1/*
2 * Touch Screen driver for EETI's I2C connected touch screen panels
3 *   Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
4 *
5 * See EETI's software guide for the protocol specification:
6 *   http://home.eeti.com.tw/web20/eg/guide.htm
7 *
8 * Based on migor_ts.c
9 *   Copyright (c) 2008 Magnus Damm
10 *   Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>
11 *
12 * This file is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU  General Public
14 * License as published by the Free Software Foundation; either
15 * version 2 of the License, or (at your option) any later version.
16 *
17 * This file is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20 *  General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public
23 * License along with this library; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
25 */
26
27#include <linux/module.h>
28#include <linux/moduleparam.h>
29#include <linux/kernel.h>
30#include <linux/input.h>
31#include <linux/interrupt.h>
32#include <linux/i2c.h>
33#include <linux/timer.h>
34#include <linux/gpio.h>
35#include <linux/input/eeti_ts.h>
36#include <linux/slab.h>
37
38static bool flip_x;
39module_param(flip_x, bool, 0644);
40MODULE_PARM_DESC(flip_x, "flip x coordinate");
41
42static bool flip_y;
43module_param(flip_y, bool, 0644);
44MODULE_PARM_DESC(flip_y, "flip y coordinate");
45
46struct eeti_ts_priv {
47	struct i2c_client *client;
48	struct input_dev *input;
49	struct work_struct work;
50	struct mutex mutex;
51	int irq_gpio, irq, irq_active_high;
52};
53
54#define EETI_TS_BITDEPTH	(11)
55#define EETI_MAXVAL		((1 << (EETI_TS_BITDEPTH + 1)) - 1)
56
57#define REPORT_BIT_PRESSED	(1 << 0)
58#define REPORT_BIT_AD0		(1 << 1)
59#define REPORT_BIT_AD1		(1 << 2)
60#define REPORT_BIT_HAS_PRESSURE	(1 << 6)
61#define REPORT_RES_BITS(v)	(((v) >> 1) + EETI_TS_BITDEPTH)
62
63static inline int eeti_ts_irq_active(struct eeti_ts_priv *priv)
64{
65	return gpio_get_value(priv->irq_gpio) == priv->irq_active_high;
66}
67
68static void eeti_ts_read(struct work_struct *work)
69{
70	char buf[6];
71	unsigned int x, y, res, pressed, to = 100;
72	struct eeti_ts_priv *priv =
73		container_of(work, struct eeti_ts_priv, work);
74
75	mutex_lock(&priv->mutex);
76
77	while (eeti_ts_irq_active(priv) && --to)
78		i2c_master_recv(priv->client, buf, sizeof(buf));
79
80	if (!to) {
81		dev_err(&priv->client->dev,
82			"unable to clear IRQ - line stuck?\n");
83		goto out;
84	}
85
86	/* drop non-report packets */
87	if (!(buf[0] & 0x80))
88		goto out;
89
90	pressed = buf[0] & REPORT_BIT_PRESSED;
91	res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
92	x = buf[2] | (buf[1] << 8);
93	y = buf[4] | (buf[3] << 8);
94
95	/* fix the range to 11 bits */
96	x >>= res - EETI_TS_BITDEPTH;
97	y >>= res - EETI_TS_BITDEPTH;
98
99	if (flip_x)
100		x = EETI_MAXVAL - x;
101
102	if (flip_y)
103		y = EETI_MAXVAL - y;
104
105	if (buf[0] & REPORT_BIT_HAS_PRESSURE)
106		input_report_abs(priv->input, ABS_PRESSURE, buf[5]);
107
108	input_report_abs(priv->input, ABS_X, x);
109	input_report_abs(priv->input, ABS_Y, y);
110	input_report_key(priv->input, BTN_TOUCH, !!pressed);
111	input_sync(priv->input);
112
113out:
114	mutex_unlock(&priv->mutex);
115}
116
117static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
118{
119	struct eeti_ts_priv *priv = dev_id;
120
121	 /* postpone I2C transactions as we are atomic */
122	schedule_work(&priv->work);
123
124	return IRQ_HANDLED;
125}
126
127static void eeti_ts_start(struct eeti_ts_priv *priv)
128{
129	enable_irq(priv->irq);
130
131	/* Read the events once to arm the IRQ */
132	eeti_ts_read(&priv->work);
133}
134
135static void eeti_ts_stop(struct eeti_ts_priv *priv)
136{
137	disable_irq(priv->irq);
138	cancel_work_sync(&priv->work);
139}
140
141static int eeti_ts_open(struct input_dev *dev)
142{
143	struct eeti_ts_priv *priv = input_get_drvdata(dev);
144
145	eeti_ts_start(priv);
146
147	return 0;
148}
149
150static void eeti_ts_close(struct input_dev *dev)
151{
152	struct eeti_ts_priv *priv = input_get_drvdata(dev);
153
154	eeti_ts_stop(priv);
155}
156
157static int eeti_ts_probe(struct i2c_client *client,
158				   const struct i2c_device_id *idp)
159{
160	struct eeti_ts_platform_data *pdata = dev_get_platdata(&client->dev);
161	struct eeti_ts_priv *priv;
162	struct input_dev *input;
163	unsigned int irq_flags;
164	int err = -ENOMEM;
165
166	/*
167	 * In contrast to what's described in the datasheet, there seems
168	 * to be no way of probing the presence of that device using I2C
169	 * commands. So we need to blindly believe it is there, and wait
170	 * for interrupts to occur.
