gpio.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * GPIO Greybus driver.
  4 *
  5 * Copyright 2014 Google Inc.
  6 * Copyright 2014 Linaro Ltd.
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/slab.h>
 12#include <linux/irq.h>
 13#include <linux/irqdomain.h>
 14#include <linux/gpio/driver.h>
 15#include <linux/mutex.h>
 16#include <linux/greybus.h>
 17
 18#include "gbphy.h"
 19
 20struct gb_gpio_line {
 21	/* The following has to be an array of line_max entries */
 22	/* --> make them just a flags field */
 23	u8			active:    1,
 24				direction: 1,	/* 0 = output, 1 = input */
 25				value:     1;	/* 0 = low, 1 = high */
 26	u16			debounce_usec;
 27
 28	u8			irq_type;
 29	bool			irq_type_pending;
 30	bool			masked;
 31	bool			masked_pending;
 32};
 33
 34struct gb_gpio_controller {
 35	struct gbphy_device	*gbphy_dev;
 36	struct gb_connection	*connection;
 37	u8			line_max;	/* max line number */
 38	struct gb_gpio_line	*lines;
 39
 40	struct gpio_chip	chip;
 41	struct irq_chip		irqc;
 42	struct mutex		irq_lock;
 43};
 44
 45static struct gpio_chip *irq_data_to_gpio_chip(struct irq_data *d)
 46{
 47	return d->domain->host_data;
 48}
 49
 50static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
 51{
 52	struct gb_gpio_line_count_response response;
 53	int ret;
 54
 55	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
 56				NULL, 0, &response, sizeof(response));
 57	if (!ret)
 58		ggc->line_max = response.count;
 59	return ret;
 60}
 61
 62static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
 63{
 64	struct gb_gpio_activate_request request;
 65	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
 66	int ret;
 67
 68	ret = gbphy_runtime_get_sync(gbphy_dev);
 69	if (ret)
 70		return ret;
 71
 72	request.which = which;
 73	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
 74				&request, sizeof(request), NULL, 0);
 75	if (ret) {
 76		gbphy_runtime_put_autosuspend(gbphy_dev);
 77		return ret;
 78	}
 79
 80	ggc->lines[which].active = true;
 81
 82	return 0;
 83}
 84
 85static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
 86					 u8 which)
 87{
 88	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
 89	struct device *dev = &gbphy_dev->dev;
 90	struct gb_gpio_deactivate_request request;
 91	int ret;
 92
 93	request.which = which;
 94	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
 95				&request, sizeof(request), NULL, 0);
 96	if (ret) {
 97		dev_err(dev, "failed to deactivate gpio %u\n", which);
 98		goto out_pm_put;
 99	}
100
101	ggc->lines[which].active = false;
102
103out_pm_put:
104	gbphy_runtime_put_autosuspend(gbphy_dev);
105}
106
107static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
108					   u8 which)
109{
110	struct device *dev = &ggc->gbphy_dev->dev;
111	struct gb_gpio_get_direction_request request;
112	struct gb_gpio_get_direction_response response;
113	int ret;
114	u8 direction;
115
116	request.which = which;
117	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
118				&request, sizeof(request),
119				&response, sizeof(response));
120	if (ret)
121		return ret;
122
123	direction = response.direction;
124	if (direction && direction != 1) {
125		dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
126			 which, direction);
127	}
128	ggc->lines[which].direction = direction ? 1 : 0;
129	return 0;
130}
131
132static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
133					  u8 which)
134{
135	struct gb_gpio_direction_in_request request;
136	int ret;
137
138	request.which = which;
139	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
140				&request, sizeof(request), NULL, 0);
141	if (!ret)
142		ggc->lines[which].direction = 1;
143	return ret;
144}
145
146static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
147					   u8 which, bool value_high)
148{
149	struct gb_gpio_direction_out_request request;
150	int ret;
151
152	request.which = which;
153	request.value = value_high ? 1 : 0;
154	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
155				&request, sizeof(request), NULL, 0);
156	if (!ret)
157		ggc->lines[which].direction = 0;
158	return ret;
159}
160
161static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
162				       u8 which)
163{
164	struct device *dev = &ggc->gbphy_dev->dev;
165	struct gb_gpio_get_value_request request;
