Input: add generic GPIO-tilt driver
There exist tilt switches that simply report their tilt-state via some gpios. The number and orientation of their axes can vary depending on the switch used and the build of the device. Also two or more one-axis switches could be combined to provide multi-dimensional orientation. One example of a device using such a switch is the family of Qisda ebook readers, where the switch provides information about the landscape / portrait orientation of the device. The example in Documentation/input/gpio-tilt.txt documents exactly this one-axis device. Signed-off-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Heiko Stübner
committed by
Dmitry Torokhov
Dmitry Torokhov
parent
a6c61789c8
commit
3bfd5c5baf
213
drivers/input/misc/gpio_tilt_polled.c
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213
drivers/input/misc/gpio_tilt_polled.c
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/*
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* Driver for tilt switches connected via GPIO lines
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* not capable of generating interrupts
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*
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* Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
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*
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* based on: drivers/input/keyboard/gpio_keys_polled.c
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*
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* Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
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* Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/input.h>
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#include <linux/input-polldev.h>
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#include <linux/ioport.h>
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#include <linux/platform_device.h>
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#include <linux/gpio.h>
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#include <linux/input/gpio_tilt.h>
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#define DRV_NAME "gpio-tilt-polled"
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struct gpio_tilt_polled_dev {
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struct input_polled_dev *poll_dev;
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struct device *dev;
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const struct gpio_tilt_platform_data *pdata;
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int last_state;
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int threshold;
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int count;
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};
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static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
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{
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struct gpio_tilt_polled_dev *tdev = dev->private;
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const struct gpio_tilt_platform_data *pdata = tdev->pdata;
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struct input_dev *input = dev->input;
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struct gpio_tilt_state *tilt_state = NULL;
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int state, i;
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if (tdev->count < tdev->threshold) {
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tdev->count++;
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} else {
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state = 0;
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for (i = 0; i < pdata->nr_gpios; i++)
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state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
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if (state != tdev->last_state) {
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for (i = 0; i < pdata->nr_states; i++)
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if (pdata->states[i].gpios == state)
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tilt_state = &pdata->states[i];
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if (tilt_state) {
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for (i = 0; i < pdata->nr_axes; i++)
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input_report_abs(input,
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pdata->axes[i].axis,
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tilt_state->axes[i]);
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input_sync(input);
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}
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tdev->count = 0;
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tdev->last_state = state;
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}
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}
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}
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static void gpio_tilt_polled_open(struct input_polled_dev *dev)
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{
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struct gpio_tilt_polled_dev *tdev = dev->private;
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const struct gpio_tilt_platform_data *pdata = tdev->pdata;
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if (pdata->enable)
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pdata->enable(tdev->dev);
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/* report initial state of the axes */
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tdev->last_state = -1;
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tdev->count = tdev->threshold;
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gpio_tilt_polled_poll(tdev->poll_dev);
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}
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static void gpio_tilt_polled_close(struct input_polled_dev *dev)
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{
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struct gpio_tilt_polled_dev *tdev = dev->private;
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const struct gpio_tilt_platform_data *pdata = tdev->pdata;
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if (pdata->disable)
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pdata->disable(tdev->dev);
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}
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static int __devinit gpio_tilt_polled_probe(struct platform_device *pdev)
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{
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const struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
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struct device *dev = &pdev->dev;
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struct gpio_tilt_polled_dev *tdev;
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struct input_polled_dev *poll_dev;
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struct input_dev *input;
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int error, i;
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if (!pdata || !pdata->poll_interval)
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return -EINVAL;
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tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
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if (!tdev) {
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dev_err(dev, "no memory for private data\n");
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return -ENOMEM;
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}
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error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
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if (error) {
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dev_err(dev,
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"Could not request tilt GPIOs: %d\n", error);
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goto err_free_tdev;
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}
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poll_dev = input_allocate_polled_device();
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if (!poll_dev) {
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dev_err(dev, "no memory for polled device\n");
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error = -ENOMEM;
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goto err_free_gpios;
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}
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poll_dev->private = tdev;
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poll_dev->poll = gpio_tilt_polled_poll;
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poll_dev->poll_interval = pdata->poll_interval;
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poll_dev->open = gpio_tilt_polled_open;
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poll_dev->close = gpio_tilt_polled_close;
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input = poll_dev->input;
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input->name = pdev->name;
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input->phys = DRV_NAME"/input0";
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input->dev.parent = &pdev->dev;
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input->id.bustype = BUS_HOST;
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input->id.vendor = 0x0001;
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input->id.product = 0x0001;
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input->id.version = 0x0100;
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__set_bit(EV_ABS, input->evbit);
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for (i = 0; i < pdata->nr_axes; i++)
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input_set_abs_params(input, pdata->axes[i].axis,
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pdata->axes[i].min, pdata->axes[i].max,
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pdata->axes[i].fuzz, pdata->axes[i].flat);
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tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
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pdata->poll_interval);
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tdev->poll_dev = poll_dev;
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tdev->dev = dev;
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tdev->pdata = pdata;
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error = input_register_polled_device(poll_dev);
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if (error) {
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dev_err(dev, "unable to register polled device, err=%d\n",
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error);
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goto err_free_polldev;
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}
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platform_set_drvdata(pdev, tdev);
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return 0;
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err_free_polldev:
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input_free_polled_device(poll_dev);
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err_free_gpios:
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gpio_free_array(pdata->gpios, pdata->nr_gpios);
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err_free_tdev:
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kfree(tdev);
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return error;
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}
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static int __devexit gpio_tilt_polled_remove(struct platform_device *pdev)
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{
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struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
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const struct gpio_tilt_platform_data *pdata = tdev->pdata;
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platform_set_drvdata(pdev, NULL);
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input_unregister_polled_device(tdev->poll_dev);
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input_free_polled_device(tdev->poll_dev);
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gpio_free_array(pdata->gpios, pdata->nr_gpios);
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kfree(tdev);
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return 0;
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}
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static struct platform_driver gpio_tilt_polled_driver = {
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.probe = gpio_tilt_polled_probe,
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.remove = __devexit_p(gpio_tilt_polled_remove),
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(gpio_tilt_polled_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
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MODULE_DESCRIPTION("Polled GPIO tilt driver");
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MODULE_ALIAS("platform:" DRV_NAME);
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