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 int virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
198{
199 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
200
201 return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, txvalue: value,
202 NULL);
203}
204
205/* Interrupt handling */
206static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio)
207{
208 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio];
209 struct virtio_gpio_irq_request *ireq = &irq_line->ireq;
210 struct virtio_gpio_irq_response *ires = &irq_line->ires;
211 struct scatterlist *sgs[2], req_sg, res_sg;
212 int ret;
213
214 if (WARN_ON(irq_line->queued || irq_line->masked || irq_line->disabled))
215 return;
216
217 ireq->gpio = cpu_to_le16(gpio);
218 sg_init_one(&req_sg, ireq, sizeof(*ireq));
219 sg_init_one(&res_sg, ires, sizeof(*ires));
220 sgs[0] = &req_sg;
221 sgs[1] = &res_sg;
222
223 ret = virtqueue_add_sgs(vq: vgpio->event_vq, sgs, out_sgs: 1, in_sgs: 1, data: irq_line, GFP_ATOMIC);
224 if (ret) {
225 dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n");
226 return;
227 }
228
229 irq_line->queued = true;
230 virtqueue_kick(vq: vgpio->event_vq);
231}
232
233static void virtio_gpio_irq_enable(struct irq_data *d)
234{
235 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
236 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
237 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
238
239 raw_spin_lock(&vgpio->eventq_lock);
240 irq_line->disabled = false;
241 irq_line->masked = false;
242 irq_line->queue_pending = true;
243 raw_spin_unlock(&vgpio->eventq_lock);
244
245 irq_line->update_pending = true;
246}
247
248static void virtio_gpio_irq_disable(struct irq_data *d)
249{
250 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
251 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
252 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
253
254 raw_spin_lock(&vgpio->eventq_lock);
255 irq_line->disabled = true;
256 irq_line->masked = true;
257 irq_line->queue_pending = false;
258 raw_spin_unlock(&vgpio->eventq_lock);
259
260 irq_line->update_pending = true;
261}
262
263static void virtio_gpio_irq_mask(struct irq_data *d)
264{
265 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
266 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
267 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
268
269 raw_spin_lock(&vgpio->eventq_lock);
270 irq_line->masked = true;
271 raw_spin_unlock(&vgpio->eventq_lock);
272}
273
274static void virtio_gpio_irq_unmask(struct irq_data *d)
275{
276 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
277 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
278 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
279
280 raw_spin_lock(&vgpio->eventq_lock);
281 irq_line->masked = false;
282
283 /* Queue the buffer unconditionally on unmask */
284 virtio_gpio_irq_prepare(vgpio, gpio: d->hwirq);
285 raw_spin_unlock(&vgpio->eventq_lock);
286}
287
288static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type)
289{
290 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
291 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
292 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
293
294 switch (type) {
295 case IRQ_TYPE_EDGE_RISING:
296 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING;
297 break;
298 case IRQ_TYPE_EDGE_FALLING:
299 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING;
300 break;
301 case IRQ_TYPE_EDGE_BOTH:
302 type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH;
303 break;
304 case IRQ_TYPE_LEVEL_LOW:
305 type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW;
306 break;
307 case IRQ_TYPE_LEVEL_HIGH:
308 type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH;
309 break;
310 default:
311 dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type);
312 return -EINVAL;
313 }
314
315 irq_line->type = type;
316 irq_line->update_pending = true;
317
318 return 0;
319}
320
321static void virtio_gpio_irq_bus_lock(struct irq_data *d)
322{
323 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
324 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
325
326 mutex_lock(&vgpio->irq_lock);
327}
328
329static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d)
330{
331 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
332 struct virtio_gpio *vgpio = gpiochip_get_data(gc);
333 struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
334 u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type;
335 unsigned long flags;
336
337 if (irq_line->update_pending) {
338 irq_line->update_pending = false;
339 virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, gpio: d->hwirq, txvalue: type,
340 NULL);
341
342 /* Queue the buffer only after interrupt is enabled */
343 raw_spin_lock_irqsave(&vgpio->eventq_lock, flags);
344 if (irq_line->queue_pending) {
345 irq_line->queue_pending = false;
346 virtio_gpio_irq_prepare(vgpio, gpio: d->hwirq);
347 }
348 raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags);
349 }
350
351 mutex_unlock(lock: &vgpio->irq_lock);
352}
353
354static bool ignore_irq(struct virtio_gpio *vgpio, int gpio,
355 struct vgpio_irq_line *irq_line)
356{
357 bool ignore = false;
358
359 raw_spin_lock(&vgpio->eventq_lock);
360 irq_line->queued = false;
361
362 /* Interrupt is disabled currently */
363 if (irq_line->masked || irq_line->disabled) {
364 ignore = true;
365 goto unlock;
366 }
367
368 /*
369 * Buffer is returned as the interrupt was disabled earlier, but is
370 * enabled again now. Requeue the buffers.
