package/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/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         char                    *action;
  53         unsigned long           seen;
  54
  55         struct sk_buff          *skb;
  56         struct work_struct      work;
  57 };
  58
  59 struct bh_map {
  60         unsigned int    code;
  61         const char      *name;
  62 };
  63
  64 struct gpio_keys_button_data {
  65         struct delayed_work work;
  66         struct bh_priv bh;
  67         int last_state;
  68         int count;
  69         int threshold;
  70         int can_sleep;
  71 };
  72
  73 extern u64 uevent_next_seqnum(void);
  74
  75 #define BH_MAP(_code, _name)            \
  76         {                               \
  77                 .code = (_code),        \
  78                 .name = (_name),        \
  79         }
  80
  81 static struct bh_map button_map[] = {
  82         BH_MAP(BTN_0,           "BTN_0"),
  83         BH_MAP(BTN_1,           "BTN_1"),
  84         BH_MAP(BTN_2,           "BTN_2"),
  85         BH_MAP(BTN_3,           "BTN_3"),
  86         BH_MAP(BTN_4,           "BTN_4"),
  87         BH_MAP(BTN_5,           "BTN_5"),
  88         BH_MAP(BTN_6,           "BTN_6"),
  89         BH_MAP(BTN_7,           "BTN_7"),
  90         BH_MAP(BTN_8,           "BTN_8"),
  91         BH_MAP(BTN_9,           "BTN_9"),
  92         BH_MAP(KEY_RESTART,     "reset"),
  93 #ifdef KEY_WPS_BUTTON
  94         BH_MAP(KEY_WPS_BUTTON,  "wps"),
  95 #endif /* KEY_WPS_BUTTON */
  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         ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
 143         if (ret)
 144                 return ret;
 145
 146         ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
 147         if (ret)
 148                 return ret;
 149
 150         ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
 151         if (ret)
 152                 return ret;
 153
 154         ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
 155         if (ret)
 156                 return ret;
 157
 158         ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
 159
 160         return ret;
 161 }
 162
 163 static void button_hotplug_work(struct work_struct *work)
 164 {
 165         struct bh_event *event = container_of(work, struct bh_event, work);
 166         int ret = 0;
 167
 168         event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
 169         if (!event->skb)
 170                 goto out_free_event;
 171
 172         ret = bh_event_add_var(event, 0, "%s@", event->action);
 173         if (ret)
 174                 goto out_free_skb;
 175
 176         ret = button_hotplug_fill_event(event);
 177         if (ret)
 178                 goto out_free_skb;
 179
 180         NETLINK_CB(event->skb).dst_group = 1;
 181         broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
 182
 183  out_free_skb:
 184         if (ret) {
 185                 BH_ERR("work error %d\n", ret);
 186                 kfree_skb(event->skb);
 187         }
 188  out_free_event:
 189         kfree(event);
 190 }
 191
 192 static int button_hotplug_create_event(const char *name, unsigned long seen,
 193                 int pressed)
 194 {
 195         struct bh_event *event;
 196
 197         BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
 198                 name, seen, pressed);
 199
 200         event = kzalloc(sizeof(*event), GFP_KERNEL);
 201         if (!event)
 202                 return -ENOMEM;
 203
 204         event->name = name;
 205         event->seen = seen;
 206         event->action = pressed ? "pressed" : "released";
 207
 208         INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
 209         schedule_work(&event->work);
 210
 211         return 0;
 212 }
 213
 214 /* -------------------------------------------------------------------------*/
 215
 216 #ifdef  CONFIG_HOTPLUG
 217 static int button_get_index(unsigned int code)
 218 {
 219         int i;
 220
 221         for (i = 0; i < ARRAY_SIZE(button_map); i++)
 222                 if (button_map[i].code == code)
 223                         return i;
 224
 225         return -1;
 226 }
 227 static void button_hotplug_event(struct gpio_keys_button_data *data,
 228                            unsigned int type, unsigned int code, int value)
 229 {
 230         struct bh_priv *priv = &data->bh;
 231         unsigned long seen = jiffies;
 232         int btn;
 233
 234         BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
 235
 236         if (type != EV_KEY)
 237                 return;
 238
 239         btn = button_get_index(code);
 240         if (btn < 0)
 241                 return;
 242
 243         button_hotplug_create_event(button_map[btn].name,
 244                         (seen - priv->seen) / HZ, value);
 245         priv->seen = seen;
 246 }
 247 #else
 248 static void button_hotplug_event(struct gpio_keys_button_data *data,
 249                            unsigned int type, unsigned int code, int value)
 250 {
 251 }
 252 #endif  /* CONFIG_HOTPLUG */
 253
 254 struct gpio_keys_polled_dev {
 255         struct delayed_work work;
 256
 257         struct device *dev;
 258         struct gpio_keys_platform_data *pdata;
 259         struct gpio_keys_button_data data[0];
 260 };
 261
 262 static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
 263                                          struct gpio_keys_button_data *bdata)
 264 {
 265         int state;
 266
 267         if (bdata->can_sleep)
 268                 state = !!gpio_get_value_cansleep(button->gpio);
 269         else
 270                 state = !!gpio_get_value(button->gpio);
 271
 272         state = !!(state ^ button->active_low);
 273         if (state != bdata->last_state) {
 274                 unsigned int type = button->type ?: EV_KEY;
 275
 276                 button_hotplug_event(bdata, type, button->code, state);
 277                 bdata->count = 0;
 278                 bdata->last_state = state;
