package/kernel/gpio-button-hotplug/src/gpio-button-hotplug.c

   1 /*
   2  *  GPIO Button Hotplug driver
   3  *
   4  *  Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   5  *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
   6  *
   7  *  Based on the diag.c - GPIO interface driver for Broadcom boards
   8  *    Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
   9  *    Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
  10  *    Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify it
  13  *  under the terms of the GNU General Public License version 2 as published
  14  *  by the Free Software Foundation.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/version.h>
  19 #include <linux/kmod.h>
  20
  21 #include <linux/workqueue.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/netlink.h>
  24 #include <linux/kobject.h>
  25 #include <linux/input.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/of_gpio.h>
  28 #include <linux/gpio_keys.h>
  29
  30 #define DRV_NAME        "gpio-keys-polled"
  31
  32 #define BH_SKB_SIZE     2048
  33
  34 #define PFX     DRV_NAME ": "
  35
  36 #undef BH_DEBUG
  37
  38 #ifdef BH_DEBUG
  39 #define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
  40 #else
  41 #define BH_DBG(fmt, args...) do {} while (0)
  42 #endif
  43
  44 #define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
  45
  46 struct bh_priv {
  47         unsigned long           seen;
  48 };
  49
  50 struct bh_event {
  51         const char              *name;
  52         unsigned int            type;
  53         char                    *action;
  54         unsigned long           seen;
  55
  56         struct sk_buff          *skb;
  57         struct work_struct      work;
  58 };
  59
  60 struct bh_map {
  61         unsigned int    code;
  62         const char      *name;
  63 };
  64
  65 struct gpio_keys_button_data {
  66         struct delayed_work work;
  67         struct bh_priv bh;
  68         int last_state;
  69         int count;
  70         int threshold;
  71         int can_sleep;
  72 };
  73
  74 extern u64 uevent_next_seqnum(void);
  75
  76 #define BH_MAP(_code, _name)            \
  77         {                               \
  78                 .code = (_code),        \
  79                 .name = (_name),        \
  80         }
  81
  82 static struct bh_map button_map[] = {
  83         BH_MAP(BTN_0,           "BTN_0"),
  84         BH_MAP(BTN_1,           "BTN_1"),
  85         BH_MAP(BTN_2,           "BTN_2"),
  86         BH_MAP(BTN_3,           "BTN_3"),
  87         BH_MAP(BTN_4,           "BTN_4"),
  88         BH_MAP(BTN_5,           "BTN_5"),
  89         BH_MAP(BTN_6,           "BTN_6"),
  90         BH_MAP(BTN_7,           "BTN_7"),
  91         BH_MAP(BTN_8,           "BTN_8"),
  92         BH_MAP(BTN_9,           "BTN_9"),
  93         BH_MAP(KEY_POWER,       "power"),
  94         BH_MAP(KEY_RESTART,     "reset"),
  95         BH_MAP(KEY_RFKILL,      "rfkill"),
  96         BH_MAP(KEY_WPS_BUTTON,  "wps"),
  97 };
  98
  99 /* -------------------------------------------------------------------------*/
 100
 101 static int bh_event_add_var(struct bh_event *event, int argv,
 102                 const char *format, ...)
