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/*
* Driver for buttons on GPIO lines not capable of generating interrupts
*
* Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
*
* This file was based on: /drivers/input/misc/cobalt_btns.c
* Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
*
* also was based on: /drivers/input/keyboard/gpio_keys.c
* Copyright 2005 Phil Blundell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/input-polldev.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/gpio_buttons.h>
#define DRV_NAME "gpio-buttons"
struct gpio_button_data {
int last_state;
int count;
int can_sleep;
};
struct gpio_buttons_dev {
struct input_polled_dev *poll_dev;
struct gpio_buttons_platform_data *pdata;
struct gpio_button_data *data;
};
static void gpio_buttons_check_state(struct input_dev *input,
struct gpio_button *button,
struct gpio_button_data *bdata)
{
int state;
if (bdata->can_sleep)
state = !!gpio_get_value_cansleep(button->gpio);
else
state = !!gpio_get_value(button->gpio);
if (state != bdata->last_state) {
unsigned int type = button->type ?: EV_KEY;
input_event(input, type, button->code,
!!(state ^ button->active_low));
input_sync(input);
bdata->count = 0;
bdata->last_state = state;
}
}
static void gpio_buttons_poll(struct input_polled_dev *dev)
{
struct gpio_buttons_dev *bdev = dev->private;
struct gpio_buttons_platform_data *pdata = bdev->pdata;
struct input_dev *input = dev->input;
int i;
for (i = 0; i < bdev->pdata->nbuttons; i++) {
struct gpio_button *button = &pdata->buttons[i];
struct gpio_button_data *bdata = &bdev->data[i];
if (bdata->count < button->threshold)
bdata->count++;
else
gpio_buttons_check_state(input, button, bdata);
}
}
static int gpio_buttons_probe(struct platform_device *pdev)
{
struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
struct device *dev = &pdev->dev;
struct gpio_buttons_dev *bdev;
struct input_polled_dev *poll_dev;
struct input_dev *input;
int error;
int i;
if (!pdata)
return -ENXIO;
bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
pdata->nbuttons * sizeof(struct gpio_button_data),
GFP_KERNEL);
if (!bdev) {
dev_err(dev, "no memory for private data\n");
return -ENOMEM;
}
bdev->data = (struct gpio_button_data *) &bdev[1];
poll_dev = input_allocate_polled_device();
if (!poll_dev) {
dev_err(dev, "no memory for polled device\n");
error = -ENOMEM;
goto err_free_bdev;
}
poll_dev->private = bdev;
poll_dev->poll = gpio_buttons_poll;
poll_dev->poll_interval = pdata->poll_interval;
input = poll_dev->input;
input->evbit[0] = BIT(EV_KEY);
input->name = pdev->name;
input->phys = "gpio-buttons/input0";
input->dev.parent = &pdev->dev;
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_button *button = &pdata->buttons[i];
unsigned int gpio = button->gpio;
unsigned int type = button->type ?: EV_KEY;
error = gpio_request(gpio,
button->desc ? button->desc : DRV_NAME);
if (error) {
dev_err(dev, "unable to claim gpio %u, err=%d\n",
gpio, error);
goto err_free_gpio;
}
error = gpio_direction_input(gpio);
if (error) {
dev_err(dev,
"unable to set direction on gpio %u, err=%d\n",
gpio, error);
goto err_free_gpio;
}
bdev->data[i].can_sleep = gpio_cansleep(gpio);
bdev->data[i].last_state = -1;
input_set_capability(input, type, button->code);
}
bdev->poll_dev = poll_dev;
bdev->pdata = pdata;
platform_set_drvdata(pdev, bdev);
error = input_register_polled_device(poll_dev);
if (error) {
dev_err(dev, "unable to register polled device, err=%d\n",
error);
goto err_free_gpio;
}
/* report initial state of the buttons */
for (i = 0; i < pdata->nbuttons; i++)
gpio_buttons_check_state(input, &pdata->buttons[i],
&bdev->data[i]);
return 0;
err_free_gpio:
for (i = i - 1; i >= 0; i--)
gpio_free(pdata->buttons[i].gpio);
input_free_polled_device(poll_dev);
err_free_bdev:
kfree(bdev);
platform_set_drvdata(pdev, NULL);
return error;
}
static int gpio_buttons_remove(struct platform_device *pdev)
{
struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
struct gpio_buttons_platform_data *pdata = bdev->pdata;
int i;
input_unregister_polled_device(bdev->poll_dev);
for (i = 0; i < pdata->nbuttons; i++)
gpio_free(pdata->buttons[i].gpio);
input_free_polled_device(bdev->poll_dev);
kfree(bdev);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver gpio_buttons_driver = {
.probe = gpio_buttons_probe,
.remove = gpio_buttons_remove,
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
};
static int __init gpio_buttons_init(void)
{
return platform_driver_register(&gpio_buttons_driver);
}
static void __exit gpio_buttons_exit(void)
{
platform_driver_unregister(&gpio_buttons_driver);
}
module_init(gpio_buttons_init);
module_exit(gpio_buttons_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_DESCRIPTION("Polled GPIO Buttons driver");
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