1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for the Diolan DLN-2 USB-GPIO adapter
4  *
5  * Copyright (c) 2014 Intel Corporation
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/slab.h>
11 #include <linux/types.h>
12 #include <linux/irqdomain.h>
13 #include <linux/irq.h>
14 #include <linux/irqchip/chained_irq.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/platform_device.h>
17 #include <linux/mfd/dln2.h>
18 
19 #define DLN2_GPIO_ID			0x01
20 
21 #define DLN2_GPIO_GET_PIN_COUNT		DLN2_CMD(0x01, DLN2_GPIO_ID)
22 #define DLN2_GPIO_SET_DEBOUNCE		DLN2_CMD(0x04, DLN2_GPIO_ID)
23 #define DLN2_GPIO_GET_DEBOUNCE		DLN2_CMD(0x05, DLN2_GPIO_ID)
24 #define DLN2_GPIO_PORT_GET_VAL		DLN2_CMD(0x06, DLN2_GPIO_ID)
25 #define DLN2_GPIO_PIN_GET_VAL		DLN2_CMD(0x0B, DLN2_GPIO_ID)
26 #define DLN2_GPIO_PIN_SET_OUT_VAL	DLN2_CMD(0x0C, DLN2_GPIO_ID)
27 #define DLN2_GPIO_PIN_GET_OUT_VAL	DLN2_CMD(0x0D, DLN2_GPIO_ID)
28 #define DLN2_GPIO_CONDITION_MET_EV	DLN2_CMD(0x0F, DLN2_GPIO_ID)
29 #define DLN2_GPIO_PIN_ENABLE		DLN2_CMD(0x10, DLN2_GPIO_ID)
30 #define DLN2_GPIO_PIN_DISABLE		DLN2_CMD(0x11, DLN2_GPIO_ID)
31 #define DLN2_GPIO_PIN_SET_DIRECTION	DLN2_CMD(0x13, DLN2_GPIO_ID)
32 #define DLN2_GPIO_PIN_GET_DIRECTION	DLN2_CMD(0x14, DLN2_GPIO_ID)
33 #define DLN2_GPIO_PIN_SET_EVENT_CFG	DLN2_CMD(0x1E, DLN2_GPIO_ID)
34 #define DLN2_GPIO_PIN_GET_EVENT_CFG	DLN2_CMD(0x1F, DLN2_GPIO_ID)
35 
36 #define DLN2_GPIO_EVENT_NONE		0
37 #define DLN2_GPIO_EVENT_CHANGE		1
38 #define DLN2_GPIO_EVENT_LVL_HIGH	2
39 #define DLN2_GPIO_EVENT_LVL_LOW		3
40 #define DLN2_GPIO_EVENT_CHANGE_RISING	0x11
41 #define DLN2_GPIO_EVENT_CHANGE_FALLING  0x21
42 #define DLN2_GPIO_EVENT_MASK		0x0F
43 
44 #define DLN2_GPIO_MAX_PINS 32
45 
46 struct dln2_gpio {
47 	struct platform_device *pdev;
48 	struct gpio_chip gpio;
49 
50 	/*
51 	 * Cache pin direction to save us one transfer, since the hardware has
52 	 * separate commands to read the in and out values.
