 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
160 {
161 	const struct i2c_client *client = to_i2c_client(dev);
162 	int rc;
163 
164 	rc = of_device_uevent_modalias(dev, env);
165 	if (rc != -ENODEV)
166 		return rc;
167 
168 	rc = acpi_device_uevent_modalias(dev, env);
169 	if (rc != -ENODEV)
170 		return rc;
171 
172 	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
173 }
174 
175 /* i2c bus recovery routines */
get_scl_gpio_value(struct i2c_adapter * adap)176 static int get_scl_gpio_value(struct i2c_adapter *adap)
177 {
178 	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
179 }
180 
set_scl_gpio_value(struct i2c_adapter * adap,int val)181 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
182 {
183 	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
184 }
185 
get_sda_gpio_value(struct i2c_adapter * adap)186 static int get_sda_gpio_value(struct i2c_adapter *adap)
187 {
188 	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
189 }
190 
set_sda_gpio_value(struct i2c_adapter * adap,int val)191 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
192 {
193 	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
194 }
195 
i2c_generic_bus_free(struct i2c_adapter * adap)196 static int i2c_generic_bus_free(struct i2c_adapter *adap)
197 {
198 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
199 	int ret = -EOPNOTSUPP;
200 
201 	if (bri->get_bus_free)
202 		ret = bri->get_bus_free(adap);
203 	else if (bri->get_sda)
204 		ret = bri->get_sda(adap);
205 
206 	if (ret < 0)
207 		return ret;
208 
209 	return ret ? 0 : -EBUSY;
210 }
211 
212 /*
213  * We are generating clock pulses. ndelay() determines durating of clk pulses.
214  * We will generate clock with rate 100 KHz and so duration of both clock levels
215  * is: delay in ns = (10^6 / 100) / 2
216  */
217 #define RECOVERY_NDELAY		5000
218 #define RECOVERY_CLK_CNT	9
219 
i2c_generic_scl_recovery(struct i2c_adapter * adap)220 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
221 {
222 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
223 	int i = 0, scl = 1, ret = 0;
224 
225 	if (bri->prepare_recovery)
226 		bri->prepare_recovery(adap);
227 	if (bri->pinctrl)
228 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
229 
230 	/*
231 	 * If we can set SDA, we will always create a STOP to ensure additional
232 	 * pulses will do no harm. This is achieved by letting SDA follow SCL
233 	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
234 	 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
235 	 * here for simplicity.
236 	 */
237 	bri->set_scl(adap, scl);
238 	ndelay(RECOVERY_NDELAY);
239 	if (bri->set_sda)
240 		bri->set_sda(adap, scl);
241 	ndelay(RECOVERY_NDELAY / 2);
242 
243 	/*
244 	 * By this time SCL is high, as we need to give 9 falling-rising edges
245 	 */
246 	while (i++ < RECOVERY_CLK_CNT * 2) {
247 		if (scl) {
248 			/* SCL shouldn't be low here */
249 			if (!bri->get_scl(adap)) {
250 				dev_err(&adap->dev,
251 					"SCL is stuck low, exit recovery\n");
252 				ret = -EBUSY;
253 				break;
254 			}
255 		}
256 
257 		scl = !scl;
258 		bri->set_scl(adap, scl);
259 		/* Creating STOP again, see above */
260 		if (scl)  {
261 			/* Honour minimum tsu:sto */
262 			ndelay(RECOVERY_NDELAY);
263 		} else {
264 			/* Honour minimum tf and thd:dat */
265 			ndelay(RECOVERY_NDELAY / 2);
266 		}
267 		if (bri->set_sda)
268 			bri->set_sda(adap, scl);
269 		ndelay(RECOVERY_NDELAY / 2);
270 
271 		if (scl) {
272 			ret = i2c_generic_bus_free(adap);
273 			if (ret == 0)
274 				break;
275 		}
276 	}
277 
278 	/* If we can't check bus status, assume recovery worked */
279 	if (ret == -EOPNOTSUPP)
280 		ret = 0;
281 
282 	if (bri->unprepare_recovery)
283 		bri->unprepare_recovery(adap);
284 	if (bri->pinctrl)
285 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
286 
287 	return ret;
288 }
289 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
290 
i2c_recover_bus(struct i2c_adapter * adap)291 int i2c_recover_bus(struct i2c_adapter *adap)
292 {
293 	if (!adap->bus_recovery_info)
294 		return -EBUSY;
295 
296 	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
297 	return adap->bus_recovery_info->recover_bus(adap);
298 }
299 EXPORT_SYMBOL_GPL(i2c_recover_bus);
300 
i2c_gpio_init_pinctrl_recovery(struct i2c_adapter * adap)301 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
302 {
303 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
304 	struct device *dev = &adap->dev;
305 	struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
306 
307 	bri->pinctrl = p;
308 
309 	/*
310 	 * we can't change states without pinctrl, so remove the states if
311 	 * populated
312 	 */
313 	if (!p) {
314 		bri->pins_default = NULL;
315 		bri->pins_gpio = NULL;
316 		return;
317 	}
318 
319 	if (!bri->pins_default) {
320 		bri->pins_default = pinctrl_lookup_state(p,
321 							 PINCTRL_STATE_DEFAULT);
322 		if (IS_ERR(bri->pins_default)) {
323 			dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
324 			bri->pins_default = NULL;
325 		}
326 	}
327 	if (!bri->pins_gpio) {
328 		bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
329 		if (IS_ERR(bri->pins_gpio))
330 			bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
331 
332 		if (IS_ERR(bri->pins_gpio)) {
333 			dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
334 			bri->pins_gpio = NULL;
335 		}
336 	}
337 
338 	/* for pinctrl state changes, we need all the information */
339 	if (bri->pins_default && bri->pins_gpio) {
340 		dev_info(dev, "using pinctrl states for GPIO recovery");
341 	} else {
342 		bri->pinctrl = NULL;
343 		bri->pins_default = NULL;
344 		bri->pins_gpio = NULL;
345 	}
346 }
347 
i2c_gpio_init_generic_recovery(struct i2c_adapter * adap)348 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
349 {
350 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
351 	struct device *dev = &adap->dev;
352 	struct gpio_desc *gpiod;
353 	int ret = 0;
354 
355 	/*
356 	 * don't touch the recovery information if the driver is not using
357 	 * generic SCL recovery
358 	 */
359 	if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
360 		return 0;
361 
362 	/*
363 	 * pins might be taken as GPIO, so we should inform pinctrl about
364 	 * this and move the state to GPIO
365 	 */
366 	if (bri->pinctrl)
367 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
368 
369 	/*
370 	 * if there is incomplete or no recovery information, see if generic
371 	 * GPIO recovery is available
372 	 */
373 	if (!bri->scl_gpiod) {
374 		gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
375 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
376 			ret  = -EPROBE_DEFER;
377 			goto cleanup_pinctrl_state;
378 		}
379 		if (!IS_ERR(gpiod)) {
380 			bri->scl_gpiod = gpiod;
381 			bri->recover_bus = i2c_generic_scl_recovery;
382 			dev_info(dev, "using generic GPIOs for recovery\n");
383 		}
384 	}
385 
386 	/* SDA GPIOD line is optional, so we care about DEFER only */
387 	if (!bri->sda_gpiod) {
388 		/*
389 		 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
390 		 * have no effect.
391 		 */
392 		gpiod_direction_output(bri->scl_gpiod, 0);
393 		udelay(10);
394 		gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
395 
396 		/* Wait a bit in case of a SDA glitch, and then release SCL. */
397 		udelay(10);
398 		gpiod_direction_output(bri->scl_gpiod, 1);
399 
400 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
401 			ret = -EPROBE_DEFER;
402 			goto cleanup_pinctrl_state;
403 		}
404 		if (!IS_ERR(gpiod))
405 			bri->sda_gpiod = gpiod;
406 	}
407 
408 cleanup_pinctrl_state:
409 	/* change the state of the pins back to their default state */
410 	if (bri->pinctrl)
411 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
412 
413 	return ret;
414 }
415 
i2c_gpio_init_recovery(struct i2c_adapter * adap)416 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
417 {
418 	i2c_gpio_init_pinctrl_recovery(adap);
419 	return i2c_gpio_init_generic_recovery(adap);
420 }
421 
i2c_init_recovery(struct i2c_adapter * adap)422 static int i2c_init_recovery(struct i2c_adapter *adap)
423 {
424 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
425 	bool is_error_level = true;
426 	char *err_str;
427 
428 	if (!bri)
429 		return 0;
430 
431 	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
432 		return -EPROBE_DEFER;
433 
434 	if (!bri->recover_bus) {
435 		err_str = "no suitable method provided";
436 		is_error_level = false;
437 		goto err;
438 	}
439 
440 	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
441 		bri->get_scl = get_scl_gpio_value;
442 		bri->set_scl = set_scl_gpio_value;
443 		if (bri->sda_gpiod) {
444 			bri->get_sda = get_sda_gpio_value;
445 			/* FIXME: add proper flag instead of '0' once available */
446 			if (gpiod_get_direction(bri->sda_gpiod) == 0)
447 				bri->set_sda = set_sda_gpio_value;
448 		}
449 	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
450 		/* Generic SCL recovery */
451 		if (!bri->set_scl || !bri->get_scl) {
452 			err_str = "no {get|set}_scl() found";
453 			goto err;
454 		}
455 		if (!bri->set_sda && !bri->get_sda) {
456 			err_str = "either get_sda() or set_sda() needed";
457 			goto err;
458 		}
459 	}
460 
461 	return 0;
462  err:
463 	if (is_error_level)
464 		dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
465 	else
466 		dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
467 	adap->bus_recovery_info = NULL;
468 
469 	return -EINVAL;
470 }
471 
i2c_smbus_host_notify_to_irq(const struct i2c_client * client)472 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
473 {
474 	struct i2c_adapter *adap = client->adapter;
475 	unsigned int irq;
476 
477 	if (!adap->host_notify_domain)
478 		return -ENXIO;
479 
480 	if (client->flags & I2C_CLIENT_TEN)
481 		return -EINVAL;
482 
483 	irq = irq_create_mapping(adap->host_notify_domain, client->addr);
484 
485 	return irq > 0 ? irq : -ENXIO;
486 }
487 
i2c_device_probe(struct device * dev)488 static int i2c_device_probe(struct device *dev)
489 {
490 	struct i2c_client	*client = i2c_verify_client(dev);
491 	struct i2c_driver	*driver;
492 	bool do_power_on;
493 	int status;
494 
495 	if (!client)
496 		return 0;
497 
498 	client->irq = client->init_irq;
499 
500 	if (!client->irq) {
501 		int irq = -ENOENT;
502 
503 		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
504 			dev_dbg(dev, "Using Host Notify IRQ\n");
505 			/* Keep adapter active when Host Notify is required */
506 			pm_runtime_get_sync(&client->adapter->dev);
507 			irq = i2c_smbus_host_notify_to_irq(client);
508 		} else if (dev->of_node) {
509 			irq = of_irq_get_byname(dev->of_node, "irq");
510 			if (irq == -EINVAL || irq == -ENODATA)
511 				irq = of_irq_get(dev->of_node, 0);
512 		} else if (ACPI_COMPANION(dev)) {
513 			bool wake_capable;
514 
515 			irq = i2c_acpi_get_irq(client, &wake_capable);
516 			if (irq > 0 && wake_capable)
517 				client->flags |= I2C_CLIENT_WAKE;
518 		}
519 		if (irq == -EPROBE_DEFER) {
520 			status = irq;
521 			goto put_sync_adapter;
522 		}
523 
524 		if (irq < 0)
525 			irq = 0;
526 
527 		client->irq = irq;
528 	}
529 
530 	driver = to_i2c_driver(dev->driver);
531 
532 	/*
533 	 * An I2C ID table is not mandatory, if and only if, a suitable OF
534 	 * or ACPI ID table is supplied for the probing device.
