package/kernel/gpio-button-hotplug/src/gpio-button-hotplug.c

   1 /*
   2  *  GPIO Button Hotplug driver
   3  *
   4  *  Copyright (C) 2012 Felix Fietkau <nbd@nbd.name>
   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@nbd.name>
  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/interrupt.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/of_gpio.h>
  29 #include <linux/gpio_keys.h>
  30
  31 #define DRV_NAME        "gpio-keys"
  32
  33 #define BH_SKB_SIZE     2048
  34
  35 #define PFX     DRV_NAME ": "
  36
  37 #undef BH_DEBUG
  38
  39 #ifdef BH_DEBUG
  40 #define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
  41 #else
  42 #define BH_DBG(fmt, args...) do {} while (0)
  43 #endif
  44
  45 #define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
  46
  47 struct bh_priv {
  48         unsigned long           seen;
  49 };
  50
  51 struct bh_event {
  52         const char              *name;
  53         unsigned int            type;
  54         char                    *action;
  55         unsigned long           seen;
  56
  57         struct sk_buff          *skb;
  58         struct work_struct      work;
  59 };
  60
  61 struct bh_map {
  62         unsigned int    code;
  63         const char      *name;
  64 };
  65
  66 struct gpio_keys_button_data {
  67         struct delayed_work work;
  68         struct bh_priv bh;
  69         int last_state;
  70         int count;
  71         int threshold;
  72         int can_sleep;
  73         struct gpio_keys_button *b;
  74 };
  75
  76 extern u64 uevent_next_seqnum(void);
  77
  78 #define BH_MAP(_code, _name)            \
  79         {                               \
  80                 .code = (_code),        \
  81                 .name = (_name),        \
  82         }
  83
  84 static struct bh_map button_map[] = {
  85         BH_MAP(BTN_0,                   "BTN_0"),
  86         BH_MAP(BTN_1,                   "BTN_1"),
  87         BH_MAP(BTN_2,                   "BTN_2"),
  88         BH_MAP(BTN_3,                   "BTN_3"),
  89         BH_MAP(BTN_4,                   "BTN_4"),
  90         BH_MAP(BTN_5,                   "BTN_5"),
  91         BH_MAP(BTN_6,                   "BTN_6"),
  92         BH_MAP(BTN_7,                   "BTN_7"),
  93         BH_MAP(BTN_8,                   "BTN_8"),
  94         BH_MAP(BTN_9,                   "BTN_9"),
  95         BH_MAP(KEY_BRIGHTNESS_ZERO,     "brightness_zero"),
  96         BH_MAP(KEY_CONFIG,              "config"),
  97         BH_MAP(KEY_COPY,                "copy"),
  98         BH_MAP(KEY_EJECTCD,             "eject"),
  99         BH_MAP(KEY_HELP,                "help"),
 100         BH_MAP(KEY_LIGHTS_TOGGLE,       "lights_toggle"),
 101         BH_MAP(KEY_PHONE,               "phone"),
 102         BH_MAP(KEY_POWER,               "power"),
 103         BH_MAP(KEY_RESTART,             "reset"),
 104         BH_MAP(KEY_RFKILL,              "rfkill"),
 105         BH_MAP(KEY_VIDEO,               "video"),
 106         BH_MAP(KEY_WIMAX,               "wwan"),
 107         BH_MAP(KEY_WLAN,                "wlan"),
 108         BH_MAP(KEY_WPS_BUTTON,          "wps"),
 109 };
 110
 111 /* -------------------------------------------------------------------------*/
 112
 113 static __printf(3, 4)
 114 int bh_event_add_var(struct bh_event *event, int argv, const char *format, ...)