171	 */
172
173	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
174	if (!priv) {
175		dev_err(&client->dev, "failed to allocate driver data\n");
176		goto err0;
177	}
178
179	mutex_init(&priv->mutex);
180	input = input_allocate_device();
181
182	if (!input) {
183		dev_err(&client->dev, "Failed to allocate input device.\n");
184		goto err1;
185	}
186
187	input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
188	input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
189
190	input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
191	input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
192	input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
193
194	input->name = client->name;
195	input->id.bustype = BUS_I2C;
196	input->dev.parent = &client->dev;
197	input->open = eeti_ts_open;
198	input->close = eeti_ts_close;
199
200	priv->client = client;
201	priv->input = input;
202	priv->irq_gpio = pdata->irq_gpio;
203	priv->irq = gpio_to_irq(pdata->irq_gpio);
204
205	err = gpio_request_one(pdata->irq_gpio, GPIOF_IN, client->name);
206	if (err < 0)
207		goto err1;
208
209	priv->irq_active_high = pdata->irq_active_high;
210
211	irq_flags = priv->irq_active_high ?
212		IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
213
214	INIT_WORK(&priv->work, eeti_ts_read);
215	i2c_set_clientdata(client, priv);
216	input_set_drvdata(input, priv);
217
218	err = input_register_device(input);
219	if (err)
220		goto err2;
221
222	err = request_irq(priv->irq, eeti_ts_isr, irq_flags,
223			  client->name, priv);
224	if (err) {
225		dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
226		goto err3;
227	}
228
229	/*
230	 * Disable the device for now. It will be enabled once the
231	 * input device is opened.
232	 */
233	eeti_ts_stop(priv);
234
235	device_init_wakeup(&client->dev, 0);
236	return 0;
237
238err3:
239	input_unregister_device(input);
240	input = NULL; /* so we dont try to free it below */
241err2:
242	gpio_free(pdata->irq_gpio);
243err1:
244	input_free_device(input);
245	kfree(priv);
246err0:
247	return err;
248}
249
250static int eeti_ts_remove(struct i2c_client *client)
251{
252	struct eeti_ts_priv *priv = i2c_get_clientdata(client);
253
254	free_irq(priv->irq, priv);
255	/*
256	 * eeti_ts_stop() leaves IRQ disabled. We need to re-enable it
257	 * so that device still works if we reload the driver.
258	 */
259	enable_irq(priv->irq);
260
261	input_unregister_device(priv->input);
262	kfree(priv);
263
264	return 0;
265}
266
267#ifdef CONFIG_PM_SLEEP
268static int eeti_ts_suspend(struct device *dev)
269{
270	struct i2c_client *client = to_i2c_client(dev);
271	struct eeti_ts_priv *priv = i2c_get_clientdata(client);
272	struct input_dev *input_dev = priv->input;
273
274	mutex_lock(&input_dev->mutex);
275
276	if (input_dev->users)
277		eeti_ts_stop(priv);
278
279	mutex_unlock(&input_dev->mutex);
280
281	if (device_may_wakeup(&client->dev))
282		enable_irq_wake(priv->irq);
283
284	return 0;
285}
286
287static int eeti_ts_resume(struct device *dev)
288{
289	struct i2c_client *client = to_i2c_client(dev);
290	struct eeti_ts_priv *priv = i2c_get_clientdata(client);
291	struct input_dev *input_dev = priv->input;
292
293	if (device_may_wakeup(&client->dev))
294		disable_irq_wake(priv->irq);
295
296	mutex_lock(&input_dev->mutex);
297
298	if (input_dev->users)
299		eeti_ts_start(priv);
300
301	mutex_unlock(&input_dev->mutex);
302
303	return 0;
304}
305#endif
306
307static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
308
309static const struct i2c_device_id eeti_ts_id[] = {
310	{ "eeti_ts", 0 },
311	{ }
312};
313MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
314
315static struct i2c_driver eeti_ts_driver = {
316	.driver = {
317		.name = "eeti_ts",
318		.pm = &eeti_ts_pm,
319	},
320	.probe = eeti_ts_probe,
321	.remove = eeti_ts_remove,
322	.id_table = eeti_ts_id,
323};
324
325module_i2c_driver(eeti_ts_driver);
326
327MODULE_DESCRIPTION("EETI Touchscreen driver");
328MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
329MODULE_LICENSE("GPL");
330