535 	 */
536 	if (!driver->id_table &&
537 	    !acpi_driver_match_device(dev, dev->driver) &&
538 	    !i2c_of_match_device(dev->driver->of_match_table, client)) {
539 		status = -ENODEV;
540 		goto put_sync_adapter;
541 	}
542 
543 	if (client->flags & I2C_CLIENT_WAKE) {
544 		int wakeirq;
545 
546 		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
547 		if (wakeirq == -EPROBE_DEFER) {
548 			status = wakeirq;
549 			goto put_sync_adapter;
550 		}
551 
552 		device_init_wakeup(&client->dev, true);
553 
554 		if (wakeirq > 0 && wakeirq != client->irq)
555 			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
556 		else if (client->irq > 0)
557 			status = dev_pm_set_wake_irq(dev, client->irq);
558 		else
559 			status = 0;
560 
561 		if (status)
562 			dev_warn(&client->dev, "failed to set up wakeup irq\n");
563 	}
564 
565 	dev_dbg(dev, "probe\n");
566 
567 	status = of_clk_set_defaults(dev->of_node, false);
568 	if (status < 0)
569 		goto err_clear_wakeup_irq;
570 
571 	do_power_on = !i2c_acpi_waive_d0_probe(dev);
572 	status = dev_pm_domain_attach(&client->dev, do_power_on);
573 	if (status)
574 		goto err_clear_wakeup_irq;
575 
576 	client->devres_group_id = devres_open_group(&client->dev, NULL,
577 						    GFP_KERNEL);
578 	if (!client->devres_group_id) {
579 		status = -ENOMEM;
580 		goto err_detach_pm_domain;
581 	}
582 
583 	if (driver->probe)
584 		status = driver->probe(client);
585 	else
586 		status = -EINVAL;
587 
588 	/*
589 	 * Note that we are not closing the devres group opened above so
590 	 * even resources that were attached to the device after probe is
591 	 * run are released when i2c_device_remove() is executed. This is
592 	 * needed as some drivers would allocate additional resources,
593 	 * for example when updating firmware.
594 	 */
595 
596 	if (status)
597 		goto err_release_driver_resources;
598 
599 	return 0;
600 
601 err_release_driver_resources:
602 	devres_release_group(&client->dev, client->devres_group_id);
603 err_detach_pm_domain:
604 	dev_pm_domain_detach(&client->dev, do_power_on);
605 err_clear_wakeup_irq:
606 	dev_pm_clear_wake_irq(&client->dev);
607 	device_init_wakeup(&client->dev, false);
608 put_sync_adapter:
609 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
610 		pm_runtime_put_sync(&client->adapter->dev);
611 
612 	return status;
613 }
614 
i2c_device_remove(struct device * dev)615 static void i2c_device_remove(struct device *dev)
616 {
617 	struct i2c_client	*client = to_i2c_client(dev);
618 	struct i2c_driver	*driver;
619 
620 	driver = to_i2c_driver(dev->driver);
621 	if (driver->remove) {
622 		dev_dbg(dev, "remove\n");
623 
624 		driver->remove(client);
625 	}
626 
627 	devres_release_group(&client->dev, client->devres_group_id);
628 
629 	dev_pm_domain_detach(&client->dev, true);
630 
631 	dev_pm_clear_wake_irq(&client->dev);
632 	device_init_wakeup(&client->dev, false);
633 
634 	client->irq = 0;
635 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
636 		pm_runtime_put(&client->adapter->dev);
637 }
638 
i2c_device_shutdown(struct device * dev)639 static void i2c_device_shutdown(struct device *dev)
640 {
641 	struct i2c_client *client = i2c_verify_client(dev);
642 	struct i2c_driver *driver;
643 
644 	if (!client || !dev->driver)
645 		return;
646 	driver = to_i2c_driver(dev->driver);
647 	if (driver->shutdown)
648 		driver->shutdown(client);
649 	else if (client->irq > 0)
650 		disable_irq(client->irq);
651 }
652 
i2c_client_dev_release(struct device * dev)653 static void i2c_client_dev_release(struct device *dev)
654 {
655 	kfree(to_i2c_client(dev));
656 }
657 
658 static ssize_t
name_show(struct device * dev,struct device_attribute * attr,char * buf)659 name_show(struct device *dev, struct device_attribute *attr, char *buf)
660 {
661 	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
662 		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
663 }
664 static DEVICE_ATTR_RO(name);
665 
666 static ssize_t
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)667 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
668 {
669 	struct i2c_client *client = to_i2c_client(dev);
670 	int len;
671 
672 	len = of_device_modalias(dev, buf, PAGE_SIZE);
673 	if (len != -ENODEV)
674 		return len;
675 
676 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
677 	if (len != -ENODEV)
678 		return len;
679 
680 	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
681 }
682 static DEVICE_ATTR_RO(modalias);
683 
684 static struct attribute *i2c_dev_attrs[] = {
685 	&dev_attr_name.attr,
686 	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
687 	&dev_attr_modalias.attr,
688 	NULL
689 };
690 ATTRIBUTE_GROUPS(i2c_dev);
691 
692 struct bus_type i2c_bus_type = {
693 	.name		= "i2c",
694 	.match		= i2c_device_match,
695 	.probe		= i2c_device_probe,
696 	.remove		= i2c_device_remove,
697 	.shutdown	= i2c_device_shutdown,
698 };
699 EXPORT_SYMBOL_GPL(i2c_bus_type);
700 
701 struct device_type i2c_client_type = {
702 	.groups		= i2c_dev_groups,
703 	.uevent		= i2c_device_uevent,
704 	.release	= i2c_client_dev_release,
705 };
706 EXPORT_SYMBOL_GPL(i2c_client_type);
707 
708 
709 /**
710  * i2c_verify_client - return parameter as i2c_client, or NULL
711  * @dev: device, probably from some driver model iterator
712  *
713  * When traversing the driver model tree, perhaps using driver model
714  * iterators like @device_for_each_child(), you can't assume very much
715  * about the nodes you find.  Use this function to avoid oopses caused
716  * by wrongly treating some non-I2C device as an i2c_client.
