drivers/input/keyboard/gpio_keys_polled.c

   1 /*
   2  *  Driver for buttons on GPIO lines not capable of generating interrupts
   3  *
   4  *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
   5  *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
   6  *
   7  *  This file was based on: /drivers/input/misc/cobalt_btns.c
   8  *      Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
   9  *
  10  *  also was based on: /drivers/input/keyboard/gpio_keys.c
  11  *      Copyright 2005 Phil Blundell
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License version 2 as
  15  *  published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/input.h>
  22 #include <linux/input-polldev.h>
  23 #include <linux/ioport.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/gpio.h>
  26 #include <linux/gpio_keys.h>
  27 #include <linux/of.h>
  28 #include <linux/of_platform.h>
  29 #include <linux/of_gpio.h>
  30
  31 #define DRV_NAME        "gpio-keys-polled"
  32
  33 struct gpio_keys_button_data {
  34         int last_state;
  35         int count;
  36         int threshold;
  37         int can_sleep;
  38 };
  39
  40 struct gpio_keys_polled_dev {
  41         struct input_polled_dev *poll_dev;
  42         struct device *dev;
  43         const struct gpio_keys_platform_data *pdata;
  44         struct gpio_keys_button_data data[0];
  45 };
  46
  47 static void gpio_keys_polled_check_state(struct input_dev *input,
  48                                          struct gpio_keys_button *button,
  49                                          struct gpio_keys_button_data *bdata)
  50 {
  51         int state;
  52
  53         if (bdata->can_sleep)
  54                 state = !!gpio_get_value_cansleep(button->gpio);
  55         else
  56                 state = !!gpio_get_value(button->gpio);
  57
  58         if (state != bdata->last_state) {
  59                 unsigned int type = button->type ?: EV_KEY;
  60
  61                 input_event(input, type, button->code,
  62                             !!(state ^ button->active_low));
  63                 input_sync(input);
  64                 bdata->count = 0;
  65                 bdata->last_state = state;
  66         }
  67 }
  68
  69 static void gpio_keys_polled_poll(struct input_polled_dev *dev)
  70 {
  71         struct gpio_keys_polled_dev *bdev = dev->private;
  72         const struct gpio_keys_platform_data *pdata = bdev->pdata;
  73         struct input_dev *input = dev->input;
  74         int i;
  75
  76         for (i = 0; i < pdata->nbuttons; i++) {
  77                 struct gpio_keys_button_data *bdata = &bdev->data[i];
  78
  79                 if (bdata->count < bdata->threshold)
  80                         bdata->count++;
  81                 else
  82                         gpio_keys_polled_check_state(input, &pdata->buttons[i],
  83                                                      bdata);
  84         }
  85 }
  86
  87 static void gpio_keys_polled_open(struct input_polled_dev *dev)
  88 {
  89         struct gpio_keys_polled_dev *bdev = dev->private;
  90         const struct gpio_keys_platform_data *pdata = bdev->pdata;
  91
  92         if (pdata->enable)
  93                 pdata->enable(bdev->dev);
  94 }
  95
  96 static void gpio_keys_polled_close(struct input_polled_dev *dev)
  97 {
  98         struct gpio_keys_polled_dev *bdev = dev->private;
  99         const struct gpio_keys_platform_data *pdata = bdev->pdata;
 100
 101         if (pdata->disable)
 102                 pdata->disable(bdev->dev);
 103 }
 104
 105 #ifdef CONFIG_OF
 106 static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct device *dev)
 107 {
 108         struct device_node *node, *pp;
 109         struct gpio_keys_platform_data *pdata;
 110         struct gpio_keys_button *button;
 111         int error;
 112         int nbuttons;
 113         int i;
 114
 115         node = dev->of_node;
 116         if (!node)
 117                 return NULL;
 118
 119         nbuttons = of_get_child_count(node);
 120         if (nbuttons == 0)
 121                 return NULL;
 122
 123         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
 124                         GFP_KERNEL);
 125         if (!pdata) {
 126                 error = -ENOMEM;
 127                 goto err_out;
 128         }
 129
 130         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 131         pdata->nbuttons = nbuttons;
