1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * GPIO driver for virtio-based virtual GPIO controllers
4 *
5 * Copyright (C) 2021 metux IT consult
6 * Enrico Weigelt, metux IT consult <info@metux.net>
7 *
8 * Copyright (C) 2021 Linaro.
9 * Viresh Kumar <viresh.kumar@linaro.org>
10 */
11
12#include <linux/completion.h>
13#include <linux/err.h>
14#include <linux/gpio/driver.h>
15#include <linux/io.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/mutex.h>
19#include <linux/spinlock.h>
20#include <linux/virtio_config.h>
21#include <uapi/linux/virtio_gpio.h>
22#include <uapi/linux/virtio_ids.h>
23
24struct virtio_gpio_line {
25 struct mutex lock; /* Protects line operation */
26 struct completion completion;
27 struct virtio_gpio_request req ____cacheline_aligned;
28 struct virtio_gpio_response res ____cacheline_aligned;
29 unsigned int rxlen;
30};
31
32struct vgpio_irq_line {
33 u8 type;
34 bool disabled;
35 bool masked;
36 bool queued;
37 bool update_pending;
38 bool queue_pending;
39
40 struct virtio_gpio_irq_request ireq ____cacheline_aligned;
41 struct virtio_gpio_irq_response ires ____cacheline_aligned;
42};
43
44struct virtio_gpio {
45 struct virtio_device *vdev;
46 struct mutex lock; /* Protects virtqueue operation */
47 struct gpio_chip gc;
48 struct virtio_gpio_line *lines;
49 struct virtqueue *request_vq;
50
51 /* irq support */
52 struct virtqueue *event_vq;
53 struct mutex irq_lock; /* Protects irq operation */
54 raw_spinlock_t eventq_lock; /* Protects queuing of the buffer */
55 struct vgpio_irq_line *irq_lines;
56};
57
58static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
59 u8 txvalue, u8 *rxvalue, void *response, u32 rxlen)
60{
61 struct virtio_gpio_line *line = &vgpio->lines[gpio];
62 struct virtio_gpio_request *req = &line->req;
63 struct virtio_gpio_response *res = response;
64 struct scatterlist *sgs[2], req_sg, res_sg;
65 struct device *dev = &vgpio->vdev->dev;
66 int ret;
67
68 /*
69 * Prevent concurrent requests for the same line since we have
70 * pre-allocated request/response buffers for each GPIO line. Moreover
71 * Linux always accesses a GPIO line sequentially, so this locking shall
72 * always go through without any delays.
73 */
74 mutex_lock(&line->lock);
75
76 req->type = cpu_to_le16(type);
77 req->gpio = cpu_to_le16(gpio);
78 req->value = cpu_to_le32(txvalue);
79
80 sg_init_one(&req_sg, req, sizeof(*req));
81 sg_init_one(&res_sg, res, rxlen);
82 sgs[0] = &req_sg;
83 sgs[1] = &res_sg;
84
85 line->rxlen = 0;
86 reinit_completion(x: &line->completion);
87
88 /*
89 * Virtqueue callers need to ensure they don't call its APIs with other
90 * virtqueue operations at the same time.
