drivers/gpio/gpio-virtio.c

   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
  24 struct 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
  32 struct 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
  44 struct 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
  58 static 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(&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(vgpio->request_vq, sgs, 1, 1, line, GFP_KERNEL);
  94         if (ret) {
  95                 dev_err(dev, "failed to add request to vq\n");
  96                 mutex_unlock(&vgpio->lock);
  97                 goto out;
  98         }
  99
 100         virtqueue_kick(vgpio->request_vq);
 101         mutex_unlock(&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
 121 out:
 122         mutex_unlock(&line->lock);
 123         return ret;
 124 }
 125
 126 static 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, res,
 133                                 sizeof(*res));
 134 }
 135
 136 static 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
 144 static 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, 0,
 151                               &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
 165 static 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
 173 static 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, 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
 187 static 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, 0, &value);
 194         return ret ? ret : value;
 195 }
 196
 197 static 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, value, NULL);
 202 }
 203
 204 /* Interrupt handling */
 205 static 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(vgpio->event_vq, sgs, 1, 1, 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(vgpio->event_vq);
 230 }
 231
 232 static 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
 247 static 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
 262 static 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
 273 static 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, d->hwirq);
 284         raw_spin_unlock(&vgpio->eventq_lock);
 285 }
 286
 287 static 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
 320 static 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
 328 static 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, d->hwirq, 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, d->hwirq);
 346                 }
 347                 raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags);
 348         }
 349
 350         mutex_unlock(&vgpio->irq_lock);
 351 }
 352
 353 static struct irq_chip vgpio_irq_chip = {
 354         .name                   = "virtio-gpio",
 355         .irq_enable             = virtio_gpio_irq_enable,
 356         .irq_disable            = virtio_gpio_irq_disable,
 357         .irq_mask               = virtio_gpio_irq_mask,
 358         .irq_unmask             = virtio_gpio_irq_unmask,
 359         .irq_set_type           = virtio_gpio_irq_set_type,
 360
 361         /* These are required to implement irqchip for slow busses */
 362         .irq_bus_lock           = virtio_gpio_irq_bus_lock,
 363         .irq_bus_sync_unlock    = virtio_gpio_irq_bus_sync_unlock,
 364 };
 365
 366 static bool ignore_irq(struct virtio_gpio *vgpio, int gpio,
 367                        struct vgpio_irq_line *irq_line)
 368 {
 369         bool ignore = false;
 370
 371         raw_spin_lock(&vgpio->eventq_lock);
 372         irq_line->queued = false;
 373
 374         /* Interrupt is disabled currently */
 375         if (irq_line->masked || irq_line->disabled) {
 376                 ignore = true;
 377                 goto unlock;
 378         }
 379
 380         /*
 381          * Buffer is returned as the interrupt was disabled earlier, but is
 382          * enabled again now. Requeue the buffers.
 383          */
 384         if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) {
 385                 virtio_gpio_irq_prepare(vgpio, gpio);
 386                 ignore = true;
 387                 goto unlock;
 388         }
 389
 390         if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID))
 391                 ignore = true;
 392
 393 unlock:
 394         raw_spin_unlock(&vgpio->eventq_lock);
 395
 396         return ignore;
 397 }
 398
 399 static void virtio_gpio_event_vq(struct virtqueue *vq)
 400 {
 401         struct virtio_gpio *vgpio = vq->vdev->priv;
 402         struct device *dev = &vgpio->vdev->dev;
 403         struct vgpio_irq_line *irq_line;
 404         int gpio, ret;
 405         unsigned int len;
 406
 407         while (true) {
 408                 irq_line = virtqueue_get_buf(vgpio->event_vq, &len);
 409                 if (!irq_line)
 410                         break;
 411
 412                 if (len != sizeof(irq_line->ires)) {
 413                         dev_err(dev, "irq with incorrect length (%u : %u)\n",
 414                                 len, (unsigned int)sizeof(irq_line->ires));
 415                         continue;
 416                 }
 417
 418                 /*
 419                  * Find GPIO line number from the offset of irq_line within the
 420                  * irq_lines block. We can also get GPIO number from
 421                  * irq-request, but better not to rely on a buffer returned by
 422                  * remote.