 132
 133         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
 134         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
 135
 136         i = 0;
 137         for_each_child_of_node(node, pp) {
 138                 int gpio;
 139                 enum of_gpio_flags flags;
 140
 141                 if (!of_find_property(pp, "gpios", NULL)) {
 142                         pdata->nbuttons--;
 143                         dev_warn(dev, "Found button without gpios\n");
 144                         continue;
 145                 }
 146
 147                 gpio = of_get_gpio_flags(pp, 0, &flags);
 148                 if (gpio < 0) {
 149                         error = gpio;
 150                         if (error != -EPROBE_DEFER)
 151                                 dev_err(dev,
 152                                         "Failed to get gpio flags, error: %d\n",
 153                                         error);
 154                         goto err_free_pdata;
 155                 }
 156
 157                 button = &pdata->buttons[i++];
 158
 159                 button->gpio = gpio;
 160                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 161
 162                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 163                         dev_err(dev, "Button without keycode: 0x%x\n",
 164                                 button->gpio);
 165                         error = -EINVAL;
 166                         goto err_free_pdata;
 167                 }
 168
 169                 button->desc = of_get_property(pp, "label", NULL);
 170
 171                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 172                         button->type = EV_KEY;
 173
 174                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 175
 176                 if (of_property_read_u32(pp, "debounce-interval",
 177                                          &button->debounce_interval))
 178                         button->debounce_interval = 5;
 179         }
 180
 181         if (pdata->nbuttons == 0) {
 182                 error = -EINVAL;
 183                 goto err_free_pdata;
 184         }
 185
 186         return pdata;
 187
 188 err_free_pdata:
 189         kfree(pdata);
 190 err_out:
 191         return ERR_PTR(error);
 192 }
 193
 194 static struct of_device_id gpio_keys_polled_of_match[] = {
 195         { .compatible = "gpio-keys-polled", },
 196         { },
 197 };
 198 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 199
 200 #else
 201
 202 static inline struct gpio_keys_platform_data *
 203 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 204 {
 205         return NULL;
 206 }
 207 #endif
 208
 209 static int gpio_keys_polled_probe(struct platform_device *pdev)
 210 {
 211         struct device *dev = &pdev->dev;
 212         const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
 213         struct gpio_keys_polled_dev *bdev;
 214         struct input_polled_dev *poll_dev;
 215         struct input_dev *input;
 216         int error;
 217         int i;
 218
 219         if (!pdata) {
 220                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 221                 if (IS_ERR(pdata))
 222                         return PTR_ERR(pdata);
 223                 if (!pdata) {
 224                         dev_err(dev, "missing platform data\n");
 225                         return -EINVAL;
 226                 }
 227         }
 228
 229         if (!pdata->poll_interval) {
 230                 dev_err(dev, "missing poll_interval value\n");
 231                 error = -EINVAL;
 232                 goto err_free_pdata;
 233         }
 234
 235         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 236                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 237                        GFP_KERNEL);
 238         if (!bdev) {
 239                 dev_err(dev, "no memory for private data\n");
 240                 error = -ENOMEM;
 241                 goto err_free_pdata;
 242         }
 243
 244         poll_dev = input_allocate_polled_device();
 245         if (!poll_dev) {
 246                 dev_err(dev, "no memory for polled device\n");
 247                 error = -ENOMEM;
 248                 goto err_free_bdev;
 249         }
 250
 251         poll_dev->private = bdev;
 252         poll_dev->poll = gpio_keys_polled_poll;
 253         poll_dev->poll_interval = pdata->poll_interval;