 115 {
 116         static char buf[128];
 117         char *s;
 118         va_list args;
 119         int len;
 120
 121         if (argv)
 122                 return 0;
 123
 124         va_start(args, format);
 125         len = vsnprintf(buf, sizeof(buf), format, args);
 126         va_end(args);
 127
 128         if (len >= sizeof(buf)) {
 129                 WARN(1, "buffer size too small");
 130                 return -ENOMEM;
 131         }
 132
 133         s = skb_put(event->skb, len + 1);
 134         strcpy(s, buf);
 135
 136         BH_DBG("added variable '%s'\n", s);
 137
 138         return 0;
 139 }
 140
 141 static int button_hotplug_fill_event(struct bh_event *event)
 142 {
 143         int ret;
 144
 145         ret = bh_event_add_var(event, 0, "HOME=%s", "/");
 146         if (ret)
 147                 return ret;
 148
 149         ret = bh_event_add_var(event, 0, "PATH=%s",
 150                                         "/sbin:/bin:/usr/sbin:/usr/bin");
 151         if (ret)
 152                 return ret;
 153
 154         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 155         if (ret)
 156                 return ret;
 157
 158         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 159         if (ret)
 160                 return ret;
 161
 162         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 163         if (ret)
 164                 return ret;
 165
 166         if (event->type == EV_SW) {
 167                 ret = bh_event_add_var(event, 0, "TYPE=%s", "switch");
 168                 if (ret)
 169                         return ret;
 170         }
 171
 172         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 173         if (ret)
 174                 return ret;
 175
 176         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 177
 178         return ret;
 179 }
 180
 181 static void button_hotplug_work(struct work_struct *work)
 182 {
 183         struct bh_event *event = container_of(work, struct bh_event, work);
 184         int ret = 0;
 185
 186         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 187         if (!event->skb)
 188                 goto out_free_event;
 189
 190         ret = bh_event_add_var(event, 0, "%s@", event->action);
 191         if (ret)
 192                 goto out_free_skb;
 193
 194         ret = button_hotplug_fill_event(event);
 195         if (ret)
 196                 goto out_free_skb;
 197
 198         NETLINK_CB(event->skb).dst_group = 1;
 199         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 200
 201  out_free_skb:
 202         if (ret) {
 203                 BH_ERR("work error %d\n", ret);
 204                 kfree_skb(event->skb);
 205         }
 206  out_free_event:
 207         kfree(event);
 208 }
 209
 210 static int button_hotplug_create_event(const char *name, unsigned int type,
 211                 unsigned long seen, int pressed)
 212 {
 213         struct bh_event *event;
 214
 215         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 216                 name, seen, pressed);
 217
 218         event = kzalloc(sizeof(*event), GFP_KERNEL);
 219         if (!event)
 220                 return -ENOMEM;
 221
 222         event->name = name;
 223         event->type = type;
 224         event->seen = seen;
 225         event->action = pressed ? "pressed" : "released";
 226
 227         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 228         schedule_work(&event->work);
 229
 230         return 0;
 231 }
 232
 233 /* -------------------------------------------------------------------------*/
 234
 235 static int button_get_index(unsigned int code)
 236 {
 237         int i;
 238
 239         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 240                 if (button_map[i].code == code)
 241                         return i;
 242
 243         return -1;
 244 }
 245
 246 static void button_hotplug_event(struct gpio_keys_button_data *data,
 247                            unsigned int type, int value)
 248 {
 249         struct bh_priv *priv = &data->bh;
 250         unsigned long seen = jiffies;
 251         int btn;
 252
 253         BH_DBG("event type=%u, code=%u, value=%d\n", type, data->b->code, value);
 254
 255         if ((type != EV_KEY) && (type != EV_SW))
 256                 return;
 257
 258         btn = button_get_index(data->b->code);
 259         if (btn < 0)
 260                 return;
 261
 262         button_hotplug_create_event(button_map[btn].name, type,
 263                         (seen - priv->seen) / HZ, value);
 264         priv->seen = seen;
 265 }
 266
 267 struct gpio_keys_button_dev {
 268         int polled;
