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
20 struct 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
34 struct 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
gpio_chip_to_gb_gpio_controller(struct gpio_chip * chip)45 static inline struct gb_gpio_controller *gpio_chip_to_gb_gpio_controller(struct gpio_chip *chip)
46 {
47 return container_of(chip, struct gb_gpio_controller, chip);
48 }
49
irq_data_to_gpio_chip(struct irq_data * d)50 static struct gpio_chip *irq_data_to_gpio_chip(struct irq_data *d)
51 {
52 return d->domain->host_data;
53 }
54
gb_gpio_line_count_operation(struct gb_gpio_controller * ggc)55 static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
56 {
57 struct gb_gpio_line_count_response response;
58 int ret;
59
60 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
61 NULL, 0, &response, sizeof(response));
62 if (!ret)
63 ggc->line_max = response.count;
64 return ret;
65 }
66
gb_gpio_activate_operation(struct gb_gpio_controller * ggc,u8 which)67 static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
68 {
69 struct gb_gpio_activate_request request;
70 struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
71 int ret;
72
73 ret = gbphy_runtime_get_sync(gbphy_dev);
74 if (ret)
75 return ret;
76
77 request.which = which;
78 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
79 &request, sizeof(request), NULL, 0);
80 if (ret) {
81 gbphy_runtime_put_autosuspend(gbphy_dev);
82 return ret;
83 }
84
85 ggc->lines[which].active = true;
86
87 return 0;
88 }
89
gb_gpio_deactivate_operation(struct gb_gpio_controller * ggc,u8 which)90 static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
91 u8 which)
92 {
93 struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
94 struct device *dev = &gbphy_dev->dev;
95 struct gb_gpio_deactivate_request request;
96 int ret;
97
98 request.which = which;
99 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
100 &request, sizeof(request), NULL, 0);
101 if (ret) {
102 dev_err(dev, "failed to deactivate gpio %u\n", which);
103 goto out_pm_put;
104 }
105
106 ggc->lines[which].active = false;
107
108 out_pm_put:
109 gbphy_runtime_put_autosuspend(gbphy_dev);
110 }
111
gb_gpio_get_direction_operation(struct gb_gpio_controller * ggc,u8 which)112 static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
113 u8 which)
114 {
115 struct device *dev = &ggc->gbphy_dev->dev;
116 struct gb_gpio_get_direction_request request;
117 struct gb_gpio_get_direction_response response;
118 int ret;
119 u8 direction;
120
121 request.which = which;
122 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
123 &request, sizeof(request),
124 &response, sizeof(response));
125 if (ret)
126 return ret;
127
128 direction = response.direction;
129 if (direction && direction != 1) {
130 dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
131 which, direction);
132 }
133 ggc->lines[which].direction = direction ? 1 : 0;
134 return 0;
135 }
136
gb_gpio_direction_in_operation(struct gb_gpio_controller * ggc,u8 which)137 static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
138 u8 which)
139 {
140 struct gb_gpio_direction_in_request request;
141 int ret;
142
143 request.which = which;
144 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
145 &request, sizeof(request), NULL, 0);
146 if (!ret)
147 ggc->lines[which].direction = 1;
148 return ret;
149 }
150
gb_gpio_direction_out_operation(struct gb_gpio_controller * ggc,u8 which,bool value_high)151 static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
152 u8 which, bool value_high)
153 {
154 struct gb_gpio_direction_out_request request;
155 int ret;
156