166	struct gb_gpio_get_value_response response;
167	int ret;
168	u8 value;
169
170	request.which = which;
171	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
172				&request, sizeof(request),
173				&response, sizeof(response));
174	if (ret) {
175		dev_err(dev, "failed to get value of gpio %u\n", which);
176		return ret;
177	}
178
179	value = response.value;
180	if (value && value != 1) {
181		dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
182			 which, value);
183	}
184	ggc->lines[which].value = value ? 1 : 0;
185	return 0;
186}
187
188static int gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
189				       u8 which, bool value_high)
190{
191	struct device *dev = &ggc->gbphy_dev->dev;
192	struct gb_gpio_set_value_request request;
193	int ret;
194
195	request.which = which;
196	request.value = value_high ? 1 : 0;
197	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
198				&request, sizeof(request), NULL, 0);
199	if (ret) {
200		dev_err(dev, "failed to set value of gpio %u\n", which);
201		return ret;
202	}
203
204	ggc->lines[which].value = request.value;
205
206	return 0;
207}
208
209static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc,
210					  u8 which, u16 debounce_usec)
211{
212	struct gb_gpio_set_debounce_request request;
213	int ret;
214
215	request.which = which;
216	request.usec = cpu_to_le16(debounce_usec);
217	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE,
218				&request, sizeof(request), NULL, 0);
219	if (!ret)
220		ggc->lines[which].debounce_usec = debounce_usec;
221	return ret;
222}
223
224static void _gb_gpio_irq_mask(struct gb_gpio_controller *ggc, u8 hwirq)
225{
226	struct device *dev = &ggc->gbphy_dev->dev;
227	struct gb_gpio_irq_mask_request request;
228	int ret;
229
230	request.which = hwirq;
231	ret = gb_operation_sync(ggc->connection,
232				GB_GPIO_TYPE_IRQ_MASK,
233				&request, sizeof(request), NULL, 0);
234	if (ret)
235		dev_err(dev, "failed to mask irq: %d\n", ret);
236}
237
238static void _gb_gpio_irq_unmask(struct gb_gpio_controller *ggc, u8 hwirq)
239{
240	struct device *dev = &ggc->gbphy_dev->dev;
241	struct gb_gpio_irq_unmask_request request;
242	int ret;
243
244	request.which = hwirq;
245	ret = gb_operation_sync(ggc->connection,
246				GB_GPIO_TYPE_IRQ_UNMASK,
247				&request, sizeof(request), NULL, 0);
248	if (ret)
249		dev_err(dev, "failed to unmask irq: %d\n", ret);
250}
251
252static void _gb_gpio_irq_set_type(struct gb_gpio_controller *ggc,
253				  u8 hwirq, u8 type)
254{
255	struct device *dev = &ggc->gbphy_dev->dev;
256	struct gb_gpio_irq_type_request request;
257	int ret;
258
259	request.which = hwirq;
260	request.type = type;
261
262	ret = gb_operation_sync(ggc->connection,
263				GB_GPIO_TYPE_IRQ_TYPE,
264				&request, sizeof(request), NULL, 0);
265	if (ret)
266		dev_err(dev, "failed to set irq type: %d\n", ret);
267}
268
269static void gb_gpio_irq_mask(struct irq_data *d)
270{
271	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
272	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
273	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
274
275	line->masked = true;
276	line->masked_pending = true;
277}
278
279static void gb_gpio_irq_unmask(struct irq_data *d)
280{
281	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
282	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
283	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
284
285	line->masked = false;
286	line->masked_pending = true;
287}
288
289static int gb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
290{
291	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
292	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
293	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
294	struct device *dev = &ggc->gbphy_dev->dev;
295	u8 irq_type;
296
297	switch (type) {
298	case IRQ_TYPE_NONE:
299		irq_type = GB_GPIO_IRQ_TYPE_NONE;
300		break;
301	case IRQ_TYPE_EDGE_RISING:
302		irq_type = GB_GPIO_IRQ_TYPE_EDGE_RISING;
303		break;
304	case IRQ_TYPE_EDGE_FALLING:
305		irq_type = GB_GPIO_IRQ_TYPE_EDGE_FALLING;
306		break;
307	case IRQ_TYPE_EDGE_BOTH:
308		irq_type = GB_GPIO_IRQ_TYPE_EDGE_BOTH;
309		break;
310	case IRQ_TYPE_LEVEL_LOW:
311		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_LOW;
312		break;
