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