package/system/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                 button_hotplug_event(bdata, type, button->code, state);
 278                 bdata->count = 0;
 279                 bdata->last_state = state;
 280         }
 281 }
 282
 283 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 284 {
 285         struct gpio_keys_platform_data *pdata = bdev->pdata;
 286         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 287
 288         if (delay >= HZ)
 289             delay = round_jiffies_relative(delay);
 290         schedule_delayed_work(&bdev->work, delay);
 291 }
 292
 293 static void gpio_keys_polled_poll(struct work_struct *work)
 294 {
 295         struct gpio_keys_polled_dev *bdev =
 296                 container_of(work, struct gpio_keys_polled_dev, work.work);
 297         struct gpio_keys_platform_data *pdata = bdev->pdata;
 298         int i;
 299
 300         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 301                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 302
 303                 if (bdata->count < bdata->threshold)
 304                         bdata->count++;
 305                 else
 306                         gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 307         }
 308         gpio_keys_polled_queue_work(bdev);
 309 }
 310
 311 static void __devinit gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 312 {
 313         struct gpio_keys_platform_data *pdata = bdev->pdata;
 314         int i;
 315
 316         if (pdata->enable)
 317                 pdata->enable(bdev->dev);
 318
 319         /* report initial state of the buttons */
 320         for (i = 0; i < pdata->nbuttons; i++)
 321                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 322
 323         gpio_keys_polled_queue_work(bdev);
 324 }
 325
 326 #ifdef CONFIG_OF
 327 static struct gpio_keys_platform_data * __devinit
 328 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 329 {
 330         struct device_node *node, *pp;
 331         struct gpio_keys_platform_data *pdata;
 332         struct gpio_keys_button *button;
 333         int error;
 334         int nbuttons;
 335         int i;
 336
 337         node = dev->of_node;
 338         if (!node)
 339                 return NULL;
 340
 341         nbuttons = of_get_child_count(node);
 342         if (nbuttons == 0)
 343                 return NULL;
 344
 345         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 346                 GFP_KERNEL);
 347         if (!pdata) {
 348                 error = -ENOMEM;
 349                 goto err_out;
 350         }
 351
 352         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 353         pdata->nbuttons = nbuttons;
 354
 355         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 356         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 357
 358         i = 0;
 359         for_each_child_of_node(node, pp) {
 360                 enum of_gpio_flags flags;
 361
 362                 if (!of_find_property(pp, "gpios", NULL)) {
 363                         pdata->nbuttons--;
 364                         dev_warn(dev, "Found button without gpios\n");
 365                         continue;
 366                 }
 367
 368                 button = &pdata->buttons[i++];
 369
 370                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 371                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 372
 373                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 374                         dev_err(dev, "Button without keycode: 0x%x\n",
 375                                 button->gpio);
 376                         error = -EINVAL;
 377                         goto err_free_pdata;
 378                 }
 379
 380                 button->desc = of_get_property(pp, "label", NULL);
 381
 382                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 383                         button->type = EV_KEY;
 384
 385                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 386
 387                 if (of_property_read_u32(pp, "debounce-interval",
 388                                         &button->debounce_interval))
 389                         button->debounce_interval = 5;
 390         }
 391
 392         if (pdata->nbuttons == 0) {
 393                 error = -EINVAL;
 394                 goto err_free_pdata;
 395         }
 396
 397         return pdata;
 398
 399 err_free_pdata:
 400         kfree(pdata);
 401 err_out:
 402         return ERR_PTR(error);
 403 }
 404
 405 static struct of_device_id gpio_keys_polled_of_match[] = {
 406         { .compatible = "gpio-keys-polled", },
 407         { },
 408 };
 409 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 410
 411 #else
 412
 413 static inline struct gpio_keys_platform_data *
 414 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 415 {
 416         return NULL;
 417 }
 418 #endif
 419
 420 static void __devexit gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 421 {
