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         int ret;
 132
 133         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 134         if (ret)
 135                 return ret;
 136
 137         ret = bh_event_add_var(event, 0, "PATH=%s",
 138                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 139         if (ret)
 140                 return ret;
 141
 142         char *s;
 143         switch (event->type) {
 144                 case EV_KEY:
 145                         s = "button";
 146                         break;
 147                 case EV_SW:
 148                         s = "switch";
 149                         break;
 150                 default:
 151                         s = "button";
 152                         break;
 153         }
 154
 155         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", s);
 156         if (ret)
 157                 return ret;
 158
 159         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 160         if (ret)
 161                 return ret;
 162
 163         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 164         if (ret)
 165                 return ret;
 166
 167         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 168         if (ret)
 169                 return ret;
 170
 171         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 172
 173         return ret;
 174 }
 175
 176 static void button_hotplug_work(struct work_struct *work)
 177 {
 178         struct bh_event *event = container_of(work, struct bh_event, work);
 179         int ret = 0;
 180
 181         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 182         if (!event->skb)
 183                 goto out_free_event;
 184
 185         ret = bh_event_add_var(event, 0, "%s@", event->action);
 186         if (ret)
 187                 goto out_free_skb;
 188
 189         ret = button_hotplug_fill_event(event);
 190         if (ret)
 191                 goto out_free_skb;
 192
 193         NETLINK_CB(event->skb).dst_group = 1;
 194         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 195
 196  out_free_skb:
 197         if (ret) {
 198                 BH_ERR("work error %d\n", ret);
 199                 kfree_skb(event->skb);
 200         }
 201  out_free_event:
 202         kfree(event);
 203 }
 204
 205 static int button_hotplug_create_event(const char *name, unsigned int type,
 206                 unsigned long seen, int pressed)
 207 {
 208         struct bh_event *event;
 209
 210         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 211                 name, seen, pressed);
 212
 213         event = kzalloc(sizeof(*event), GFP_KERNEL);
 214         if (!event)
 215                 return -ENOMEM;
 216
 217         event->name = name;
 218         event->type = type;
 219         event->seen = seen;
 220         event->action = pressed ? "pressed" : "released";
 221
 222         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 223         schedule_work(&event->work);
 224
 225         return 0;
 226 }
 227
 228 /* -------------------------------------------------------------------------*/
 229
 230 #ifdef  CONFIG_HOTPLUG
 231 static int button_get_index(unsigned int code)
 232 {
 233         int i;
 234
 235         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 236                 if (button_map[i].code == code)
 237                         return i;
 238
 239         return -1;
 240 }
 241
 242 static void button_hotplug_event(struct gpio_keys_button_data *data,
 243                            unsigned int type, unsigned int code, int value)
 244 {
 245         struct bh_priv *priv = &data->bh;
 246         unsigned long seen = jiffies;
 247         int btn;
 248
 249         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 250
 251         if ((type != EV_KEY) && (type != EV_SW))
 252                 return;
 253
 254         btn = button_get_index(code);
 255         if (btn < 0)
 256                 return;
 257
 258         button_hotplug_create_event(button_map[btn].name, type,
 259                         (seen - priv->seen) / HZ, value);
 260         priv->seen = seen;
 261 }
 262 #else
 263 static void button_hotplug_event(struct gpio_keys_button_data *data,
 264                            unsigned int type, unsigned int code, int value)
 265 {
 266 }
 267 #endif  /* CONFIG_HOTPLUG */
 268
 269 struct gpio_keys_polled_dev {
 270         struct delayed_work work;
 271
 272         struct device *dev;
 273         struct gpio_keys_platform_data *pdata;
 274         struct gpio_keys_button_data data[0];
 275 };
 276
 277 static inline int gpio_button_get_value(struct gpio_keys_button *button,
 278                           struct gpio_keys_button_data *bdata)
 279 {
 280         if (bdata->can_sleep)
 281                 return !!gpio_get_value_cansleep(button->gpio);
 282         else
 283                 return !!gpio_get_value(button->gpio);
 284 }
 285
 286 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 287                                          struct gpio_keys_button_data *bdata)
