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         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 145         if (ret)
 146                 return ret;
 147
 148         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 149         if (ret)
 150                 return ret;
 151
 152         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 153         if (ret)
 154                 return ret;
 155
 156         if (event->type == EV_SW) {
 157                 ret = bh_event_add_var(event, 0, "TYPE=%s", "switch");
 158                 if (ret)
 159                         return ret;
 160         }
 161
 162         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 163         if (ret)
 164                 return ret;
 165
 166         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 167
 168         return ret;
 169 }
 170
 171 static void button_hotplug_work(struct work_struct *work)
 172 {
 173         struct bh_event *event = container_of(work, struct bh_event, work);
 174         int ret = 0;
 175
 176         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 177         if (!event->skb)
 178                 goto out_free_event;
 179
 180         ret = bh_event_add_var(event, 0, "%s@", event->action);
 181         if (ret)
 182                 goto out_free_skb;
 183
 184         ret = button_hotplug_fill_event(event);
 185         if (ret)
 186                 goto out_free_skb;
 187
 188         NETLINK_CB(event->skb).dst_group = 1;
 189         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 190
 191  out_free_skb:
 192         if (ret) {
 193                 BH_ERR("work error %d\n", ret);
 194                 kfree_skb(event->skb);
 195         }
 196  out_free_event:
 197         kfree(event);
 198 }
 199
 200 static int button_hotplug_create_event(const char *name, unsigned int type,
 201                 unsigned long seen, int pressed)
 202 {
 203         struct bh_event *event;
 204
 205         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 206                 name, seen, pressed);
 207
 208         event = kzalloc(sizeof(*event), GFP_KERNEL);
 209         if (!event)
 210                 return -ENOMEM;
 211
 212         event->name = name;
 213         event->type = type;
 214         event->seen = seen;
 215         event->action = pressed ? "pressed" : "released";
 216
 217         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 218         schedule_work(&event->work);
 219
 220         return 0;
 221 }
 222
 223 /* -------------------------------------------------------------------------*/
 224
 225 #ifdef  CONFIG_HOTPLUG
 226 static int button_get_index(unsigned int code)
 227 {
 228         int i;
 229
 230         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 231                 if (button_map[i].code == code)
 232                         return i;
 233
 234         return -1;
 235 }
 236
 237 static void button_hotplug_event(struct gpio_keys_button_data *data,
 238                            unsigned int type, unsigned int code, int value)
 239 {
 240         struct bh_priv *priv = &data->bh;
 241         unsigned long seen = jiffies;
 242         int btn;
 243
 244         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 245
 246         if ((type != EV_KEY) && (type != EV_SW))
 247                 return;
 248
 249         btn = button_get_index(code);
 250         if (btn < 0)
 251                 return;
 252
 253         button_hotplug_create_event(button_map[btn].name, type,
 254                         (seen - priv->seen) / HZ, value);
 255         priv->seen = seen;
 256 }
 257 #else
 258 static void button_hotplug_event(struct gpio_keys_button_data *data,
 259                            unsigned int type, unsigned int code, int value)
 260 {
 261 }
 262 #endif  /* CONFIG_HOTPLUG */
 263
 264 struct gpio_keys_polled_dev {
 265         struct delayed_work work;
 266
 267         struct device *dev;
 268         struct gpio_keys_platform_data *pdata;
 269         struct gpio_keys_button_data data[0];
 270 };
 271
 272 static int gpio_button_get_value(struct gpio_keys_button *button,
 273                                  struct gpio_keys_button_data *bdata)
 274 {
 275         int val;
 276
 277         if (bdata->can_sleep)
 278                 val = !!gpio_get_value_cansleep(button->gpio);
 279         else
 280                 val = !!gpio_get_value(button->gpio);
 281
 282         return val ^ button->active_low;
 283 }
 284
 285 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 286                                          struct gpio_keys_button_data *bdata)
 287 {
 288         int state = gpio_button_get_value(button, bdata);
 289
 290         if (state != bdata->last_state) {
 291                 unsigned int type = button->type ?: EV_KEY;
 292
 293                 if (bdata->count < bdata->threshold) {
 294                         bdata->count++;
 295                         return;
 296                 }