 269         struct delayed_work work;
 270
 271         struct device *dev;
 272         struct gpio_keys_platform_data *pdata;
 273         struct gpio_keys_button_data data[0];
 274 };
 275
 276 static int gpio_button_get_value(struct gpio_keys_button_data *bdata)
 277 {
 278         int val;
 279
 280         if (bdata->can_sleep)
 281                 val = !!gpio_get_value_cansleep(bdata->b->gpio);
 282         else
 283                 val = !!gpio_get_value(bdata->b->gpio);
 284
 285         return val ^ bdata->b->active_low;
 286 }
 287
 288 static void gpio_keys_polled_check_state(struct gpio_keys_button_data *bdata)
 289 {
 290         int state = gpio_button_get_value(bdata);
 291
 292         if (state != bdata->last_state) {
 293                 unsigned int type = bdata->b->type ?: EV_KEY;
 294
 295                 if (bdata->count < bdata->threshold) {
 296                         bdata->count++;
 297                         return;
 298                 }
 299
 300                 if ((bdata->last_state != -1) || (type == EV_SW))
 301                         button_hotplug_event(bdata, type, state);
 302
 303                 bdata->last_state = state;
 304         }
 305
 306         bdata->count = 0;
 307 }
 308
 309 static void gpio_keys_polled_queue_work(struct gpio_keys_button_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_button_dev *bdev =
 322                 container_of(work, struct gpio_keys_button_dev, work.work);
 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(bdata);
 328         }
 329         gpio_keys_polled_queue_work(bdev);
 330 }
 331
 332 static void gpio_keys_polled_close(struct gpio_keys_button_dev *bdev)
 333 {
 334         struct gpio_keys_platform_data *pdata = bdev->pdata;
 335
 336         cancel_delayed_work_sync(&bdev->work);
 337
 338         if (pdata->disable)
 339                 pdata->disable(bdev->dev);
 340 }
 341
 342 static irqreturn_t button_handle_irq(int irq, void *_bdata)
 343 {
 344         struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *) _bdata;
 345
 346         button_hotplug_event(bdata, bdata->b->type ?: EV_KEY, gpio_button_get_value(bdata));
 347
 348         return IRQ_HANDLED;
 349 }
 350
 351 #ifdef CONFIG_OF
 352 static struct gpio_keys_platform_data *
 353 gpio_keys_get_devtree_pdata(struct device *dev)
 354 {
 355         struct device_node *node, *pp;
 356         struct gpio_keys_platform_data *pdata;
 357         struct gpio_keys_button *button;
 358         int error;
 359         int nbuttons;
 360         int i = 0;
 361
 362         node = dev->of_node;
 363         if (!node)
 364                 return NULL;
 365
 366         nbuttons = of_get_child_count(node);
 367         if (nbuttons == 0)
 368                 return NULL;
 369
 370         pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * (sizeof *button),
 371                 GFP_KERNEL);
 372         if (!pdata) {
 373                 error = -ENOMEM;
 374                 goto err_out;
 375         }
 376
 377         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 378         pdata->nbuttons = nbuttons;
 379
 380         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 381         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 382
 383         for_each_child_of_node(node, pp) {
 384                 enum of_gpio_flags flags;
 385
 386                 if (!of_find_property(pp, "gpios", NULL)) {
 387                         pdata->nbuttons--;
 388                         dev_warn(dev, "Found button without gpios\n");
 389                         continue;
 390                 }
 391
 392                 button = &pdata->buttons[i++];
 393
 394                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 395                 if (button->gpio < 0) {
 396                         error = button->gpio;
 397                         if (error != -ENOENT) {
 398                                 if (error != -EPROBE_DEFER)
 399                                         dev_err(dev,
 400                                                 "Failed to get gpio flags, error: %d\n",
 401                                                 error);
 402                                 return ERR_PTR(error);
 403                         }
 404                 } else {
 405                         button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 406                 }
 407
 408                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 409                         dev_err(dev, "Button without keycode: 0x%x\n",
 410                                 button->gpio);
 411                         error = -EINVAL;