 288 {
 289         int state;
 290
 291         state = gpio_button_get_value(button, bdata);
 292
 293         state = !!(state ^ button->active_low);
 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                 button_hotplug_event(bdata, type, button->code, state);
 303                 bdata->last_state = state;
 304         }
 305
 306         bdata->count = 0;
 307 }
 308
 309 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 310 {
 311         struct gpio_keys_platform_data *pdata = bdev->pdata;
 312         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 313
 314         if (delay >= HZ)
 315             delay = round_jiffies_relative(delay);
 316         schedule_delayed_work(&bdev->work, delay);
 317 }
 318
 319 static void gpio_keys_polled_poll(struct work_struct *work)
 320 {
 321         struct gpio_keys_polled_dev *bdev =
 322                 container_of(work, struct gpio_keys_polled_dev, work.work);
 323         struct gpio_keys_platform_data *pdata = bdev->pdata;
 324         int i;
 325
 326         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 327                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 328                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 329         }
 330         gpio_keys_polled_queue_work(bdev);
 331 }
 332
 333 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 334 {
 335         struct gpio_keys_platform_data *pdata = bdev->pdata;
 336         int i;
 337
 338         if (pdata->enable)
 339                 pdata->enable(bdev->dev);
 340
 341         /* report initial state of the buttons */
 342         for (i = 0; i < pdata->nbuttons; i++)
 343                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 344
 345         gpio_keys_polled_queue_work(bdev);
 346 }
 347
 348 #ifdef CONFIG_OF
 349 static struct gpio_keys_platform_data *
 350 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 351 {
 352         struct device_node *node, *pp;
 353         struct gpio_keys_platform_data *pdata;
 354         struct gpio_keys_button *button;
 355         int error;
 356         int nbuttons;
 357         int i;
 358
 359         node = dev->of_node;
 360         if (!node)
 361                 return NULL;
 362
 363         nbuttons = of_get_child_count(node);
 364         if (nbuttons == 0)
 365                 return NULL;
 366
 367         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 368                 GFP_KERNEL);
 369         if (!pdata) {
 370                 error = -ENOMEM;
 371                 goto err_out;
 372         }
 373
 374         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 375         pdata->nbuttons = nbuttons;
 376
 377         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 378         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 379
 380         i = 0;
 381         for_each_child_of_node(node, pp) {
 382                 enum of_gpio_flags flags;
 383
 384                 if (!of_find_property(pp, "gpios", NULL)) {
 385                         pdata->nbuttons--;
 386                         dev_warn(dev, "Found button without gpios\n");
 387                         continue;
 388                 }
 389
 390                 button = &pdata->buttons[i++];
 391
 392                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 393                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 394
 395                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 396                         dev_err(dev, "Button without keycode: 0x%x\n",
 397                                 button->gpio);
 398                         error = -EINVAL;
 399                         goto err_free_pdata;
 400                 }
 401
 402                 button->desc = of_get_property(pp, "label", NULL);
 403
 404                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 405                         button->type = EV_KEY;
 406
 407                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 408
 409                 if (of_property_read_u32(pp, "debounce-interval",
 410                                         &button->debounce_interval))
 411                         button->debounce_interval = 5;
 412         }
 413
 414         if (pdata->nbuttons == 0) {
 415                 error = -EINVAL;
 416                 goto err_free_pdata;
 417         }
 418
 419         return pdata;
 420
 421 err_free_pdata:
 422         kfree(pdata);
 423 err_out:
 424         return ERR_PTR(error);
 425 }
 426
 427 static struct of_device_id gpio_keys_polled_of_match[] = {
 428         { .compatible = "gpio-keys-polled", },
 429         { },
 430 };
 431 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 432
 433 #else
 434
 435 static inline struct gpio_keys_platform_data *
 436 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 437 {
 438         return NULL;
 439 }
 440 #endif
 441
 442 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 443 {