371 */
372 if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) {
373 virtio_gpio_irq_prepare(vgpio, gpio);
374 ignore = true;
375 goto unlock;
376 }
377
378 if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID))
379 ignore = true;
380
381unlock:
382 raw_spin_unlock(&vgpio->eventq_lock);
383
384 return ignore;
385}
386
387static void virtio_gpio_event_vq(struct virtqueue *vq)
388{
389 struct virtio_gpio *vgpio = vq->vdev->priv;
390 struct device *dev = &vgpio->vdev->dev;
391 struct vgpio_irq_line *irq_line;
392 int gpio, ret;
393 unsigned int len;
394
395 while (true) {
396 irq_line = virtqueue_get_buf(vq: vgpio->event_vq, len: &len);
397 if (!irq_line)
398 break;
399
400 if (len != sizeof(irq_line->ires)) {
401 dev_err(dev, "irq with incorrect length (%u : %u)\n",
402 len, (unsigned int)sizeof(irq_line->ires));
403 continue;
404 }
405
406 /*
407 * Find GPIO line number from the offset of irq_line within the
408 * irq_lines block. We can also get GPIO number from
409 * irq-request, but better not to rely on a buffer returned by
410 * remote.
411 */
412 gpio = irq_line - vgpio->irq_lines;
413 WARN_ON(gpio >= vgpio->gc.ngpio);
414
415 if (unlikely(ignore_irq(vgpio, gpio, irq_line)))
416 continue;
417
418 ret = generic_handle_domain_irq(domain: vgpio->gc.irq.domain, hwirq: gpio);
419 if (ret)
420 dev_err(dev, "failed to handle interrupt: %d\n", ret);
421 }
422}
423
424static void virtio_gpio_request_vq(struct virtqueue *vq)
425{
426 struct virtio_gpio_line *line;
427 unsigned int len;
428
429 do {
430 line = virtqueue_get_buf(vq, len: &len);
431 if (!line)
432 return;
433
434 line->rxlen = len;
435 complete(&line->completion);
436 } while (1);
437}
438
439static void virtio_gpio_free_vqs(struct virtio_device *vdev)
440{
441 virtio_reset_device(dev: vdev);
442 vdev->config->del_vqs(vdev);
443}
444
445static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,
446 struct virtio_device *vdev)
447{
448 struct virtqueue_info vqs_info[] = {
449 { "requestq", virtio_gpio_request_vq },
450 { "eventq", virtio_gpio_event_vq },
451 };
452 struct virtqueue *vqs[2] = { NULL, NULL };
453 int ret;
454
455 ret = virtio_find_vqs(vdev, nvqs: vgpio->irq_lines ? 2 : 1, vqs,
456 vqs_info, NULL);
457 if (ret) {
458 dev_err(&vdev->dev, "failed to find vqs: %d\n", ret);
459 return ret;
460 }
461
462 if (!vqs[0]) {
463 dev_err(&vdev->dev, "failed to find requestq vq\n");
464 goto out;
465 }
466 vgpio->request_vq = vqs[0];
467
468 if (vgpio->irq_lines && !vqs[1]) {
469 dev_err(&vdev->dev, "failed to find eventq vq\n");
470 goto out;
471 }
472 vgpio->event_vq = vqs[1];
473
474 return 0;
475
476out:
477 if (vqs[0] || vqs[1])
478 virtio_gpio_free_vqs(vdev);
479
480 return -ENODEV;
481}
482
483static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio,
484 u32 gpio_names_size, u16 ngpio)
485{
486 struct virtio_gpio_response_get_names *res;
487 struct device *dev = &vgpio->vdev->dev;
488 u8 *gpio_names, *str;
489 const char **names;
490 int i, ret, len;
491
492 if (!gpio_names_size)
493 return NULL;
494
495 len = sizeof(*res) + gpio_names_size;
496 res = devm_kzalloc(dev, size: len, GFP_KERNEL);
497 if (!res)
498 return NULL;
499 gpio_names = res->value;
500
501 ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, gpio: 0, txvalue: 0, NULL,
502 response: res, rxlen: len);
503 if (ret) {
504 dev_err(dev, "Failed to get GPIO names: %d\n", ret);
505 return NULL;
506 }
507
508 names = devm_kcalloc(dev, n: ngpio, size: sizeof(*names), GFP_KERNEL);
509 if (!names)
510 return NULL;
511
512 /* NULL terminate the string instead of checking it */
513 gpio_names[gpio_names_size - 1] = '\0';
514
515 for (i = 0, str = gpio_names; i < ngpio; i++) {
516 names[i] = str;
517 str += strlen(str) + 1; /* zero-length strings are allowed */
518
519 if (str > gpio_names + gpio_names_size) {
520 dev_err(dev, "gpio_names block is too short (%d)\n", i);
521 return NULL;
522 }
523 }
524
525 return names;
526}
527
528static int virtio_gpio_probe(struct virtio_device *vdev)
529{
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 gpio_names_size =