 254         poll_dev->open = gpio_keys_polled_open;
 255         poll_dev->close = gpio_keys_polled_close;
 256
 257         input = poll_dev->input;
 258
 259         input->name = pdev->name;
 260         input->phys = DRV_NAME"/input0";
 261         input->dev.parent = &pdev->dev;
 262
 263         input->id.bustype = BUS_HOST;
 264         input->id.vendor = 0x0001;
 265         input->id.product = 0x0001;
 266         input->id.version = 0x0100;
 267
 268         __set_bit(EV_KEY, input->evbit);
 269         if (pdata->rep)
 270                 __set_bit(EV_REP, input->evbit);
 271
 272         for (i = 0; i < pdata->nbuttons; i++) {
 273                 struct gpio_keys_button *button = &pdata->buttons[i];
 274                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 275                 unsigned int gpio = button->gpio;
 276                 unsigned int type = button->type ?: EV_KEY;
 277
 278                 if (button->wakeup) {
 279                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 280                         error = -EINVAL;
 281                         goto err_free_gpio;
 282                 }
 283
 284                 error = gpio_request_one(gpio, GPIOF_IN,
 285                                          button->desc ?: DRV_NAME);
 286                 if (error) {
 287                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 288                                 gpio, error);
 289                         goto err_free_gpio;
 290                 }
 291
 292                 bdata->can_sleep = gpio_cansleep(gpio);
 293                 bdata->last_state = -1;
 294                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 295                                                 pdata->poll_interval);
 296
 297                 input_set_capability(input, type, button->code);
 298         }
 299
 300         bdev->poll_dev = poll_dev;
 301         bdev->dev = dev;
 302         bdev->pdata = pdata;
 303         platform_set_drvdata(pdev, bdev);
 304
 305         error = input_register_polled_device(poll_dev);
 306         if (error) {
 307                 dev_err(dev, "unable to register polled device, err=%d\n",
 308                         error);
 309                 goto err_free_gpio;
 310         }
 311
 312         /* report initial state of the buttons */
 313         for (i = 0; i < pdata->nbuttons; i++)
 314                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
 315                                              &bdev->data[i]);
 316
 317         return 0;
 318
 319 err_free_gpio:
 320         while (--i >= 0)
 321                 gpio_free(pdata->buttons[i].gpio);
 322
 323         input_free_polled_device(poll_dev);
 324
 325 err_free_bdev:
 326         kfree(bdev);
 327
 328 err_free_pdata:
 329         /* If we have no platform_data, we allocated pdata dynamically.  */
 330         if (!dev_get_platdata(&pdev->dev))
 331                 kfree(pdata);
 332
 333         return error;
 334 }
 335
 336 static int gpio_keys_polled_remove(struct platform_device *pdev)
 337 {
 338         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 339         const struct gpio_keys_platform_data *pdata = bdev->pdata;
 340         int i;
 341
 342         input_unregister_polled_device(bdev->poll_dev);
 343
 344         for (i = 0; i < pdata->nbuttons; i++)
 345                 gpio_free(pdata->buttons[i].gpio);
 346
 347         input_free_polled_device(bdev->poll_dev);
 348
 349         /*
 350          * If we had no platform_data, we allocated pdata dynamically and
 351          * must free it here.
 352          */
 353         if (!dev_get_platdata(&pdev->dev))
 354                 kfree(pdata);
 355
 356         kfree(bdev);
 357
 358         return 0;
 359 }
 360
 361 static struct platform_driver gpio_keys_polled_driver = {
 362         .probe  = gpio_keys_polled_probe,
 363         .remove = gpio_keys_polled_remove,
 364         .driver = {
 365                 .name   = DRV_NAME,
 366                 .owner  = THIS_MODULE,
 367                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 368         },
 369 };
 370 module_platform_driver(gpio_keys_polled_driver);
 371
 372 MODULE_LICENSE("GPL v2");
 373 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 374 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
 375 MODULE_ALIAS("platform:" DRV_NAME);