 444         struct gpio_keys_platform_data *pdata = bdev->pdata;
 445
 446         cancel_delayed_work_sync(&bdev->work);
 447
 448         if (pdata->disable)
 449                 pdata->disable(bdev->dev);
 450 }
 451
 452 static int gpio_keys_polled_probe(struct platform_device *pdev)
 453 {
 454         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 455         struct device *dev = &pdev->dev;
 456         struct gpio_keys_polled_dev *bdev;
 457         int error;
 458         int i;
 459
 460         if (!pdata) {
 461                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 462                 if (IS_ERR(pdata))
 463                         return PTR_ERR(pdata);
 464                 if (!pdata) {
 465                         dev_err(dev, "missing platform data\n");
 466                         return -EINVAL;
 467                 }
 468         }
 469
 470         if (!pdata->poll_interval) {
 471                 dev_err(dev, "missing poll_interval value\n");
 472                 error = -EINVAL;
 473                 goto err_free_pdata;
 474         }
 475
 476         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 477                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 478                        GFP_KERNEL);
 479         if (!bdev) {
 480                 dev_err(dev, "no memory for private data\n");
 481                 return -ENOMEM;
 482         }
 483
 484         for (i = 0; i < pdata->nbuttons; i++) {
 485                 struct gpio_keys_button *button = &pdata->buttons[i];
 486                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 487                 unsigned int gpio = button->gpio;
 488
 489                 if (button->wakeup) {
 490                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 491                         error = -EINVAL;
 492                         goto err_free_gpio;
 493                 }
 494
 495                 error = gpio_request(gpio,
 496                                      button->desc ? button->desc : DRV_NAME);
 497                 if (error) {
 498                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 499                                 gpio, error);
 500                         goto err_free_gpio;
 501                 }
 502
 503                 error = gpio_direction_input(gpio);
 504                 if (error) {
 505                         dev_err(dev,
 506                                 "unable to set direction on gpio %u, err=%d\n",
 507                                 gpio, error);
 508                         goto err_free_gpio;
 509                 }
 510
 511                 bdata->can_sleep = gpio_cansleep(gpio);
 512                 bdata->last_state = 0;
 513                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 514                                                 pdata->poll_interval);
 515         }
 516
 517         bdev->dev = &pdev->dev;
 518         bdev->pdata = pdata;
 519         platform_set_drvdata(pdev, bdev);
 520
 521         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 522
 523         gpio_keys_polled_open(bdev);
 524
 525         return 0;
 526
 527 err_free_gpio:
 528         while (--i >= 0)
 529                 gpio_free(pdata->buttons[i].gpio);
 530
 531         kfree(bdev);
 532         platform_set_drvdata(pdev, NULL);
 533
 534 err_free_pdata:
 535         /* If we have no platform_data, we allocated pdata dynamically.  */
 536         if (!dev_get_platdata(&pdev->dev))
 537                 kfree(pdata);
 538
 539         return error;
 540 }
 541
 542 static int gpio_keys_polled_remove(struct platform_device *pdev)
 543 {
 544         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 545         struct gpio_keys_platform_data *pdata = bdev->pdata;
 546         int i = pdata->nbuttons;
 547
 548         gpio_keys_polled_close(bdev);
 549
 550         while (--i >= 0)
 551                 gpio_free(pdata->buttons[i].gpio);
 552
 553         kfree(bdev);
 554         platform_set_drvdata(pdev, NULL);
 555
 556         return 0;
 557 }
 558
 559 static struct platform_driver gpio_keys_polled_driver = {
 560         .probe  = gpio_keys_polled_probe,
 561         .remove = gpio_keys_polled_remove,
 562         .driver = {
 563                 .name   = DRV_NAME,
 564                 .owner  = THIS_MODULE,
 565                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 566         },
 567 };
 568
 569 static int __init gpio_keys_polled_init(void)
 570 {
 571         return platform_driver_register(&gpio_keys_polled_driver);
 572 }
 573
 574 static void __exit gpio_keys_polled_exit(void)
 575 {
 576         platform_driver_unregister(&gpio_keys_polled_driver);
 577 }
 578
 579 module_init(gpio_keys_polled_init);
 580 module_exit(gpio_keys_polled_exit);
 581
 582 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 583 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 584 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 585 MODULE_LICENSE("GPL v2");
 586 MODULE_ALIAS("platform:" DRV_NAME);