1/*
  2 *  Driver for tilt switches connected via GPIO lines
  3 *  not capable of generating interrupts
  4 *
  5 *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
  6 *
  7 *  based on: drivers/input/keyboard/gpio_keys_polled.c
  8 *
  9 *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
 10 *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
 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#include <linux/kernel.h>
 18#include <linux/module.h>
 19#include <linux/init.h>
 20#include <linux/slab.h>
 21#include <linux/input.h>
 22#include <linux/input-polldev.h>
 23#include <linux/ioport.h>
 24#include <linux/platform_device.h>
 25#include <linux/gpio.h>
 26#include <linux/input/gpio_tilt.h>
 27
 28#define DRV_NAME	"gpio-tilt-polled"
 29
 30struct gpio_tilt_polled_dev {
 31	struct input_polled_dev *poll_dev;
 32	struct device *dev;
 33	const struct gpio_tilt_platform_data *pdata;
 34
 35	int last_state;
 36
 37	int threshold;
 38	int count;
 39};
 40
 41static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
 42{
 43	struct gpio_tilt_polled_dev *tdev = dev->private;
 44	const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 45	struct input_dev *input = dev->input;
 46	struct gpio_tilt_state *tilt_state = NULL;
 47	int state, i;
 48
 49	if (tdev->count < tdev->threshold) {
 50		tdev->count++;
 51	} else {
 52		state = 0;
 53		for (i = 0; i < pdata->nr_gpios; i++)
 54			state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
 55
 56		if (state != tdev->last_state) {
 57			for (i = 0; i < pdata->nr_states; i++)
 58				if (pdata->states[i].gpios == state)
 59					tilt_state = &pdata->states[i];
 60
 61			if (tilt_state) {
 62				for (i = 0; i < pdata->nr_axes; i++)
 63					input_report_abs(input,
 64							 pdata->axes[i].axis,
 65							 tilt_state->axes[i]);
 66
 67				input_sync(input);
 68			}
 69
 70			tdev->count = 0;
 71			tdev->last_state = state;
 72		}
 73	}
 74}
 75
 76static void gpio_tilt_polled_open(struct input_polled_dev *dev)
 77{
 78	struct gpio_tilt_polled_dev *tdev = dev->private;
 79	const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 80
 81	if (pdata->enable)
 82		pdata->enable(tdev->dev);
 83
 84	/* report initial state of the axes */
 85	tdev->last_state = -1;
 86	tdev->count = tdev->threshold;
 87	gpio_tilt_polled_poll(tdev->poll_dev);
 88}
 89
 90static void gpio_tilt_polled_close(struct input_polled_dev *dev)
 91{
 92	struct gpio_tilt_polled_dev *tdev = dev->private;
 93	const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 94
 95	if (pdata->disable)
 96		pdata->disable(tdev->dev);
 97}
 98
 99static int __devinit gpio_tilt_polled_probe(struct platform_device *pdev)
100{
101	const struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
102	struct device *dev = &pdev->dev;
103	struct gpio_tilt_polled_dev *tdev;
104	struct input_polled_dev *poll_dev;
105	struct input_dev *input;
106	int error, i;
107
108	if (!pdata || !pdata->poll_interval)
109		return -EINVAL;
110
111	tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
112	if (!tdev) {
113		dev_err(dev, "no memory for private data\n");
114		return -ENOMEM;
115	}
116
117	error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
118	if (error) {
119		dev_err(dev,
120			"Could not request tilt GPIOs: %d\n", error);
121		goto err_free_tdev;
122	}
123
124	poll_dev = input_allocate_polled_device();
125	if (!poll_dev) {
126		dev_err(dev, "no memory for polled device\n");
127		error = -ENOMEM;
128		goto err_free_gpios;
129	}
130
131	poll_dev->private = tdev;
132	poll_dev->poll = gpio_tilt_polled_poll;
133	poll_dev->poll_interval = pdata->poll_interval;
134	poll_dev->open = gpio_tilt_polled_open;
135	poll_dev->close = gpio_tilt_polled_close;
136
137	input = poll_dev->input;
138
139	input->name = pdev->name;
140	input->phys = DRV_NAME"/input0";
141	input->dev.parent = &pdev->dev;
142
143	input->id.bustype = BUS_HOST;
144	input->id.vendor = 0x0001;
145	input->id.product = 0x0001;
146	input->id.version = 0x0100;
147
148	__set_bit(EV_ABS, input->evbit);
149	for (i = 0; i < pdata->nr_axes; i++)
150		input_set_abs_params(input, pdata->axes[i].axis,
151				     pdata->axes[i].min, pdata->axes[i].max,
152				     pdata->axes[i].fuzz, pdata->axes[i].flat);
153
154	tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
155				       pdata->poll_interval);
156
157	tdev->poll_dev = poll_dev;
158	tdev->dev = dev;
159	tdev->pdata = pdata;
160
161	error = input_register_polled_device(poll_dev);
162	if (error) {
163		dev_err(dev, "unable to register polled device, err=%d\n",
164			error);
165		goto err_free_polldev;
166	}
167
168	platform_set_drvdata(pdev, tdev);
169
170	return 0;
171
172err_free_polldev:
173	input_free_polled_device(poll_dev);
174err_free_gpios:
175	gpio_free_array(pdata->gpios, pdata->nr_gpios);
176err_free_tdev:
177	kfree(tdev);
178
179	return error;
180}
181
182static int __devexit gpio_tilt_polled_remove(struct platform_device *pdev)
183{
184	struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
185	const struct gpio_tilt_platform_data *pdata = tdev->pdata;
186
187	platform_set_drvdata(pdev, NULL);
188
189	input_unregister_polled_device(tdev->poll_dev);
190	input_free_polled_device(tdev->poll_dev);
191
192	gpio_free_array(pdata->gpios, pdata->nr_gpios);
193
194	kfree(tdev);
195
196	return 0;
197}
198
199static struct platform_driver gpio_tilt_polled_driver = {
200	.probe	= gpio_tilt_polled_probe,
201	.remove	= __devexit_p(gpio_tilt_polled_remove),
202	.driver	= {
203		.name	= DRV_NAME,
204		.owner	= THIS_MODULE,
205	},
206};
207
208module_platform_driver(gpio_tilt_polled_driver);
209
210MODULE_LICENSE("GPL v2");
211MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
212MODULE_DESCRIPTION("Polled GPIO tilt driver");
213MODULE_ALIAS("platform:" DRV_NAME);