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_RESTART,     "reset"),
  94         BH_MAP(KEY_RFKILL,      "rfkill"),
  95         BH_MAP(KEY_WPS_BUTTON,  "wps"),
  96 };
  97
  98 /* -------------------------------------------------------------------------*/
  99
 100 static int bh_event_add_var(struct bh_event *event, int argv,
 101                 const char *format, ...)
 102 {
 103         static char buf[128];
 104         char *s;
 105         va_list args;
 106         int len;
 107
 108         if (argv)
 109                 return 0;
 110
 111         va_start(args, format);
 112         len = vsnprintf(buf, sizeof(buf), format, args);
 113         va_end(args);
 114
 115         if (len >= sizeof(buf)) {
 116                 BH_ERR("buffer size too small\n");
 117                 WARN_ON(1);
 118                 return -ENOMEM;
 119         }
 120
 121         s = skb_put(event->skb, len + 1);
 122         strcpy(s, buf);
 123
 124         BH_DBG("added variable '%s'\n", s);
 125
 126         return 0;
 127 }
 128
 129 static int button_hotplug_fill_event(struct bh_event *event)
 130 {
 131         char *s;
 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         switch (event->type) {
 144                 case EV_SW:
 145                         s = "switch";
 146                         break;
 147                 case EV_KEY:
 148                 default:
 149                         s = "button";
 150                         break;
 151         }
 152
 153         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", s);
 154         if (ret)
 155                 return ret;
 156
 157         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 158         if (ret)
 159                 return ret;
 160
 161         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 162         if (ret)
 163                 return ret;
 164
 165         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 166         if (ret)
 167                 return ret;
 168
 169         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 170
 171         return ret;
 172 }
 173
 174 static void button_hotplug_work(struct work_struct *work)
 175 {
 176         struct bh_event *event = container_of(work, struct bh_event, work);
 177         int ret = 0;
 178
 179         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 180         if (!event->skb)
 181                 goto out_free_event;
 182
 183         ret = bh_event_add_var(event, 0, "%s@", event->action);
 184         if (ret)
 185                 goto out_free_skb;
 186
 187         ret = button_hotplug_fill_event(event);
 188         if (ret)
 189                 goto out_free_skb;
 190
 191         NETLINK_CB(event->skb).dst_group = 1;
 192         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 193
 194  out_free_skb:
 195         if (ret) {
 196                 BH_ERR("work error %d\n", ret);
 197                 kfree_skb(event->skb);
 198         }
 199  out_free_event:
 200         kfree(event);
 201 }
 202
 203 static int button_hotplug_create_event(const char *name, unsigned int type,
 204                 unsigned long seen, int pressed)
 205 {
 206         struct bh_event *event;
 207
 208         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 209                 name, seen, pressed);
 210
 211         event = kzalloc(sizeof(*event), GFP_KERNEL);
 212         if (!event)
 213                 return -ENOMEM;
 214
 215         event->name = name;
 216         event->type = type;
 217         event->seen = seen;
 218         event->action = pressed ? "pressed" : "released";
 219
 220         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 221         schedule_work(&event->work);
 222
 223         return 0;
 224 }
 225
 226 /* -------------------------------------------------------------------------*/
 227
 228 #ifdef  CONFIG_HOTPLUG
 229 static int button_get_index(unsigned int code)
 230 {
 231         int i;
 232
 233         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 234                 if (button_map[i].code == code)
 235                         return i;
 236
 237         return -1;
 238 }
 239
 240 static void button_hotplug_event(struct gpio_keys_button_data *data,
 241                            unsigned int type, unsigned int code, int value)
 242 {
 243         struct bh_priv *priv = &data->bh;
 244         unsigned long seen = jiffies;
 245         int btn;
 246
 247         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 248
 249         if ((type != EV_KEY) && (type != EV_SW))
 250                 return;
 251
 252         btn = button_get_index(code);
 253         if (btn < 0)
 254                 return;
 255
 256         button_hotplug_create_event(button_map[btn].name, type,
 257                         (seen - priv->seen) / HZ, value);
 258         priv->seen = seen;
 259 }
 260 #else
 261 static void button_hotplug_event(struct gpio_keys_button_data *data,
 262                            unsigned int type, unsigned int code, int value)
 263 {
 264 }
 265 #endif  /* CONFIG_HOTPLUG */
 266
 267 struct gpio_keys_polled_dev {
 268         struct delayed_work work;
 269
 270         struct device *dev;
 271         struct gpio_keys_platform_data *pdata;
 272         struct gpio_keys_button_data data[0];
 273 };
 274
 275 static int gpio_button_get_value(struct gpio_keys_button *button,
