target/linux/generic/files/drivers/input/misc/gpio_buttons.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
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <linux/input.h>
  24 #include <linux/input-polldev.h>
  25 #include <linux/ioport.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/gpio.h>
  28 #include <linux/gpio_buttons.h>
  29
  30 #define DRV_NAME        "gpio-buttons"
  31
  32 struct gpio_button_data {
  33         int last_state;
  34         int count;
  35         int can_sleep;
  36 };
  37
  38 struct gpio_buttons_dev {
  39         struct input_polled_dev *poll_dev;
  40         struct gpio_buttons_platform_data *pdata;
  41         struct gpio_button_data *data;
  42 };
  43
  44 static void gpio_buttons_check_state(struct input_dev *input,
  45                                       struct gpio_button *button,
  46                                       struct gpio_button_data *bdata)
  47 {
  48         int state;
  49
  50         if (bdata->can_sleep)
  51                 state = !!gpio_get_value_cansleep(button->gpio);
  52         else
  53                 state = !!gpio_get_value(button->gpio);
  54
  55         if (state != bdata->last_state) {
  56                 unsigned int type = button->type ?: EV_KEY;
  57
  58                 input_event(input, type, button->code,
  59                             !!(state ^ button->active_low));
  60                 input_sync(input);
  61                 bdata->count = 0;
  62                 bdata->last_state = state;
  63         }
  64 }
  65
  66 static void gpio_buttons_poll(struct input_polled_dev *dev)
  67 {
  68         struct gpio_buttons_dev *bdev = dev->private;
  69         struct gpio_buttons_platform_data *pdata = bdev->pdata;
  70         struct input_dev *input = dev->input;
  71         int i;
  72
  73         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  74                 struct gpio_button *button = &pdata->buttons[i];
  75                 struct gpio_button_data *bdata = &bdev->data[i];
  76
  77                 if (bdata->count < button->threshold)
  78                         bdata->count++;
  79                 else
  80                         gpio_buttons_check_state(input, button, bdata);
  81
  82         }
  83 }
  84
  85 static int gpio_buttons_probe(struct platform_device *pdev)
  86 {
  87         struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
  88         struct device *dev = &pdev->dev;
  89         struct gpio_buttons_dev *bdev;
  90         struct input_polled_dev *poll_dev;
  91         struct input_dev *input;
  92         int error;
  93         int i;
  94
  95         if (!pdata)
  96                 return -ENXIO;
  97
  98         bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
  99                        pdata->nbuttons * sizeof(struct gpio_button_data),
 100                        GFP_KERNEL);
 101         if (!bdev) {
 102                 dev_err(dev, "no memory for private data\n");
 103                 return -ENOMEM;
 104         }
 105
 106         bdev->data = (struct gpio_button_data *) &bdev[1];
 107
 108         poll_dev = input_allocate_polled_device();
 109         if (!poll_dev) {
 110                 dev_err(dev, "no memory for polled device\n");
 111                 error = -ENOMEM;
 112                 goto err_free_bdev;
 113         }
 114
 115         poll_dev->private = bdev;
 116         poll_dev->poll = gpio_buttons_poll;
 117         poll_dev->poll_interval = pdata->poll_interval;
 118
 119         input = poll_dev->input;
 120
 121         input->evbit[0] = BIT(EV_KEY);
 122         input->name = pdev->name;
 123         input->phys = "gpio-buttons/input0";
 124         input->dev.parent = &pdev->dev;
 125
 126         input->id.bustype = BUS_HOST;
 127         input->id.vendor = 0x0001;
 128         input->id.product = 0x0001;
 129         input->id.version = 0x0100;
 130
 131         for (i = 0; i < pdata->nbuttons; i++) {
 132                 struct gpio_button *button = &pdata->buttons[i];
 133                 unsigned int gpio = button->gpio;
 134                 unsigned int type = button->type ?: EV_KEY;
 135
 136                 error = gpio_request(gpio,
 137                                      button->desc ? button->desc : DRV_NAME);
 138                 if (error) {
 139                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
 140                                 gpio, error);
 141                         goto err_free_gpio;
 142                 }
 143
 144                 error = gpio_direction_input(gpio);
 145                 if (error) {
 146                         dev_err(dev,
 147                                 "unable to set direction on gpio %u, err=%d\n",
 148                                 gpio, error);
 149                         goto err_free_gpio;
 150                 }
 151
 152                 bdev->data[i].can_sleep = gpio_cansleep(gpio);
 153                 bdev->data[i].last_state = -1;
 154
 155                 input_set_capability(input, type, button->code);
 156         }
 157
 158         bdev->poll_dev = poll_dev;
 159         bdev->pdata = pdata;
 160         platform_set_drvdata(pdev, bdev);
 161
 162         error = input_register_polled_device(poll_dev);
 163         if (error) {
 164                 dev_err(dev, "unable to register polled device, err=%d\n",
 165                         error);
 166                 goto err_free_gpio;
 167         }
 168
 169         /* report initial state of the buttons */
 170         for (i = 0; i < pdata->nbuttons; i++)
 171                 gpio_buttons_check_state(input, &pdata->buttons[i],
 172                                          &bdev->data[i]);
 173
 174         return 0;
 175
 176 err_free_gpio:
 177         for (i = i - 1; i >= 0; i--)
 178                 gpio_free(pdata->buttons[i].gpio);
 179
 180         input_free_polled_device(poll_dev);
 181
 182 err_free_bdev:
 183         kfree(bdev);
 184
 185         platform_set_drvdata(pdev, NULL);
 186         return error;
 187 }
 188
 189 static int gpio_buttons_remove(struct platform_device *pdev)
 190 {
 191         struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
 192         struct gpio_buttons_platform_data *pdata = bdev->pdata;
 193         int i;
 194
 195         input_unregister_polled_device(bdev->poll_dev);
 196
 197         for (i = 0; i < pdata->nbuttons; i++)
 198                 gpio_free(pdata->buttons[i].gpio);
 199
 200         input_free_polled_device(bdev->poll_dev);
 201
 202         kfree(bdev);
 203         platform_set_drvdata(pdev, NULL);
 204
 205         return 0;
 206 }
 207
 208 static struct platform_driver gpio_buttons_driver = {
 209         .probe  = gpio_buttons_probe,
 210         .remove = gpio_buttons_remove,
 211         .driver = {
 212                 .name   = DRV_NAME,
 213                 .owner  = THIS_MODULE,
 214         },
 215 };
 216
 217 static int __init gpio_buttons_init(void)
 218 {
 219         return platform_driver_register(&gpio_buttons_driver);
 220 }
 221
 222 static void __exit gpio_buttons_exit(void)
 223 {
 224         platform_driver_unregister(&gpio_buttons_driver);
 225 }
 226
 227 module_init(gpio_buttons_init);
 228 module_exit(gpio_buttons_exit);
 229
 230 MODULE_LICENSE("GPL v2");
 231 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 232 MODULE_DESCRIPTION("Polled GPIO Buttons driver");