53 	 */
54 	DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS);
55 
56 	/* active IRQs - not synced to hardware */
57 	DECLARE_BITMAP(unmasked_irqs, DLN2_GPIO_MAX_PINS);
58 	/* active IRQS - synced to hardware */
59 	DECLARE_BITMAP(enabled_irqs, DLN2_GPIO_MAX_PINS);
60 	int irq_type[DLN2_GPIO_MAX_PINS];
61 	struct mutex irq_lock;
62 };
63 
64 struct dln2_gpio_pin {
65 	__le16 pin;
66 };
67 
68 struct dln2_gpio_pin_val {
69 	__le16 pin __packed;
70 	u8 value;
71 };
72 
dln2_gpio_get_pin_count(struct platform_device * pdev)73 static int dln2_gpio_get_pin_count(struct platform_device *pdev)
74 {
75 	int ret;
76 	__le16 count;
77 	int len = sizeof(count);
78 
79 	ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len);
80 	if (ret < 0)
81 		return ret;
82 	if (len < sizeof(count))
83 		return -EPROTO;
84 
85 	return le16_to_cpu(count);
86 }
87 
dln2_gpio_pin_cmd(struct dln2_gpio * dln2,int cmd,unsigned pin)88 static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin)
89 {
90 	struct dln2_gpio_pin req = {
91 		.pin = cpu_to_le16(pin),
92 	};
93 
94 	return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req));
95 }
96 
dln2_gpio_pin_val(struct dln2_gpio * dln2,int cmd,unsigned int pin)97 static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin)
98 {
99 	int ret;
100 	struct dln2_gpio_pin req = {
101 		.pin = cpu_to_le16(pin),
102 	};
103 	struct dln2_gpio_pin_val rsp;
104 	int len = sizeof(rsp);
105 
106 	ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len);
107 	if (ret < 0)
108 		return ret;
109 	if (len < sizeof(rsp) || req.pin != rsp.pin)
110 		return -EPROTO;
111 
112 	return rsp.value;
113 }
114 
dln2_gpio_pin_get_in_val(struct dln2_gpio * dln2,unsigned int pin)115 static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin)
116 {
117 	int ret;
118 
119 	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin);
120 	if (ret < 0)
121 		return ret;
122 	return !!ret;
123 }
124 
dln2_gpio_pin_get_out_val(struct dln2_gpio * dln2,unsigned int pin)125 static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin)
126 {
127 	int ret;
128 
129 	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin);
130 	if (ret < 0)
131 		return ret;
132 	return !!ret;
133 }
134 
dln2_gpio_pin_set_out_val(struct dln2_gpio * dln2,unsigned int pin,int value)135 static int dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
136 				     unsigned int pin, int value)
137 {
138 	struct dln2_gpio_pin_val req = {
139 		.pin = cpu_to_le16(pin),
140 		.value = value,
141 	};
142 
143 	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
144 				sizeof(req));
145 }
146 
147 #define DLN2_GPIO_DIRECTION_IN		0
148 #define DLN2_GPIO_DIRECTION_OUT		1
149 
dln2_gpio_request(struct gpio_chip * chip,unsigned offset)150 static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
151 {
152 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
153 	struct dln2_gpio_pin req = {
154 		.pin = cpu_to_le16(offset),
155 	};
156 	struct dln2_gpio_pin_val rsp;
157 	int len = sizeof(rsp);
158 	int ret;
159 
160 	ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
161 	if (ret < 0)
162 		return ret;
163 
164 	/* cache the pin direction */
165 	ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
166 			    &req, sizeof(req), &rsp, &len);
167 	if (ret < 0)
168 		return ret;
169 	if (len < sizeof(rsp) || req.pin != rsp.pin) {
170 		ret = -EPROTO;
171 		goto out_disable;
172 	}
173 
174 	switch (rsp.value) {
175 	case DLN2_GPIO_DIRECTION_IN:
176 		clear_bit(offset, dln2->output_enabled);
177 		return 0;
178 	case DLN2_GPIO_DIRECTION_OUT:
