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 int gpio_button_get_value(struct gpio_keys_button *button,
 278                                  struct gpio_keys_button_data *bdata)
 279 {
 280         int val;
 281
 282         if (bdata->can_sleep)
 283                 val = !!gpio_get_value_cansleep(button->gpio);
 284         else
 285                 val = !!gpio_get_value(button->gpio);
 286
 287         return val ^ button->active_low;
 288 }
 289
 290 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 291                                          struct gpio_keys_button_data *bdata)
 292 {
 293         int state = gpio_button_get_value(button, bdata);
 294
 295         if (state != bdata->last_state) {
 296                 unsigned int type = button->type ?: EV_KEY;
 297
 298                 if (bdata->count < bdata->threshold) {
 299                         bdata->count++;
 300                         return;
 301                 }
 302
 303                 button_hotplug_event(bdata, type, button->code, state);
 304                 bdata->last_state = state;
 305         }
 306
 307         bdata->count = 0;
 308 }
 309
 310 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 311 {
 312         struct gpio_keys_platform_data *pdata = bdev->pdata;
 313         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 314
 315         if (delay >= HZ)
 316             delay = round_jiffies_relative(delay);
 317         schedule_delayed_work(&bdev->work, delay);
 318 }
 319
 320 static void gpio_keys_polled_poll(struct work_struct *work)
 321 {
 322         struct gpio_keys_polled_dev *bdev =
 323                 container_of(work, struct gpio_keys_polled_dev, work.work);
 324         struct gpio_keys_platform_data *pdata = bdev->pdata;
 325         int i;
 326
 327         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 328                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 329                 gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 330         }
 331         gpio_keys_polled_queue_work(bdev);
 332 }
 333
 334 static void gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 335 {
 336         struct gpio_keys_platform_data *pdata = bdev->pdata;
 337         int i;
 338
 339         if (pdata->enable)
 340                 pdata->enable(bdev->dev);
 341
 342         /* report initial state of the buttons */
 343         for (i = 0; i < pdata->nbuttons; i++)
 344                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 345
 346         gpio_keys_polled_queue_work(bdev);
 347 }
 348
 349 #ifdef CONFIG_OF
 350 static struct gpio_keys_platform_data *
 351 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 352 {
 353         struct device_node *node, *pp;
 354         struct gpio_keys_platform_data *pdata;
 355         struct gpio_keys_button *button;
 356         int error;
 357         int nbuttons;
 358         int i;
 359
 360         node = dev->of_node;
 361         if (!node)
 362                 return NULL;
 363
 364         nbuttons = of_get_child_count(node);
 365         if (nbuttons == 0)
 366                 return NULL;
 367
 368         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 369                 GFP_KERNEL);
 370         if (!pdata) {
 371                 error = -ENOMEM;
 372                 goto err_out;
 373         }
 374
 375         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 376         pdata->nbuttons = nbuttons;
 377
 378         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 379         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 380
 381         i = 0;
 382         for_each_child_of_node(node, pp) {
 383                 enum of_gpio_flags flags;
 384
 385                 if (!of_find_property(pp, "gpios", NULL)) {
 386                         pdata->nbuttons--;
 387                         dev_warn(dev, "Found button without gpios\n");
 388                         continue;
 389                 }
 390
 391                 button = &pdata->buttons[i++];
 392
 393                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 394                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 395
 396                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 397                         dev_err(dev, "Button without keycode: 0x%x\n",
 398                                 button->gpio);
 399                         error = -EINVAL;
 400                         goto err_free_pdata;
 401                 }
 402
 403                 button->desc = of_get_property(pp, "label", NULL);
 404
 405                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 406                         button->type = EV_KEY;
 407
 408                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 409
 410                 if (of_property_read_u32(pp, "debounce-interval",
 411                                         &button->debounce_interval))
 412                         button->debounce_interval = 5;
 413         }
 414
 415         if (pdata->nbuttons == 0) {
 416                 error = -EINVAL;
 417                 goto err_free_pdata;
 418         }
 419
 420         return pdata;
 421
 422 err_free_pdata:
 423         kfree(pdata);
 424 err_out:
 425         return ERR_PTR(error);
 426 }
 427
 428 static struct of_device_id gpio_keys_polled_of_match[] = {
 429         { .compatible = "gpio-keys-polled", },
 430         { },