 422         struct gpio_keys_platform_data *pdata = bdev->pdata;
 423
 424         cancel_delayed_work_sync(&bdev->work);
 425
 426         if (pdata->disable)
 427                 pdata->disable(bdev->dev);
 428 }
 429
 430 static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
 431 {
 432         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 433         struct device *dev = &pdev->dev;
 434         struct gpio_keys_polled_dev *bdev;
 435         int error;
 436         int i;
 437
 438         if (!pdata) {
 439                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 440                 if (IS_ERR(pdata))
 441                         return PTR_ERR(pdata);
 442                 if (!pdata) {
 443                         dev_err(dev, "missing platform data\n");
 444                         return -EINVAL;
 445                 }
 446         }
 447
 448         if (!pdata->poll_interval) {
 449                 dev_err(dev, "missing poll_interval value\n");
 450                 error = -EINVAL;
 451                 goto err_free_pdata;
 452         }
 453
 454         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 455                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 456                        GFP_KERNEL);
 457         if (!bdev) {
 458                 dev_err(dev, "no memory for private data\n");
 459                 return -ENOMEM;
 460         }
 461
 462         for (i = 0; i < pdata->nbuttons; i++) {
 463                 struct gpio_keys_button *button = &pdata->buttons[i];
 464                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 465                 unsigned int gpio = button->gpio;
 466
 467                 if (button->wakeup) {
 468                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 469                         error = -EINVAL;
 470                         goto err_free_gpio;
 471                 }
 472
 473                 error = gpio_request(gpio,
 474                                      button->desc ? button->desc : DRV_NAME);
 475                 if (error) {
 476                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 477                                 gpio, error);
 478                         goto err_free_gpio;
 479                 }
 480
 481                 error = gpio_direction_input(gpio);
 482                 if (error) {
 483                         dev_err(dev,
 484                                 "unable to set direction on gpio %u, err=%d\n",
 485                                 gpio, error);
 486                         goto err_free_gpio;
 487                 }
 488
 489                 bdata->can_sleep = gpio_cansleep(gpio);
 490                 bdata->last_state = 0;
 491                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 492                                                 pdata->poll_interval);
 493         }
 494
 495         bdev->dev = &pdev->dev;
 496         bdev->pdata = pdata;
 497         platform_set_drvdata(pdev, bdev);
 498
 499         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 500
 501         gpio_keys_polled_open(bdev);
 502
 503         return 0;
 504
 505 err_free_gpio:
 506         while (--i >= 0)
 507                 gpio_free(pdata->buttons[i].gpio);
 508
 509         kfree(bdev);
 510         platform_set_drvdata(pdev, NULL);
 511
 512 err_free_pdata:
 513         /* If we have no platform_data, we allocated pdata dynamically.  */
 514         if (!dev_get_platdata(&pdev->dev))
 515                 kfree(pdata);
 516
 517         return error;
 518 }
 519
 520 static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
 521 {
 522         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 523         struct gpio_keys_platform_data *pdata = bdev->pdata;
 524         int i = pdata->nbuttons;
 525
 526         gpio_keys_polled_close(bdev);
 527
 528         while (--i >= 0)
 529                 gpio_free(pdata->buttons[i].gpio);
 530
 531         kfree(bdev);
 532         platform_set_drvdata(pdev, NULL);
 533
 534         return 0;
 535 }
 536
 537 static struct platform_driver gpio_keys_polled_driver = {
 538         .probe  = gpio_keys_polled_probe,
 539         .remove = __devexit_p(gpio_keys_polled_remove),
 540         .driver = {
 541                 .name   = DRV_NAME,
 542                 .owner  = THIS_MODULE,
 543                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 544         },
 545 };
 546
 547 static int __init gpio_keys_polled_init(void)
 548 {
 549         return platform_driver_register(&gpio_keys_polled_driver);
 550 }
 551
 552 static void __exit gpio_keys_polled_exit(void)
 553 {
 554         platform_driver_unregister(&gpio_keys_polled_driver);
 555 }
 556
 557 module_init(gpio_keys_polled_init);
 558 module_exit(gpio_keys_polled_exit);
 559
 560 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 561 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 562 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 563 MODULE_LICENSE("GPL v2");
 564 MODULE_ALIAS("platform:" DRV_NAME);