179 		set_bit(offset, dln2->output_enabled);
180 		return 0;
181 	default:
182 		ret = -EPROTO;
183 		goto out_disable;
184 	}
185 
186 out_disable:
187 	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
188 	return ret;
189 }
190 
dln2_gpio_free(struct gpio_chip * chip,unsigned offset)191 static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
192 {
193 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
194 
195 	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
196 }
197 
dln2_gpio_get_direction(struct gpio_chip * chip,unsigned offset)198 static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
199 {
200 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
201 
202 	if (test_bit(offset, dln2->output_enabled))
203 		return GPIO_LINE_DIRECTION_OUT;
204 
205 	return GPIO_LINE_DIRECTION_IN;
206 }
207 
dln2_gpio_get(struct gpio_chip * chip,unsigned int offset)208 static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
209 {
210 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
211 	int dir;
212 
213 	dir = dln2_gpio_get_direction(chip, offset);
214 	if (dir < 0)
215 		return dir;
216 
217 	if (dir == GPIO_LINE_DIRECTION_IN)
218 		return dln2_gpio_pin_get_in_val(dln2, offset);
219 
220 	return dln2_gpio_pin_get_out_val(dln2, offset);
221 }
222 
dln2_gpio_set(struct gpio_chip * chip,unsigned offset,int value)223 static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
224 {
225 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
226 
227 	dln2_gpio_pin_set_out_val(dln2, offset, value);
228 }
229 
dln2_gpio_set_direction(struct gpio_chip * chip,unsigned offset,unsigned dir)230 static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
231 				   unsigned dir)
232 {
233 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
234 	struct dln2_gpio_pin_val req = {
235 		.pin = cpu_to_le16(offset),
236 		.value = dir,
237 	};
238 	int ret;
239 
240 	ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION,
241 			       &req, sizeof(req));
242 	if (ret < 0)
243 		return ret;
244 
245 	if (dir == DLN2_GPIO_DIRECTION_OUT)
246 		set_bit(offset, dln2->output_enabled);
247 	else
248 		clear_bit(offset, dln2->output_enabled);
249 
250 	return ret;
251 }
252 
dln2_gpio_direction_input(struct gpio_chip * chip,unsigned offset)253 static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
254 {
255 	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN);
256 }
257 
dln2_gpio_direction_output(struct gpio_chip * chip,unsigned offset,int value)258 static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
259 				      int value)
260 {
261 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
262 	int ret;
263 
264 	ret = dln2_gpio_pin_set_out_val(dln2, offset, value);
265 	if (ret < 0)
266 		return ret;
267 
268 	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
269 }
270 
dln2_gpio_set_config(struct gpio_chip * chip,unsigned offset,unsigned long config)271 static int dln2_gpio_set_config(struct gpio_chip *chip, unsigned offset,
272 				unsigned long config)
273 {
274 	struct dln2_gpio *dln2 = gpiochip_get_data(chip);
275 	__le32 duration;
276 
277 	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
278 		return -ENOTSUPP;
279 
280 	duration = cpu_to_le32(pinconf_to_config_argument(config));
281 	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE,
282 				&duration, sizeof(duration));
283 }
284 
dln2_gpio_set_event_cfg(struct dln2_gpio * dln2,unsigned pin,unsigned type,unsigned period)285 static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin,
286 				   unsigned type, unsigned period)
287 {
288 	struct {