 103 {
 104         static char buf[128];
 105         char *s;
 106         va_list args;
 107         int len;
 108
 109         if (argv)
 110                 return 0;
 111
 112         va_start(args, format);
 113         len = vsnprintf(buf, sizeof(buf), format, args);
 114         va_end(args);
 115
 116         if (len >= sizeof(buf)) {
 117                 BH_ERR("buffer size too small\n");
 118                 WARN_ON(1);
 119                 return -ENOMEM;
 120         }
 121
 122         s = skb_put(event->skb, len + 1);
 123         strcpy(s, buf);
 124
 125         BH_DBG("added variable '%s'\n", s);
 126
 127         return 0;
 128 }
 129
 130 static int button_hotplug_fill_event(struct bh_event *event)
 131 {
 132         char *s;
 133         int ret;
 134
 135         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 136         if (ret)
 137                 return ret;
 138
 139         ret = bh_event_add_var(event, 0, "PATH=%s",
 140                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 141         if (ret)
 142                 return ret;
 143
 144         switch (event->type) {
 145                 case EV_SW:
 146                         s = "switch";
 147                         break;
 148                 case EV_KEY:
 149                 default:
 150                         s = "button";
 151                         break;
 152         }
 153
 154         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", s);
 155         if (ret)
 156                 return ret;
 157
 158         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 159         if (ret)
 160                 return ret;
 161
 162         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 163         if (ret)
 164                 return ret;
 165
 166         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 167         if (ret)
 168                 return ret;
 169
 170         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 171
 172         return ret;
 173 }
 174
 175 static void button_hotplug_work(struct work_struct *work)
 176 {
 177         struct bh_event *event = container_of(work, struct bh_event, work);
 178         int ret = 0;
 179
 180         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 181         if (!event->skb)
 182                 goto out_free_event;
 183
 184         ret = bh_event_add_var(event, 0, "%s@", event->action);
 185         if (ret)
 186                 goto out_free_skb;
 187
 188         ret = button_hotplug_fill_event(event);
 189         if (ret)
 190                 goto out_free_skb;
 191
 192         NETLINK_CB(event->skb).dst_group = 1;
 193         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 194
 195  out_free_skb:
 196         if (ret) {
 197                 BH_ERR("work error %d\n", ret);
 198                 kfree_skb(event->skb);
 199         }
 200  out_free_event:
 201         kfree(event);
 202 }
 203
 204 static int button_hotplug_create_event(const char *name, unsigned int type,
 205                 unsigned long seen, int pressed)
 206 {
 207         struct bh_event *event;
 208
 209         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 210                 name, seen, pressed);
 211
 212         event = kzalloc(sizeof(*event), GFP_KERNEL);
 213         if (!event)
 214                 return -ENOMEM;
 215
 216         event->name = name;
 217         event->type = type;
 218         event->seen = seen;
 219         event->action = pressed ? "pressed" : "released";
 220
 221         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 222         schedule_work(&event->work);
 223
 224         return 0;
 225 }
 226
 227 /* -------------------------------------------------------------------------*/
 228
 229 #ifdef  CONFIG_HOTPLUG
 230 static int button_get_index(unsigned int code)
 231 {
 232         int i;
 233
 234         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 235                 if (button_map[i].code == code)
 236                         return i;
 237
 238         return -1;
 239 }
 240
 241 static void button_hotplug_event(struct gpio_keys_button_data *data,
 242                            unsigned int type, unsigned int code, int value)
 243 {
 244         struct bh_priv *priv = &data->bh;
 245         unsigned long seen = jiffies;
 246         int btn;
 247
 248         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 249
 250         if ((type != EV_KEY) && (type != EV_SW))
 251                 return;
 252
 253         btn = button_get_index(code);
 254         if (btn < 0)
 255                 return;
 256
 257         button_hotplug_create_event(button_map[btn].name, type,
 258                         (seen - priv->seen) / HZ, value);
 259         priv->seen = seen;
 260 }
 261 #else
 262 static void button_hotplug_event(struct gpio_keys_button_data *data,
 263                            unsigned int type, unsigned int code, int value)
 264 {
 265 }
 266 #endif  /* CONFIG_HOTPLUG */
 267
 268 struct gpio_keys_polled_dev {
 269         struct delayed_work work;
 270
 271         struct device *dev;
 272         struct gpio_keys_platform_data *pdata;
 273         struct gpio_keys_button_data data[0];
 274 };
 275
 276 static int gpio_button_get_value(struct gpio_keys_button *button,
 277                                  struct gpio_keys_button_data *bdata)
