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