717  */
i2c_verify_client(struct device * dev)718 struct i2c_client *i2c_verify_client(struct device *dev)
719 {
720 	return (dev->type == &i2c_client_type)
721 			? to_i2c_client(dev)
722 			: NULL;
723 }
724 EXPORT_SYMBOL(i2c_verify_client);
725 
726 
727 /* Return a unique address which takes the flags of the client into account */
i2c_encode_flags_to_addr(struct i2c_client * client)728 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
729 {
730 	unsigned short addr = client->addr;
731 
732 	/* For some client flags, add an arbitrary offset to avoid collisions */
733 	if (client->flags & I2C_CLIENT_TEN)
734 		addr |= I2C_ADDR_OFFSET_TEN_BIT;
735 
736 	if (client->flags & I2C_CLIENT_SLAVE)
737 		addr |= I2C_ADDR_OFFSET_SLAVE;
738 
739 	return addr;
740 }
741 
742 /* This is a permissive address validity check, I2C address map constraints
743  * are purposely not enforced, except for the general call address. */
i2c_check_addr_validity(unsigned int addr,unsigned short flags)744 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
745 {
746 	if (flags & I2C_CLIENT_TEN) {
747 		/* 10-bit address, all values are valid */
748 		if (addr > 0x3ff)
749 			return -EINVAL;
750 	} else {
751 		/* 7-bit address, reject the general call address */
752 		if (addr == 0x00 || addr > 0x7f)
753 			return -EINVAL;
754 	}
755 	return 0;
756 }
757 
758 /* And this is a strict address validity check, used when probing. If a
759  * device uses a reserved address, then it shouldn't be probed. 7-bit
760  * addressing is assumed, 10-bit address devices are rare and should be
761  * explicitly enumerated. */
i2c_check_7bit_addr_validity_strict(unsigned short addr)762 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
763 {
764 	/*
765 	 * Reserved addresses per I2C specification:
766 	 *  0x00       General call address / START byte
767 	 *  0x01       CBUS address
768 	 *  0x02       Reserved for different bus format
769 	 *  0x03       Reserved for future purposes
770 	 *  0x04-0x07  Hs-mode master code
771 	 *  0x78-0x7b  10-bit slave addressing
772 	 *  0x7c-0x7f  Reserved for future purposes
773 	 */
774 	if (addr < 0x08 || addr > 0x77)
775 		return -EINVAL;
776 	return 0;
777 }
778 
__i2c_check_addr_busy(struct device * dev,void * addrp)779 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
780 {
781 	struct i2c_client	*client = i2c_verify_client(dev);
782 	int			addr = *(int *)addrp;
783 
784 	if (client && i2c_encode_flags_to_addr(client) == addr)
785 		return -EBUSY;
786 	return 0;
787 }
788 
789 /* walk up mux tree */
i2c_check_mux_parents(struct i2c_adapter * adapter,int addr)790 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
791 {
792 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
793 	int result;
794 
795 	result = device_for_each_child(&adapter->dev, &addr,
796 					__i2c_check_addr_busy);
797 
798 	if (!result && parent)
799 		result = i2c_check_mux_parents(parent, addr);
800 
801 	return result;
802 }
803 
804 /* recurse down mux tree */
i2c_check_mux_children(struct device * dev,void * addrp)805 static int i2c_check_mux_children(struct device *dev, void *addrp)
806 {
807 	int result;
808 
809 	if (dev->type == &i2c_adapter_type)
810 		result = device_for_each_child(dev, addrp,
811 						i2c_check_mux_children);
812 	else
813 		result = __i2c_check_addr_busy(dev, addrp);
814 
815 	return result;
816 }
817 
i2c_check_addr_busy(struct i2c_adapter * adapter,int addr)818 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
819 {
820 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
821 	int result = 0;
822 
823 	if (parent)
824 		result = i2c_check_mux_parents(parent, addr);
825 
826 	if (!result)
827 		result = device_for_each_child(&adapter->dev, &addr,
828 						i2c_check_mux_children);
829 
830 	return result;
831 }
832 
833 /**
834  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
835  * @adapter: Target I2C bus segment
836  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
837  *	locks only this branch in the adapter tree
838  */
i2c_adapter_lock_bus(struct i2c_adapter * adapter,unsigned int flags)839 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
840 				 unsigned int flags)
841 {
842 	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
843 }
844 
845 /**
846  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
847  * @adapter: Target I2C bus segment
848  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
849  *	trylocks only this branch in the adapter tree
850  */
i2c_adapter_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)851 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
852 				   unsigned int flags)
853 {
854 	return rt_mutex_trylock(&adapter->bus_lock);
855 }
856 
857 /**
858  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
859  * @adapter: Target I2C bus segment
860  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
861  *	unlocks only this branch in the adapter tree
862  */
i2c_adapter_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)863 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
864 				   unsigned int flags)
865 {
866 	rt_mutex_unlock(&adapter->bus_lock);
867 }
868 
i2c_dev_set_name(struct i2c_adapter * adap,struct i2c_client * client,struct i2c_board_info const * info)869 static void i2c_dev_set_name(struct i2c_adapter *adap,
870 			     struct i2c_client *client,
871 			     struct i2c_board_info const *info)
872 {
873 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
874 
875 	if (info && info->dev_name) {
876 		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
877 		return;
878 	}
879 
880 	if (adev) {
881 		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
882 		return;
883 	}
884 
885 	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
886 		     i2c_encode_flags_to_addr(client));
887 }
888 
i2c_dev_irq_from_resources(const struct resource * resources,unsigned int num_resources)889 int i2c_dev_irq_from_resources(const struct resource *resources,
890 			       unsigned int num_resources)
891 {
892 	struct irq_data *irqd;
893 	int i;
894 
895 	for (i = 0; i < num_resources; i++) {
896 		const struct resource *r = &resources[i];
897 
898 		if (resource_type(r) != IORESOURCE_IRQ)
899 			continue;
900 
901 		if (r->flags & IORESOURCE_BITS) {
902 			irqd = irq_get_irq_data(r->start);
903 			if (!irqd)
904 				break;
905 
906 			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
907 		}
908 
909 		return r->start;
910 	}
911 
912 	return 0;
913 }
914 
915 /**
916  * i2c_new_client_device - instantiate an i2c device
917  * @adap: the adapter managing the device
918  * @info: describes one I2C device; bus_num is ignored
919  * Context: can sleep
920  *
921  * Create an i2c device. Binding is handled through driver model
922  * probe()/remove() methods.  A driver may be bound to this device when we
923  * return from this function, or any later moment (e.g. maybe hotplugging will
924  * load the driver module).  This call is not appropriate for use by mainboard
925  * initialization logic, which usually runs during an arch_initcall() long
926  * before any i2c_adapter could exist.
927  *
928  * This returns the new i2c client, which may be saved for later use with
929  * i2c_unregister_device(); or an ERR_PTR to describe the error.
930  */
931 struct i2c_client *
i2c_new_client_device(struct i2c_adapter * adap,struct i2c_board_info const * info)932 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
933 {
934 	struct i2c_client *client;
935 	bool need_put = false;
936 	int status;
937 
938 	client = kzalloc(sizeof *client, GFP_KERNEL);
939 	if (!client)
940 		return ERR_PTR(-ENOMEM);
941 
942 	client->adapter = adap;
943 
944 	client->dev.platform_data = info->platform_data;
945 	client->flags = info->flags;
946 	client->addr = info->addr;
947 
948 	client->init_irq = info->irq;
949 	if (!client->init_irq)
950 		client->init_irq = i2c_dev_irq_from_resources(info->resources,
951 							 info->num_resources);
952 
953 	strscpy(client->name, info->type, sizeof(client->name));
954 
955 	status = i2c_check_addr_validity(client->addr, client->flags);
956 	if (status) {
957 		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
958 			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
959 		goto out_err_silent;
960 	}
961 
962 	/* Check for address business */
963 	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
964 	if (status)
965 		goto out_err;
966 
967 	client->dev.parent = &client->adapter->dev;
968 	client->dev.bus = &i2c_bus_type;
969 	client->dev.type = &i2c_client_type;
970 	client->dev.of_node = of_node_get(info->of_node);
971 	client->dev.fwnode = info->fwnode;
972 
973 	device_enable_async_suspend(&client->dev);
974 
975 	if (info->swnode) {
976 		status = device_add_software_node(&client->dev, info->swnode);
977 		if (status) {
978 			dev_err(&adap->dev,
979 				"Failed to add software node to client %s: %d\n",
980 				client->name, status);
981 			goto out_err_put_of_node;
982 		}
983 	}
984 
985 	i2c_dev_set_name(adap, client, info);
986 	status = device_register(&client->dev);
987 	if (status)
988 		goto out_remove_swnode;
989 
990 	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
991 		client->name, dev_name(&client->dev));
992 
993 	return client;
994 
995 out_remove_swnode:
996 	device_remove_software_node(&client->dev);
997 	need_put = true;
998 out_err_put_of_node:
999 	of_node_put(info->of_node);
1000 out_err:
1001 	dev_err(&adap->dev,
1002 		"Failed to register i2c client %s at 0x%02x (%d)\n",
1003 		client->name, client->addr, status);
1004 out_err_silent:
1005 	if (need_put)
1006 		put_device(&client->dev);
1007 	else
1008 		kfree(client);
1009 	return ERR_PTR(status);
1010 }
1011 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1012 
1013 /**
1014  * i2c_unregister_device - reverse effect of i2c_new_*_device()
1015  * @client: value returned from i2c_new_*_device()
1016  * Context: can sleep
1017  */
i2c_unregister_device(struct i2c_client * client)1018 void i2c_unregister_device(struct i2c_client *client)
1019 {
1020 	if (IS_ERR_OR_NULL(client))
1021 		return;
1022 
1023 	if (client->dev.of_node) {
1024 		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1025 		of_node_put(client->dev.of_node);
1026 	}
1027 
1028 	if (ACPI_COMPANION(&client->dev))
1029 		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1030 	device_remove_software_node(&client->dev);
1031 	device_unregister(&client->dev);
1032 }
1033 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1034 
1035 /**
1036  * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1037  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1038  *
1039  * Look up and return the &struct i2c_client corresponding to the @fwnode.
1040  * If no client can be found, or @fwnode is NULL, this returns NULL.
1041  *
1042  * The user must call put_device(&client->dev) once done with the i2c client.
1043  */
i2c_find_device_by_fwnode(struct fwnode_handle * fwnode)1044 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1045 {
1046 	struct i2c_client *client;
1047 	struct device *dev;
1048 
1049 	if (!fwnode)
1050 		return NULL;
1051 
1052 	dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1053 	if (!dev)
1054 		return NULL;
1055 
1056 	client = i2c_verify_client(dev);
1057 	if (!client)
1058 		put_device(dev);
1059 
1060 	return client;
1061 }
1062 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1063 
1064 
1065 static const struct i2c_device_id dummy_id[] = {
1066 	{ "dummy", 0 },
1067 	{ },
1068 };
1069 
dummy_probe(struct i2c_client * client)1070 static int dummy_probe(struct i2c_client *client)
1071 {
1072 	return 0;
1073 }
1074 
1075 static struct i2c_driver dummy_driver = {
1076 	.driver.name	= "dummy",
1077 	.probe		= dummy_probe,
1078 	.id_table	= dummy_id,
1079 };
1080 
1081 /**
1082  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1083  * @adapter: the adapter managing the device
1084  * @address: seven bit address to be used
1085  * Context: can sleep
1086  *
1087  * This returns an I2C client bound to the "dummy" driver, intended for use
1088  * with devices that consume multiple addresses.  Examples of such chips
1089  * include various EEPROMS (like 24c04 and 24c08 models).
1090  *
1091  * These dummy devices have two main uses.  First, most I2C and SMBus calls
1092  * except i2c_transfer() need a client handle; the dummy will be that handle.
1093  * And second, this prevents the specified address from being bound to a
1094  * different driver.
1095  *
1096  * This returns the new i2c client, which should be saved for later use with
1097  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1098  */
i2c_new_dummy_device(struct i2c_adapter * adapter,u16 address)1099 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1100 {
1101 	struct i2c_board_info info = {
1102 		I2C_BOARD_INFO("dummy", address),
1103 	};
1104 
1105 	return i2c_new_client_device(adapter, &info);
1106 }
1107 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1108 
devm_i2c_release_dummy(void * client)1109 static void devm_i2c_release_dummy(void *client)
1110 {
1111 	i2c_unregister_device(client);
1112 }
1113 
1114 /**
1115  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1116  * @dev: device the managed resource is bound to
1117  * @adapter: the adapter managing the device
1118  * @address: seven bit address to be used
1119  * Context: can sleep
1120  *
1121  * This is the device-managed version of @i2c_new_dummy_device. It returns the
1122  * new i2c client or an ERR_PTR in case of an error.