 276                                  struct gpio_keys_button_data *bdata)
 277 {
 278         int val;
 279
 280         if (bdata->can_sleep)
 281                 val = !!gpio_get_value_cansleep(button->gpio);
 282         else
 283                 val = !!gpio_get_value(button->gpio);
 284
 285         return val ^ button->active_low;
 286 }
 287
 288 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 289                                          struct gpio_keys_button_data *bdata)
 290 {
 291         int state = gpio_button_get_value(button, bdata);
 292
 293         if (state != bdata->last_state) {
 294                 unsigned int type = button->type ?: EV_KEY;
 295
 296                 if (bdata->count < bdata->threshold) {
 297                         bdata->count++;
 298                         return;
 299                 }
 300
 301                 button_hotplug_event(bdata, type, button->code, state);
 302                 bdata->last_state = state;
 303         }
 304
 305         bdata->count = 0;
 306 }
 307
 308 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 309 {
 310         struct gpio_keys_platform_data *pdata = bdev->pdata;
 311         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 312
 313         if (delay >= HZ)
 314             delay = round_jiffies_relative(delay);
 315         schedule_delayed_work(&bdev->work, delay);
 316 }
 317
 318 static void gpio_keys_polled_poll(struct work_struct *work)
 319 {
 320         struct gpio_keys_polled_dev *bdev =
 321                 container_of(work, struct gpio_keys_polled_dev, work.work);
 322         struct gpio_keys_platform_data *pdata = bdev->pdata;
 323         int i;
 324
 325         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 326                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 327                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 328         }
 329         gpio_keys_polled_queue_work(bdev);
 330 }
 331
 332 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 333 {
 334         struct gpio_keys_platform_data *pdata = bdev->pdata;
 335         int i;
 336
 337         if (pdata->enable)
 338                 pdata->enable(bdev->dev);
 339
 340         /* report initial state of the buttons */
 341         for (i = 0; i < pdata->nbuttons; i++)
 342                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 343
 344         gpio_keys_polled_queue_work(bdev);
 345 }
 346
 347 #ifdef CONFIG_OF
 348 static struct gpio_keys_platform_data *
 349 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 350 {
 351         struct device_node *node, *pp;
 352         struct gpio_keys_platform_data *pdata;
 353         struct gpio_keys_button *button;
 354         int error;
 355         int nbuttons;
 356         int i;
 357
 358         node = dev->of_node;
 359         if (!node)
 360                 return NULL;
 361
 362         nbuttons = of_get_child_count(node);
 363         if (nbuttons == 0)
 364                 return NULL;
 365
 366         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 367                 GFP_KERNEL);
 368         if (!pdata) {
 369                 error = -ENOMEM;
 370                 goto err_out;
 371         }
 372
 373         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 374         pdata->nbuttons = nbuttons;
 375
 376         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 377         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 378
 379         i = 0;
 380         for_each_child_of_node(node, pp) {
 381                 enum of_gpio_flags flags;
 382
 383                 if (!of_find_property(pp, "gpios", NULL)) {
 384                         pdata->nbuttons--;
 385                         dev_warn(dev, "Found button without gpios\n");
 386                         continue;
 387                 }
 388
 389                 button = &pdata->buttons[i++];
 390
 391                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 392                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 393
 394                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 395                         dev_err(dev, "Button without keycode: 0x%x\n",
 396                                 button->gpio);
 397                         error = -EINVAL;
 398                         goto err_free_pdata;
 399                 }
 400
 401                 button->desc = of_get_property(pp, "label", NULL);
 402
 403                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 404                         button->type = EV_KEY;
 405
 406                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 407
 408                 if (of_property_read_u32(pp, "debounce-interval",
 409                                         &button->debounce_interval))
 410                         button->debounce_interval = 5;
 411         }
 412
 413         if (pdata->nbuttons == 0) {
 414                 error = -EINVAL;
 415                 goto err_free_pdata;
 416         }
 417
 418         return pdata;
 419
 420 err_free_pdata:
 421         kfree(pdata);
 422 err_out:
 423         return ERR_PTR(error);
 424 }
 425
 426 static struct of_device_id gpio_keys_polled_of_match[] = {
 427         { .compatible = "gpio-keys-polled", },
 428         { },
 429 };
 430 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 431