91 */
92 mutex_lock(&vgpio->lock);
93 ret = virtqueue_add_sgs(vq: vgpio->request_vq, sgs, out_sgs: 1, in_sgs: 1, data: line, GFP_KERNEL);
94 if (ret) {
95 dev_err(dev, "failed to add request to vq\n");
96 mutex_unlock(lock: &vgpio->lock);
97 goto out;
98 }
99
100 virtqueue_kick(vq: vgpio->request_vq);
101 mutex_unlock(lock: &vgpio->lock);
102
103 wait_for_completion(&line->completion);
104
105 if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) {
106 dev_err(dev, "GPIO request failed: %d\n", gpio);
107 ret = -EINVAL;
108 goto out;
109 }
110
111 if (unlikely(line->rxlen != rxlen)) {
112 dev_err(dev, "GPIO operation returned incorrect len (%u : %u)\n",
113 rxlen, line->rxlen);
114 ret = -EINVAL;
115 goto out;
116 }
117
118 if (rxvalue)
119 *rxvalue = res->value;
120
121out:
122 mutex_unlock(lock: &line->lock);
123 return ret;
124}
125
126static int virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
127 u8 txvalue, u8 *rxvalue)
128{
129 struct virtio_gpio_line *line = &vgpio->lines[gpio];
130 struct virtio_gpio_response *res = &line->res;
131
132 return _virtio_gpio_req(vgpio, type, gpio, txvalue, rxvalue, response: res,
133 rxlen: sizeof(*res));
134}
135
136static void virtio_gpio_free(struct gpio_chip *gc, unsigned int gpio)
137{
138 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
139
140 virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
141 VIRTIO_GPIO_DIRECTION_NONE, NULL);
142}
143
144static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
145{
146 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
147 u8 direction;
148 int ret;
149
150 ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_DIRECTION, gpio, txvalue: 0,
151 rxvalue: &direction);
152 if (ret)
153 return ret;
154
155 switch (direction) {
156 case VIRTIO_GPIO_DIRECTION_IN:
157 return GPIO_LINE_DIRECTION_IN;
158 case VIRTIO_GPIO_DIRECTION_OUT:
159 return GPIO_LINE_DIRECTION_OUT;
160 default:
161 return -EINVAL;
162 }
163}
164
165static int virtio_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
166{
167 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
168
169 return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
170 VIRTIO_GPIO_DIRECTION_IN, NULL);
171}
172
173static int virtio_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio,
174 int value)
175{
176 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
177 int ret;
178
179 ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, txvalue: value, NULL);
180 if (ret)
181 return ret;
182
183 return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
184 VIRTIO_GPIO_DIRECTION_OUT, NULL);
185}
186
187static int virtio_gpio_get(struct gpio_chip *gc, unsigned int gpio)
188{
189 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
190 u8 value;
191 int ret;
192
193 ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_VALUE, gpio, txvalue: 0, rxvalue: &value);
194 return ret ? ret : value;
195}
196
197static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
198{
199 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
200
201 virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, txvalue: value, NULL);
202}
203
204/* Interrupt handling */
205static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio)
206{
207 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio];
208 struct virtio_gpio_irq_request *ireq = &irq_line->ireq;
209 struct virtio_gpio_irq_response *ires = &irq_line->ires;
210 struct scatterlist *sgs[2], req_sg, res_sg;
211 int ret;
212
213 if (WARN_ON(irq_line->queued || irq_line->masked || irq_line->disabled))
214 return;
215
216 ireq->gpio = cpu_to_le16(gpio);
217 sg_init_one(&req_sg, ireq, sizeof(*ireq));
218 sg_init_one(&res_sg, ires, sizeof(*ires));
219 sgs[0] = &req_sg;
220 sgs[1] = &res_sg;
221
222 ret = virtqueue_add_sgs(vq: vgpio->event_vq, sgs, out_sgs: 1, in_sgs: 1, data: irq_line, GFP_ATOMIC);
223 if (ret) {
224 dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n");
225 return;
226 }
227
228 irq_line->queued = true;
229 virtqueue_kick(vq: vgpio->event_vq);
230}
231
232static void virtio_gpio_irq_enable(struct irq_data *d)
233{
234 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
235 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
236 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
237
238 raw_spin_lock(&vgpio->eventq_lock);
239 irq_line->disabled = false;
240 irq_line->masked = false;
241 irq_line->queue_pending = true;
242 raw_spin_unlock(&vgpio->eventq_lock);
243
244 irq_line->update_pending = true;
245}
246
247static void virtio_gpio_irq_disable(struct irq_data *d)
248{
249 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
250 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
251 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