1123  */
devm_i2c_new_dummy_device(struct device * dev,struct i2c_adapter * adapter,u16 address)1124 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1125 					     struct i2c_adapter *adapter,
1126 					     u16 address)
1127 {
1128 	struct i2c_client *client;
1129 	int ret;
1130 
1131 	client = i2c_new_dummy_device(adapter, address);
1132 	if (IS_ERR(client))
1133 		return client;
1134 
1135 	ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1136 	if (ret)
1137 		return ERR_PTR(ret);
1138 
1139 	return client;
1140 }
1141 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1142 
1143 /**
1144  * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1145  * and create the associated device
1146  * @client: Handle to the primary client
1147  * @name: Handle to specify which secondary address to get
1148  * @default_addr: Used as a fallback if no secondary address was specified
1149  * Context: can sleep
1150  *
1151  * I2C clients can be composed of multiple I2C slaves bound together in a single
1152  * component. The I2C client driver then binds to the master I2C slave and needs
1153  * to create I2C dummy clients to communicate with all the other slaves.
1154  *
1155  * This function creates and returns an I2C dummy client whose I2C address is
1156  * retrieved from the platform firmware based on the given slave name. If no
1157  * address is specified by the firmware default_addr is used.
1158  *
1159  * On DT-based platforms the address is retrieved from the "reg" property entry
1160  * cell whose "reg-names" value matches the slave name.
1161  *
1162  * This returns the new i2c client, which should be saved for later use with
1163  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1164  */
i2c_new_ancillary_device(struct i2c_client * client,const char * name,u16 default_addr)1165 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1166 						const char *name,
1167 						u16 default_addr)
1168 {
1169 	struct device_node *np = client->dev.of_node;
1170 	u32 addr = default_addr;
1171 	int i;
1172 
1173 	if (np) {
1174 		i = of_property_match_string(np, "reg-names", name);
1175 		if (i >= 0)
1176 			of_property_read_u32_index(np, "reg", i, &addr);
1177 	}
1178 
1179 	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1180 	return i2c_new_dummy_device(client->adapter, addr);
1181 }
1182 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1183 
1184 /* ------------------------------------------------------------------------- */
1185 
1186 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1187 
i2c_adapter_dev_release(struct device * dev)1188 static void i2c_adapter_dev_release(struct device *dev)
1189 {
1190 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1191 	complete(&adap->dev_released);
1192 }
1193 
i2c_adapter_depth(struct i2c_adapter * adapter)1194 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1195 {
1196 	unsigned int depth = 0;
1197 
1198 	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1199 		depth++;
1200 
1201 	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1202 		  "adapter depth exceeds lockdep subclass limit\n");
1203 
1204 	return depth;
1205 }
1206 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1207 
1208 /*
1209  * Let users instantiate I2C devices through sysfs. This can be used when
1210  * platform initialization code doesn't contain the proper data for
1211  * whatever reason. Also useful for drivers that do device detection and
1212  * detection fails, either because the device uses an unexpected address,
1213  * or this is a compatible device with different ID register values.
1214  *
1215  * Parameter checking may look overzealous, but we really don't want
1216  * the user to provide incorrect parameters.
1217  */
1218 static ssize_t
new_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1219 new_device_store(struct device *dev, struct device_attribute *attr,
1220 		 const char *buf, size_t count)
1221 {
1222 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1223 	struct i2c_board_info info;
1224 	struct i2c_client *client;
1225 	char *blank, end;
1226 	int res;
1227 
1228 	memset(&info, 0, sizeof(struct i2c_board_info));
1229 
1230 	blank = strchr(buf, ' ');
1231 	if (!blank) {
1232 		dev_err(dev, "%s: Missing parameters\n", "new_device");
1233 		return -EINVAL;
1234 	}
1235 	if (blank - buf > I2C_NAME_SIZE - 1) {
1236 		dev_err(dev, "%s: Invalid device name\n", "new_device");
1237 		return -EINVAL;
1238 	}
1239 	memcpy(info.type, buf, blank - buf);
1240 
1241 	/* Parse remaining parameters, reject extra parameters */
1242 	res = sscanf(++blank, "%hi%c", &info.addr, &end);
1243 	if (res < 1) {
1244 		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1245 		return -EINVAL;
1246 	}
1247 	if (res > 1  && end != '\n') {
1248 		dev_err(dev, "%s: Extra parameters\n", "new_device");
1249 		return -EINVAL;
1250 	}
1251 
1252 	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1253 		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1254 		info.flags |= I2C_CLIENT_TEN;
1255 	}
1256 
1257 	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1258 		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1259 		info.flags |= I2C_CLIENT_SLAVE;
1260 	}
1261 
1262 	client = i2c_new_client_device(adap, &info);
1263 	if (IS_ERR(client))
1264 		return PTR_ERR(client);
1265 
1266 	/* Keep track of the added device */
1267 	mutex_lock(&adap->userspace_clients_lock);
1268 	list_add_tail(&client->detected, &adap->userspace_clients);
1269 	mutex_unlock(&adap->userspace_clients_lock);
1270 	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1271 		 info.type, info.addr);
1272 
1273 	return count;
1274 }
1275 static DEVICE_ATTR_WO(new_device);
1276 
1277 /*
1278  * And of course let the users delete the devices they instantiated, if
1279  * they got it wrong. This interface can only be used to delete devices
1280  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1281  * don't delete devices to which some kernel code still has references.
1282  *
1283  * Parameter checking may look overzealous, but we really don't want
1284  * the user to delete the wrong device.
1285  */
1286 static ssize_t
delete_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1287 delete_device_store(struct device *dev, struct device_attribute *attr,
1288 		    const char *buf, size_t count)
1289 {
1290 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1291 	struct i2c_client *client, *next;
1292 	unsigned short addr;
1293 	char end;
1294 	int res;
1295 
1296 	/* Parse parameters, reject extra parameters */
1297 	res = sscanf(buf, "%hi%c", &addr, &end);
1298 	if (res < 1) {
1299 		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1300 		return -EINVAL;
1301 	}
1302 	if (res > 1  && end != '\n') {
1303 		dev_err(dev, "%s: Extra parameters\n", "delete_device");
1304 		return -EINVAL;
1305 	}
1306 
1307 	/* Make sure the device was added through sysfs */
1308 	res = -ENOENT;
1309 	mutex_lock_nested(&adap->userspace_clients_lock,
1310 			  i2c_adapter_depth(adap));
1311 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1312 				 detected) {
1313 		if (i2c_encode_flags_to_addr(client) == addr) {
1314 			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1315 				 "delete_device", client->name, client->addr);
1316 
1317 			list_del(&client->detected);
1318 			i2c_unregister_device(client);
1319 			res = count;
1320 			break;
1321 		}
1322 	}
1323 	mutex_unlock(&adap->userspace_clients_lock);
1324 
1325 	if (res < 0)
1326 		dev_err(dev, "%s: Can't find device in list\n",
1327 			"delete_device");
1328 	return res;
1329 }
1330 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1331 				  delete_device_store);
1332 
1333 static struct attribute *i2c_adapter_attrs[] = {
1334 	&dev_attr_name.attr,
1335 	&dev_attr_new_device.attr,
1336 	&dev_attr_delete_device.attr,
1337 	NULL
1338 };
1339 ATTRIBUTE_GROUPS(i2c_adapter);
1340 
1341 struct device_type i2c_adapter_type = {
1342 	.groups		= i2c_adapter_groups,
1343 	.release	= i2c_adapter_dev_release,
1344 };
1345 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1346 
1347 /**
1348  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1349  * @dev: device, probably from some driver model iterator
1350  *
1351  * When traversing the driver model tree, perhaps using driver model
1352  * iterators like @device_for_each_child(), you can't assume very much
1353  * about the nodes you find.  Use this function to avoid oopses caused
1354  * by wrongly treating some non-I2C device as an i2c_adapter.
1355  */
i2c_verify_adapter(struct device * dev)1356 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1357 {
1358 	return (dev->type == &i2c_adapter_type)
1359 			? to_i2c_adapter(dev)
1360 			: NULL;
1361 }
1362 EXPORT_SYMBOL(i2c_verify_adapter);
1363 
1364 #ifdef CONFIG_I2C_COMPAT
1365 static struct class_compat *i2c_adapter_compat_class;
1366 #endif
1367 
i2c_scan_static_board_info(struct i2c_adapter * adapter)1368 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1369 {
1370 	struct i2c_devinfo	*devinfo;
1371 
1372 	down_read(&__i2c_board_lock);
1373 	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1374 		if (devinfo->busnum == adapter->nr &&
1375 		    IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1376 			dev_err(&adapter->dev,
1377 				"Can't create device at 0x%02x\n",
1378 				devinfo->board_info.addr);
1379 	}
1380 	up_read(&__i2c_board_lock);
1381 }
1382 
i2c_do_add_adapter(struct i2c_driver * driver,struct i2c_adapter * adap)1383 static int i2c_do_add_adapter(struct i2c_driver *driver,
1384 			      struct i2c_adapter *adap)
1385 {
1386 	/* Detect supported devices on that bus, and instantiate them */
1387 	i2c_detect(adap, driver);
1388 
1389 	return 0;
1390 }
1391 
__process_new_adapter(struct device_driver * d,void * data)1392 static int __process_new_adapter(struct device_driver *d, void *data)
1393 {
1394 	return i2c_do_add_adapter(to_i2c_driver(d), data);
1395 }
1396 
1397 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1398 	.lock_bus =    i2c_adapter_lock_bus,
1399 	.trylock_bus = i2c_adapter_trylock_bus,
1400 	.unlock_bus =  i2c_adapter_unlock_bus,
1401 };
1402 
i2c_host_notify_irq_teardown(struct i2c_adapter * adap)1403 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1404 {
1405 	struct irq_domain *domain = adap->host_notify_domain;
1406 	irq_hw_number_t hwirq;
1407 
1408 	if (!domain)
1409 		return;
1410 
1411 	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1412 		irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1413 
1414 	irq_domain_remove(domain);
1415 	adap->host_notify_domain = NULL;
1416 }
1417 
i2c_host_notify_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw_irq_num)1418 static int i2c_host_notify_irq_map(struct irq_domain *h,
1419 					  unsigned int virq,
1420 					  irq_hw_number_t hw_irq_num)
1421 {
1422 	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1423 
1424 	return 0;
1425 }
1426 
1427 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1428 	.map = i2c_host_notify_irq_map,
1429 };
1430 
i2c_setup_host_notify_irq_domain(struct i2c_adapter * adap)1431 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1432 {
1433 	struct irq_domain *domain;
1434 
1435 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1436 		return 0;
1437 
1438 	domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1439 					  I2C_ADDR_7BITS_COUNT,
1440 					  &i2c_host_notify_irq_ops, adap);
1441 	if (!domain)
1442 		return -ENOMEM;
1443 
1444 	adap->host_notify_domain = domain;
1445 
1446 	return 0;
1447 }
1448 
1449 /**
1450  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1451  * I2C client.