157 request.which = which;
158 request.value = value_high ? 1 : 0;
159 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
160 &request, sizeof(request), NULL, 0);
161 if (!ret)
162 ggc->lines[which].direction = 0;
163 return ret;
164 }
165
gb_gpio_get_value_operation(struct gb_gpio_controller * ggc,u8 which)166 static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
167 u8 which)
168 {
169 struct device *dev = &ggc->gbphy_dev->dev;
170 struct gb_gpio_get_value_request request;
171 struct gb_gpio_get_value_response response;
172 int ret;
173 u8 value;
174
175 request.which = which;
176 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
177 &request, sizeof(request),
178 &response, sizeof(response));
179 if (ret) {
180 dev_err(dev, "failed to get value of gpio %u\n", which);
181 return ret;
182 }
183
184 value = response.value;
185 if (value && value != 1) {
186 dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
187 which, value);
188 }
189 ggc->lines[which].value = value ? 1 : 0;
190 return 0;
191 }
192
gb_gpio_set_value_operation(struct gb_gpio_controller * ggc,u8 which,bool value_high)193 static void gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
194 u8 which, bool value_high)
195 {
196 struct device *dev = &ggc->gbphy_dev->dev;
197 struct gb_gpio_set_value_request request;
198 int ret;
199
200 if (ggc->lines[which].direction == 1) {
201 dev_warn(dev, "refusing to set value of input gpio %u\n",
202 which);
203 return;
204 }
205
206 request.which = which;
207 request.value = value_high ? 1 : 0;
208 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
209 &request, sizeof(request), NULL, 0);
210 if (ret) {
211 dev_err(dev, "failed to set value of gpio %u\n", which);
212 return;
213 }
214
215 ggc->lines[which].value = request.value;
216 }
217
gb_gpio_set_debounce_operation(struct gb_gpio_controller * ggc,u8 which,u16 debounce_usec)218 static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc,
219 u8 which, u16 debounce_usec)
220 {
221 struct gb_gpio_set_debounce_request request;
222 int ret;
223
224 request.which = which;
225 request.usec = cpu_to_le16(debounce_usec);
226 ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE,
227 &request, sizeof(request), NULL, 0);
228 if (!ret)
229 ggc->lines[which].debounce_usec = debounce_usec;
230 return ret;
231 }
232
_gb_gpio_irq_mask(struct gb_gpio_controller * ggc,u8 hwirq)233 static void _gb_gpio_irq_mask(struct gb_gpio_controller *ggc, u8 hwirq)
234 {
235 struct device *dev = &ggc->gbphy_dev->dev;
236 struct gb_gpio_irq_mask_request request;
237 int ret;
238
239 request.which = hwirq;
240 ret = gb_operation_sync(ggc->connection,
241 GB_GPIO_TYPE_IRQ_MASK,
242 &request, sizeof(request), NULL, 0);
243 if (ret)
244 dev_err(dev, "failed to mask irq: %d\n", ret);
245 }
246
_gb_gpio_irq_unmask(struct gb_gpio_controller * ggc,u8 hwirq)247 static void _gb_gpio_irq_unmask(struct gb_gpio_controller *ggc, u8 hwirq)
248 {
249 struct device *dev = &ggc->gbphy_dev->dev;
250 struct gb_gpio_irq_unmask_request request;
251 int ret;
252
253 request.which = hwirq;
254 ret = gb_operation_sync(ggc->connection,
255 GB_GPIO_TYPE_IRQ_UNMASK,
256 &request, sizeof(request), NULL, 0);
257 if (ret)
258 dev_err(dev, "failed to unmask irq: %d\n", ret);
259 }
260
_gb_gpio_irq_set_type(struct gb_gpio_controller * ggc,u8 hwirq,u8 type)261 static void _gb_gpio_irq_set_type(struct gb_gpio_controller *ggc,
262 u8 hwirq, u8 type)
263 {
264 struct device *dev = &ggc->gbphy_dev->dev;
265 struct gb_gpio_irq_type_request request;
266 int ret;
267
268 request.which = hwirq;
269 request.type = type;
270
271 ret = gb_operation_sync(ggc->connection,
272 GB_GPIO_TYPE_IRQ_TYPE,