 412                         goto err_out;
 413                 }
 414
 415                 button->desc = of_get_property(pp, "label", NULL);
 416
 417                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 418                         button->type = EV_KEY;
 419
 420                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 421
 422                 if (of_property_read_u32(pp, "debounce-interval",
 423                                         &button->debounce_interval))
 424                         button->debounce_interval = 5;
 425         }
 426
 427         if (pdata->nbuttons == 0) {
 428                 error = -EINVAL;
 429                 goto err_out;
 430         }
 431
 432         return pdata;
 433
 434 err_out:
 435         return ERR_PTR(error);
 436 }
 437
 438 static struct of_device_id gpio_keys_of_match[] = {
 439         { .compatible = "gpio-keys", },
 440         { },
 441 };
 442 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
 443
 444 static struct of_device_id gpio_keys_polled_of_match[] = {
 445         { .compatible = "gpio-keys-polled", },
 446         { },
 447 };
 448 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 449
 450 #else
 451
 452 static inline struct gpio_keys_platform_data *
 453 gpio_keys_get_devtree_pdata(struct device *dev)
 454 {
 455         return NULL;
 456 }
 457 #endif
 458
 459 static int gpio_keys_button_probe(struct platform_device *pdev,
 460                 struct gpio_keys_button_dev **_bdev, int polled)
 461 {
 462         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 463         struct device *dev = &pdev->dev;
 464         struct gpio_keys_button_dev *bdev;
 465         struct gpio_keys_button *buttons;
 466         int error;
 467         int i;
 468
 469         if (!pdata) {
 470                 pdata = gpio_keys_get_devtree_pdata(dev);
 471                 if (IS_ERR(pdata))
 472                         return PTR_ERR(pdata);
 473                 if (!pdata) {
 474                         dev_err(dev, "missing platform data\n");
 475                         return -EINVAL;
 476                 }
 477                 pdev->dev.platform_data = pdata;
 478         }
 479
 480         if (polled && !pdata->poll_interval) {
 481                 dev_err(dev, "missing poll_interval value\n");
 482                 return -EINVAL;
 483         }
 484
 485         buttons = devm_kzalloc(dev, pdata->nbuttons * sizeof(struct gpio_keys_button),
 486                        GFP_KERNEL);
 487         if (!buttons) {
 488                 dev_err(dev, "no memory for button data\n");
 489                 return -ENOMEM;
 490         }
 491         memcpy(buttons, pdata->buttons, pdata->nbuttons * sizeof(struct gpio_keys_button));
 492
 493         bdev = devm_kzalloc(dev, sizeof(struct gpio_keys_button_dev) +
 494                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 495                        GFP_KERNEL);
 496         if (!bdev) {
 497                 dev_err(dev, "no memory for private data\n");
 498                 return -ENOMEM;
 499         }
 500
 501         bdev->polled = polled;
 502
 503         for (i = 0; i < pdata->nbuttons; i++) {
 504                 struct gpio_keys_button *button = &buttons[i];
 505                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 506                 unsigned int gpio = button->gpio;
 507
 508                 if (button->wakeup) {
 509                         dev_err(dev, DRV_NAME "does not support wakeup\n");
 510                         return -EINVAL;
 511                 }
 512
 513                 error = devm_gpio_request(dev, gpio,
 514                                      button->desc ? button->desc : DRV_NAME);
 515                 if (error) {
 516                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 517                                 gpio, error);
 518                         return error;
 519                 }
 520
 521                 error = gpio_direction_input(gpio);
 522                 if (error) {
 523                         dev_err(dev,
 524                                 "unable to set direction on gpio %u, err=%d\n",
 525                                 gpio, error);
 526                         return error;
 527                 }
 528
 529                 bdata->can_sleep = gpio_cansleep(gpio);
 530                 bdata->last_state = -1;
 531
 532                 if (bdev->polled)
 533                         bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 534                                                 pdata->poll_interval);
 535                 else
 536                         bdata->threshold = 1;