1452  * @adap: the adapter
1453  * @addr: the I2C address of the notifying device
1454  * Context: can't sleep
1455  *
1456  * Helper function to be called from an I2C bus driver's interrupt
1457  * handler. It will schedule the Host Notify IRQ.
1458  */
i2c_handle_smbus_host_notify(struct i2c_adapter * adap,unsigned short addr)1459 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1460 {
1461 	int irq;
1462 
1463 	if (!adap)
1464 		return -EINVAL;
1465 
1466 	irq = irq_find_mapping(adap->host_notify_domain, addr);
1467 	if (irq <= 0)
1468 		return -ENXIO;
1469 
1470 	generic_handle_irq_safe(irq);
1471 
1472 	return 0;
1473 }
1474 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1475 
i2c_register_adapter(struct i2c_adapter * adap)1476 static int i2c_register_adapter(struct i2c_adapter *adap)
1477 {
1478 	int res = -EINVAL;
1479 
1480 	/* Can't register until after driver model init */
1481 	if (WARN_ON(!is_registered)) {
1482 		res = -EAGAIN;
1483 		goto out_list;
1484 	}
1485 
1486 	/* Sanity checks */
1487 	if (WARN(!adap->name[0], "i2c adapter has no name"))
1488 		goto out_list;
1489 
1490 	if (!adap->algo) {
1491 		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1492 		goto out_list;
1493 	}
1494 
1495 	if (!adap->lock_ops)
1496 		adap->lock_ops = &i2c_adapter_lock_ops;
1497 
1498 	adap->locked_flags = 0;
1499 	rt_mutex_init(&adap->bus_lock);
1500 	rt_mutex_init(&adap->mux_lock);
1501 	mutex_init(&adap->userspace_clients_lock);
1502 	INIT_LIST_HEAD(&adap->userspace_clients);
1503 
1504 	/* Set default timeout to 1 second if not already set */
1505 	if (adap->timeout == 0)
1506 		adap->timeout = HZ;
1507 
1508 	/* register soft irqs for Host Notify */
1509 	res = i2c_setup_host_notify_irq_domain(adap);
1510 	if (res) {
1511 		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1512 		       adap->name, res);
1513 		goto out_list;
1514 	}
1515 
1516 	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1517 	adap->dev.bus = &i2c_bus_type;
1518 	adap->dev.type = &i2c_adapter_type;
1519 	res = device_register(&adap->dev);
1520 	if (res) {
1521 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1522 		goto out_list;
1523 	}
1524 
1525 	res = i2c_setup_smbus_alert(adap);
1526 	if (res)
1527 		goto out_reg;
1528 
1529 	device_enable_async_suspend(&adap->dev);
1530 	pm_runtime_no_callbacks(&adap->dev);
1531 	pm_suspend_ignore_children(&adap->dev, true);
1532 	pm_runtime_enable(&adap->dev);
1533 
1534 	res = i2c_init_recovery(adap);
1535 	if (res == -EPROBE_DEFER)
1536 		goto out_reg;
1537 
1538 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1539 
1540 #ifdef CONFIG_I2C_COMPAT
1541 	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1542 				       adap->dev.parent);
1543 	if (res)
1544 		dev_warn(&adap->dev,
1545 			 "Failed to create compatibility class link\n");
1546 #endif
1547 
1548 	/* create pre-declared device nodes */
1549 	of_i2c_register_devices(adap);
1550 	i2c_acpi_install_space_handler(adap);
1551 	i2c_acpi_register_devices(adap);
1552 
1553 	if (adap->nr < __i2c_first_dynamic_bus_num)
1554 		i2c_scan_static_board_info(adap);
1555 
1556 	/* Notify drivers */
1557 	mutex_lock(&core_lock);
1558 	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1559 	mutex_unlock(&core_lock);
1560 
1561 	return 0;
1562 
1563 out_reg:
1564 	init_completion(&adap->dev_released);
1565 	device_unregister(&adap->dev);
1566 	wait_for_completion(&adap->dev_released);
1567 out_list:
1568 	mutex_lock(&core_lock);
1569 	idr_remove(&i2c_adapter_idr, adap->nr);
1570 	mutex_unlock(&core_lock);
1571 	return res;
1572 }
1573 
1574 /**
1575  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1576  * @adap: the adapter to register (with adap->nr initialized)
1577  * Context: can sleep
1578  *
1579  * See i2c_add_numbered_adapter() for details.
1580  */
__i2c_add_numbered_adapter(struct i2c_adapter * adap)1581 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1582 {
1583 	int id;
1584 
1585 	mutex_lock(&core_lock);
1586 	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1587 	mutex_unlock(&core_lock);
1588 	if (WARN(id < 0, "couldn't get idr"))
1589 		return id == -ENOSPC ? -EBUSY : id;
1590 
1591 	return i2c_register_adapter(adap);
1592 }
1593 
1594 /**
1595  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1596  * @adapter: the adapter to add
1597  * Context: can sleep
1598  *
1599  * This routine is used to declare an I2C adapter when its bus number
1600  * doesn't matter or when its bus number is specified by an dt alias.
1601  * Examples of bases when the bus number doesn't matter: I2C adapters
1602  * dynamically added by USB links or PCI plugin cards.
1603  *
1604  * When this returns zero, a new bus number was allocated and stored
1605  * in adap->nr, and the specified adapter became available for clients.
1606  * Otherwise, a negative errno value is returned.
1607  */
i2c_add_adapter(struct i2c_adapter * adapter)1608 int i2c_add_adapter(struct i2c_adapter *adapter)
1609 {
1610 	struct device *dev = &adapter->dev;
1611 	int id;
1612 
1613 	if (dev->of_node) {
1614 		id = of_alias_get_id(dev->of_node, "i2c");
1615 		if (id >= 0) {
1616 			adapter->nr = id;
1617 			return __i2c_add_numbered_adapter(adapter);
1618 		}
1619 	}
1620 
1621 	mutex_lock(&core_lock);
1622 	id = idr_alloc(&i2c_adapter_idr, adapter,
1623 		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1624 	mutex_unlock(&core_lock);
1625 	if (WARN(id < 0, "couldn't get idr"))
1626 		return id;
1627 
1628 	adapter->nr = id;
1629 
1630 	return i2c_register_adapter(adapter);
1631 }
1632 EXPORT_SYMBOL(i2c_add_adapter);
1633 
1634 /**
1635  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1636  * @adap: the adapter to register (with adap->nr initialized)
1637  * Context: can sleep
1638  *
1639  * This routine is used to declare an I2C adapter when its bus number
1640  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1641  * or otherwise built in to the system's mainboard, and where i2c_board_info
1642  * is used to properly configure I2C devices.
1643  *
1644  * If the requested bus number is set to -1, then this function will behave
1645  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1646  *
1647  * If no devices have pre-been declared for this bus, then be sure to
1648  * register the adapter before any dynamically allocated ones.  Otherwise
1649  * the required bus ID may not be available.
1650  *
1651  * When this returns zero, the specified adapter became available for
1652  * clients using the bus number provided in adap->nr.  Also, the table
1653  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1654  * and the appropriate driver model device nodes are created.  Otherwise, a
1655  * negative errno value is returned.
