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         char                    *action;
  53         unsigned long           seen;
  54
  55         struct sk_buff          *skb;
  56         struct work_struct      work;
  57 };
  58
  59 struct bh_map {
  60         unsigned int    code;
  61         const char      *name;
  62 };
  63
  64 struct gpio_keys_button_data {
  65         struct delayed_work work;
  66         struct bh_priv bh;
  67         int last_state;
  68         int count;
  69         int threshold;
  70         int can_sleep;
  71 };
  72
  73 extern u64 uevent_next_seqnum(void);
  74
  75 #define BH_MAP(_code, _name)            \
  76         {                               \
  77                 .code = (_code),        \
  78                 .name = (_name),        \
  79         }
  80
  81 static struct bh_map button_map[] = {
  82         BH_MAP(BTN_0,           "BTN_0"),
  83         BH_MAP(BTN_1,           "BTN_1"),
  84         BH_MAP(BTN_2,           "BTN_2"),
  85         BH_MAP(BTN_3,           "BTN_3"),
  86         BH_MAP(BTN_4,           "BTN_4"),
  87         BH_MAP(BTN_5,           "BTN_5"),
  88         BH_MAP(BTN_6,           "BTN_6"),
  89         BH_MAP(BTN_7,           "BTN_7"),
  90         BH_MAP(BTN_8,           "BTN_8"),
  91         BH_MAP(BTN_9,           "BTN_9"),
  92         BH_MAP(KEY_RESTART,     "reset"),
  93         BH_MAP(KEY_RFKILL,      "rfkill"),
  94 #ifdef KEY_WPS_BUTTON
  95         BH_MAP(KEY_WPS_BUTTON,  "wps"),
  96 #endif /* KEY_WPS_BUTTON */
  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         int ret;
 133
 134         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 135         if (ret)
 136                 return ret;
 137
 138         ret = bh_event_add_var(event, 0, "PATH=%s",
 139                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 140         if (ret)
 141                 return ret;
 142
 143         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 144         if (ret)
 145                 return ret;
 146
 147         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 148         if (ret)
 149                 return ret;
 150
 151         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 152         if (ret)
 153                 return ret;
 154
 155         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 156         if (ret)
 157                 return ret;
 158
 159         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 160
 161         return ret;
 162 }
 163
 164 static void button_hotplug_work(struct work_struct *work)
 165 {
 166         struct bh_event *event = container_of(work, struct bh_event, work);
 167         int ret = 0;
 168
 169         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 170         if (!event->skb)
 171                 goto out_free_event;
 172
 173         ret = bh_event_add_var(event, 0, "%s@", event->action);
 174         if (ret)
 175                 goto out_free_skb;
 176
 177         ret = button_hotplug_fill_event(event);
 178         if (ret)
 179                 goto out_free_skb;
 180
 181         NETLINK_CB(event->skb).dst_group = 1;
 182         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 183
 184  out_free_skb:
 185         if (ret) {
 186                 BH_ERR("work error %d\n", ret);
 187                 kfree_skb(event->skb);
 188         }
 189  out_free_event:
 190         kfree(event);
 191 }
 192
 193 static int button_hotplug_create_event(const char *name, unsigned long seen,
 194                 int pressed)
 195 {
 196         struct bh_event *event;
 197
 198         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 199                 name, seen, pressed);
 200
 201         event = kzalloc(sizeof(*event), GFP_KERNEL);
 202         if (!event)
 203                 return -ENOMEM;
 204
 205         event->name = name;
 206         event->seen = seen;
 207         event->action = pressed ? "pressed" : "released";
 208
 209         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 210         schedule_work(&event->work);
 211
 212         return 0;
 213 }
 214
 215 /* -------------------------------------------------------------------------*/
 216
 217 #ifdef  CONFIG_HOTPLUG
 218 static int button_get_index(unsigned int code)
 219 {
 220         int i;
 221
 222         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 223                 if (button_map[i].code == code)
 224                         return i;
 225
 226         return -1;
 227 }
 228 static void button_hotplug_event(struct gpio_keys_button_data *data,
 229                            unsigned int type, unsigned int code, int value)
 230 {
 231         struct bh_priv *priv = &data->bh;
 232         unsigned long seen = jiffies;
 233         int btn;
 234
 235         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 236
 237         if (type != EV_KEY)
 238                 return;
 239
 240         btn = button_get_index(code);
 241         if (btn < 0)
 242                 return;
 243
 244         button_hotplug_create_event(button_map[btn].name,
 245                         (seen - priv->seen) / HZ, value);
 246         priv->seen = seen;
 247 }
 248 #else
 249 static void button_hotplug_event(struct gpio_keys_button_data *data,
 250                            unsigned int type, unsigned int code, int value)
 251 {
 252 }