273 &request, sizeof(request), NULL, 0);
274 if (ret)
275 dev_err(dev, "failed to set irq type: %d\n", ret);
276 }
277
gb_gpio_irq_mask(struct irq_data * d)278 static void gb_gpio_irq_mask(struct irq_data *d)
279 {
280 struct gpio_chip *chip = irq_data_to_gpio_chip(d);
281 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
282 struct gb_gpio_line *line = &ggc->lines[d->hwirq];
283
284 line->masked = true;
285 line->masked_pending = true;
286 }
287
gb_gpio_irq_unmask(struct irq_data * d)288 static void gb_gpio_irq_unmask(struct irq_data *d)
289 {
290 struct gpio_chip *chip = irq_data_to_gpio_chip(d);
291 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
292 struct gb_gpio_line *line = &ggc->lines[d->hwirq];
293
294 line->masked = false;
295 line->masked_pending = true;
296 }
297
gb_gpio_irq_set_type(struct irq_data * d,unsigned int type)298 static int gb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
299 {
300 struct gpio_chip *chip = irq_data_to_gpio_chip(d);
301 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
302 struct gb_gpio_line *line = &ggc->lines[d->hwirq];
303 struct device *dev = &ggc->gbphy_dev->dev;
304 u8 irq_type;
305
306 switch (type) {
307 case IRQ_TYPE_NONE:
308 irq_type = GB_GPIO_IRQ_TYPE_NONE;
309 break;
310 case IRQ_TYPE_EDGE_RISING:
311 irq_type = GB_GPIO_IRQ_TYPE_EDGE_RISING;
312 break;
313 case IRQ_TYPE_EDGE_FALLING:
314 irq_type = GB_GPIO_IRQ_TYPE_EDGE_FALLING;
315 break;
316 case IRQ_TYPE_EDGE_BOTH:
317 irq_type = GB_GPIO_IRQ_TYPE_EDGE_BOTH;
318 break;
319 case IRQ_TYPE_LEVEL_LOW:
320 irq_type = GB_GPIO_IRQ_TYPE_LEVEL_LOW;
321 break;
322 case IRQ_TYPE_LEVEL_HIGH:
323 irq_type = GB_GPIO_IRQ_TYPE_LEVEL_HIGH;
324 break;
325 default:
326 dev_err(dev, "unsupported irq type: %u\n", type);
327 return -EINVAL;
328 }
329
330 line->irq_type = irq_type;
331 line->irq_type_pending = true;
332
333 return 0;
334 }
335
gb_gpio_irq_bus_lock(struct irq_data * d)336 static void gb_gpio_irq_bus_lock(struct irq_data *d)
337 {
338 struct gpio_chip *chip = irq_data_to_gpio_chip(d);
339 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
340
341 mutex_lock(&ggc->irq_lock);
342 }
343
gb_gpio_irq_bus_sync_unlock(struct irq_data * d)344 static void gb_gpio_irq_bus_sync_unlock(struct irq_data *d)
345 {
346 struct gpio_chip *chip = irq_data_to_gpio_chip(d);
347 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
348 struct gb_gpio_line *line = &ggc->lines[d->hwirq];
349
350 if (line->irq_type_pending) {
351 _gb_gpio_irq_set_type(ggc, d->hwirq, line->irq_type);
352 line->irq_type_pending = false;
353 }
354
355 if (line->masked_pending) {
356 if (line->masked)
357 _gb_gpio_irq_mask(ggc, d->hwirq);
358 else
359 _gb_gpio_irq_unmask(ggc, d->hwirq);
360 line->masked_pending = false;
361 }
362
363 mutex_unlock(&ggc->irq_lock);
364 }
365
gb_gpio_request_handler(struct gb_operation * op)366 static int gb_gpio_request_handler(struct gb_operation *op)
367 {
368 struct gb_connection *connection = op->connection;
369 struct gb_gpio_controller *ggc = gb_connection_get_data(connection);
370 struct device *dev = &ggc->gbphy_dev->dev;
371 struct gb_message *request;
372 struct gb_gpio_irq_event_request *event;
373 u8 type = op->type;
374 int irq, ret;
375
376 if (type != GB_GPIO_TYPE_IRQ_EVENT) {
377 dev_err(dev, "unsupported unsolicited request: %u\n", type);
378 return -EINVAL;
379 }
380
381 request = op->request;
382
383 if (request->payload_size < sizeof(*event)) {
384 dev_err(dev, "short event received (%zu < %zu)\n",
385 request->payload_size, sizeof(*event));
386 return -EINVAL;
387 }
388
389 event = request->payload;
390 if (event->which > ggc->line_max) {