1656  */
i2c_add_numbered_adapter(struct i2c_adapter * adap)1657 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1658 {
1659 	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1660 		return i2c_add_adapter(adap);
1661 
1662 	return __i2c_add_numbered_adapter(adap);
1663 }
1664 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1665 
i2c_do_del_adapter(struct i2c_driver * driver,struct i2c_adapter * adapter)1666 static void i2c_do_del_adapter(struct i2c_driver *driver,
1667 			      struct i2c_adapter *adapter)
1668 {
1669 	struct i2c_client *client, *_n;
1670 
1671 	/* Remove the devices we created ourselves as the result of hardware
1672 	 * probing (using a driver's detect method) */
1673 	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1674 		if (client->adapter == adapter) {
1675 			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1676 				client->name, client->addr);
1677 			list_del(&client->detected);
1678 			i2c_unregister_device(client);
1679 		}
1680 	}
1681 }
1682 
__unregister_client(struct device * dev,void * dummy)1683 static int __unregister_client(struct device *dev, void *dummy)
1684 {
1685 	struct i2c_client *client = i2c_verify_client(dev);
1686 	if (client && strcmp(client->name, "dummy"))
1687 		i2c_unregister_device(client);
1688 	return 0;
1689 }
1690 
__unregister_dummy(struct device * dev,void * dummy)1691 static int __unregister_dummy(struct device *dev, void *dummy)
1692 {
1693 	struct i2c_client *client = i2c_verify_client(dev);
1694 	i2c_unregister_device(client);
1695 	return 0;
1696 }
1697 
__process_removed_adapter(struct device_driver * d,void * data)1698 static int __process_removed_adapter(struct device_driver *d, void *data)
1699 {
1700 	i2c_do_del_adapter(to_i2c_driver(d), data);
1701 	return 0;
1702 }
1703 
1704 /**
1705  * i2c_del_adapter - unregister I2C adapter
1706  * @adap: the adapter being unregistered
1707  * Context: can sleep
1708  *
1709  * This unregisters an I2C adapter which was previously registered
1710  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1711  */
i2c_del_adapter(struct i2c_adapter * adap)1712 void i2c_del_adapter(struct i2c_adapter *adap)
1713 {
1714 	struct i2c_adapter *found;
1715 	struct i2c_client *client, *next;
1716 
1717 	/* First make sure that this adapter was ever added */
1718 	mutex_lock(&core_lock);
1719 	found = idr_find(&i2c_adapter_idr, adap->nr);
1720 	mutex_unlock(&core_lock);
1721 	if (found != adap) {
1722 		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1723 		return;
1724 	}
1725 
1726 	i2c_acpi_remove_space_handler(adap);
1727 	/* Tell drivers about this removal */
1728 	mutex_lock(&core_lock);
1729 	bus_for_each_drv(&i2c_bus_type, NULL, adap,
1730 			       __process_removed_adapter);
1731 	mutex_unlock(&core_lock);
1732 
1733 	/* Remove devices instantiated from sysfs */
1734 	mutex_lock_nested(&adap->userspace_clients_lock,
1735 			  i2c_adapter_depth(adap));
1736 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1737 				 detected) {
1738 		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1739 			client->addr);
1740 		list_del(&client->detected);
1741 		i2c_unregister_device(client);
1742 	}
1743 	mutex_unlock(&adap->userspace_clients_lock);
1744 
1745 	/* Detach any active clients. This can't fail, thus we do not
1746 	 * check the returned value. This is a two-pass process, because
1747 	 * we can't remove the dummy devices during the first pass: they
1748 	 * could have been instantiated by real devices wishing to clean
1749 	 * them up properly, so we give them a chance to do that first. */
1750 	device_for_each_child(&adap->dev, NULL, __unregister_client);
1751 	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1752 
1753 #ifdef CONFIG_I2C_COMPAT
1754 	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1755 				 adap->dev.parent);
1756 #endif
1757 
1758 	/* device name is gone after device_unregister */
1759 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1760 
1761 	pm_runtime_disable(&adap->dev);
1762 
1763 	i2c_host_notify_irq_teardown(adap);
1764 
1765 	/* wait until all references to the device are gone
1766 	 *
1767 	 * FIXME: This is old code and should ideally be replaced by an
1768 	 * alternative which results in decoupling the lifetime of the struct
1769 	 * device from the i2c_adapter, like spi or netdev do. Any solution
1770 	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1771 	 */
1772 	init_completion(&adap->dev_released);
1773 	device_unregister(&adap->dev);
1774 	wait_for_completion(&adap->dev_released);
1775 
1776 	/* free bus id */
1777 	mutex_lock(&core_lock);
1778 	idr_remove(&i2c_adapter_idr, adap->nr);
1779 	mutex_unlock(&core_lock);
1780 
1781 	/* Clear the device structure in case this adapter is ever going to be
1782 	   added again */
1783 	memset(&adap->dev, 0, sizeof(adap->dev));
1784 }
1785 EXPORT_SYMBOL(i2c_del_adapter);
1786 
devm_i2c_del_adapter(void * adapter)1787 static void devm_i2c_del_adapter(void *adapter)
1788 {
1789 	i2c_del_adapter(adapter);
1790 }
1791 
1792 /**
1793  * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1794  * @dev: managing device for adding this I2C adapter
1795  * @adapter: the adapter to add
1796  * Context: can sleep
1797  *
1798  * Add adapter with dynamic bus number, same with i2c_add_adapter()
1799  * but the adapter will be auto deleted on driver detach.
1800  */
devm_i2c_add_adapter(struct device * dev,struct i2c_adapter * adapter)1801 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1802 {
1803 	int ret;
1804 
1805 	ret = i2c_add_adapter(adapter);
1806 	if (ret)
1807 		return ret;
1808 
1809 	return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1810 }
1811 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1812 
i2c_dev_or_parent_fwnode_match(struct device * dev,const void * data)1813 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1814 {
1815 	if (dev_fwnode(dev) == data)
1816 		return 1;
1817 
1818 	if (dev->parent && dev_fwnode(dev->parent) == data)
1819 		return 1;
1820 
1821 	return 0;
1822 }
1823 
1824 /**
1825  * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1826  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1827  *
1828  * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1829  * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1830  *
1831  * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1832  */
i2c_find_adapter_by_fwnode(struct fwnode_handle * fwnode)1833 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1834 {
1835 	struct i2c_adapter *adapter;
1836 	struct device *dev;
1837 
1838 	if (!fwnode)
1839 		return NULL;
1840 
1841 	dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1842 			      i2c_dev_or_parent_fwnode_match);
1843 	if (!dev)
1844 		return NULL;
1845 
1846 	adapter = i2c_verify_adapter(dev);
1847 	if (!adapter)
1848 		put_device(dev);
1849 
1850 	return adapter;
1851 }
1852 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1853 
1854 /**
1855  * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1856  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1857  *
1858  * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1859  * and increment the adapter module's use count. If no adapter can be found,
1860  * or @fwnode is NULL, this returns NULL.
1861  *
1862  * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1863  * Note that this is different from i2c_find_adapter_by_node().
1864  */
i2c_get_adapter_by_fwnode(struct fwnode_handle * fwnode)1865 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1866 {
1867 	struct i2c_adapter *adapter;
1868 
1869 	adapter = i2c_find_adapter_by_fwnode(fwnode);
1870 	if (!adapter)
1871 		return NULL;
1872 
1873 	if (!try_module_get(adapter->owner)) {
1874 		put_device(&adapter->dev);
1875 		adapter = NULL;
1876 	}
1877 
1878 	return adapter;
1879 }
1880 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1881 
i2c_parse_timing(struct device * dev,char * prop_name,u32 * cur_val_p,u32 def_val,bool use_def)1882 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1883 			    u32 def_val, bool use_def)
1884 {
1885 	int ret;
1886 
1887 	ret = device_property_read_u32(dev, prop_name, cur_val_p);
1888 	if (ret && use_def)
1889 		*cur_val_p = def_val;
1890 
1891 	dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1892 }
1893 
1894 /**
1895  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1896  * @dev: The device to scan for I2C timing properties
1897  * @t: the i2c_timings struct to be filled with values
1898  * @use_defaults: bool to use sane defaults derived from the I2C specification
1899  *		  when properties are not found, otherwise don't update
1900  *
1901  * Scan the device for the generic I2C properties describing timing parameters
1902  * for the signal and fill the given struct with the results. If a property was
1903  * not found and use_defaults was true, then maximum timings are assumed which
1904  * are derived from the I2C specification. If use_defaults is not used, the
1905  * results will be as before, so drivers can apply their own defaults before
1906  * calling this helper. The latter is mainly intended for avoiding regressions
1907  * of existing drivers which want to switch to this function. New drivers
1908  * almost always should use the defaults.
1909  */
i2c_parse_fw_timings(struct device * dev,struct i2c_timings * t,bool use_defaults)1910 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1911 {
1912 	bool u = use_defaults;
1913 	u32 d;
1914 
1915 	i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1916 			 I2C_MAX_STANDARD_MODE_FREQ, u);
1917 
1918 	d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1919 	    t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1920 	i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1921 
1922 	d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1923 	i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1924 
1925 	i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1926 			 &t->scl_int_delay_ns, 0, u);
1927 	i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1928 			 t->scl_fall_ns, u);
1929 	i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1930 	i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1931 			 &t->digital_filter_width_ns, 0, u);
1932 	i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1933 			 &t->analog_filter_cutoff_freq_hz, 0, u);
1934 }
1935 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1936 
1937 /* ------------------------------------------------------------------------- */
1938 
i2c_for_each_dev(void * data,int (* fn)(struct device * dev,void * data))1939 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1940 {
1941 	int res;
1942 
1943 	mutex_lock(&core_lock);
1944 	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1945 	mutex_unlock(&core_lock);
1946 
1947 	return res;
1948 }
1949 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1950 
__process_new_driver(struct device * dev,void * data)1951 static int __process_new_driver(struct device *dev, void *data)
1952 {
1953 	if (dev->type != &i2c_adapter_type)
1954 		return 0;
1955 	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1956 }
1957 
1958 /*
1959  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1960  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1961  */
1962 
i2c_register_driver(struct module * owner,struct i2c_driver * driver)1963 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1964 {
1965 	int res;
1966 
1967 	/* Can't register until after driver model init */
1968 	if (WARN_ON(!is_registered))
1969 		return -EAGAIN;
1970 
1971 	/* add the driver to the list of i2c drivers in the driver core */
1972 	driver->driver.owner = owner;
1973 	driver->driver.bus = &i2c_bus_type;
1974 	INIT_LIST_HEAD(&driver->clients);
1975 
1976 	/* When registration returns, the driver core
1977 	 * will have called probe() for all matching-but-unbound devices.