 297
 298                 if ((bdata->last_state != -1) || (type == EV_SW))
 299                         button_hotplug_event(bdata, type, button->code, state);
 300
 301                 bdata->last_state = state;
 302         }
 303
 304         bdata->count = 0;
 305 }
 306
 307 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 308 {
 309         struct gpio_keys_platform_data *pdata = bdev->pdata;
 310         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 311
 312         if (delay >= HZ)
 313             delay = round_jiffies_relative(delay);
 314         schedule_delayed_work(&bdev->work, delay);
 315 }
 316
 317 static void gpio_keys_polled_poll(struct work_struct *work)
 318 {
 319         struct gpio_keys_polled_dev *bdev =
 320                 container_of(work, struct gpio_keys_polled_dev, work.work);
 321         struct gpio_keys_platform_data *pdata = bdev->pdata;
 322         int i;
 323
 324         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 325                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 326                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 327         }
 328         gpio_keys_polled_queue_work(bdev);
 329 }
 330
 331 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 332 {
 333         struct gpio_keys_platform_data *pdata = bdev->pdata;
 334         int i;
 335
 336         if (pdata->enable)
 337                 pdata->enable(bdev->dev);
 338
 339         /* report initial state of the buttons */
 340         for (i = 0; i < pdata->nbuttons; i++)
 341                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 342
 343         gpio_keys_polled_queue_work(bdev);
 344 }
 345
 346 #ifdef CONFIG_OF
 347 static struct gpio_keys_platform_data *
 348 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 349 {
 350         struct device_node *node, *pp;
 351         struct gpio_keys_platform_data *pdata;
 352         struct gpio_keys_button *button;
 353         int error;
 354         int nbuttons;
 355         int i;
 356
 357         node = dev->of_node;
 358         if (!node)
 359                 return NULL;
 360
 361         nbuttons = of_get_child_count(node);
 362         if (nbuttons == 0)
 363                 return NULL;
 364
 365         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 366                 GFP_KERNEL);
 367         if (!pdata) {
 368                 error = -ENOMEM;
 369                 goto err_out;
 370         }
 371
 372         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 373         pdata->nbuttons = nbuttons;
 374
 375         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 376         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 377
 378         i = 0;
 379         for_each_child_of_node(node, pp) {
 380                 enum of_gpio_flags flags;
 381
 382                 if (!of_find_property(pp, "gpios", NULL)) {
 383                         pdata->nbuttons--;
 384                         dev_warn(dev, "Found button without gpios\n");
 385                         continue;
 386                 }
 387
 388                 button = &pdata->buttons[i++];
 389
 390                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 391                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 392
 393                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 394                         dev_err(dev, "Button without keycode: 0x%x\n",
 395                                 button->gpio);
 396                         error = -EINVAL;
 397                         goto err_free_pdata;
 398                 }
 399
 400                 button->desc = of_get_property(pp, "label", NULL);
 401
 402                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 403                         button->type = EV_KEY;
 404
 405                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 406
 407                 if (of_property_read_u32(pp, "debounce-interval",
 408                                         &button->debounce_interval))
 409                         button->debounce_interval = 5;
 410         }
 411
 412         if (pdata->nbuttons == 0) {
 413                 error = -EINVAL;
 414                 goto err_free_pdata;
 415         }
 416
 417         return pdata;
 418
 419 err_free_pdata:
 420         kfree(pdata);
 421 err_out:
 422         return ERR_PTR(error);
 423 }
 424
 425 static struct of_device_id gpio_keys_polled_of_match[] = {
 426         { .compatible = "gpio-keys-polled", },
 427         { },
 428 };
 429 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 430
 431 #else
 432
 433 static inline struct gpio_keys_platform_data *
 434 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 435 {
 436         return NULL;
 437 }
 438 #endif
 439
 440 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 441 {
 442         struct gpio_keys_platform_data *pdata = bdev->pdata;
 443