313	case IRQ_TYPE_LEVEL_HIGH:
314		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_HIGH;
315		break;
316	default:
317		dev_err(dev, "unsupported irq type: %u\n", type);
318		return -EINVAL;
319	}
320
321	line->irq_type = irq_type;
322	line->irq_type_pending = true;
323
324	return 0;
325}
326
327static void gb_gpio_irq_bus_lock(struct irq_data *d)
328{
329	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
330	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
331
332	mutex_lock(&ggc->irq_lock);
333}
334
335static void gb_gpio_irq_bus_sync_unlock(struct irq_data *d)
336{
337	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
338	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
339	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
340
341	if (line->irq_type_pending) {
342		_gb_gpio_irq_set_type(ggc, d->hwirq, line->irq_type);
343		line->irq_type_pending = false;
344	}
345
346	if (line->masked_pending) {
347		if (line->masked)
348			_gb_gpio_irq_mask(ggc, d->hwirq);
349		else
350			_gb_gpio_irq_unmask(ggc, d->hwirq);
351		line->masked_pending = false;
352	}
353
354	mutex_unlock(&ggc->irq_lock);
355}
356
357static int gb_gpio_request_handler(struct gb_operation *op)
358{
359	struct gb_connection *connection = op->connection;
360	struct gb_gpio_controller *ggc = gb_connection_get_data(connection);
361	struct device *dev = &ggc->gbphy_dev->dev;
362	struct gb_message *request;
363	struct gb_gpio_irq_event_request *event;
364	u8 type = op->type;
365	int irq, ret;
366
367	if (type != GB_GPIO_TYPE_IRQ_EVENT) {
368		dev_err(dev, "unsupported unsolicited request: %u\n", type);
369		return -EINVAL;
370	}
371
372	request = op->request;
373
374	if (request->payload_size < sizeof(*event)) {
375		dev_err(dev, "short event received (%zu < %zu)\n",
376			request->payload_size, sizeof(*event));
377		return -EINVAL;
378	}
379
380	event = request->payload;
381	if (event->which > ggc->line_max) {
382		dev_err(dev, "invalid hw irq: %d\n", event->which);
383		return -EINVAL;
384	}
385
386	irq = irq_find_mapping(ggc->chip.irq.domain, event->which);
387	if (!irq) {
388		dev_err(dev, "failed to find IRQ\n");
389		return -EINVAL;
390	}
391
392	ret = generic_handle_irq_safe(irq);
393	if (ret)
394		dev_err(dev, "failed to invoke irq handler\n");
395
396	return ret;
397}
398
399static int gb_gpio_request(struct gpio_chip *chip, unsigned int offset)
400{
401	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
402
403	return gb_gpio_activate_operation(ggc, (u8)offset);
404}
405
406static void gb_gpio_free(struct gpio_chip *chip, unsigned int offset)
407{
408	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
409
410	gb_gpio_deactivate_operation(ggc, (u8)offset);
411}
412
413static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
414{
415	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
416	u8 which;
417	int ret;
418
419	which = (u8)offset;
420	ret = gb_gpio_get_direction_operation(ggc, which);
421	if (ret)
422		return ret;
423
424	return ggc->lines[which].direction ? 1 : 0;
425}
426
427static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
428{
429	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
430
431	return gb_gpio_direction_in_operation(ggc, (u8)offset);
432}
433
434static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned int offset,
435				    int value)
436{
437	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
438
439	return gb_gpio_direction_out_operation(ggc, (u8)offset, !!value);
440}
441
442static int gb_gpio_get(struct gpio_chip *chip, unsigned int offset)
443{
444	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
445	u8 which;
446	int ret;
447
448	which = (u8)offset;
449	ret = gb_gpio_get_value_operation(ggc, which);
450	if (ret)
451		return ret;
452
453	return ggc->lines[which].value;
454}
455
456static int gb_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
457{
458	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
459
460	return gb_gpio_set_value_operation(ggc, (u8)offset, !!value);
461}
462
463static int gb_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
464			      unsigned long config)
465{
466	struct gb_gpio_controller *ggc = gpiochip_get_data(chip);
467	u32 debounce;
468
469	if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
