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/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21
  22 #include <linux/input.h>
  23 #include <linux/input-polldev.h>
  24 #include <linux/ioport.h>
  25 #include <linux/platform_device.h>
  26
  27 #include <linux/gpio_buttons.h>
  28
  29 #include <asm/gpio.h>
  30
  31 #define DRV_NAME        "gpio-buttons"
  32 #define DRV_VERSION     "0.1.1"
  33 #define PFX             DRV_NAME ": "
  34
  35 struct gpio_buttons_dev {
  36         struct input_polled_dev *poll_dev;
  37         struct gpio_buttons_platform_data *pdata;
  38 };
  39
  40 static void gpio_buttons_poll(struct input_polled_dev *dev)
  41 {
  42         struct gpio_buttons_dev *bdev = dev->private;
  43         struct gpio_buttons_platform_data *pdata = bdev->pdata;
  44         struct input_dev *input = dev->input;
  45         int i;
  46
  47         for (i = 0; i < bdev->pdata->nbuttons; i++) {
  48                 struct gpio_button *button = &pdata->buttons[i];
  49                 unsigned int type = button->type ?: EV_KEY;
  50                 int state;
  51
  52                 state = gpio_get_value(button->gpio) ? 1 : 0;
  53                 state ^= button->active_low;
  54
  55                 if (state) {
  56                         button->count++;
  57                 } else {
  58                         if (button->count >= button->threshold) {
  59                                 input_event(input, type, button->code, 1);
  60                                 input_sync(input);
  61                         }
  62                         button->count = 0;
  63                 }
  64
  65                 if (button->count == button->threshold) {
  66                         input_event(input, type, button->code, 0);
  67                         input_sync(input);
  68                 }
  69         }
  70 }
  71
  72 static int __devinit gpio_buttons_probe(struct platform_device *pdev)
  73 {
  74         struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
  75         struct gpio_buttons_dev *bdev;
  76         struct input_polled_dev *poll_dev;
  77         struct input_dev *input;
  78         int error, i;
  79
  80
  81         if (!pdata)
  82                 return -ENXIO;
  83
  84         bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
  85         if (!bdev) {
  86                 printk(KERN_ERR DRV_NAME "no memory for device\n");
  87                 return -ENOMEM;
  88         }
  89
  90         poll_dev = input_allocate_polled_device();
  91         if (!poll_dev) {
  92                 printk(KERN_ERR DRV_NAME "no memory for polled device\n");
  93                 error = -ENOMEM;
  94                 goto err_free_bdev;
  95         }
  96
  97         poll_dev->private = bdev;
  98         poll_dev->poll = gpio_buttons_poll;
  99         poll_dev->poll_interval = pdata->poll_interval;
 100
 101         input = poll_dev->input;
 102
 103         input->evbit[0] = BIT(EV_KEY);
 104         input->name = pdev->name;
 105         input->phys = "gpio-buttons/input0";
 106         input->dev.parent = &pdev->dev;
 107
 108         input->id.bustype = BUS_HOST;
 109         input->id.vendor = 0x0001;
 110         input->id.product = 0x0001;
 111         input->id.version = 0x0100;
 112
 113         for (i = 0; i < pdata->nbuttons; i++) {
 114                 struct gpio_button *button = &pdata->buttons[i];
 115                 unsigned int gpio = button->gpio;
 116                 unsigned int type = button->type ?: EV_KEY;
 117
 118                 error = gpio_request(gpio, button->desc ?
 119                                 button->desc : DRV_NAME);
 120                 if (error) {
 121                         printk(KERN_ERR PFX "unable to claim gpio %u, "
 122                                 "error %d\n", gpio, error);
 123                         goto err_free_gpio;
 124                 }
 125
 126                 error = gpio_direction_input(gpio);
 127                 if (error) {
 128                         printk(KERN_ERR PFX "unable to set direction on "
 129                                 "gpio %u, error %d\n", gpio, error);
 130                         goto err_free_gpio;
 131                 }
 132
 133                 input_set_capability(input, type, button->code);
 134                 button->count = 0;
 135         }
 136
 137         bdev->poll_dev = poll_dev;
 138         bdev->pdata = pdata;
 139         platform_set_drvdata(pdev, bdev);
 140
 141         error = input_register_polled_device(poll_dev);
 142         if (error) {
 143                 printk(KERN_ERR PFX "unable to register polled device, "
 144                         "error %d\n", error);
 145                 goto err_free_gpio;
 146         }
 147
 148         return 0;
 149
 150 err_free_gpio:
 151         for (i = i - 1; i >= 0; i--)
 152                 gpio_free(pdata->buttons[i].gpio);
 153
 154         input_free_polled_device(poll_dev);
 155
 156 err_free_bdev:
 157         kfree(bdev);
 158
 159         platform_set_drvdata(pdev, NULL);
 160         return error;
 161 }
 162
 163 static int __devexit gpio_buttons_remove(struct platform_device *pdev)
 164 {
 165         struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
 166         struct gpio_buttons_platform_data *pdata = bdev->pdata;
 167         int i;
 168
 169         input_unregister_polled_device(bdev->poll_dev);
 170
 171         for (i = 0; i < pdata->nbuttons; i++)
 172                 gpio_free(pdata->buttons[i].gpio);
 173
 174         input_free_polled_device(bdev->poll_dev);
 175
 176         kfree(bdev);
 177         platform_set_drvdata(pdev, NULL);
 178
 179         return 0;
 180 }
 181
 182 static struct platform_driver gpio_buttons_driver = {
 183         .probe  = gpio_buttons_probe,
 184         .remove = __devexit_p(gpio_buttons_remove),
 185         .driver = {
 186                 .name   = DRV_NAME,
 187                 .owner  = THIS_MODULE,
 188         },
 189 };
 190
 191 static int __init gpio_buttons_init(void)
 192 {
 193         printk(KERN_INFO DRV_NAME " driver version " DRV_VERSION "\n");
 194         return platform_driver_register(&gpio_buttons_driver);
 195 }
 196
 197 static void __exit gpio_buttons_exit(void)
 198 {
 199         platform_driver_unregister(&gpio_buttons_driver);
 200 }
 201
 202 module_init(gpio_buttons_init);
 203 module_exit(gpio_buttons_exit);
 204
 205 MODULE_LICENSE("GPL");
 206 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
 207 MODULE_VERSION(DRV_VERSION);
 208 MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");
 209