 278 {
 279         int val;
 280
 281         if (bdata->can_sleep)
 282                 val = !!gpio_get_value_cansleep(button->gpio);
 283         else
 284                 val = !!gpio_get_value(button->gpio);
 285
 286         return val ^ button->active_low;
 287 }
 288
 289 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 290                                          struct gpio_keys_button_data *bdata)
 291 {
 292         int state = gpio_button_get_value(button, bdata);
 293
 294         if (state != bdata->last_state) {
 295                 unsigned int type = button->type ?: EV_KEY;
 296
 297                 if (bdata->count < bdata->threshold) {
 298                         bdata->count++;
 299                         return;
 300                 }
 301
 302                 if (bdata->last_state != -1)
 303                         button_hotplug_event(bdata, type, button->code, state);
 304
 305                 bdata->last_state = state;
 306         }
 307
 308         bdata->count = 0;
 309 }
 310
 311 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 312 {
 313         struct gpio_keys_platform_data *pdata = bdev->pdata;
 314         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 315
 316         if (delay >= HZ)
 317             delay = round_jiffies_relative(delay);
 318         schedule_delayed_work(&bdev->work, delay);
 319 }
 320
 321 static void gpio_keys_polled_poll(struct work_struct *work)
 322 {
 323         struct gpio_keys_polled_dev *bdev =
 324                 container_of(work, struct gpio_keys_polled_dev, work.work);
 325         struct gpio_keys_platform_data *pdata = bdev->pdata;
 326         int i;
 327
 328         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 329                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 330                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 331         }
 332         gpio_keys_polled_queue_work(bdev);
 333 }
 334
 335 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 336 {
 337         struct gpio_keys_platform_data *pdata = bdev->pdata;
 338         int i;
 339
 340         if (pdata->enable)
 341                 pdata->enable(bdev->dev);
 342
 343         /* report initial state of the buttons */
 344         for (i = 0; i < pdata->nbuttons; i++)
 345                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 346
 347         gpio_keys_polled_queue_work(bdev);
 348 }
 349
 350 #ifdef CONFIG_OF
 351 static struct gpio_keys_platform_data *
 352 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 353 {
 354         struct device_node *node, *pp;
 355         struct gpio_keys_platform_data *pdata;
 356         struct gpio_keys_button *button;
 357         int error;
 358         int nbuttons;
 359         int i;
 360
 361         node = dev->of_node;
 362         if (!node)
 363                 return NULL;
 364
 365         nbuttons = of_get_child_count(node);
 366         if (nbuttons == 0)
 367                 return NULL;
 368
 369         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 370                 GFP_KERNEL);
 371         if (!pdata) {
 372                 error = -ENOMEM;
 373                 goto err_out;
 374         }
 375
 376         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 377         pdata->nbuttons = nbuttons;
 378
 379         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 380         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 381
 382         i = 0;
 383         for_each_child_of_node(node, pp) {
 384                 enum of_gpio_flags flags;
 385
 386                 if (!of_find_property(pp, "gpios", NULL)) {
 387                         pdata->nbuttons--;
 388                         dev_warn(dev, "Found button without gpios\n");
 389                         continue;
 390                 }
 391
 392                 button = &pdata->buttons[i++];
 393
 394                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 395                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 396
 397                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 398                         dev_err(dev, "Button without keycode: 0x%x\n",
 399                                 button->gpio);
 400                         error = -EINVAL;
 401                         goto err_free_pdata;
 402                 }
 403
 404                 button->desc = of_get_property(pp, "label", NULL);
 405
 406                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 407                         button->type = EV_KEY;
 408
 409                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 410
 411                 if (of_property_read_u32(pp, "debounce-interval",
 412                                         &button->debounce_interval))
 413                         button->debounce_interval = 5;
 414         }
 415
 416         if (pdata->nbuttons == 0) {
 417                 error = -EINVAL;
 418                 goto err_free_pdata;
 419         }
 420
 421         return pdata;
 422
 423 err_free_pdata:
 424         kfree(pdata);
 425 err_out:
 426         return ERR_PTR(error);
 427 }
 428
 429 static struct of_device_id gpio_keys_polled_of_match[] = {
 430         { .compatible = "gpio-keys-polled", },
 431         { },
 432 };
