target/linux/generic-2.6/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
  23 #include <linux/input.h>
  24 #include <linux/input-polldev.h>
  25 #include <linux/ioport.h>
  26 #include <linux/platform_device.h>
  27
  28 #include <linux/gpio_buttons.h>
  29
  30 #include <asm/gpio.h>
  31
  32 #define DRV_NAME        "gpio-buttons"
  33 #define DRV_VERSION     "0.1.2"
  34 #define PFX             DRV_NAME ": "
  35
  36 struct gpio_button_data {
  37         int last_state;
  38         int count;
  39 };
  40
  41 struct gpio_buttons_dev {
  42         struct input_polled_dev *poll_dev;
  43         struct gpio_buttons_platform_data *pdata;
  44         struct gpio_button_data *data;
  45 };
  46
  47 static void gpio_buttons_poll(struct input_polled_dev *dev)
  48 {
  49         struct gpio_buttons_dev *bdev = dev->private;
  50         struct gpio_buttons_platform_data *pdata = bdev->pdata;
  51         struct input_dev *input = dev->input;
  52         int i;
  53
  54         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  55                 struct gpio_button *button = &pdata->buttons[i];
  56                 unsigned int type = button->type ?: EV_KEY;
  57                 int state;
  58
  59                 if (bdev->data[i].count < button->threshold) {
  60                         bdev->data[i].count++;
  61                         continue;
  62                 }
  63
  64                 state = gpio_get_value(button->gpio) ? 1 : 0;
  65                 if (state != bdev->data[i].last_state) {
  66                         input_event(input, type, button->code,
  67                                     !!(state ^ button->active_low));
  68                         input_sync(input);
  69                         bdev->data[i].count = 0;
  70                         bdev->data[i].last_state = state;
  71                 }
  72         }
  73 }
  74
  75 static int __devinit gpio_buttons_probe(struct platform_device *pdev)
  76 {
  77         struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
  78         struct gpio_buttons_dev *bdev;
  79         struct input_polled_dev *poll_dev;
  80         struct input_dev *input;
  81         int error, i;
  82
  83         if (!pdata)
  84                 return -ENXIO;
  85
  86         bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
  87                        sizeof(struct gpio_button_data) * pdata->nbuttons,
  88                        GFP_KERNEL);
  89         if (!bdev) {
  90                 printk(KERN_ERR DRV_NAME "no memory for device\n");
  91                 return -ENOMEM;
  92         }
  93
  94         bdev->data = (struct gpio_button_data *) &bdev[1];
  95
  96         poll_dev = input_allocate_polled_device();
  97         if (!poll_dev) {
  98                 printk(KERN_ERR DRV_NAME "no memory for polled device\n");
  99                 error = -ENOMEM;
 100                 goto err_free_bdev;
 101         }
 102
 103         poll_dev->private = bdev;
 104         poll_dev->poll = gpio_buttons_poll;
 105         poll_dev->poll_interval = pdata->poll_interval;
 106
 107         input = poll_dev->input;
 108
 109         input->evbit[0] = BIT(EV_KEY);
 110         input->name = pdev->name;
 111         input->phys = "gpio-buttons/input0";
 112         input->dev.parent = &pdev->dev;
 113
 114         input->id.bustype = BUS_HOST;
 115         input->id.vendor = 0x0001;
 116         input->id.product = 0x0001;
 117         input->id.version = 0x0100;
 118
 119         for (i = 0; i < pdata->nbuttons; i++) {
 120                 struct gpio_button *button = &pdata->buttons[i];
 121                 unsigned int gpio = button->gpio;
 122                 unsigned int type = button->type ?: EV_KEY;
 123
 124                 error = gpio_request(gpio, button->desc ?
 125                                 button->desc : DRV_NAME);
 126                 if (error) {
 127                         printk(KERN_ERR PFX "unable to claim gpio %u, "
 128                                 "error %d\n", gpio, error);
 129                         goto err_free_gpio;
 130                 }
 131
 132                 error = gpio_direction_input(gpio);
 133                 if (error) {
 134                         printk(KERN_ERR PFX "unable to set direction on "
 135                                 "gpio %u, error %d\n", gpio, error);
 136                         goto err_free_gpio;
 137                 }
 138
 139                 input_set_capability(input, type, button->code);
 140                 bdev->data[i].last_state = gpio_get_value(button->gpio) ? 1 : 0;
 141         }
 142
 143         bdev->poll_dev = poll_dev;
 144         bdev->pdata = pdata;
 145         platform_set_drvdata(pdev, bdev);
 146
 147         error = input_register_polled_device(poll_dev);
 148         if (error) {
 149                 printk(KERN_ERR PFX "unable to register polled device, "
 150                         "error %d\n", error);
 151                 goto err_free_gpio;
 152         }
 153
 154         return 0;
 155
 156 err_free_gpio:
 157         for (i = i - 1; i >= 0; i--)
 158                 gpio_free(pdata->buttons[i].gpio);
 159
 160         input_free_polled_device(poll_dev);
 161
 162 err_free_bdev:
 163         kfree(bdev);
 164
 165         platform_set_drvdata(pdev, NULL);
 166         return error;
 167 }
 168
 169 static int __devexit gpio_buttons_remove(struct platform_device *pdev)
 170 {
 171         struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
 172         struct gpio_buttons_platform_data *pdata = bdev->pdata;
 173         int i;
 174
 175         input_unregister_polled_device(bdev->poll_dev);
 176
 177         for (i = 0; i < pdata->nbuttons; i++)
 178                 gpio_free(pdata->buttons[i].gpio);
 179
 180         input_free_polled_device(bdev->poll_dev);
 181
 182         kfree(bdev);
 183         platform_set_drvdata(pdev, NULL);
 184
 185         return 0;
 186 }
 187
 188 static struct platform_driver gpio_buttons_driver = {
 189         .probe  = gpio_buttons_probe,
 190         .remove = __devexit_p(gpio_buttons_remove),
 191         .driver = {
 192                 .name   = DRV_NAME,
 193                 .owner  = THIS_MODULE,
 194         },
 195 };
 196
 197 static int __init gpio_buttons_init(void)
 198 {
 199         printk(KERN_INFO DRV_NAME " driver version " DRV_VERSION "\n");
 200         return platform_driver_register(&gpio_buttons_driver);
 201 }
 202
 203 static void __exit gpio_buttons_exit(void)
 204 {
 205         platform_driver_unregister(&gpio_buttons_driver);
 206 }
 207
 208 module_init(gpio_buttons_init);
 209 module_exit(gpio_buttons_exit);
 210
 211 MODULE_LICENSE("GPL");
 212 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
 213 MODULE_VERSION(DRV_VERSION);
 214 MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");
 215