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/*
* Driver for tilt switches connected via GPIO lines
* not capable of generating interrupts
*
* Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
*
* based on: drivers/input/keyboard/gpio_keys_polled.c
*
* Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
*
* 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/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/input/gpio_tilt.h>
#define DRV_NAME "gpio-tilt-polled"
struct gpio_tilt_polled_dev {
struct input_polled_dev *poll_dev;
struct device *dev;
const struct gpio_tilt_platform_data *pdata;
int last_state;
int threshold;
int count;
};
static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
{
struct gpio_tilt_polled_dev *tdev = dev->private;
const struct gpio_tilt_platform_data *pdata = tdev->pdata;
struct input_dev *input = dev->input;
struct gpio_tilt_state *tilt_state = NULL;
int state, i;
if (tdev->count < tdev->threshold) {
tdev->count++;
} else {
state = 0;
for (i = 0; i < pdata->nr_gpios; i++)
state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
if (state != tdev->last_state) {
for (i = 0; i < pdata->nr_states; i++)
if (pdata->states[i].gpios == state)
tilt_state = &pdata->states[i];
if (tilt_state) {
for (i = 0; i < pdata->nr_axes; i++)
input_report_abs(input,
pdata->axes[i].axis,
tilt_state->axes[i]);
input_sync(input);
}
tdev->count = 0;
tdev->last_state = state;
}
}
}
static void gpio_tilt_polled_open(struct input_polled_dev *dev)
{
struct gpio_tilt_polled_dev *tdev = dev->private;
const struct gpio_tilt_platform_data *pdata = tdev->pdata;
if (pdata->enable)
pdata->enable(tdev->dev);
/* report initial state of the axes */
tdev->last_state = -1;
tdev->count = tdev->threshold;
gpio_tilt_polled_poll(tdev->poll_dev);
}
static void gpio_tilt_polled_close(struct input_polled_dev *dev)
{
struct gpio_tilt_polled_dev *tdev = dev->private;
const struct gpio_tilt_platform_data *pdata = tdev->pdata;
if (pdata->disable)
pdata->disable(tdev->dev);
}
static int gpio_tilt_polled_probe(struct platform_device *pdev)
{
const struct gpio_tilt_platform_data *pdata =
dev_get_platdata(&pdev->dev);
struct device *dev = &pdev->dev;
struct gpio_tilt_polled_dev *tdev;
struct input_polled_dev *poll_dev;
struct input_dev *input;
int error, i;
if (!pdata || !pdata->poll_interval)
return -EINVAL;
tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
if (!tdev) {
dev_err(dev, "no memory for private data\n");
return -ENOMEM;
}
error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
if (error) {
dev_err(dev,
"Could not request tilt GPIOs: %d\n", error);
goto err_free_tdev;
}
poll_dev = input_allocate_polled_device();
if (!poll_dev) {
dev_err(dev, "no memory for polled device\n");
error = -ENOMEM;
goto err_free_gpios;
}
poll_dev->private = tdev;
poll_dev->poll = gpio_tilt_polled_poll;
poll_dev->poll_interval = pdata->poll_interval;
poll_dev->open = gpio_tilt_polled_open;
poll_dev->close = gpio_tilt_polled_close;
input = poll_dev->input;
input->name = pdev->name;
input->phys = DRV_NAME"/input0";
input->dev.parent = &pdev->dev;
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
__set_bit(EV_ABS, input->evbit);
for (i = 0; i < pdata->nr_axes; i++)
input_set_abs_params(input, pdata->axes[i].axis,
pdata->axes[i].min, pdata->axes[i].max,
pdata->axes[i].fuzz, pdata->axes[i].flat);
tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
pdata->poll_interval);
tdev->poll_dev = poll_dev;
tdev->dev = dev;
tdev->pdata = pdata;
error = input_register_polled_device(poll_dev);
if (error) {
dev_err(dev, "unable to register polled device, err=%d\n",
error);
goto err_free_polldev;
}
platform_set_drvdata(pdev, tdev);
return 0;
err_free_polldev:
input_free_polled_device(poll_dev);
err_free_gpios:
gpio_free_array(pdata->gpios, pdata->nr_gpios);
err_free_tdev:
kfree(tdev);
return error;
}
static int gpio_tilt_polled_remove(struct platform_device *pdev)
{
struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
const struct gpio_tilt_platform_data *pdata = tdev->pdata;
input_unregister_polled_device(tdev->poll_dev);
input_free_polled_device(tdev->poll_dev);
gpio_free_array(pdata->gpios, pdata->nr_gpios);
kfree(tdev);
return 0;
}
static struct platform_driver gpio_tilt_polled_driver = {
.probe = gpio_tilt_polled_probe,
.remove = gpio_tilt_polled_remove,
.driver = {
.name = DRV_NAME,
},
};
module_platform_driver(gpio_tilt_polled_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
MODULE_DESCRIPTION("Polled GPIO tilt driver");
MODULE_ALIAS("platform:" DRV_NAME);
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