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
  24 #include <linux/input.h>
  25 #include <linux/input-polldev.h>
  26 #include <linux/ioport.h>
  27 #include <linux/platform_device.h>
  28
  29 #include <linux/gpio_buttons.h>
  30
  31 #include <asm/gpio.h>
  32
  33 #define DRV_NAME        "gpio-buttons"
  34 #define DRV_VERSION     "0.1.2"
  35 #define PFX             DRV_NAME ": "
  36
  37 struct gpio_button_data {
  38         int last_state;
  39         int count;
  40 };
  41
  42 struct gpio_buttons_dev {
  43         struct input_polled_dev *poll_dev;
  44         struct gpio_buttons_platform_data *pdata;
  45         struct gpio_button_data *data;
  46 };
  47
  48 static void gpio_buttons_poll(struct input_polled_dev *dev)
  49 {
  50         struct gpio_buttons_dev *bdev = dev->private;
  51         struct gpio_buttons_platform_data *pdata = bdev->pdata;
  52         struct input_dev *input = dev->input;
  53         int i;
  54
  55         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  56                 struct gpio_button *button = &pdata->buttons[i];
  57                 unsigned int type = button->type ?: EV_KEY;
  58                 int state;
  59
  60                 if (bdev->data[i].count < button->threshold) {
  61                         bdev->data[i].count++;
  62                         continue;
  63                 }
  64
  65                 state = gpio_get_value(button->gpio) ? 1 : 0;
  66                 if (state != bdev->data[i].last_state) {
  67                         input_event(input, type, button->code,
  68                                     !!(state ^ button->active_low));
  69                         input_sync(input);
  70                         bdev->data[i].count = 0;
  71                         bdev->data[i].last_state = state;
  72                 }
  73         }
  74 }
  75
  76 static int __devinit gpio_buttons_probe(struct platform_device *pdev)
  77 {
  78         struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
  79         struct gpio_buttons_dev *bdev;
  80         struct input_polled_dev *poll_dev;
  81         struct input_dev *input;
  82         int error, i;
  83
  84         if (!pdata)
  85                 return -ENXIO;
  86
  87         bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
  88                        sizeof(struct gpio_button_data) * pdata->nbuttons,
  89                        GFP_KERNEL);
  90         if (!bdev) {
  91                 printk(KERN_ERR DRV_NAME "no memory for device\n");
  92                 return -ENOMEM;
  93         }
  94
  95         bdev->data = (struct gpio_button_data *) &bdev[1];
  96
  97         poll_dev = input_allocate_polled_device();
  98         if (!poll_dev) {
  99                 printk(KERN_ERR DRV_NAME "no memory for polled device\n");
 100                 error = -ENOMEM;
 101                 goto err_free_bdev;
 102         }
 103
 104         poll_dev->private = bdev;
 105         poll_dev->poll = gpio_buttons_poll;
 106         poll_dev->poll_interval = pdata->poll_interval;
 107
 108         input = poll_dev->input;
 109
 110         input->evbit[0] = BIT(EV_KEY);
 111         input->name = pdev->name;
 112         input->phys = "gpio-buttons/input0";
 113         input->dev.parent = &pdev->dev;
 114
 115         input->id.bustype = BUS_HOST;
 116         input->id.vendor = 0x0001;
 117         input->id.product = 0x0001;
 118         input->id.version = 0x0100;
 119
 120         for (i = 0; i < pdata->nbuttons; i++) {
 121                 struct gpio_button *button = &pdata->buttons[i];
 122                 unsigned int gpio = button->gpio;
 123                 unsigned int type = button->type ?: EV_KEY;
 124
 125                 error = gpio_request(gpio, button->desc ?
 126                                 button->desc : DRV_NAME);
 127                 if (error) {
 128                         printk(KERN_ERR PFX "unable to claim gpio %u, "
 129                                 "error %d\n", gpio, error);
 130                         goto err_free_gpio;
 131                 }
 132
 133                 error = gpio_direction_input(gpio);
 134                 if (error) {
 135                         printk(KERN_ERR PFX "unable to set direction on "
 136                                 "gpio %u, error %d\n", gpio, error);
 137                         goto err_free_gpio;
 138                 }
 139
 140                 input_set_capability(input, type, button->code);
 141                 bdev->data[i].last_state = gpio_get_value(button->gpio) ? 1 : 0;
 142         }
 143
 144         bdev->poll_dev = poll_dev;
 145         bdev->pdata = pdata;
 146         platform_set_drvdata(pdev, bdev);
 147
 148         error = input_register_polled_device(poll_dev);
 149         if (error) {
 150                 printk(KERN_ERR PFX "unable to register polled device, "
 151                         "error %d\n", error);
 152                 goto err_free_gpio;
 153         }
 154
 155         return 0;
 156
 157 err_free_gpio:
 158         for (i = i - 1; i >= 0; i--)
 159                 gpio_free(pdata->buttons[i].gpio);
 160
 161         input_free_polled_device(poll_dev);
 162
 163 err_free_bdev:
 164         kfree(bdev);
 165
 166         platform_set_drvdata(pdev, NULL);
 167         return error;
 168 }
 169
 170 static int __devexit gpio_buttons_remove(struct platform_device *pdev)
 171 {
 172         struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
 173         struct gpio_buttons_platform_data *pdata = bdev->pdata;
 174         int i;
 175
 176         input_unregister_polled_device(bdev->poll_dev);
 177
 178         for (i = 0; i < pdata->nbuttons; i++)
 179                 gpio_free(pdata->buttons[i].gpio);
 180
 181         input_free_polled_device(bdev->poll_dev);
 182
 183         kfree(bdev);
 184         platform_set_drvdata(pdev, NULL);
 185
 186         return 0;
 187 }
 188
 189 static struct platform_driver gpio_buttons_driver = {
 190         .probe  = gpio_buttons_probe,
 191         .remove = __devexit_p(gpio_buttons_remove),
 192         .driver = {
 193                 .name   = DRV_NAME,
 194                 .owner  = THIS_MODULE,
 195         },
 196 };
 197
 198 static int __init gpio_buttons_init(void)
 199 {
 200         printk(KERN_INFO DRV_NAME " driver version " DRV_VERSION "\n");
 201         return platform_driver_register(&gpio_buttons_driver);
 202 }
 203
 204 static void __exit gpio_buttons_exit(void)
 205 {
 206         platform_driver_unregister(&gpio_buttons_driver);
 207 }
 208
 209 module_init(gpio_buttons_init);
 210 module_exit(gpio_buttons_exit);
 211
 212 MODULE_LICENSE("GPL");
 213 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
 214 MODULE_VERSION(DRV_VERSION);
 215 MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");
 216