391 dev_err(dev, "invalid hw irq: %d\n", event->which);
392 return -EINVAL;
393 }
394
395 irq = irq_find_mapping(ggc->chip.irq.domain, event->which);
396 if (!irq) {
397 dev_err(dev, "failed to find IRQ\n");
398 return -EINVAL;
399 }
400
401 ret = generic_handle_irq_safe(irq);
402 if (ret)
403 dev_err(dev, "failed to invoke irq handler\n");
404
405 return ret;
406 }
407
gb_gpio_request(struct gpio_chip * chip,unsigned int offset)408 static int gb_gpio_request(struct gpio_chip *chip, unsigned int offset)
409 {
410 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
411
412 return gb_gpio_activate_operation(ggc, (u8)offset);
413 }
414
gb_gpio_free(struct gpio_chip * chip,unsigned int offset)415 static void gb_gpio_free(struct gpio_chip *chip, unsigned int offset)
416 {
417 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
418
419 gb_gpio_deactivate_operation(ggc, (u8)offset);
420 }
421
gb_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)422 static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
423 {
424 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
425 u8 which;
426 int ret;
427
428 which = (u8)offset;
429 ret = gb_gpio_get_direction_operation(ggc, which);
430 if (ret)
431 return ret;
432
433 return ggc->lines[which].direction ? 1 : 0;
434 }
435
gb_gpio_direction_input(struct gpio_chip * chip,unsigned int offset)436 static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
437 {
438 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
439
440 return gb_gpio_direction_in_operation(ggc, (u8)offset);
441 }
442
gb_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)443 static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned int offset,
444 int value)
445 {
446 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
447
448 return gb_gpio_direction_out_operation(ggc, (u8)offset, !!value);
449 }
450
gb_gpio_get(struct gpio_chip * chip,unsigned int offset)451 static int gb_gpio_get(struct gpio_chip *chip, unsigned int offset)
452 {
453 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
454 u8 which;
455 int ret;
456
457 which = (u8)offset;
458 ret = gb_gpio_get_value_operation(ggc, which);
459 if (ret)
460 return ret;
461
462 return ggc->lines[which].value;
463 }
464
gb_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)465 static void gb_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
466 {
467 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
468
469 gb_gpio_set_value_operation(ggc, (u8)offset, !!value);
470 }
471
gb_gpio_set_config(struct gpio_chip * chip,unsigned int offset,unsigned long config)472 static int gb_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
473 unsigned long config)
474 {
475 struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
476 u32 debounce;
477
478 if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
479 return -ENOTSUPP;
480
481 debounce = pinconf_to_config_argument(config);
482 if (debounce > U16_MAX)
483 return -EINVAL;
484
485 return gb_gpio_set_debounce_operation(ggc, (u8)offset, (u16)debounce);
486 }
487
gb_gpio_controller_setup(struct gb_gpio_controller * ggc)488 static int gb_gpio_controller_setup(struct gb_gpio_controller *ggc)
489 {
490 int ret;
491
492 /* Now find out how many lines there are */
493 ret = gb_gpio_line_count_operation(ggc);
494 if (ret)
495 return ret;
496
497 ggc->lines = kcalloc(ggc->line_max + 1, sizeof(*ggc->lines),
498 GFP_KERNEL);
499 if (!ggc->lines)
500 return -ENOMEM;
501
502 return ret;
503 }
504
gb_gpio_probe(struct gbphy_device * gbphy_dev,const struct gbphy_device_id * id)505 static int gb_gpio_probe(struct gbphy_device *gbphy_dev,
506 const struct gbphy_device_id *id)