 431 };
 432 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 433
 434 #else
 435
 436 static inline struct gpio_keys_platform_data *
 437 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 438 {
 439         return NULL;
 440 }
 441 #endif
 442
 443 static void gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 444 {
 445         struct gpio_keys_platform_data *pdata = bdev->pdata;
 446
 447         cancel_delayed_work_sync(&bdev->work);
 448
 449         if (pdata->disable)
 450                 pdata->disable(bdev->dev);
 451 }
 452
 453 static int gpio_keys_polled_probe(struct platform_device *pdev)
 454 {
 455         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 456         struct device *dev = &pdev->dev;
 457         struct gpio_keys_polled_dev *bdev;
 458         int error;
 459         int i;
 460
 461         if (!pdata) {
 462                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 463                 if (IS_ERR(pdata))
 464                         return PTR_ERR(pdata);
 465                 if (!pdata) {
 466                         dev_err(dev, "missing platform data\n");
 467                         return -EINVAL;
 468                 }
 469         }
 470
 471         if (!pdata->poll_interval) {
 472                 dev_err(dev, "missing poll_interval value\n");
 473                 error = -EINVAL;
 474                 goto err_free_pdata;
 475         }
 476
 477         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 478                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 479                        GFP_KERNEL);
 480         if (!bdev) {
 481                 dev_err(dev, "no memory for private data\n");
 482                 return -ENOMEM;
 483         }
 484
 485         for (i = 0; i < pdata->nbuttons; i++) {
 486                 struct gpio_keys_button *button = &pdata->buttons[i];
 487                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 488                 unsigned int gpio = button->gpio;
 489
 490                 if (button->wakeup) {
 491                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 492                         error = -EINVAL;
 493                         goto err_free_gpio;
 494                 }
 495
 496                 error = gpio_request(gpio,
 497                                      button->desc ? button->desc : DRV_NAME);
 498                 if (error) {
 499                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 500                                 gpio, error);
 501                         goto err_free_gpio;
 502                 }
 503
 504                 error = gpio_direction_input(gpio);
 505                 if (error) {
 506                         dev_err(dev,
 507                                 "unable to set direction on gpio %u, err=%d\n",
 508                                 gpio, error);
 509                         goto err_free_gpio;
 510                 }
 511
 512                 bdata->can_sleep = gpio_cansleep(gpio);
 513                 bdata->last_state = gpio_button_get_value(button, bdata);
 514                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 515                                                 pdata->poll_interval);
 516         }
 517
 518         bdev->dev = &pdev->dev;
 519         bdev->pdata = pdata;
 520         platform_set_drvdata(pdev, bdev);
 521
 522         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 523
 524         gpio_keys_polled_open(bdev);
 525
 526         return 0;
 527
 528 err_free_gpio:
 529         while (--i >= 0)
 530                 gpio_free(pdata->buttons[i].gpio);
 531
 532         kfree(bdev);
 533         platform_set_drvdata(pdev, NULL);
 534
 535 err_free_pdata:
 536         /* If we have no platform_data, we allocated pdata dynamically.  */
 537         if (!dev_get_platdata(&pdev->dev))
 538                 kfree(pdata);
 539
 540         return error;
 541 }
 542
 543 static int gpio_keys_polled_remove(struct platform_device *pdev)
 544 {
 545         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 546         struct gpio_keys_platform_data *pdata = bdev->pdata;
 547         int i = pdata->nbuttons;
 548
 549         gpio_keys_polled_close(bdev);
 550
 551         while (--i >= 0)
 552                 gpio_free(pdata->buttons[i].gpio);
 553
 554         kfree(bdev);
 555         platform_set_drvdata(pdev, NULL);
 556
 557         return 0;
 558 }
 559
 560 static struct platform_driver gpio_keys_polled_driver = {
 561         .probe  = gpio_keys_polled_probe,
 562         .remove = gpio_keys_polled_remove,
 563         .driver = {
 564                 .name   = DRV_NAME,
 565                 .owner  = THIS_MODULE,
 566                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 567         },
 568 };
 569
 570 static int __init gpio_keys_polled_init(void)
 571 {
 572         return platform_driver_register(&gpio_keys_polled_driver);
 573 }
 574
 575 static void __exit gpio_keys_polled_exit(void)
 576 {
 577         platform_driver_unregister(&gpio_keys_polled_driver);
 578 }
 579
 580 module_init(gpio_keys_polled_init);
 581 module_exit(gpio_keys_polled_exit);
 582
 583 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 584 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 585 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 586 MODULE_LICENSE("GPL v2");
 587 MODULE_ALIAS("platform:" DRV_NAME);