543 virtio_cread32(vdev, offsetof(struct virtio_gpio_config,
544 gpio_names_size));
545 ngpio = virtio_cread16(vdev, offsetof(struct virtio_gpio_config,
546 ngpio));
547 if (!ngpio) {
548 dev_err(dev, "Number of GPIOs can't be zero\n");
549 return -EINVAL;
550 }
551
552 vgpio->lines = devm_kcalloc(dev, n: ngpio, size: sizeof(*vgpio->lines), GFP_KERNEL);
553 if (!vgpio->lines)
554 return -ENOMEM;
555
556 for (i = 0; i < ngpio; i++) {
557 mutex_init(&vgpio->lines[i].lock);
558 init_completion(x: &vgpio->lines[i].completion);
559 }
560
561 mutex_init(&vgpio->lock);
562 vdev->priv = vgpio;
563
564 vgpio->vdev = vdev;
565 vgpio->gc.free = virtio_gpio_free;
566 vgpio->gc.get_direction = virtio_gpio_get_direction;
567 vgpio->gc.direction_input = virtio_gpio_direction_input;
568 vgpio->gc.direction_output = virtio_gpio_direction_output;
569 vgpio->gc.get = virtio_gpio_get;
570 vgpio->gc.set = virtio_gpio_set;
571 vgpio->gc.ngpio = ngpio;
572 vgpio->gc.base = -1; /* Allocate base dynamically */
573 vgpio->gc.label = dev_name(dev);
574 vgpio->gc.parent = dev;
575 vgpio->gc.owner = THIS_MODULE;
576 vgpio->gc.can_sleep = true;
577
578 /* Interrupt support */
579 if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) {
580 vgpio->irq_lines = devm_kcalloc(dev, n: ngpio, size: sizeof(*vgpio->irq_lines), GFP_KERNEL);
581 if (!vgpio->irq_lines)
582 return -ENOMEM;
583
584 gpio_irq_chip = devm_kzalloc(dev, size: sizeof(*gpio_irq_chip), GFP_KERNEL);
585 if (!gpio_irq_chip)
586 return -ENOMEM;
587
588 gpio_irq_chip->name = dev_name(dev);
589 gpio_irq_chip->irq_enable = virtio_gpio_irq_enable;
590 gpio_irq_chip->irq_disable = virtio_gpio_irq_disable;
591 gpio_irq_chip->irq_mask = virtio_gpio_irq_mask;
592 gpio_irq_chip->irq_unmask = virtio_gpio_irq_unmask;
593 gpio_irq_chip->irq_set_type = virtio_gpio_irq_set_type;
594 gpio_irq_chip->irq_bus_lock = virtio_gpio_irq_bus_lock;
595 gpio_irq_chip->irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock;
596
597 /* The event comes from the outside so no parent handler */
598 vgpio->gc.irq.parent_handler = NULL;
599 vgpio->gc.irq.num_parents = 0;
600 vgpio->gc.irq.parents = NULL;
601 vgpio->gc.irq.default_type = IRQ_TYPE_NONE;
602 vgpio->gc.irq.handler = handle_level_irq;
603 vgpio->gc.irq.chip = gpio_irq_chip;
604
605 for (i = 0; i < ngpio; i++) {
606 vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE;
607 vgpio->irq_lines[i].disabled = true;
608 vgpio->irq_lines[i].masked = true;
609 }
610
611 mutex_init(&vgpio->irq_lock);
612 raw_spin_lock_init(&vgpio->eventq_lock);
613 }
614
615 ret = virtio_gpio_alloc_vqs(vgpio, vdev);
616 if (ret)
617 return ret;
618
619 /* Mark the device ready to perform operations from within probe() */
620 virtio_device_ready(dev: vdev);
621
622 vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio);
623
624 ret = gpiochip_add_data(&vgpio->gc, vgpio);
625 if (ret) {
626 virtio_gpio_free_vqs(vdev);
627 dev_err(dev, "Failed to add virtio-gpio controller\n");
628 }
629
630 return ret;
631}
632
633static void virtio_gpio_remove(struct virtio_device *vdev)
634{
635 struct virtio_gpio *vgpio = vdev->priv;
636
637 gpiochip_remove(gc: &vgpio->gc);
638 virtio_gpio_free_vqs(vdev);
639}
640
641static const struct virtio_device_id id_table[] = {
642 { VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID },
643 {},
644};
645MODULE_DEVICE_TABLE(virtio, id_table);
646
647static const unsigned int features[] = {
648 VIRTIO_GPIO_F_IRQ,
649};
650
651static struct virtio_driver virtio_gpio_driver = {
652 .feature_table = features,
653 .feature_table_size = ARRAY_SIZE(features),
654 .id_table = id_table,
655 .probe = virtio_gpio_probe,
656 .remove = virtio_gpio_remove,
657 .driver = {
658 .name = KBUILD_MODNAME,
659 },
660};
661module_virtio_driver(virtio_gpio_driver);
662
663MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
664MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
665MODULE_DESCRIPTION("VirtIO GPIO driver");
666MODULE_LICENSE("GPL");
667

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