 432 #else
 433
 434 static inline struct gpio_keys_platform_data *
 435 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 436 {
 437         return NULL;
 438 }
 439 #endif
 440
 441 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 442 {
 443         struct gpio_keys_platform_data *pdata = bdev->pdata;
 444
 445         cancel_delayed_work_sync(&bdev->work);
 446
 447         if (pdata->disable)
 448                 pdata->disable(bdev->dev);
 449 }
 450
 451 static int gpio_keys_polled_probe(struct platform_device *pdev)
 452 {
 453         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 454         struct device *dev = &pdev->dev;
 455         struct gpio_keys_polled_dev *bdev;
 456         int error;
 457         int i;
 458
 459         if (!pdata) {
 460                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 461                 if (IS_ERR(pdata))
 462                         return PTR_ERR(pdata);
 463                 if (!pdata) {
 464                         dev_err(dev, "missing platform data\n");
 465                         return -EINVAL;
 466                 }
 467         }
 468
 469         if (!pdata->poll_interval) {
 470                 dev_err(dev, "missing poll_interval value\n");
 471                 error = -EINVAL;
 472                 goto err_free_pdata;
 473         }
 474
 475         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 476                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 477                        GFP_KERNEL);
 478         if (!bdev) {
 479                 dev_err(dev, "no memory for private data\n");
 480                 return -ENOMEM;
 481         }
 482
 483         for (i = 0; i < pdata->nbuttons; i++) {
 484                 struct gpio_keys_button *button = &pdata->buttons[i];
 485                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 486                 unsigned int gpio = button->gpio;
 487
 488                 if (button->wakeup) {
 489                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 490                         error = -EINVAL;
 491                         goto err_free_gpio;
 492                 }
 493
 494                 error = gpio_request(gpio,
 495                                      button->desc ? button->desc : DRV_NAME);
 496                 if (error) {
 497                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 498                                 gpio, error);
 499                         goto err_free_gpio;
 500                 }
 501
 502                 error = gpio_direction_input(gpio);
 503                 if (error) {
 504                         dev_err(dev,
 505                                 "unable to set direction on gpio %u, err=%d\n",
 506                                 gpio, error);
 507                         goto err_free_gpio;
 508                 }
 509
 510                 bdata->can_sleep = gpio_cansleep(gpio);
 511                 bdata->last_state = gpio_button_get_value(button, bdata);
 512                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 513                                                 pdata->poll_interval);
 514         }
 515
 516         bdev->dev = &pdev->dev;
 517         bdev->pdata = pdata;
 518         platform_set_drvdata(pdev, bdev);
 519
 520         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 521
 522         gpio_keys_polled_open(bdev);
 523
 524         return 0;
 525
 526 err_free_gpio:
 527         while (--i >= 0)
 528                 gpio_free(pdata->buttons[i].gpio);
 529
 530         kfree(bdev);
 531         platform_set_drvdata(pdev, NULL);
 532
 533 err_free_pdata:
 534         /* If we have no platform_data, we allocated pdata dynamically.  */
 535         if (!dev_get_platdata(&pdev->dev))
 536                 kfree(pdata);
 537
 538         return error;
 539 }
 540
 541 static int gpio_keys_polled_remove(struct platform_device *pdev)
 542 {
 543         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 544         struct gpio_keys_platform_data *pdata = bdev->pdata;
 545         int i = pdata->nbuttons;
 546
 547         gpio_keys_polled_close(bdev);
 548
 549         while (--i >= 0)
 550                 gpio_free(pdata->buttons[i].gpio);
 551
 552         kfree(bdev);
 553         platform_set_drvdata(pdev, NULL);
 554
 555         return 0;
 556 }
 557
 558 static struct platform_driver gpio_keys_polled_driver = {
 559         .probe  = gpio_keys_polled_probe,
 560         .remove = gpio_keys_polled_remove,
 561         .driver = {
 562                 .name   = DRV_NAME,
 563                 .owner  = THIS_MODULE,
 564                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 565         },
 566 };
 567
 568 static int __init gpio_keys_polled_init(void)
 569 {
 570         return platform_driver_register(&gpio_keys_polled_driver);
 571 }
 572
 573 static void __exit gpio_keys_polled_exit(void)
 574 {
 575         platform_driver_unregister(&gpio_keys_polled_driver);
 576 }
 577
 578 module_init(gpio_keys_polled_init);
 579 module_exit(gpio_keys_polled_exit);
 580
 581 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 582 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 583 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 584 MODULE_LICENSE("GPL v2");
 585 MODULE_ALIAS("platform:" DRV_NAME);