 423                  */
 424                 gpio = irq_line - vgpio->irq_lines;
 425                 WARN_ON(gpio >= vgpio->gc.ngpio);
 426
 427                 if (unlikely(ignore_irq(vgpio, gpio, irq_line)))
 428                         continue;
 429
 430                 ret = generic_handle_domain_irq(vgpio->gc.irq.domain, gpio);
 431                 if (ret)
 432                         dev_err(dev, "failed to handle interrupt: %d\n", ret);
 433         }
 434 }
 435
 436 static void virtio_gpio_request_vq(struct virtqueue *vq)
 437 {
 438         struct virtio_gpio_line *line;
 439         unsigned int len;
 440
 441         do {
 442                 line = virtqueue_get_buf(vq, &len);
 443                 if (!line)
 444                         return;
 445
 446                 line->rxlen = len;
 447                 complete(&line->completion);
 448         } while (1);
 449 }
 450
 451 static void virtio_gpio_free_vqs(struct virtio_device *vdev)
 452 {
 453         virtio_reset_device(vdev);
 454         vdev->config->del_vqs(vdev);
 455 }
 456
 457 static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,
 458                                  struct virtio_device *vdev)
 459 {
 460         struct virtqueue_info vqs_info[] = {
 461                 { "requestq", virtio_gpio_request_vq },
 462                 { "eventq", virtio_gpio_event_vq },
 463         };
 464         struct virtqueue *vqs[2] = { NULL, NULL };
 465         int ret;
 466
 467         ret = virtio_find_vqs(vdev, vgpio->irq_lines ? 2 : 1, vqs,
 468                               vqs_info, NULL);
 469         if (ret) {
 470                 dev_err(&vdev->dev, "failed to find vqs: %d\n", ret);
 471                 return ret;
 472         }
 473
 474         if (!vqs[0]) {
 475                 dev_err(&vdev->dev, "failed to find requestq vq\n");
 476                 goto out;
 477         }
 478         vgpio->request_vq = vqs[0];
 479
 480         if (vgpio->irq_lines && !vqs[1]) {
 481                 dev_err(&vdev->dev, "failed to find eventq vq\n");
 482                 goto out;
 483         }
 484         vgpio->event_vq = vqs[1];
 485
 486         return 0;
 487
 488 out:
 489         if (vqs[0] || vqs[1])
 490                 virtio_gpio_free_vqs(vdev);
 491
 492         return -ENODEV;
 493 }
 494
 495 static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio,
 496                                           u32 gpio_names_size, u16 ngpio)
 497 {
 498         struct virtio_gpio_response_get_names *res;
 499         struct device *dev = &vgpio->vdev->dev;
 500         u8 *gpio_names, *str;
 501         const char **names;
 502         int i, ret, len;
 503
 504         if (!gpio_names_size)
 505                 return NULL;
 506
 507         len = sizeof(*res) + gpio_names_size;
 508         res = devm_kzalloc(dev, len, GFP_KERNEL);
 509         if (!res)
 510                 return NULL;
 511         gpio_names = res->value;
 512
 513         ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, 0, 0, NULL,
 514                                res, len);
 515         if (ret) {
 516                 dev_err(dev, "Failed to get GPIO names: %d\n", ret);
 517                 return NULL;
 518         }
 519
 520         names = devm_kcalloc(dev, ngpio, sizeof(*names), GFP_KERNEL);
 521         if (!names)
 522                 return NULL;
 523
 524         /* NULL terminate the string instead of checking it */
 525         gpio_names[gpio_names_size - 1] = '\0';
 526
 527         for (i = 0, str = gpio_names; i < ngpio; i++) {
 528                 names[i] = str;
 529                 str += strlen(str) + 1; /* zero-length strings are allowed */
 530
 531                 if (str > gpio_names + gpio_names_size) {
 532                         dev_err(dev, "gpio_names block is too short (%d)\n", i);
 533                         return NULL;
 534                 }
 535         }
 536
 537         return names;
 538 }
 539
 540 static int virtio_gpio_probe(struct virtio_device *vdev)
 541 {
 542         struct virtio_gpio_config config;
 543         struct device *dev = &vdev->dev;
 544         struct virtio_gpio *vgpio;
 545         u32 gpio_names_size;
 546         u16 ngpio;
 547         int ret, i;
 548
 549         vgpio = devm_kzalloc(dev, sizeof(*vgpio), GFP_KERNEL);
 550         if (!vgpio)
 551                 return -ENOMEM;
 552
 553         /* Read configuration */
 554         virtio_cread_bytes(vdev, 0, &config, sizeof(config));