 253 #endif  /* CONFIG_HOTPLUG */
 254
 255 struct gpio_keys_polled_dev {
 256         struct delayed_work work;
 257
 258         struct device *dev;
 259         struct gpio_keys_platform_data *pdata;
 260         struct gpio_keys_button_data data[0];
 261 };
 262
 263 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 264                                          struct gpio_keys_button_data *bdata)
 265 {
 266         int state;
 267
 268         if (bdata->can_sleep)
 269                 state = !!gpio_get_value_cansleep(button->gpio);
 270         else
 271                 state = !!gpio_get_value(button->gpio);
 272
 273         state = !!(state ^ button->active_low);
 274         if (state != bdata->last_state) {
 275                 unsigned int type = button->type ?: EV_KEY;
 276
 277                 if (bdata->count < bdata->threshold) {
 278                         bdata->count++;
 279                         return;
 280                 }
 281
 282                 button_hotplug_event(bdata, type, button->code, state);
 283                 bdata->last_state = state;
 284         }
 285
 286         bdata->count = 0;
 287 }
 288
 289 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 290 {
 291         struct gpio_keys_platform_data *pdata = bdev->pdata;
 292         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 293
 294         if (delay >= HZ)
 295             delay = round_jiffies_relative(delay);
 296         schedule_delayed_work(&bdev->work, delay);
 297 }
 298
 299 static void gpio_keys_polled_poll(struct work_struct *work)
 300 {
 301         struct gpio_keys_polled_dev *bdev =
 302                 container_of(work, struct gpio_keys_polled_dev, work.work);
 303         struct gpio_keys_platform_data *pdata = bdev->pdata;
 304         int i;
 305
 306         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 307                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 308                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 309         }
 310         gpio_keys_polled_queue_work(bdev);
 311 }
 312
 313 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 314 {
 315         struct gpio_keys_platform_data *pdata = bdev->pdata;
 316         int i;
 317
 318         if (pdata->enable)
 319                 pdata->enable(bdev->dev);
 320
 321         /* report initial state of the buttons */
 322         for (i = 0; i < pdata->nbuttons; i++)
 323                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 324
 325         gpio_keys_polled_queue_work(bdev);
 326 }
 327
 328 #ifdef CONFIG_OF
 329 static struct gpio_keys_platform_data *
 330 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 331 {
 332         struct device_node *node, *pp;
 333         struct gpio_keys_platform_data *pdata;
 334         struct gpio_keys_button *button;
 335         int error;
 336         int nbuttons;
 337         int i;
 338
 339         node = dev->of_node;
 340         if (!node)
 341                 return NULL;
 342
 343         nbuttons = of_get_child_count(node);
 344         if (nbuttons == 0)
 345                 return NULL;
 346
 347         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 348                 GFP_KERNEL);
 349         if (!pdata) {
 350                 error = -ENOMEM;
 351                 goto err_out;
 352         }
 353
 354         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 355         pdata->nbuttons = nbuttons;
 356
 357         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 358         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 359
 360         i = 0;
 361         for_each_child_of_node(node, pp) {
 362                 enum of_gpio_flags flags;
 363
 364                 if (!of_find_property(pp, "gpios", NULL)) {
 365                         pdata->nbuttons--;
 366                         dev_warn(dev, "Found button without gpios\n");
 367                         continue;
 368                 }
 369
 370                 button = &pdata->buttons[i++];
 371
 372                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 373                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 374
 375                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 376                         dev_err(dev, "Button without keycode: 0x%x\n",
 377                                 button->gpio);
 378                         error = -EINVAL;
 379                         goto err_free_pdata;
 380                 }
 381
 382                 button->desc = of_get_property(pp, "label", NULL);
 383
 384                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 385                         button->type = EV_KEY;
 386
 387                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 388
 389                 if (of_property_read_u32(pp, "debounce-interval",
 390                                         &button->debounce_interval))
 391                         button->debounce_interval = 5;
 392         }
 393
 394         if (pdata->nbuttons == 0) {
 395                 error = -EINVAL;
 396                 goto err_free_pdata;
 397         }
 398
 399         return pdata;
 400
 401 err_free_pdata:
 402         kfree(pdata);
 403 err_out:
 404         return ERR_PTR(error);
 405 }
 406
 407 static struct of_device_id gpio_keys_polled_of_match[] = {
 408         { .compatible = "gpio-keys-polled", },