252
253 raw_spin_lock(&vgpio->eventq_lock);
254 irq_line->disabled = true;
255 irq_line->masked = true;
256 irq_line->queue_pending = false;
257 raw_spin_unlock(&vgpio->eventq_lock);
258
259 irq_line->update_pending = true;
260}
261
262static void virtio_gpio_irq_mask(struct irq_data *d)
263{
264 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
265 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
266 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
267
268 raw_spin_lock(&vgpio->eventq_lock);
269 irq_line->masked = true;
270 raw_spin_unlock(&vgpio->eventq_lock);
271}
272
273static void virtio_gpio_irq_unmask(struct irq_data *d)
274{
275 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
276 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
277 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
278
279 raw_spin_lock(&vgpio->eventq_lock);
280 irq_line->masked = false;
281
282 /* Queue the buffer unconditionally on unmask */
283 virtio_gpio_irq_prepare(vgpio, gpio: d->hwirq);
284 raw_spin_unlock(&vgpio->eventq_lock);
285}
286
287static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type)
288{
289 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
290 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
291 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
292
293 switch (type) {
294 case IRQ_TYPE_EDGE_RISING:
295 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING;
296 break;
297 case IRQ_TYPE_EDGE_FALLING:
298 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING;
299 break;
300 case IRQ_TYPE_EDGE_BOTH:
301 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH;
302 break;
303 case IRQ_TYPE_LEVEL_LOW:
304 type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW;
305 break;
306 case IRQ_TYPE_LEVEL_HIGH:
307 type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH;
308 break;
309 default:
310 dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type);
311 return -EINVAL;
312 }
313
314 irq_line->type = type;
315 irq_line->update_pending = true;
316
317 return 0;
318}
319
320static void virtio_gpio_irq_bus_lock(struct irq_data *d)
321{
322 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
323 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
324
325 mutex_lock(&vgpio->irq_lock);
326}
327
328static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d)
329{
330 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
331 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
332 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
333 u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type;
334 unsigned long flags;
335
336 if (irq_line->update_pending) {
337 irq_line->update_pending = false;
338 virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, gpio: d->hwirq, txvalue: type,
339 NULL);
340
341 /* Queue the buffer only after interrupt is enabled */
342 raw_spin_lock_irqsave(&vgpio->eventq_lock, flags);
343 if (irq_line->queue_pending) {
344 irq_line->queue_pending = false;
345 virtio_gpio_irq_prepare(vgpio, gpio: d->hwirq);
346 }
347 raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags);
348 }
349
350 mutex_unlock(lock: &vgpio->irq_lock);
351}
352
353static bool ignore_irq(struct virtio_gpio *vgpio, int gpio,
354 struct vgpio_irq_line *irq_line)
355{
356 bool ignore = false;
357
358 raw_spin_lock(&vgpio->eventq_lock);
359 irq_line->queued = false;
360
361 /* Interrupt is disabled currently */
362 if (irq_line->masked || irq_line->disabled) {
363 ignore = true;
364 goto unlock;
365 }
366
367 /*
368 * Buffer is returned as the interrupt was disabled earlier, but is
369 * enabled again now. Requeue the buffers.
370 */
371 if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) {
372 virtio_gpio_irq_prepare(vgpio, gpio);
373 ignore = true;
374 goto unlock;
375 }
376
377 if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID))
378 ignore = true;
379
380unlock:
381 raw_spin_unlock(&vgpio->eventq_lock);
382
383 return ignore;
384}
385
386static void virtio_gpio_event_vq(struct virtqueue *vq)
387{
388 struct virtio_gpio *vgpio = vq->vdev->priv;
389 struct device *dev = &vgpio->vdev->dev;
390 struct vgpio_irq_line *irq_line;
391 int gpio, ret;
392 unsigned int len;
393
394 while (true) {
395 irq_line = virtqueue_get_buf(vq: vgpio->event_vq, len: &len);
396 if (!irq_line)
397 break;
398
399 if (len != sizeof(irq_line->ires)) {
400 dev_err(dev, "irq with incorrect length (%u : %u)\n",
401 len, (unsigned int)sizeof(irq_line->ires));
402 continue;
403 }
404
405 /*
406 * Find GPIO line number from the offset of irq_line within the
407 * irq_lines block. We can also get GPIO number from
408 * irq-request, but better not to rely on a buffer returned by
409 * remote.