 555         gpio_names_size = le32_to_cpu(config.gpio_names_size);
 556         ngpio = le16_to_cpu(config.ngpio);
 557         if (!ngpio) {
 558                 dev_err(dev, "Number of GPIOs can't be zero\n");
 559                 return -EINVAL;
 560         }
 561
 562         vgpio->lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->lines), GFP_KERNEL);
 563         if (!vgpio->lines)
 564                 return -ENOMEM;
 565
 566         for (i = 0; i < ngpio; i++) {
 567                 mutex_init(&vgpio->lines[i].lock);
 568                 init_completion(&vgpio->lines[i].completion);
 569         }
 570
 571         mutex_init(&vgpio->lock);
 572         vdev->priv = vgpio;
 573
 574         vgpio->vdev                     = vdev;
 575         vgpio->gc.free                  = virtio_gpio_free;
 576         vgpio->gc.get_direction         = virtio_gpio_get_direction;
 577         vgpio->gc.direction_input       = virtio_gpio_direction_input;
 578         vgpio->gc.direction_output      = virtio_gpio_direction_output;
 579         vgpio->gc.get                   = virtio_gpio_get;
 580         vgpio->gc.set                   = virtio_gpio_set;
 581         vgpio->gc.ngpio                 = ngpio;
 582         vgpio->gc.base                  = -1; /* Allocate base dynamically */
 583         vgpio->gc.label                 = dev_name(dev);
 584         vgpio->gc.parent                = dev;
 585         vgpio->gc.owner                 = THIS_MODULE;
 586         vgpio->gc.can_sleep             = true;
 587
 588         /* Interrupt support */
 589         if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) {
 590                 vgpio->irq_lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->irq_lines), GFP_KERNEL);
 591                 if (!vgpio->irq_lines)
 592                         return -ENOMEM;
 593
 594                 /* The event comes from the outside so no parent handler */
 595                 vgpio->gc.irq.parent_handler    = NULL;
 596                 vgpio->gc.irq.num_parents       = 0;
 597                 vgpio->gc.irq.parents           = NULL;
 598                 vgpio->gc.irq.default_type      = IRQ_TYPE_NONE;
 599                 vgpio->gc.irq.handler           = handle_level_irq;
 600                 vgpio->gc.irq.chip              = &vgpio_irq_chip;
 601
 602                 for (i = 0; i < ngpio; i++) {
 603                         vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE;
 604                         vgpio->irq_lines[i].disabled = true;
 605                         vgpio->irq_lines[i].masked = true;
 606                 }
 607
 608                 mutex_init(&vgpio->irq_lock);
 609                 raw_spin_lock_init(&vgpio->eventq_lock);
 610         }
 611
 612         ret = virtio_gpio_alloc_vqs(vgpio, vdev);
 613         if (ret)
 614                 return ret;
 615
 616         /* Mark the device ready to perform operations from within probe() */
 617         virtio_device_ready(vdev);
 618
 619         vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio);
 620
 621         ret = gpiochip_add_data(&vgpio->gc, vgpio);
 622         if (ret) {
 623                 virtio_gpio_free_vqs(vdev);
 624                 dev_err(dev, "Failed to add virtio-gpio controller\n");
 625         }
 626
 627         return ret;
 628 }
 629
 630 static void virtio_gpio_remove(struct virtio_device *vdev)
 631 {
 632         struct virtio_gpio *vgpio = vdev->priv;
 633
 634         gpiochip_remove(&vgpio->gc);
 635         virtio_gpio_free_vqs(vdev);
 636 }
 637
 638 static const struct virtio_device_id id_table[] = {
 639         { VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID },
 640         {},
 641 };
 642 MODULE_DEVICE_TABLE(virtio, id_table);
 643
 644 static const unsigned int features[] = {
 645         VIRTIO_GPIO_F_IRQ,
 646 };
 647
 648 static struct virtio_driver virtio_gpio_driver = {
 649         .feature_table          = features,
 650         .feature_table_size     = ARRAY_SIZE(features),
 651         .id_table               = id_table,
 652         .probe                  = virtio_gpio_probe,
 653         .remove                 = virtio_gpio_remove,
 654         .driver                 = {
 655                 .name           = KBUILD_MODNAME,
 656         },
 657 };
 658 module_virtio_driver(virtio_gpio_driver);
 659
 660 MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
 661 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 662 MODULE_DESCRIPTION("VirtIO GPIO driver");
 663 MODULE_LICENSE("GPL");