470		return -ENOTSUPP;
471
472	debounce = pinconf_to_config_argument(config);
473	if (debounce > U16_MAX)
474		return -EINVAL;
475
476	return gb_gpio_set_debounce_operation(ggc, (u8)offset, (u16)debounce);
477}
478
479static int gb_gpio_controller_setup(struct gb_gpio_controller *ggc)
480{
481	int ret;
482
483	/* Now find out how many lines there are */
484	ret = gb_gpio_line_count_operation(ggc);
485	if (ret)
486		return ret;
487
488	ggc->lines = kcalloc(ggc->line_max + 1, sizeof(*ggc->lines),
489			     GFP_KERNEL);
490	if (!ggc->lines)
491		return -ENOMEM;
492
493	return ret;
494}
495
496static int gb_gpio_probe(struct gbphy_device *gbphy_dev,
497			 const struct gbphy_device_id *id)
498{
499	struct gb_connection *connection;
500	struct gb_gpio_controller *ggc;
501	struct gpio_chip *gpio;
502	struct gpio_irq_chip *girq;
503	struct irq_chip *irqc;
504	int ret;
505
506	ggc = kzalloc(sizeof(*ggc), GFP_KERNEL);
507	if (!ggc)
508		return -ENOMEM;
509
510	connection =
511		gb_connection_create(gbphy_dev->bundle,
512				     le16_to_cpu(gbphy_dev->cport_desc->id),
513				     gb_gpio_request_handler);
514	if (IS_ERR(connection)) {
515		ret = PTR_ERR(connection);
516		goto exit_ggc_free;
517	}
518
519	ggc->connection = connection;
520	gb_connection_set_data(connection, ggc);
521	ggc->gbphy_dev = gbphy_dev;
522	gb_gbphy_set_data(gbphy_dev, ggc);
523
524	ret = gb_connection_enable_tx(connection);
525	if (ret)
526		goto exit_connection_destroy;
527
528	ret = gb_gpio_controller_setup(ggc);
529	if (ret)
530		goto exit_connection_disable;
531
532	irqc = &ggc->irqc;
533	irqc->irq_mask = gb_gpio_irq_mask;
534	irqc->irq_unmask = gb_gpio_irq_unmask;
535	irqc->irq_set_type = gb_gpio_irq_set_type;
536	irqc->irq_bus_lock = gb_gpio_irq_bus_lock;
537	irqc->irq_bus_sync_unlock = gb_gpio_irq_bus_sync_unlock;
538	irqc->name = "greybus_gpio";
539
540	mutex_init(&ggc->irq_lock);
541
542	gpio = &ggc->chip;
543
544	gpio->label = "greybus_gpio";
545	gpio->parent = &gbphy_dev->dev;
546	gpio->owner = THIS_MODULE;
547
548	gpio->request = gb_gpio_request;
549	gpio->free = gb_gpio_free;
550	gpio->get_direction = gb_gpio_get_direction;
551	gpio->direction_input = gb_gpio_direction_input;
552	gpio->direction_output = gb_gpio_direction_output;
553	gpio->get = gb_gpio_get;
554	gpio->set = gb_gpio_set;
555	gpio->set_config = gb_gpio_set_config;
556	gpio->base = -1;		/* Allocate base dynamically */
557	gpio->ngpio = ggc->line_max + 1;
558	gpio->can_sleep = true;
559
560	girq = &gpio->irq;
561	girq->chip = irqc;
562	/* The event comes from the outside so no parent handler */
563	girq->parent_handler = NULL;
564	girq->num_parents = 0;
565	girq->parents = NULL;
566	girq->default_type = IRQ_TYPE_NONE;
567	girq->handler = handle_level_irq;
568
569	ret = gb_connection_enable(connection);
570	if (ret)
571		goto exit_line_free;
572
573	ret = gpiochip_add_data(gpio, ggc);
574	if (ret) {
575		dev_err(&gbphy_dev->dev, "failed to add gpio chip: %d\n", ret);
576		goto exit_line_free;
577	}
578
579	gbphy_runtime_put_autosuspend(gbphy_dev);
580	return 0;
581
582exit_line_free:
583	kfree(ggc->lines);
584exit_connection_disable:
585	gb_connection_disable(connection);
586exit_connection_destroy:
587	gb_connection_destroy(connection);
588exit_ggc_free:
589	kfree(ggc);
590	return ret;
591}
592
593static void gb_gpio_remove(struct gbphy_device *gbphy_dev)
594{
595	struct gb_gpio_controller *ggc = gb_gbphy_get_data(gbphy_dev);
596	struct gb_connection *connection = ggc->connection;
597	int ret;
598
599	ret = gbphy_runtime_get_sync(gbphy_dev);
600	if (ret)
601		gbphy_runtime_get_noresume(gbphy_dev);
602
603	gb_connection_disable_rx(connection);
604	gpiochip_remove(&ggc->chip);
605	gb_connection_disable(connection);
606	gb_connection_destroy(connection);
607	kfree(ggc->lines);
608	kfree(ggc);
609}
610
611static const struct gbphy_device_id gb_gpio_id_table[] = {
612	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_GPIO) },
613	{ },
614};
615MODULE_DEVICE_TABLE(gbphy, gb_gpio_id_table);
616
617static struct gbphy_driver gpio_driver = {
618	.name		= "gpio",
619	.probe		= gb_gpio_probe,
620	.remove		= gb_gpio_remove,
621	.id_table	= gb_gpio_id_table,
622};
623
624module_gbphy_driver(gpio_driver);
625MODULE_DESCRIPTION("GPIO Greybus driver");
626MODULE_LICENSE("GPL v2");