 409         { },
 410 };
 411 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 412
 413 #else
 414
 415 static inline struct gpio_keys_platform_data *
 416 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 417 {
 418         return NULL;
 419 }
 420 #endif
 421
 422 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 423 {
 424         struct gpio_keys_platform_data *pdata = bdev->pdata;
 425
 426         cancel_delayed_work_sync(&bdev->work);
 427
 428         if (pdata->disable)
 429                 pdata->disable(bdev->dev);
 430 }
 431
 432 static int gpio_keys_polled_probe(struct platform_device *pdev)
 433 {
 434         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 435         struct device *dev = &pdev->dev;
 436         struct gpio_keys_polled_dev *bdev;
 437         int error;
 438         int i;
 439
 440         if (!pdata) {
 441                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 442                 if (IS_ERR(pdata))
 443                         return PTR_ERR(pdata);
 444                 if (!pdata) {
 445                         dev_err(dev, "missing platform data\n");
 446                         return -EINVAL;
 447                 }
 448         }
 449
 450         if (!pdata->poll_interval) {
 451                 dev_err(dev, "missing poll_interval value\n");
 452                 error = -EINVAL;
 453                 goto err_free_pdata;
 454         }
 455
 456         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 457                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 458                        GFP_KERNEL);
 459         if (!bdev) {
 460                 dev_err(dev, "no memory for private data\n");
 461                 return -ENOMEM;
 462         }
 463
 464         for (i = 0; i < pdata->nbuttons; i++) {
 465                 struct gpio_keys_button *button = &pdata->buttons[i];
 466                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 467                 unsigned int gpio = button->gpio;
 468
 469                 if (button->wakeup) {
 470                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 471                         error = -EINVAL;
 472                         goto err_free_gpio;
 473                 }
 474
 475                 error = gpio_request(gpio,
 476                                      button->desc ? button->desc : DRV_NAME);
 477                 if (error) {
 478                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 479                                 gpio, error);
 480                         goto err_free_gpio;
 481                 }
 482
 483                 error = gpio_direction_input(gpio);
 484                 if (error) {
 485                         dev_err(dev,
 486                                 "unable to set direction on gpio %u, err=%d\n",
 487                                 gpio, error);
 488                         goto err_free_gpio;
 489                 }
 490
 491                 bdata->can_sleep = gpio_cansleep(gpio);
 492                 bdata->last_state = 0;
 493                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 494                                                 pdata->poll_interval);
 495         }
 496
 497         bdev->dev = &pdev->dev;
 498         bdev->pdata = pdata;
 499         platform_set_drvdata(pdev, bdev);
 500
 501         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 502
 503         gpio_keys_polled_open(bdev);
 504
 505         return 0;
 506
 507 err_free_gpio:
 508         while (--i >= 0)
 509                 gpio_free(pdata->buttons[i].gpio);
 510
 511         kfree(bdev);
 512         platform_set_drvdata(pdev, NULL);
 513
 514 err_free_pdata:
 515         /* If we have no platform_data, we allocated pdata dynamically.  */
 516         if (!dev_get_platdata(&pdev->dev))
 517                 kfree(pdata);
 518
 519         return error;
 520 }
 521
 522 static int gpio_keys_polled_remove(struct platform_device *pdev)
 523 {
 524         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 525         struct gpio_keys_platform_data *pdata = bdev->pdata;
 526         int i = pdata->nbuttons;
 527
 528         gpio_keys_polled_close(bdev);
 529
 530         while (--i >= 0)
 531                 gpio_free(pdata->buttons[i].gpio);
 532
 533         kfree(bdev);
 534         platform_set_drvdata(pdev, NULL);
 535
 536         return 0;
 537 }
 538
 539 static struct platform_driver gpio_keys_polled_driver = {
 540         .probe  = gpio_keys_polled_probe,
 541         .remove = gpio_keys_polled_remove,
 542         .driver = {
 543                 .name   = DRV_NAME,
 544                 .owner  = THIS_MODULE,
 545                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 546         },
 547 };
 548
 549 static int __init gpio_keys_polled_init(void)
 550 {
 551         return platform_driver_register(&gpio_keys_polled_driver);
 552 }
 553
 554 static void __exit gpio_keys_polled_exit(void)
 555 {
 556         platform_driver_unregister(&gpio_keys_polled_driver);
 557 }
 558
 559 module_init(gpio_keys_polled_init);
 560 module_exit(gpio_keys_polled_exit);
 561
 562 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 563 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 564 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 565 MODULE_LICENSE("GPL v2");
 566 MODULE_ALIAS("platform:" DRV_NAME);