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
  29 #define DRV_NAME        "gpio-keys-polled"
  30
  31 struct gpio_keys_button_data {
  32         int last_state;
  33         int count;
  34         int threshold;
  35         int can_sleep;
  36 };
  37
  38 struct gpio_keys_polled_dev {
  39         struct input_polled_dev *poll_dev;
  40         struct device *dev;
  41         struct gpio_keys_platform_data *pdata;
  42         struct gpio_keys_button_data data[0];
  43 };
  44
  45 static void gpio_keys_polled_check_state(struct input_dev *input,
  46                                          struct gpio_keys_button *button,
  47                                          struct gpio_keys_button_data *bdata)
  48 {
  49         int state;
  50
  51         if (bdata->can_sleep)
  52                 state = !!gpio_get_value_cansleep(button->gpio);
  53         else
  54                 state = !!gpio_get_value(button->gpio);
  55
  56         if (state != bdata->last_state) {
  57                 unsigned int type = button->type ?: EV_KEY;
  58
  59                 input_event(input, type, button->code,
  60                             !!(state ^ button->active_low));
  61                 input_sync(input);
  62                 bdata->count = 0;
  63                 bdata->last_state = state;
  64         }
  65 }
  66
  67 static void gpio_keys_polled_poll(struct input_polled_dev *dev)
  68 {
  69         struct gpio_keys_polled_dev *bdev = dev->private;
  70         struct gpio_keys_platform_data *pdata = bdev->pdata;
  71         struct input_dev *input = dev->input;
  72         int i;
  73
  74         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  75                 struct gpio_keys_button_data *bdata = &bdev->data[i];
  76
  77                 if (bdata->count < bdata->threshold)
  78                         bdata->count++;
  79                 else
  80                         gpio_keys_polled_check_state(input, &pdata->buttons[i],
  81                                                      bdata);
  82         }
  83 }
  84
  85 static void gpio_keys_polled_open(struct input_polled_dev *dev)
  86 {
  87         struct gpio_keys_polled_dev *bdev = dev->private;
  88         struct gpio_keys_platform_data *pdata = bdev->pdata;
  89
  90         if (pdata->enable)
  91                 pdata->enable(bdev->dev);
  92 }
  93
  94 static void gpio_keys_polled_close(struct input_polled_dev *dev)
  95 {
  96         struct gpio_keys_polled_dev *bdev = dev->private;
  97         struct gpio_keys_platform_data *pdata = bdev->pdata;
  98
  99         if (pdata->disable)
 100                 pdata->disable(bdev->dev);
 101 }
 102
 103 static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
 104 {
 105         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 106         struct device *dev = &pdev->dev;
 107         struct gpio_keys_polled_dev *bdev;
 108         struct input_polled_dev *poll_dev;
 109         struct input_dev *input;
 110         int error;
 111         int i;
 112
 113         if (!pdata || !pdata->poll_interval)
 114                 return -EINVAL;
 115
 116         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
 117                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
 118                        GFP_KERNEL);
 119         if (!bdev) {
 120                 dev_err(dev, "no memory for private data\n");
 121                 return -ENOMEM;
 122         }
 123
 124         poll_dev = input_allocate_polled_device();
 125         if (!poll_dev) {
 126                 dev_err(dev, "no memory for polled device\n");
 127                 error = -ENOMEM;
 128                 goto err_free_bdev;
 129         }
 130
 131         poll_dev->private = bdev;
 132         poll_dev->poll = gpio_keys_polled_poll;
 133         poll_dev->poll_interval = pdata->poll_interval;
 134         poll_dev->open = gpio_keys_polled_open;
 135         poll_dev->close = gpio_keys_polled_close;
 136
 137         input = poll_dev->input;
 138
 139         input->evbit[0] = BIT(EV_KEY);
 140         input->name = pdev->name;
 141         input->phys = DRV_NAME"/input0";
 142         input->dev.parent = &pdev->dev;
 143
 144         input->id.bustype = BUS_HOST;
 145         input->id.vendor = 0x0001;
 146         input->id.product = 0x0001;
 147         input->id.version = 0x0100;
 148
 149         for (i = 0; i < pdata->nbuttons; i++) {
 150                 struct gpio_keys_button *button = &pdata->buttons[i];
 151                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 152                 unsigned int gpio = button->gpio;
 153                 unsigned int type = button->type ?: EV_KEY;
 154
 155                 if (button->wakeup) {
 156                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 157                         error = -EINVAL;
 158                         goto err_free_gpio;
 159                 }
 160
 161                 error = gpio_request(gpio,
 162                                      button->desc ? button->desc : DRV_NAME);
 163                 if (error) {
 164                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 165                                 gpio, error);
 166                         goto err_free_gpio;
 167                 }
 168
 169                 error = gpio_direction_input(gpio);
 170                 if (error) {
 171                         dev_err(dev,
 172                                 "unable to set direction on gpio %u, err=%d\n",
 173                                 gpio, error);
 174                         goto err_free_gpio;
 175                 }
 176
 177                 bdata->can_sleep = gpio_cansleep(gpio);
 178                 bdata->last_state = -1;
 179                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 180                                                 pdata->poll_interval);
 181
 182                 input_set_capability(input, type, button->code);
 183         }
 184
 185         bdev->poll_dev = poll_dev;
 186         bdev->dev = dev;
 187         bdev->pdata = pdata;
 188         platform_set_drvdata(pdev, bdev);
 189
 190         error = input_register_polled_device(poll_dev);
 191         if (error) {
 192                 dev_err(dev, "unable to register polled device, err=%d\n",
 193                         error);
 194                 goto err_free_gpio;
 195         }
 196
 197         /* report initial state of the buttons */
 198         for (i = 0; i < pdata->nbuttons; i++)
 199                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
 200                                          &bdev->data[i]);
 201
 202         return 0;
 203
 204 err_free_gpio:
 205         while (--i >= 0)
 206                 gpio_free(pdata->buttons[i].gpio);
 207
 208         input_free_polled_device(poll_dev);
 209
 210 err_free_bdev:
 211         kfree(bdev);
 212
 213         platform_set_drvdata(pdev, NULL);
 214         return error;
 215 }
 216
 217 static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
 218 {
 219         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
 220         struct gpio_keys_platform_data *pdata = bdev->pdata;
 221         int i;
 222
 223         input_unregister_polled_device(bdev->poll_dev);
 224
 225         for (i = 0; i < pdata->nbuttons; i++)
 226                 gpio_free(pdata->buttons[i].gpio);
 227
 228         input_free_polled_device(bdev->poll_dev);
 229
 230         kfree(bdev);
 231         platform_set_drvdata(pdev, NULL);
 232
 233         return 0;
 234 }
 235
 236 static struct platform_driver gpio_keys_polled_driver = {
 237         .probe  = gpio_keys_polled_probe,
 238         .remove = __devexit_p(gpio_keys_polled_remove),
 239         .driver = {
 240                 .name   = DRV_NAME,
 241                 .owner  = THIS_MODULE,
 242         },
 243 };
 244
 245 static int __init gpio_keys_polled_init(void)
 246 {
 247         return platform_driver_register(&gpio_keys_polled_driver);
 248 }
 249
 250 static void __exit gpio_keys_polled_exit(void)
 251 {
 252         platform_driver_unregister(&gpio_keys_polled_driver);
 253 }
 254
 255 module_init(gpio_keys_polled_init);
 256 module_exit(gpio_keys_polled_exit);
 257
 258 MODULE_LICENSE("GPL v2");
 259 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 260 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
 261 MODULE_ALIAS("platform:" DRV_NAME);