507 {
508 struct gb_connection *connection;
509 struct gb_gpio_controller *ggc;
510 struct gpio_chip *gpio;
511 struct gpio_irq_chip *girq;
512 struct irq_chip *irqc;
513 int ret;
514
515 ggc = kzalloc(sizeof(*ggc), GFP_KERNEL);
516 if (!ggc)
517 return -ENOMEM;
518
519 connection =
520 gb_connection_create(gbphy_dev->bundle,
521 le16_to_cpu(gbphy_dev->cport_desc->id),
522 gb_gpio_request_handler);
523 if (IS_ERR(connection)) {
524 ret = PTR_ERR(connection);
525 goto exit_ggc_free;
526 }
527
528 ggc->connection = connection;
529 gb_connection_set_data(connection, ggc);
530 ggc->gbphy_dev = gbphy_dev;
531 gb_gbphy_set_data(gbphy_dev, ggc);
532
533 ret = gb_connection_enable_tx(connection);
534 if (ret)
535 goto exit_connection_destroy;
536
537 ret = gb_gpio_controller_setup(ggc);
538 if (ret)
539 goto exit_connection_disable;
540
541 irqc = &ggc->irqc;
542 irqc->irq_mask = gb_gpio_irq_mask;
543 irqc->irq_unmask = gb_gpio_irq_unmask;
544 irqc->irq_set_type = gb_gpio_irq_set_type;
545 irqc->irq_bus_lock = gb_gpio_irq_bus_lock;
546 irqc->irq_bus_sync_unlock = gb_gpio_irq_bus_sync_unlock;
547 irqc->name = "greybus_gpio";
548
549 mutex_init(&ggc->irq_lock);
550
551 gpio = &ggc->chip;
552
553 gpio->label = "greybus_gpio";
554 gpio->parent = &gbphy_dev->dev;
555 gpio->owner = THIS_MODULE;
556
557 gpio->request = gb_gpio_request;
558 gpio->free = gb_gpio_free;
559 gpio->get_direction = gb_gpio_get_direction;
560 gpio->direction_input = gb_gpio_direction_input;
561 gpio->direction_output = gb_gpio_direction_output;
562 gpio->get = gb_gpio_get;
563 gpio->set = gb_gpio_set;
564 gpio->set_config = gb_gpio_set_config;
565 gpio->base = -1; /* Allocate base dynamically */
566 gpio->ngpio = ggc->line_max + 1;
567 gpio->can_sleep = true;
568
569 girq = &gpio->irq;
570 girq->chip = irqc;
571 /* The event comes from the outside so no parent handler */
572 girq->parent_handler = NULL;
573 girq->num_parents = 0;
574 girq->parents = NULL;
575 girq->default_type = IRQ_TYPE_NONE;
576 girq->handler = handle_level_irq;
577
578 ret = gb_connection_enable(connection);
579 if (ret)
580 goto exit_line_free;
581
582 ret = gpiochip_add_data(gpio, NULL);
583 if (ret) {
584 dev_err(&gbphy_dev->dev, "failed to add gpio chip: %d\n", ret);
585 goto exit_line_free;
586 }
587
588 gbphy_runtime_put_autosuspend(gbphy_dev);
589 return 0;
590
591 exit_line_free:
592 kfree(ggc->lines);
593 exit_connection_disable:
594 gb_connection_disable(connection);
595 exit_connection_destroy:
596 gb_connection_destroy(connection);
597 exit_ggc_free:
598 kfree(ggc);
599 return ret;
600 }
601
gb_gpio_remove(struct gbphy_device * gbphy_dev)602 static void gb_gpio_remove(struct gbphy_device *gbphy_dev)
603 {
604 struct gb_gpio_controller *ggc = gb_gbphy_get_data(gbphy_dev);
605 struct gb_connection *connection = ggc->connection;
606 int ret;
607
608 ret = gbphy_runtime_get_sync(gbphy_dev);
609 if (ret)
610 gbphy_runtime_get_noresume(gbphy_dev);
611
612 gb_connection_disable_rx(connection);
613 gpiochip_remove(&ggc->chip);
614 gb_connection_disable(connection);
615 gb_connection_destroy(connection);
616 kfree(ggc->lines);
617 kfree(ggc);
618 }
619
620 static const struct gbphy_device_id gb_gpio_id_table[] = {
621 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_GPIO) },
622 { },
623 };
624 MODULE_DEVICE_TABLE(gbphy, gb_gpio_id_table);
625
626 static struct gbphy_driver gpio_driver = {
627 .name = "gpio",
628 .probe = gb_gpio_probe,
629 .remove = gb_gpio_remove,
630 .id_table = gb_gpio_id_table,
631 };
632
633 module_gbphy_driver(gpio_driver);
634 MODULE_DESCRIPTION("GPIO Greybus driver");
635 MODULE_LICENSE("GPL v2");
636