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_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 * __devinit
 107 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                 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                 button = &pdata->buttons[i++];
 148
 149                 button->gpio = of_get_gpio_flags(pp, 0, &flags);
 150                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
 151
 152                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
 153                         dev_err(dev, "Button without keycode: 0x%x\n",
 154                                 button->gpio);
 155                         error = -EINVAL;
 156                         goto err_free_pdata;
 157                 }
 158
 159                 button->desc = of_get_property(pp, "label", NULL);
 160
 161                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
 162                         button->type = EV_KEY;
 163
 164                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
 165
 166                 if (of_property_read_u32(pp, "debounce-interval",
 167                                          &button->debounce_interval))
 168                         button->debounce_interval = 5;
 169         }
 170
 171         if (pdata->nbuttons == 0) {
 172                 error = -EINVAL;
 173                 goto err_free_pdata;
 174         }
 175
 176         return pdata;
 177
 178 err_free_pdata:
 179         kfree(pdata);
 180 err_out:
 181         return ERR_PTR(error);
 182 }
 183
 184 static struct of_device_id gpio_keys_polled_of_match[] = {
 185         { .compatible = "gpio-keys-polled", },
 186         { },
 187 };
 188 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 189
 190 #else
 191
 192 static inline struct gpio_keys_platform_data *
 193 gpio_keys_polled_get_devtree_pdata(struct device *dev)
 194 {
 195         return NULL;
 196 }
 197 #endif
 198
 199 static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
 200 {
 201         struct device *dev = &pdev->dev;
 202         const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
 203         struct gpio_keys_polled_dev *bdev;
 204         struct input_polled_dev *poll_dev;
 205         struct input_dev *input;
 206         int error;
 207         int i;
 208
 209         if (!pdata) {
 210                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 211                 if (IS_ERR(pdata))
 212                         return PTR_ERR(pdata);
 213                 if (!pdata) {
 214                         dev_err(dev, "missing platform data\n");
 215                         return -EINVAL;
 216                 }
 217         }
 218
 219         if (!pdata->poll_interval) {
 220                 dev_err(dev, "missing poll_interval value\n");
 221                 error = -EINVAL;
 222                 goto err_free_pdata;
 223         }
 224
 225         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 226                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 227                        GFP_KERNEL);
 228         if (!bdev) {
 229                 dev_err(dev, "no memory for private data\n");
 230                 error = -ENOMEM;
 231                 goto err_free_pdata;
 232         }
 233
 234         poll_dev = input_allocate_polled_device();
 235         if (!poll_dev) {
 236                 dev_err(dev, "no memory for polled device\n");
 237                 error = -ENOMEM;
 238                 goto err_free_bdev;
 239         }
 240
 241         poll_dev->private = bdev;
 242         poll_dev->poll = gpio_keys_polled_poll;
 243         poll_dev->poll_interval = pdata->poll_interval;
 244         poll_dev->open = gpio_keys_polled_open;
 245         poll_dev->close = gpio_keys_polled_close;
 246
 247         input = poll_dev->input;
 248
 249         input->evbit[0] = BIT(EV_KEY);
 250         input->name = pdev->name;
 251         input->phys = DRV_NAME"/input0";
 252         input->dev.parent = &pdev->dev;
 253
 254         input->id.bustype = BUS_HOST;
 255         input->id.vendor = 0x0001;
 256         input->id.product = 0x0001;
 257         input->id.version = 0x0100;
 258
 259         for (i = 0; i < pdata->nbuttons; i++) {
 260                 struct gpio_keys_button *button = &pdata->buttons[i];
 261                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 262                 unsigned int gpio = button->gpio;
 263                 unsigned int type = button->type ?: EV_KEY;
 264
 265                 if (button->wakeup) {
 266                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 267                         error = -EINVAL;
 268                         goto err_free_gpio;
 269                 }
 270
 271                 error = gpio_request(gpio,
 272                                      button->desc ? button->desc : DRV_NAME);
 273                 if (error) {
 274                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 275                                 gpio, error);
 276                         goto err_free_gpio;
 277                 }
 278
 279                 error = gpio_direction_input(gpio);
 280                 if (error) {
 281                         dev_err(dev,
 282                                 "unable to set direction on gpio %u, err=%d\n",
 283                                 gpio, error);
 284                         goto err_free_gpio;
 285                 }
 286
 287                 bdata->can_sleep = gpio_cansleep(gpio);
 288                 bdata->last_state = -1;
 289                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 290                                                 pdata->poll_interval);
 291
 292                 input_set_capability(input, type, button->code);
 293         }
 294
 295         bdev->poll_dev = poll_dev;
 296         bdev->dev = dev;
 297         bdev->pdata = pdata;
 298         platform_set_drvdata(pdev, bdev);
 299
 300         error = input_register_polled_device(poll_dev);
 301         if (error) {
 302                 dev_err(dev, "unable to register polled device, err=%d\n",
 303                         error);
 304                 goto err_free_gpio;
 305         }
 306
 307         /* report initial state of the buttons */
 308         for (i = 0; i < pdata->nbuttons; i++)
 309                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
 310                                              &bdev->data[i]);
 311
 312         return 0;
 313
 314 err_free_gpio:
 315         while (--i >= 0)
 316                 gpio_free(pdata->buttons[i].gpio);
 317
 318         input_free_polled_device(poll_dev);
 319
 320 err_free_bdev:
 321         kfree(bdev);
 322         platform_set_drvdata(pdev, NULL);
 323
 324 err_free_pdata:
 325         /* If we have no platform_data, we allocated pdata dynamically.  */
 326         if (!dev_get_platdata(&pdev->dev))
 327                 kfree(pdata);
 328
 329         return error;
 330 }
 331
 332 static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
 333 {
 334         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 335         const struct gpio_keys_platform_data *pdata = bdev->pdata;
 336         int i;
 337
 338         input_unregister_polled_device(bdev->poll_dev);
 339
 340         for (i = 0; i < pdata->nbuttons; i++)
 341                 gpio_free(pdata->buttons[i].gpio);
 342
 343         input_free_polled_device(bdev->poll_dev);
 344
 345         /*
 346          * If we had no platform_data, we allocated pdata dynamically and
 347          * must free it here.
 348          */
 349         if (!dev_get_platdata(&pdev->dev))
 350                 kfree(pdata);
 351
 352         kfree(bdev);
 353         platform_set_drvdata(pdev, NULL);
 354
 355         return 0;
 356 }
 357
 358 static struct platform_driver gpio_keys_polled_driver = {
 359         .probe  = gpio_keys_polled_probe,
 360         .remove = __devexit_p(gpio_keys_polled_remove),
 361         .driver = {
 362                 .name   = DRV_NAME,
 363                 .owner  = THIS_MODULE,
 364                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
 365         },
 366 };
 367 module_platform_driver(gpio_keys_polled_driver);
 368
 369 MODULE_LICENSE("GPL v2");
 370 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 371 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
 372 MODULE_ALIAS("platform:" DRV_NAME);