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) 2007,2008 Gabor Juhos <juhosg at openwrt.org>
   5  *
   6  *  This file was based on: /drivers/input/misc/cobalt_btns.c
   7  *      Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
   8  *
   9  *  also was based on: /drivers/input/keyboard/gpio_keys.c
  10  *      Copyright 2005 Phil Blundell
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License version 2 as
  14  *  published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/input-polldev.h>
  20 #include <linux/ioport.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23
  24 #include <linux/gpio_buttons.h>
  25
  26 #include <asm/gpio.h>
  27
  28 #define DRV_NAME        "gpio-buttons"
  29 #define DRV_VERSION     "0.1.0"
  30 #define PFX             DRV_NAME ": "
  31
  32 struct gpio_buttons_dev {
  33         struct input_polled_dev *poll_dev;
  34         struct gpio_buttons_platform_data *pdata;
  35 };
  36
  37 static void gpio_buttons_poll(struct input_polled_dev *dev)
  38 {
  39         struct gpio_buttons_dev *bdev = dev->private;
  40         struct gpio_buttons_platform_data *pdata = bdev->pdata;
  41         struct input_dev *input = dev->input;
  42         int i;
  43
  44         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  45                 struct gpio_button *button = &pdata->buttons[i];
  46                 unsigned int type = button->type ?: EV_KEY;
  47                 int state;
  48
  49                 state = gpio_get_value(button->gpio) ? 1 : 0;
  50                 state ^= button->active_low;
  51
  52                 if (state) {
  53                         button->count++;
  54                 } else {
  55                         if (button->count >= button->threshold) {
  56                                 input_event(input, type, button->code, 1);
  57                                 input_sync(input);
  58                         }
  59                         button->count = 0;
  60                 }
  61
  62                 if (button->count == button->threshold) {
  63                         input_event(input, type, button->code, 0);
  64                         input_sync(input);
  65                 }
  66         }
  67 }
  68
  69 static int __devinit gpio_buttons_probe(struct platform_device *pdev)
  70 {
  71         struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
  72         struct gpio_buttons_dev *bdev;
  73         struct input_polled_dev *poll_dev;
  74         struct input_dev *input;
  75         int error, i;
  76
  77
  78         if (!pdata)
  79                 return -ENXIO;
  80
  81         bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
  82         if (!bdev) {
  83                 pr_err(DRV_NAME "no memory for device\n");
  84                 return -ENOMEM;
  85         }
  86
  87         poll_dev = input_allocate_polled_device();
  88         if (!poll_dev) {
  89                 pr_err(DRV_NAME "no memory for polled device\n");
  90                 error = -ENOMEM;
  91                 goto err_free_bdev;
  92         }
  93
  94         poll_dev->private = bdev;
  95         poll_dev->poll = gpio_buttons_poll;
  96         poll_dev->poll_interval = pdata->poll_interval;
  97
  98         input = poll_dev->input;
  99
 100         input->evbit[0] = BIT_MASK(EV_KEY);
 101         input->name = pdev->name;
 102         input->phys = "gpio-buttons/input0";
 103         input->dev.parent = &pdev->dev;
 104
 105         input->id.bustype = BUS_HOST;
 106         input->id.vendor = 0x0001;
 107         input->id.product = 0x0001;
 108         input->id.version = 0x0100;
 109
 110         for (i = 0; i < pdata->nbuttons; i++) {
 111                 struct gpio_button *button = &pdata->buttons[i];
 112                 unsigned int gpio = button->gpio;
 113                 unsigned int type = button->type ?: EV_KEY;
 114
 115                 error = gpio_request(gpio, button->desc ?
 116                                 button->desc : DRV_NAME);
 117                 if (error) {
 118                         pr_err(PFX "unable to claim gpio %u, error %d\n",
 119                                 gpio, error);
 120                         goto err_free_gpio;
 121                 }
 122
 123                 error = gpio_direction_input(gpio);
 124                 if (error) {
 125                         pr_err(PFX "unable to set direction on gpio %u, "
 126                                 "error %d\n", gpio, error);
 127                         goto err_free_gpio;
 128                 }
 129
 130                 input_set_capability(input, type, button->code);
 131                 button->count = 0;
 132         }
 133
 134         bdev->poll_dev = poll_dev;
 135         bdev->pdata = pdata;
 136         platform_set_drvdata(pdev, bdev);
 137
 138         error = input_register_polled_device(poll_dev);
 139         if (error) {
 140                 pr_err(PFX "unable to register polled device, error %d\n",
 141                             error);
 142                 goto err_free_gpio;
 143         }
 144
 145         return 0;
 146
 147 err_free_gpio:
 148         for (i = i - 1; i >= 0; i--)
 149                 gpio_free(pdata->buttons[i].gpio);
 150
 151         input_free_polled_device(poll_dev);
 152
 153 err_free_bdev:
 154         kfree(bdev);
 155 err:
 156         platform_set_drvdata(pdev, NULL);
 157         return error;
 158 }
 159
 160 static int __devexit gpio_buttons_remove(struct platform_device *pdev)
 161 {
 162         struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
 163         struct gpio_buttons_platform_data *pdata = bdev->pdata;
 164         int i;
 165
 166         input_unregister_polled_device(bdev->poll_dev);
 167
 168         for (i = 0; i < pdata->nbuttons; i++)
 169                 gpio_free(pdata->buttons[i].gpio);
 170
 171         input_free_polled_device(bdev->poll_dev);
 172
 173         kfree(bdev);
 174         platform_set_drvdata(pdev, NULL);
 175
 176         return 0;
 177 }
 178
 179 static struct platform_driver gpio_buttons_driver = {
 180         .probe  = gpio_buttons_probe,
 181         .remove = __devexit_p(gpio_buttons_remove),
 182         .driver = {
 183                 .name   = DRV_NAME,
 184                 .owner  = THIS_MODULE,
 185         },
 186 };
 187
 188 static int __init gpio_buttons_init(void)
 189 {
 190         pr_info(DRV_NAME " driver version " DRV_VERSION "\n");
 191         return platform_driver_register(&gpio_buttons_driver);
 192 }
 193
 194 static void __exit gpio_buttons_exit(void)
 195 {
 196         platform_driver_unregister(&gpio_buttons_driver);
 197 }
 198
 199 module_init(gpio_buttons_init);
 200 module_exit(gpio_buttons_exit);
 201
 202 MODULE_LICENSE("GPL");
 203 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
 204 MODULE_VERSION(DRV_VERSION);
 205 MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");
 206