 433 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 434
 435 #else
 436
 437 static inline struct gpio_keys_platform_data *
 438 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 439 {
 440         return NULL;
 441 }
 442 #endif
 443
 444 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 445 {
 446         struct gpio_keys_platform_data *pdata = bdev->pdata;
 447
 448         cancel_delayed_work_sync(&bdev->work);
 449
 450         if (pdata->disable)
 451                 pdata->disable(bdev->dev);
 452 }
 453
 454 static int gpio_keys_polled_probe(struct platform_device *pdev)
 455 {
 456         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 457         struct device *dev = &pdev->dev;
 458         struct gpio_keys_polled_dev *bdev;
 459         int error;
 460         int i;
 461
 462         if (!pdata) {
 463                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 464                 if (IS_ERR(pdata))
 465                         return PTR_ERR(pdata);
 466                 if (!pdata) {
 467                         dev_err(dev, "missing platform data\n");
 468                         return -EINVAL;
 469                 }
 470         }
 471
 472         if (!pdata->poll_interval) {
 473                 dev_err(dev, "missing poll_interval value\n");
 474                 error = -EINVAL;
 475                 goto err_free_pdata;
 476         }
 477
 478         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 479                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 480                        GFP_KERNEL);
 481         if (!bdev) {
 482                 dev_err(dev, "no memory for private data\n");
 483                 return -ENOMEM;
 484         }
 485
 486         for (i = 0; i < pdata->nbuttons; i++) {
 487                 struct gpio_keys_button *button = &pdata->buttons[i];
 488                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 489                 unsigned int gpio = button->gpio;
 490
 491                 if (button->wakeup) {
 492                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 493                         error = -EINVAL;
 494                         goto err_free_gpio;
 495                 }
 496
 497                 error = gpio_request(gpio,
 498                                      button->desc ? button->desc : DRV_NAME);
 499                 if (error) {
 500                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 501                                 gpio, error);
 502                         goto err_free_gpio;
 503                 }
 504
 505                 error = gpio_direction_input(gpio);
 506                 if (error) {
 507                         dev_err(dev,
 508                                 "unable to set direction on gpio %u, err=%d\n",
 509                                 gpio, error);
 510                         goto err_free_gpio;
 511                 }
 512
 513                 bdata->can_sleep = gpio_cansleep(gpio);
 514                 bdata->last_state = -1;
 515                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 516                                                 pdata->poll_interval);
 517         }
 518
 519         bdev->dev = &pdev->dev;
 520         bdev->pdata = pdata;
 521         platform_set_drvdata(pdev, bdev);
 522
 523         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 524
 525         gpio_keys_polled_open(bdev);
 526
 527         return 0;
 528
 529 err_free_gpio:
 530         while (--i >= 0)
 531                 gpio_free(pdata->buttons[i].gpio);
 532
 533         kfree(bdev);
 534         platform_set_drvdata(pdev, NULL);
 535
 536 err_free_pdata:
 537         /* If we have no platform_data, we allocated pdata dynamically.  */
 538         if (!dev_get_platdata(&pdev->dev))
 539                 kfree(pdata);
 540
 541         return error;
 542 }
 543
 544 static int gpio_keys_polled_remove(struct platform_device *pdev)
 545 {
 546         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 547         struct gpio_keys_platform_data *pdata = bdev->pdata;
 548         int i = pdata->nbuttons;
 549
 550         gpio_keys_polled_close(bdev);
 551
 552         while (--i >= 0)
 553                 gpio_free(pdata->buttons[i].gpio);
 554
 555         kfree(bdev);
 556         platform_set_drvdata(pdev, NULL);
 557
 558         return 0;
 559 }
 560
 561 static struct platform_driver gpio_keys_polled_driver = {
 562         .probe  = gpio_keys_polled_probe,
 563         .remove = gpio_keys_polled_remove,
 564         .driver = {
 565                 .name   = DRV_NAME,
 566                 .owner  = THIS_MODULE,
 567                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 568         },
 569 };
 570
 571 static int __init gpio_keys_polled_init(void)
 572 {
 573         return platform_driver_register(&gpio_keys_polled_driver);
 574 }
 575
 576 static void __exit gpio_keys_polled_exit(void)
 577 {
 578         platform_driver_unregister(&gpio_keys_polled_driver);
 579 }
 580
 581 module_init(gpio_keys_polled_init);
 582 module_exit(gpio_keys_polled_exit);
 583
 584 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 585 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 586 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 587 MODULE_LICENSE("GPL v2");
 588 MODULE_ALIAS("platform:" DRV_NAME);