 444         cancel_delayed_work_sync(&bdev->work);
 445
 446         if (pdata->disable)
 447                 pdata->disable(bdev->dev);
 448 }
 449
 450 static int gpio_keys_polled_probe(struct platform_device *pdev)
 451 {
 452         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 453         struct device *dev = &pdev->dev;
 454         struct gpio_keys_polled_dev *bdev;
 455         int error;
 456         int i;
 457
 458         if (!pdata) {
 459                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 460                 if (IS_ERR(pdata))
 461                         return PTR_ERR(pdata);
 462                 if (!pdata) {
 463                         dev_err(dev, "missing platform data\n");
 464                         return -EINVAL;
 465                 }
 466         }
 467
 468         if (!pdata->poll_interval) {
 469                 dev_err(dev, "missing poll_interval value\n");
 470                 error = -EINVAL;
 471                 goto err_free_pdata;
 472         }
 473
 474         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 475                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 476                        GFP_KERNEL);
 477         if (!bdev) {
 478                 dev_err(dev, "no memory for private data\n");
 479                 return -ENOMEM;
 480         }
 481
 482         for (i = 0; i < pdata->nbuttons; i++) {
 483                 struct gpio_keys_button *button = &pdata->buttons[i];
 484                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 485                 unsigned int gpio = button->gpio;
 486
 487                 if (button->wakeup) {
 488                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 489                         error = -EINVAL;
 490                         goto err_free_gpio;
 491                 }
 492
 493                 error = gpio_request(gpio,
 494                                      button->desc ? button->desc : DRV_NAME);
 495                 if (error) {
 496                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 497                                 gpio, error);
 498                         goto err_free_gpio;
 499                 }
 500
 501                 error = gpio_direction_input(gpio);
 502                 if (error) {
 503                         dev_err(dev,
 504                                 "unable to set direction on gpio %u, err=%d\n",
 505                                 gpio, error);
 506                         goto err_free_gpio;
 507                 }
 508
 509                 bdata->can_sleep = gpio_cansleep(gpio);
 510                 bdata->last_state = -1;
 511                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 512                                                 pdata->poll_interval);
 513         }
 514
 515         bdev->dev = &pdev->dev;
 516         bdev->pdata = pdata;
 517         platform_set_drvdata(pdev, bdev);
 518
 519         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 520
 521         gpio_keys_polled_open(bdev);
 522
 523         return 0;
 524
 525 err_free_gpio:
 526         while (--i >= 0)
 527                 gpio_free(pdata->buttons[i].gpio);
 528
 529         kfree(bdev);
 530         platform_set_drvdata(pdev, NULL);
 531
 532 err_free_pdata:
 533         /* If we have no platform_data, we allocated pdata dynamically.  */
 534         if (!dev_get_platdata(&pdev->dev))
 535                 kfree(pdata);
 536
 537         return error;
 538 }
 539
 540 static int gpio_keys_polled_remove(struct platform_device *pdev)
 541 {
 542         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 543         struct gpio_keys_platform_data *pdata = bdev->pdata;
 544         int i = pdata->nbuttons;
 545
 546         gpio_keys_polled_close(bdev);
 547
 548         while (--i >= 0)
 549                 gpio_free(pdata->buttons[i].gpio);
 550
 551         kfree(bdev);
 552         platform_set_drvdata(pdev, NULL);
 553
 554         return 0;
 555 }
 556
 557 static struct platform_driver gpio_keys_polled_driver = {
 558         .probe  = gpio_keys_polled_probe,
 559         .remove = gpio_keys_polled_remove,
 560         .driver = {
 561                 .name   = DRV_NAME,
 562                 .owner  = THIS_MODULE,
 563                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 564         },
 565 };
 566
 567 static int __init gpio_keys_polled_init(void)
 568 {
 569         return platform_driver_register(&gpio_keys_polled_driver);
 570 }
 571
 572 static void __exit gpio_keys_polled_exit(void)
 573 {
 574         platform_driver_unregister(&gpio_keys_polled_driver);
 575 }
 576
 577 module_init(gpio_keys_polled_init);
 578 module_exit(gpio_keys_polled_exit);
 579
 580 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 581 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 582 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 583 MODULE_LICENSE("GPL v2");
 584 MODULE_ALIAS("platform:" DRV_NAME);