 279         }
 280 }
 281
 282 static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
 283 {
 284         struct gpio_keys_platform_data *pdata = bdev->pdata;
 285         unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
 286
 287         if (delay >= HZ)
 288             delay = round_jiffies_relative(delay);
 289         schedule_delayed_work(&bdev->work, delay);
 290 }
 291
 292 static void gpio_keys_polled_poll(struct work_struct *work)
 293 {
 294         struct gpio_keys_polled_dev *bdev =
 295                 container_of(work, struct gpio_keys_polled_dev, work.work);
 296         struct gpio_keys_platform_data *pdata = bdev->pdata;
 297         int i;
 298
 299         for (i = 0; i < bdev->pdata->nbuttons; i++) {
 300                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 301
 302                 if (bdata->count < bdata->threshold)
 303                         bdata->count++;
 304                 else
 305                         gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
 306         }
 307         gpio_keys_polled_queue_work(bdev);
 308 }
 309
 310 static void __devinit gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
 311 {
 312         struct gpio_keys_platform_data *pdata = bdev->pdata;
 313         int i;
 314
 315         if (pdata->enable)
 316                 pdata->enable(bdev->dev);
 317
 318         /* report initial state of the buttons */
 319         for (i = 0; i < pdata->nbuttons; i++)
 320                 gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
 321
 322         gpio_keys_polled_queue_work(bdev);
 323 }
 324
 325 static void __devexit gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
 326 {
 327         struct gpio_keys_platform_data *pdata = bdev->pdata;
 328
 329         cancel_delayed_work_sync(&bdev->work);
 330
 331         if (pdata->disable)
 332                 pdata->disable(bdev->dev);
 333 }
 334
 335 static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
 336 {
 337         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 338         struct device *dev = &pdev->dev;
 339         struct gpio_keys_polled_dev *bdev;
 340         int error;
 341         int i;
 342
 343         if (!pdata || !pdata->poll_interval)
 344                 return -EINVAL;
 345
 346         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 347                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 348                        GFP_KERNEL);
 349         if (!bdev) {
 350                 dev_err(dev, "no memory for private data\n");
 351                 return -ENOMEM;
 352         }
 353
 354         for (i = 0; i < pdata->nbuttons; i++) {
 355                 struct gpio_keys_button *button = &pdata->buttons[i];
 356                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 357                 unsigned int gpio = button->gpio;
 358
 359                 if (button->wakeup) {
 360                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 361                         error = -EINVAL;
 362                         goto err_free_gpio;
 363                 }
 364
 365                 error = gpio_request(gpio,
 366                                      button->desc ? button->desc : DRV_NAME);
 367                 if (error) {
 368                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 369                                 gpio, error);
 370                         goto err_free_gpio;
 371                 }
 372
 373                 error = gpio_direction_input(gpio);
 374                 if (error) {
 375                         dev_err(dev,
 376                                 "unable to set direction on gpio %u, err=%d\n",
 377                                 gpio, error);
 378                         goto err_free_gpio;
 379                 }
 380
 381                 bdata->can_sleep = gpio_cansleep(gpio);
 382                 bdata->last_state = 0;
 383                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 384                                                 pdata->poll_interval);
 385         }
 386
 387         bdev->dev = &pdev->dev;
 388         bdev->pdata = pdata;
 389         platform_set_drvdata(pdev, bdev);
 390
 391         INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
 392
 393         gpio_keys_polled_open(bdev);
 394
 395         return 0;
 396
 397 err_free_gpio:
 398         while (--i >= 0)
 399                 gpio_free(pdata->buttons[i].gpio);
 400
 401         kfree(bdev);
 402         platform_set_drvdata(pdev, NULL);
 403
 404         return error;
 405 }
 406
 407 static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
 408 {
 409         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 410         struct gpio_keys_platform_data *pdata = bdev->pdata;
 411         int i = pdata->nbuttons;
 412
 413         gpio_keys_polled_close(bdev);
 414
 415         while (--i >= 0)
 416                 gpio_free(pdata->buttons[i].gpio);
 417
 418         kfree(bdev);
 419         platform_set_drvdata(pdev, NULL);
 420
 421         return 0;
 422 }
 423
 424 static struct platform_driver gpio_keys_polled_driver = {
 425         .probe  = gpio_keys_polled_probe,
 426         .remove = __devexit_p(gpio_keys_polled_remove),
 427         .driver = {
 428                 .name   = DRV_NAME,
 429                 .owner  = THIS_MODULE,
 430         },
 431 };
 432
 433 static int __init gpio_keys_polled_init(void)
 434 {
 435         return platform_driver_register(&gpio_keys_polled_driver);
 436 }
 437
 438 static void __exit gpio_keys_polled_exit(void)
 439 {
 440         platform_driver_unregister(&gpio_keys_polled_driver);
 441 }
 442
 443 module_init(gpio_keys_polled_init);
 444 module_exit(gpio_keys_polled_exit);
 445
 446 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 447 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 448 MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
 449 MODULE_LICENSE("GPL v2");
 450 MODULE_ALIAS("platform:" DRV_NAME);