 537
 538                 bdata->b = &pdata->buttons[i];
 539         }
 540
 541         bdev->dev = &pdev->dev;
 542         bdev->pdata = pdata;
 543         platform_set_drvdata(pdev, bdev);
 544
 545         *_bdev = bdev;
 546
 547         return 0;
 548 }
 549
 550 static int gpio_keys_probe(struct platform_device *pdev)
 551 {
 552         struct gpio_keys_platform_data *pdata;
 553         struct gpio_keys_button_dev *bdev;
 554         int ret, i;
 555
 556
 557         ret = gpio_keys_button_probe(pdev, &bdev, 0);
 558
 559         if (ret)
 560                 return ret;
 561
 562         pdata = pdev->dev.platform_data;
 563         for (i = 0; i < pdata->nbuttons; i++) {
 564                 struct gpio_keys_button *button = &pdata->buttons[i];
 565                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 566
 567                 if (!button->irq)
 568                         button->irq = gpio_to_irq(button->gpio);
 569                 if (button->irq < 0) {
 570                         dev_err(&pdev->dev, "failed to get irq for gpio:%d\n", button->gpio);
 571                         continue;
 572                 }
 573
 574                 ret = devm_request_threaded_irq(&pdev->dev, button->irq, NULL, button_handle_irq,
 575                                                 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 576                                                 dev_name(&pdev->dev), bdata);
 577                 if (ret < 0)
 578                         dev_err(&pdev->dev, "failed to request irq:%d for gpio:%d\n", button->irq, button->gpio);
 579                 else
 580                         dev_dbg(&pdev->dev, "gpio:%d has irq:%d\n", button->gpio, button->irq);
 581
 582                 if (bdata->b->type == EV_SW)
 583                         button_hotplug_event(bdata, EV_SW, gpio_button_get_value(bdata));
 584         }
 585
 586         return 0;
 587 }
 588
 589 static int gpio_keys_polled_probe(struct platform_device *pdev)
 590 {
 591         struct gpio_keys_platform_data *pdata;
 592         struct gpio_keys_button_dev *bdev;
 593         int ret;
 594         int i;
 595
 596         ret = gpio_keys_button_probe(pdev, &bdev, 1);
 597
 598         if (ret)
 599                 return ret;
 600
 601         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 602
 603         pdata = bdev->pdata;
 604
 605         if (pdata->enable)
 606                 pdata->enable(bdev->dev);
 607
 608         for (i = 0; i < pdata->nbuttons; i++)
 609                 gpio_keys_polled_check_state(&bdev->data[i]);
 610
 611         gpio_keys_polled_queue_work(bdev);
 612
 613         return ret;
 614 }
 615
 616 static int gpio_keys_remove(struct platform_device *pdev)
 617 {
 618         struct gpio_keys_button_dev *bdev = platform_get_drvdata(pdev);
 619
 620         platform_set_drvdata(pdev, NULL);
 621
 622         if (bdev->polled)
 623                 gpio_keys_polled_close(bdev);
 624
 625         return 0;
 626 }
 627
 628 static struct platform_driver gpio_keys_driver = {
 629         .probe  = gpio_keys_probe,
 630         .remove = gpio_keys_remove,
 631         .driver = {
 632                 .name   = "gpio-keys",
 633                 .owner  = THIS_MODULE,
 634                 .of_match_table = of_match_ptr(gpio_keys_of_match),
 635         },
 636 };
 637
 638 static struct platform_driver gpio_keys_polled_driver = {
 639         .probe  = gpio_keys_polled_probe,
 640         .remove = gpio_keys_remove,
 641         .driver = {
 642                 .name   = "gpio-keys-polled",
 643                 .owner  = THIS_MODULE,
 644                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 645         },
 646 };
 647
 648 static int __init gpio_button_init(void)
 649 {
 650         int ret;
 651
 652         ret = platform_driver_register(&gpio_keys_driver);
 653         if (ret)
 654                 return ret;
 655
 656         ret = platform_driver_register(&gpio_keys_polled_driver);
 657         if (ret)
 658                 platform_driver_unregister(&gpio_keys_driver);
 659
 660         return ret;
 661 }
 662
 663 static void __exit gpio_button_exit(void)
 664 {
 665         platform_driver_unregister(&gpio_keys_driver);
 666         platform_driver_unregister(&gpio_keys_polled_driver);
 667 }
 668
 669 module_init(gpio_button_init);
 670 module_exit(gpio_button_exit);
 671
 672 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 673 MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
 674 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 675 MODULE_LICENSE("GPL v2");
 676 MODULE_ALIAS("platform:" DRV_NAME);