410 */
411 gpio = irq_line - vgpio->irq_lines;
412 WARN_ON(gpio >= vgpio->gc.ngpio);
413
414 if (unlikely(ignore_irq(vgpio, gpio, irq_line)))
415 continue;
416
417 ret = generic_handle_domain_irq(domain: vgpio->gc.irq.domain, hwirq: gpio);
418 if (ret)
419 dev_err(dev, "failed to handle interrupt: %d\n", ret);
420 }
421}
422
423static void virtio_gpio_request_vq(struct virtqueue *vq)
424{
425 struct virtio_gpio_line *line;
426 unsigned int len;
427
428 do {
429 line = virtqueue_get_buf(vq, len: &len);
430 if (!line)
431 return;
432
433 line->rxlen = len;
434 complete(&line->completion);
435 } while (1);
436}
437
438static void virtio_gpio_free_vqs(struct virtio_device *vdev)
439{
440 virtio_reset_device(dev: vdev);
441 vdev->config->del_vqs(vdev);
442}
443
444static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,
445 struct virtio_device *vdev)
446{
447 struct virtqueue_info vqs_info[] = {
448 { "requestq", virtio_gpio_request_vq },
449 { "eventq", virtio_gpio_event_vq },
450 };
451 struct virtqueue *vqs[2] = { NULL, NULL };
452 int ret;
453
454 ret = virtio_find_vqs(vdev, nvqs: vgpio->irq_lines ? 2 : 1, vqs,
455 vqs_info, NULL);
456 if (ret) {
457 dev_err(&vdev->dev, "failed to find vqs: %d\n", ret);
458 return ret;
459 }
460
461 if (!vqs[0]) {
462 dev_err(&vdev->dev, "failed to find requestq vq\n");
463 goto out;
464 }
465 vgpio->request_vq = vqs[0];
466
467 if (vgpio->irq_lines && !vqs[1]) {
468 dev_err(&vdev->dev, "failed to find eventq vq\n");
469 goto out;
470 }
471 vgpio->event_vq = vqs[1];
472
473 return 0;
474
475out:
476 if (vqs[0] || vqs[1])
477 virtio_gpio_free_vqs(vdev);
478
479 return -ENODEV;
480}
481
482static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio,
483 u32 gpio_names_size, u16 ngpio)
484{
485 struct virtio_gpio_response_get_names *res;
486 struct device *dev = &vgpio->vdev->dev;
487 u8 *gpio_names, *str;
488 const char **names;
489 int i, ret, len;
490
491 if (!gpio_names_size)
492 return NULL;
493
494 len = sizeof(*res) + gpio_names_size;
495 res = devm_kzalloc(dev, size: len, GFP_KERNEL);
496 if (!res)
497 return NULL;
498 gpio_names = res->value;
499
500 ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, gpio: 0, txvalue: 0, NULL,
501 response: res, rxlen: len);
502 if (ret) {
503 dev_err(dev, "Failed to get GPIO names: %d\n", ret);
504 return NULL;
505 }
506
507 names = devm_kcalloc(dev, n: ngpio, size: sizeof(*names), GFP_KERNEL);
508 if (!names)
509 return NULL;
510
511 /* NULL terminate the string instead of checking it */
512 gpio_names[gpio_names_size - 1] = '\0';
513
514 for (i = 0, str = gpio_names; i < ngpio; i++) {
515 names[i] = str;
516 str += strlen(str) + 1; /* zero-length strings are allowed */
517
518 if (str > gpio_names + gpio_names_size) {
519 dev_err(dev, "gpio_names block is too short (%d)\n", i);
520 return NULL;
521 }
522 }
523
524 return names;
525}
526
527static int virtio_gpio_probe(struct virtio_device *vdev)
528{
529 struct virtio_gpio_config config;
530 struct device *dev = &vdev->dev;
531 struct virtio_gpio *vgpio;
532 struct irq_chip *gpio_irq_chip;
533 u32 gpio_names_size;
534 u16 ngpio;
535 int ret, i;
536
537 vgpio = devm_kzalloc(dev, size: sizeof(*vgpio), GFP_KERNEL);
538 if (!vgpio)
539 return -ENOMEM;
540
541 /* Read configuration */
542 virtio_cread_bytes(vdev, offset: 0, buf: &config, len: sizeof(config));
543 gpio_names_size = le32_to_cpu(config.gpio_names_size);
544 ngpio = le16_to_cpu(config.ngpio);
545 if (!ngpio) {
546 dev_err(dev, "Number of GPIOs can't be zero\n");
547 return -EINVAL;
548 }
549
550 vgpio->lines = devm_kcalloc(dev, n: ngpio, size: sizeof(*vgpio->lines), GFP_KERNEL);
551 if (!vgpio->lines)