1978 	 */
1979 	res = driver_register(&driver->driver);
1980 	if (res)
1981 		return res;
1982 
1983 	pr_debug("driver [%s] registered\n", driver->driver.name);
1984 
1985 	/* Walk the adapters that are already present */
1986 	i2c_for_each_dev(driver, __process_new_driver);
1987 
1988 	return 0;
1989 }
1990 EXPORT_SYMBOL(i2c_register_driver);
1991 
__process_removed_driver(struct device * dev,void * data)1992 static int __process_removed_driver(struct device *dev, void *data)
1993 {
1994 	if (dev->type == &i2c_adapter_type)
1995 		i2c_do_del_adapter(data, to_i2c_adapter(dev));
1996 	return 0;
1997 }
1998 
1999 /**
2000  * i2c_del_driver - unregister I2C driver
2001  * @driver: the driver being unregistered
2002  * Context: can sleep
2003  */
i2c_del_driver(struct i2c_driver * driver)2004 void i2c_del_driver(struct i2c_driver *driver)
2005 {
2006 	i2c_for_each_dev(driver, __process_removed_driver);
2007 
2008 	driver_unregister(&driver->driver);
2009 	pr_debug("driver [%s] unregistered\n", driver->driver.name);
2010 }
2011 EXPORT_SYMBOL(i2c_del_driver);
2012 
2013 /* ------------------------------------------------------------------------- */
2014 
2015 struct i2c_cmd_arg {
2016 	unsigned	cmd;
2017 	void		*arg;
2018 };
2019 
i2c_cmd(struct device * dev,void * _arg)2020 static int i2c_cmd(struct device *dev, void *_arg)
2021 {
2022 	struct i2c_client	*client = i2c_verify_client(dev);
2023 	struct i2c_cmd_arg	*arg = _arg;
2024 	struct i2c_driver	*driver;
2025 
2026 	if (!client || !client->dev.driver)
2027 		return 0;
2028 
2029 	driver = to_i2c_driver(client->dev.driver);
2030 	if (driver->command)
2031 		driver->command(client, arg->cmd, arg->arg);
2032 	return 0;
2033 }
2034 
i2c_clients_command(struct i2c_adapter * adap,unsigned int cmd,void * arg)2035 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2036 {
2037 	struct i2c_cmd_arg	cmd_arg;
2038 
2039 	cmd_arg.cmd = cmd;
2040 	cmd_arg.arg = arg;
2041 	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2042 }
2043 EXPORT_SYMBOL(i2c_clients_command);
2044 
i2c_init(void)2045 static int __init i2c_init(void)
2046 {
2047 	int retval;
2048 
2049 	retval = of_alias_get_highest_id("i2c");
2050 
2051 	down_write(&__i2c_board_lock);
2052 	if (retval >= __i2c_first_dynamic_bus_num)
2053 		__i2c_first_dynamic_bus_num = retval + 1;
2054 	up_write(&__i2c_board_lock);
2055 
2056 	retval = bus_register(&i2c_bus_type);
2057 	if (retval)
2058 		return retval;
2059 
2060 	is_registered = true;
2061 
2062 #ifdef CONFIG_I2C_COMPAT
2063 	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2064 	if (!i2c_adapter_compat_class) {
2065 		retval = -ENOMEM;
2066 		goto bus_err;
2067 	}
2068 #endif
2069 	retval = i2c_add_driver(&dummy_driver);
2070 	if (retval)
2071 		goto class_err;
2072 
2073 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2074 		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2075 	if (IS_ENABLED(CONFIG_ACPI))
2076 		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2077 
2078 	return 0;
2079 
2080 class_err:
2081 #ifdef CONFIG_I2C_COMPAT
2082 	class_compat_unregister(i2c_adapter_compat_class);
2083 bus_err:
2084 #endif
2085 	is_registered = false;
2086 	bus_unregister(&i2c_bus_type);
2087 	return retval;
2088 }
2089 
i2c_exit(void)2090 static void __exit i2c_exit(void)
2091 {
2092 	if (IS_ENABLED(CONFIG_ACPI))
2093 		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2094 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2095 		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2096 	i2c_del_driver(&dummy_driver);
2097 #ifdef CONFIG_I2C_COMPAT
2098 	class_compat_unregister(i2c_adapter_compat_class);
2099 #endif
2100 	bus_unregister(&i2c_bus_type);
2101 	tracepoint_synchronize_unregister();
2102 }
2103 
2104 /* We must initialize early, because some subsystems register i2c drivers
2105  * in subsys_initcall() code, but are linked (and initialized) before i2c.
2106  */
2107 postcore_initcall(i2c_init);
2108 module_exit(i2c_exit);
2109 
2110 /* ----------------------------------------------------
2111  * the functional interface to the i2c busses.
2112  * ----------------------------------------------------
2113  */
2114 
2115 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2116 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2117 
i2c_quirk_error(struct i2c_adapter * adap,struct i2c_msg * msg,char * err_msg)2118 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2119 {
2120 	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2121 			    err_msg, msg->addr, msg->len,
2122 			    msg->flags & I2C_M_RD ? "read" : "write");
2123 	return -EOPNOTSUPP;
2124 }
2125 
i2c_check_for_quirks(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2126 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2127 {
2128 	const struct i2c_adapter_quirks *q = adap->quirks;
2129 	int max_num = q->max_num_msgs, i;
2130 	bool do_len_check = true;
2131 
2132 	if (q->flags & I2C_AQ_COMB) {
2133 		max_num = 2;
2134 
2135 		/* special checks for combined messages */
2136 		if (num == 2) {
2137 			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2138 				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2139 
2140 			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2141 				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2142 
2143 			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2144 				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2145 
2146 			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2147 				return i2c_quirk_error(adap, &msgs[0], "msg too long");
2148 
2149 			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2150 				return i2c_quirk_error(adap, &msgs[1], "msg too long");
2151 
2152 			do_len_check = false;
2153 		}
2154 	}
2155 
2156 	if (i2c_quirk_exceeded(num, max_num))
2157 		return i2c_quirk_error(adap, &msgs[0], "too many messages");
2158 
2159 	for (i = 0; i < num; i++) {
2160 		u16 len = msgs[i].len;
2161 
2162 		if (msgs[i].flags & I2C_M_RD) {
2163 			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2164 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2165 
2166 			if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2167 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2168 		} else {
2169 			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2170 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2171 
2172 			if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2173 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2174 		}
2175 	}
2176 
2177 	return 0;
2178 }
2179 
2180 /**
2181  * __i2c_transfer - unlocked flavor of i2c_transfer
2182  * @adap: Handle to I2C bus
2183  * @msgs: One or more messages to execute before STOP is issued to
2184  *	terminate the operation; each message begins with a START.
2185  * @num: Number of messages to be executed.
2186  *
2187  * Returns negative errno, else the number of messages executed.
2188  *
2189  * Adapter lock must be held when calling this function. No debug logging
2190  * takes place. adap->algo->master_xfer existence isn't checked.
2191  */
__i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2192 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2193 {
2194 	unsigned long orig_jiffies;
2195 	int ret, try;
2196 
2197 	if (WARN_ON(!msgs || num < 1))
2198 		return -EINVAL;
2199 
2200 	ret = __i2c_check_suspended(adap);
2201 	if (ret)
2202 		return ret;
2203 
2204 	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2205 		return -EOPNOTSUPP;
2206 
2207 	/*
2208 	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2209 	 * enabled.  This is an efficient way of keeping the for-loop from
2210 	 * being executed when not needed.
2211 	 */
2212 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2213 		int i;
2214 		for (i = 0; i < num; i++)
2215 			if (msgs[i].flags & I2C_M_RD)
2216 				trace_i2c_read(adap, &msgs[i], i);
2217 			else
2218 				trace_i2c_write(adap, &msgs[i], i);
2219 	}
2220 
2221 	/* Retry automatically on arbitration loss */
2222 	orig_jiffies = jiffies;
2223 	for (ret = 0, try = 0; try <= adap->retries; try++) {
2224 		if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2225 			ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2226 		else
2227 			ret = adap->algo->master_xfer(adap, msgs, num);
2228 
2229 		if (ret != -EAGAIN)
2230 			break;
2231 		if (time_after(jiffies, orig_jiffies + adap->timeout))
2232 			break;
2233 	}
2234 
2235 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2236 		int i;
2237 		for (i = 0; i < ret; i++)
2238 			if (msgs[i].flags & I2C_M_RD)
2239 				trace_i2c_reply(adap, &msgs[i], i);
2240 		trace_i2c_result(adap, num, ret);
2241 	}
2242 
2243 	return ret;
2244 }
2245 EXPORT_SYMBOL(__i2c_transfer);
2246 
2247 /**
2248  * i2c_transfer - execute a single or combined I2C message
2249  * @adap: Handle to I2C bus
2250  * @msgs: One or more messages to execute before STOP is issued to
2251  *	terminate the operation; each message begins with a START.
2252  * @num: Number of messages to be executed.
2253  *
2254  * Returns negative errno, else the number of messages executed.
2255  *
2256  * Note that there is no requirement that each message be sent to
2257  * the same slave address, although that is the most common model.
2258  */
i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2259 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2260 {
2261 	int ret;
2262 
2263 	if (!adap->algo->master_xfer) {
2264 		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2265 		return -EOPNOTSUPP;
2266 	}
2267 
2268 	/* REVISIT the fault reporting model here is weak:
2269 	 *
2270 	 *  - When we get an error after receiving N bytes from a slave,
2271 	 *    there is no way to report "N".
2272 	 *
2273 	 *  - When we get a NAK after transmitting N bytes to a slave,
2274 	 *    there is no way to report "N" ... or to let the master
2275 	 *    continue executing the rest of this combined message, if
2276 	 *    that's the appropriate response.
2277 	 *
2278 	 *  - When for example "num" is two and we successfully complete
2279 	 *    the first message but get an error part way through the
2280 	 *    second, it's unclear whether that should be reported as
2281 	 *    one (discarding status on the second message) or errno
2282 	 *    (discarding status on the first one).
2283 	 */
2284 	ret = __i2c_lock_bus_helper(adap);
2285 	if (ret)
2286 		return ret;
2287 
2288 	ret = __i2c_transfer(adap, msgs, num);
2289 	i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2290 
2291 	return ret;
2292 }
2293 EXPORT_SYMBOL(i2c_transfer);
2294 
2295 /**
2296  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2297  *			       to/from a buffer
2298  * @client: Handle to slave device
2299  * @buf: Where the data is stored
2300  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2301  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2302  *
2303  * Returns negative errno, or else the number of bytes transferred.
2304  */
i2c_transfer_buffer_flags(const struct i2c_client * client,char * buf,int count,u16 flags)2305 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2306 			      int count, u16 flags)
2307 {
2308 	int ret;
2309 	struct i2c_msg msg = {
2310 		.addr = client->addr,
2311 		.flags = flags | (client->flags & I2C_M_TEN),
2312 		.len = count,
2313 		.buf = buf,
2314 	};
2315 
2316 	ret = i2c_transfer(client->adapter, &msg, 1);
2317 
2318 	/*
2319 	 * If everything went ok (i.e. 1 msg transferred), return #bytes
2320 	 * transferred, else error code.
2321 	 */
2322 	return (ret == 1) ? count : ret;
2323 }
2324 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2325 
2326 /**
2327  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2328  * @client: The device to query
2329  * @id: The queried information
2330  *
2331  * Returns negative errno on error, zero on success.
2332  */
i2c_get_device_id(const struct i2c_client * client,struct i2c_device_identity * id)2333 int i2c_get_device_id(const struct i2c_client *client,
2334 		      struct i2c_device_identity *id)
2335 {
2336 	struct i2c_adapter *adap = client->adapter;
2337 	union i2c_smbus_data raw_id;
2338 	int ret;
2339 
2340 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2341 		return -EOPNOTSUPP;
2342 
2343 	raw_id.block[0] = 3;
2344 	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2345 			     I2C_SMBUS_READ, client->addr << 1,
2346 			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2347 	if (ret)
2348 		return ret;
2349 
2350 	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2351 	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2352 	id->die_revision = raw_id.block[3] & 0x7;
2353 	return 0;
2354 }
2355 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2356 
2357 /**
2358  * i2c_client_get_device_id - get the driver match table entry of a device
2359  * @client: the device to query. The device must be bound to a driver
2360  *
2361  * Returns a pointer to the matching entry if found, NULL otherwise.