289 		__le16 pin;
290 		u8 type;
291 		__le16 period;
292 	} __packed req = {
293 		.pin = cpu_to_le16(pin),
294 		.type = type,
295 		.period = cpu_to_le16(period),
296 	};
297 
298 	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG,
299 				&req, sizeof(req));
300 }
301 
dln2_irq_unmask(struct irq_data * irqd)302 static void dln2_irq_unmask(struct irq_data *irqd)
303 {
304 	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
305 	struct dln2_gpio *dln2 = gpiochip_get_data(gc);
306 	int pin = irqd_to_hwirq(irqd);
307 
308 	gpiochip_enable_irq(gc, pin);
309 	set_bit(pin, dln2->unmasked_irqs);
310 }
311 
dln2_irq_mask(struct irq_data * irqd)312 static void dln2_irq_mask(struct irq_data *irqd)
313 {
314 	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
315 	struct dln2_gpio *dln2 = gpiochip_get_data(gc);
316 	int pin = irqd_to_hwirq(irqd);
317 
318 	clear_bit(pin, dln2->unmasked_irqs);
319 	gpiochip_disable_irq(gc, pin);
320 }
321 
dln2_irq_set_type(struct irq_data * irqd,unsigned type)322 static int dln2_irq_set_type(struct irq_data *irqd, unsigned type)
323 {
324 	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
325 	struct dln2_gpio *dln2 = gpiochip_get_data(gc);
326 	int pin = irqd_to_hwirq(irqd);
327 
328 	switch (type) {
329 	case IRQ_TYPE_LEVEL_HIGH:
330 		dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_HIGH;
331 		break;
332 	case IRQ_TYPE_LEVEL_LOW:
333 		dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_LOW;
334 		break;
335 	case IRQ_TYPE_EDGE_BOTH:
336 		dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE;
337 		break;
338 	case IRQ_TYPE_EDGE_RISING:
339 		dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_RISING;
340 		break;
341 	case IRQ_TYPE_EDGE_FALLING:
342 		dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_FALLING;
343 		break;
344 	default:
345 		return -EINVAL;
346 	}
347 
348 	return 0;
349 }
350 
dln2_irq_bus_lock(struct irq_data * irqd)351 static void dln2_irq_bus_lock(struct irq_data *irqd)
352 {
353 	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
354 	struct dln2_gpio *dln2 = gpiochip_get_data(gc);
355 
356 	mutex_lock(&dln2->irq_lock);
357 }
358 
dln2_irq_bus_unlock(struct irq_data * irqd)359 static void dln2_irq_bus_unlock(struct irq_data *irqd)
360 {
361 	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
362 	struct dln2_gpio *dln2 = gpiochip_get_data(gc);
363 	int pin = irqd_to_hwirq(irqd);
364 	int enabled, unmasked;
365 	unsigned type;
366 	int ret;
367 
368 	enabled = test_bit(pin, dln2->enabled_irqs);
369 	unmasked = test_bit(pin, dln2->unmasked_irqs);
370 
371 	if (enabled != unmasked) {
372 		if (unmasked) {
373 			type = dln2->irq_type[pin] & DLN2_GPIO_EVENT_MASK;
374 			set_bit(pin, dln2->enabled_irqs);
375 		} else {
376 			type = DLN2_GPIO_EVENT_NONE;
377 			clear_bit(pin, dln2->enabled_irqs);
378 		}
379 
380 		ret = dln2_gpio_set_event_cfg(dln2, pin, type, 0);
381 		if (ret)
382 			dev_err(dln2->gpio.parent, "failed to set event\n");
383 	}
384 
385 	mutex_unlock(&dln2->irq_lock);
386 }
387 
388 static const struct irq_chip dln2_irqchip = {
389 	.name = "dln2-irq",
390 	.irq_mask = dln2_irq_mask,
391 	.irq_unmask = dln2_irq_unmask,
392 	.irq_set_type = dln2_irq_set_type,
393 	.irq_bus_lock = dln2_irq_bus_lock,
394 	.irq_bus_sync_unlock = dln2_irq_bus_unlock,
395 	.flags = IRQCHIP_IMMUTABLE,
396 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
397 };
398 
dln2_gpio_event(struct platform_device * pdev,u16 echo,const void * data,int len)399 static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
400 			    const void *data, int len)