552 return -ENOMEM;
553
554 for (i = 0; i < ngpio; i++) {
555 mutex_init(&vgpio->lines[i].lock);
556 init_completion(x: &vgpio->lines[i].completion);
557 }
558
559 mutex_init(&vgpio->lock);
560 vdev->priv = vgpio;
561
562 vgpio->vdev = vdev;
563 vgpio->gc.free = virtio_gpio_free;
564 vgpio->gc.get_direction = virtio_gpio_get_direction;
565 vgpio->gc.direction_input = virtio_gpio_direction_input;
566 vgpio->gc.direction_output = virtio_gpio_direction_output;
567 vgpio->gc.get = virtio_gpio_get;
568 vgpio->gc.set = virtio_gpio_set;
569 vgpio->gc.ngpio = ngpio;
570 vgpio->gc.base = -1; /* Allocate base dynamically */
571 vgpio->gc.label = dev_name(dev);
572 vgpio->gc.parent = dev;
573 vgpio->gc.owner = THIS_MODULE;
574 vgpio->gc.can_sleep = true;
575
576 /* Interrupt support */
577 if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) {
578 vgpio->irq_lines = devm_kcalloc(dev, n: ngpio, size: sizeof(*vgpio->irq_lines), GFP_KERNEL);
579 if (!vgpio->irq_lines)
580 return -ENOMEM;
581
582 gpio_irq_chip = devm_kzalloc(dev, size: sizeof(*gpio_irq_chip), GFP_KERNEL);
583 if (!gpio_irq_chip)
584 return -ENOMEM;
585
586 gpio_irq_chip->name = dev_name(dev);
587 gpio_irq_chip->irq_enable = virtio_gpio_irq_enable;
588 gpio_irq_chip->irq_disable = virtio_gpio_irq_disable;
589 gpio_irq_chip->irq_mask = virtio_gpio_irq_mask;
590 gpio_irq_chip->irq_unmask = virtio_gpio_irq_unmask;
591 gpio_irq_chip->irq_set_type = virtio_gpio_irq_set_type;
592 gpio_irq_chip->irq_bus_lock = virtio_gpio_irq_bus_lock;
593 gpio_irq_chip->irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock;
594
595 /* The event comes from the outside so no parent handler */
596 vgpio->gc.irq.parent_handler = NULL;
597 vgpio->gc.irq.num_parents = 0;
598 vgpio->gc.irq.parents = NULL;
599 vgpio->gc.irq.default_type = IRQ_TYPE_NONE;
600 vgpio->gc.irq.handler = handle_level_irq;
601 vgpio->gc.irq.chip = gpio_irq_chip;
602
603 for (i = 0; i < ngpio; i++) {
604 vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE;
605 vgpio->irq_lines[i].disabled = true;
606 vgpio->irq_lines[i].masked = true;
607 }
608
609 mutex_init(&vgpio->irq_lock);
610 raw_spin_lock_init(&vgpio->eventq_lock);
611 }
612
613 ret = virtio_gpio_alloc_vqs(vgpio, vdev);
614 if (ret)
615 return ret;
616
617 /* Mark the device ready to perform operations from within probe() */
618 virtio_device_ready(dev: vdev);
619
620 vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio);
621
622 ret = gpiochip_add_data(&vgpio->gc, vgpio);
623 if (ret) {
624 virtio_gpio_free_vqs(vdev);
625 dev_err(dev, "Failed to add virtio-gpio controller\n");
626 }
627
628 return ret;
629}
630
631static void virtio_gpio_remove(struct virtio_device *vdev)
632{
633 struct virtio_gpio *vgpio = vdev->priv;
634
635 gpiochip_remove(gc: &vgpio->gc);
636 virtio_gpio_free_vqs(vdev);
637}
638
639static const struct virtio_device_id id_table[] = {
640 { VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID },
641 {},
642};
643MODULE_DEVICE_TABLE(virtio, id_table);
644
645static const unsigned int features[] = {
646 VIRTIO_GPIO_F_IRQ,
647};
648
649static struct virtio_driver virtio_gpio_driver = {
650 .feature_table = features,
651 .feature_table_size = ARRAY_SIZE(features),
652 .id_table = id_table,
653 .probe = virtio_gpio_probe,
654 .remove = virtio_gpio_remove,
655 .driver = {
656 .name = KBUILD_MODNAME,
657 },
658};
659module_virtio_driver(virtio_gpio_driver);
660
661MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
662MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
663MODULE_DESCRIPTION("VirtIO GPIO driver");
664MODULE_LICENSE("GPL");
665

source code of linux/drivers/gpio/gpio-virtio.c