2362  */
i2c_client_get_device_id(const struct i2c_client * client)2363 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2364 {
2365 	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2366 
2367 	return i2c_match_id(drv->id_table, client);
2368 }
2369 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2370 
2371 /* ----------------------------------------------------
2372  * the i2c address scanning function
2373  * Will not work for 10-bit addresses!
2374  * ----------------------------------------------------
2375  */
2376 
2377 /*
2378  * Legacy default probe function, mostly relevant for SMBus. The default
2379  * probe method is a quick write, but it is known to corrupt the 24RF08
2380  * EEPROMs due to a state machine bug, and could also irreversibly
2381  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2382  * we use a short byte read instead. Also, some bus drivers don't implement
2383  * quick write, so we fallback to a byte read in that case too.
2384  * On x86, there is another special case for FSC hardware monitoring chips,
2385  * which want regular byte reads (address 0x73.) Fortunately, these are the
2386  * only known chips using this I2C address on PC hardware.
2387  * Returns 1 if probe succeeded, 0 if not.
2388  */
i2c_default_probe(struct i2c_adapter * adap,unsigned short addr)2389 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2390 {
2391 	int err;
2392 	union i2c_smbus_data dummy;
2393 
2394 #ifdef CONFIG_X86
2395 	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2396 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2397 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2398 				     I2C_SMBUS_BYTE_DATA, &dummy);
2399 	else
2400 #endif
2401 	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2402 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2403 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2404 				     I2C_SMBUS_QUICK, NULL);
2405 	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2406 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2407 				     I2C_SMBUS_BYTE, &dummy);
2408 	else {
2409 		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2410 			 addr);
2411 		err = -EOPNOTSUPP;
2412 	}
2413 
2414 	return err >= 0;
2415 }
2416 
i2c_detect_address(struct i2c_client * temp_client,struct i2c_driver * driver)2417 static int i2c_detect_address(struct i2c_client *temp_client,
2418 			      struct i2c_driver *driver)
2419 {
2420 	struct i2c_board_info info;
2421 	struct i2c_adapter *adapter = temp_client->adapter;
2422 	int addr = temp_client->addr;
2423 	int err;
2424 
2425 	/* Make sure the address is valid */
2426 	err = i2c_check_7bit_addr_validity_strict(addr);
2427 	if (err) {
2428 		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2429 			 addr);
2430 		return err;
2431 	}
2432 
2433 	/* Skip if already in use (7 bit, no need to encode flags) */
2434 	if (i2c_check_addr_busy(adapter, addr))
2435 		return 0;
2436 
2437 	/* Make sure there is something at this address */
2438 	if (!i2c_default_probe(adapter, addr))
2439 		return 0;
2440 
2441 	/* Finally call the custom detection function */
2442 	memset(&info, 0, sizeof(struct i2c_board_info));
2443 	info.addr = addr;
2444 	err = driver->detect(temp_client, &info);
2445 	if (err) {
2446 		/* -ENODEV is returned if the detection fails. We catch it
2447 		   here as this isn't an error. */
2448 		return err == -ENODEV ? 0 : err;
2449 	}
2450 
2451 	/* Consistency check */
2452 	if (info.type[0] == '\0') {
2453 		dev_err(&adapter->dev,
2454 			"%s detection function provided no name for 0x%x\n",
2455 			driver->driver.name, addr);
2456 	} else {
2457 		struct i2c_client *client;
2458 
2459 		/* Detection succeeded, instantiate the device */
2460 		if (adapter->class & I2C_CLASS_DEPRECATED)
2461 			dev_warn(&adapter->dev,
2462 				"This adapter will soon drop class based instantiation of devices. "
2463 				"Please make sure client 0x%02x gets instantiated by other means. "
2464 				"Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2465 				info.addr);
2466 
2467 		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2468 			info.type, info.addr);
2469 		client = i2c_new_client_device(adapter, &info);
2470 		if (!IS_ERR(client))
2471 			list_add_tail(&client->detected, &driver->clients);
2472 		else
2473 			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2474 				info.type, info.addr);
2475 	}
2476 	return 0;
2477 }
2478 
i2c_detect(struct i2c_adapter * adapter,struct i2c_driver * driver)2479 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2480 {
2481 	const unsigned short *address_list;
2482 	struct i2c_client *temp_client;
2483 	int i, err = 0;
2484 
2485 	address_list = driver->address_list;
2486 	if (!driver->detect || !address_list)
2487 		return 0;
2488 
2489 	/* Warn that the adapter lost class based instantiation */
2490 	if (adapter->class == I2C_CLASS_DEPRECATED) {
2491 		dev_dbg(&adapter->dev,
2492 			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2493 			"If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2494 			driver->driver.name);
2495 		return 0;
2496 	}
2497 
2498 	/* Stop here if the classes do not match */
2499 	if (!(adapter->class & driver->class))
2500 		return 0;
2501 
2502 	/* Set up a temporary client to help detect callback */
2503 	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2504 	if (!temp_client)
2505 		return -ENOMEM;
2506 	temp_client->adapter = adapter;
2507 
2508 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2509 		dev_dbg(&adapter->dev,
2510 			"found normal entry for adapter %d, addr 0x%02x\n",
2511 			i2c_adapter_id(adapter), address_list[i]);
2512 		temp_client->addr = address_list[i];
2513 		err = i2c_detect_address(temp_client, driver);
2514 		if (unlikely(err))
2515 			break;
2516 	}
2517 
2518 	kfree(temp_client);
2519 	return err;
2520 }
2521 
i2c_probe_func_quick_read(struct i2c_adapter * adap,unsigned short addr)2522 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2523 {
2524 	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2525 			      I2C_SMBUS_QUICK, NULL) >= 0;
2526 }
2527 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2528 
2529 struct i2c_client *
i2c_new_scanned_device(struct i2c_adapter * adap,struct i2c_board_info * info,unsigned short const * addr_list,int (* probe)(struct i2c_adapter * adap,unsigned short addr))2530 i2c_new_scanned_device(struct i2c_adapter *adap,
2531 		       struct i2c_board_info *info,
2532 		       unsigned short const *addr_list,
2533 		       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2534 {
2535 	int i;
2536 
2537 	if (!probe)
2538 		probe = i2c_default_probe;
2539 
2540 	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2541 		/* Check address validity */
2542 		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2543 			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2544 				 addr_list[i]);
2545 			continue;
2546 		}
2547 
2548 		/* Check address availability (7 bit, no need to encode flags) */
2549 		if (i2c_check_addr_busy(adap, addr_list[i])) {
2550 			dev_dbg(&adap->dev,
2551 				"Address 0x%02x already in use, not probing\n",
2552 				addr_list[i]);
2553 			continue;
2554 		}
2555 
2556 		/* Test address responsiveness */
2557 		if (probe(adap, addr_list[i]))
2558 			break;
2559 	}
2560 
2561 	if (addr_list[i] == I2C_CLIENT_END) {
2562 		dev_dbg(&adap->dev, "Probing failed, no device found\n");
2563 		return ERR_PTR(-ENODEV);
2564 	}
2565 
2566 	info->addr = addr_list[i];
2567 	return i2c_new_client_device(adap, info);
2568 }
2569 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2570 
i2c_get_adapter(int nr)2571 struct i2c_adapter *i2c_get_adapter(int nr)
2572 {
2573 	struct i2c_adapter *adapter;
2574 
2575 	mutex_lock(&core_lock);
2576 	adapter = idr_find(&i2c_adapter_idr, nr);
2577 	if (!adapter)
2578 		goto exit;
2579 
2580 	if (try_module_get(adapter->owner))
2581 		get_device(&adapter->dev);
2582 	else
2583 		adapter = NULL;
2584 
2585  exit:
2586 	mutex_unlock(&core_lock);
2587 	return adapter;
2588 }
2589 EXPORT_SYMBOL(i2c_get_adapter);
2590 
i2c_put_adapter(struct i2c_adapter * adap)2591 void i2c_put_adapter(struct i2c_adapter *adap)
2592 {
2593 	if (!adap)
2594 		return;
2595 
2596 	module_put(adap->owner);
2597 	/* Should be last, otherwise we risk use-after-free with 'adap' */
2598 	put_device(&adap->dev);
2599 }
2600 EXPORT_SYMBOL(i2c_put_adapter);
2601 
2602 /**
2603  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2604  * @msg: the message to be checked
2605  * @threshold: the minimum number of bytes for which using DMA makes sense.
2606  *	       Should at least be 1.
2607  *
2608  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2609  *	   Or a valid pointer to be used with DMA. After use, release it by
2610  *	   calling i2c_put_dma_safe_msg_buf().
2611  *
2612  * This function must only be called from process context!
2613  */
i2c_get_dma_safe_msg_buf(struct i2c_msg * msg,unsigned int threshold)2614 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2615 {
2616 	/* also skip 0-length msgs for bogus thresholds of 0 */
2617 	if (!threshold)
2618 		pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2619 			 msg->addr);
2620 	if (msg->len < threshold || msg->len == 0)
2621 		return NULL;
2622 
2623 	if (msg->flags & I2C_M_DMA_SAFE)
2624 		return msg->buf;
2625 
2626 	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2627 		 msg->addr, msg->len);
2628 
2629 	if (msg->flags & I2C_M_RD)
2630 		return kzalloc(msg->len, GFP_KERNEL);
2631 	else
2632 		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2633 }
2634 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2635 
2636 /**
2637  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2638  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2639  * @msg: the message which the buffer corresponds to
2640  * @xferred: bool saying if the message was transferred
2641  */
i2c_put_dma_safe_msg_buf(u8 * buf,struct i2c_msg * msg,bool xferred)2642 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2643 {
2644 	if (!buf || buf == msg->buf)
2645 		return;
2646 
2647 	if (xferred && msg->flags & I2C_M_RD)
2648 		memcpy(msg->buf, buf, msg->len);
2649 
2650 	kfree(buf);
2651 }
2652 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2653 
2654 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2655 MODULE_DESCRIPTION("I2C-Bus main module");
2656 MODULE_LICENSE("GPL");
2657