401 {
402 	int pin, ret;
403 
404 	const struct {
405 		__le16 count;
406 		__u8 type;
407 		__le16 pin;
408 		__u8 value;
409 	} __packed *event = data;
410 	struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
411 
412 	if (len < sizeof(*event)) {
413 		dev_err(dln2->gpio.parent, "short event message\n");
414 		return;
415 	}
416 
417 	pin = le16_to_cpu(event->pin);
418 	if (pin >= dln2->gpio.ngpio) {
419 		dev_err(dln2->gpio.parent, "out of bounds pin %d\n", pin);
420 		return;
421 	}
422 
423 	switch (dln2->irq_type[pin]) {
424 	case DLN2_GPIO_EVENT_CHANGE_RISING:
425 		if (!event->value)
426 			return;
427 		break;
428 	case DLN2_GPIO_EVENT_CHANGE_FALLING:
429 		if (event->value)
430 			return;
431 		break;
432 	}
433 
434 	ret = generic_handle_domain_irq(dln2->gpio.irq.domain, pin);
435 	if (unlikely(ret))
436 		dev_err(dln2->gpio.parent, "pin %d not mapped to IRQ\n", pin);
437 }
438 
dln2_gpio_probe(struct platform_device * pdev)439 static int dln2_gpio_probe(struct platform_device *pdev)
440 {
441 	struct dln2_gpio *dln2;
442 	struct device *dev = &pdev->dev;
443 	struct gpio_irq_chip *girq;
444 	int pins;
445 	int ret;
446 
447 	pins = dln2_gpio_get_pin_count(pdev);
448 	if (pins < 0) {
449 		dev_err(dev, "failed to get pin count: %d\n", pins);
450 		return pins;
451 	}
452 	if (pins > DLN2_GPIO_MAX_PINS) {
453 		pins = DLN2_GPIO_MAX_PINS;
454 		dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS);
455 	}
456 
457 	dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL);
458 	if (!dln2)
459 		return -ENOMEM;
460 
461 	mutex_init(&dln2->irq_lock);
462 
463 	dln2->pdev = pdev;
464 
465 	dln2->gpio.label = "dln2";
466 	dln2->gpio.parent = dev;
467 	dln2->gpio.owner = THIS_MODULE;
468 	dln2->gpio.base = -1;
469 	dln2->gpio.ngpio = pins;
470 	dln2->gpio.can_sleep = true;
471 	dln2->gpio.set = dln2_gpio_set;
472 	dln2->gpio.get = dln2_gpio_get;
473 	dln2->gpio.request = dln2_gpio_request;
474 	dln2->gpio.free = dln2_gpio_free;
475 	dln2->gpio.get_direction = dln2_gpio_get_direction;
476 	dln2->gpio.direction_input = dln2_gpio_direction_input;
477 	dln2->gpio.direction_output = dln2_gpio_direction_output;
478 	dln2->gpio.set_config = dln2_gpio_set_config;
479 
480 	girq = &dln2->gpio.irq;
481 	gpio_irq_chip_set_chip(girq, &dln2_irqchip);
482 	/* The event comes from the outside so no parent handler */
483 	girq->parent_handler = NULL;
484 	girq->num_parents = 0;
485 	girq->parents = NULL;
486 	girq->default_type = IRQ_TYPE_NONE;
487 	girq->handler = handle_simple_irq;
488 
489 	platform_set_drvdata(pdev, dln2);
490 
491 	ret = devm_gpiochip_add_data(dev, &dln2->gpio, dln2);
492 	if (ret < 0) {
493 		dev_err(dev, "failed to add gpio chip: %d\n", ret);
494 		return ret;
495 	}
496 
497 	ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV,
498 				     dln2_gpio_event);
499 	if (ret) {
500 		dev_err(dev, "failed to register event cb: %d\n", ret);
501 		return ret;
502 	}
503 
504 	return 0;
505 }
506 
dln2_gpio_remove(struct platform_device * pdev)507 static int dln2_gpio_remove(struct platform_device *pdev)
508 {
509 	dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
510 
511 	return 0;
512 }
513 
514 static struct platform_driver dln2_gpio_driver = {
515 	.driver.name	= "dln2-gpio",
516 	.probe		= dln2_gpio_probe,
517 	.remove		= dln2_gpio_remove,
518 };
519 
520 module_platform_driver(dln2_gpio_driver);
521 
522 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
523 MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface");
524 MODULE_LICENSE("GPL v2");
525 MODULE_ALIAS("platform:dln2-gpio");
526