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 
38 static bool flip_x;
39 module_param(flip_x, bool, 0644);
40 MODULE_PARM_DESC(flip_x, "flip x coordinate");
41 
42 static bool flip_y;
43 module_param(flip_y, bool, 0644);
44 MODULE_PARM_DESC(flip_y, "flip y coordinate");
45 
46 struct 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 
63 static 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 
68 static 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 
113 out:
114 	mutex_unlock(&priv->mutex);
115 }
116 
117 static 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 
127 static 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 
135 static void eeti_ts_stop(struct eeti_ts_priv *priv)
136 {
137 	disable_irq(priv->irq);
138 	cancel_work_sync(&priv->work);
139 }
140 
141 static 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 
150 static 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 
157 static int eeti_ts_probe(struct i2c_client *client,
158 				   const struct i2c_device_id *idp)
159 {
160 	struct eeti_ts_platform_data *pdata = client->dev.platform_data;
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 
238 err3:
239 	input_unregister_device(input);
240 	input = NULL; /* so we dont try to free it below */
241 err2:
242 	gpio_free(pdata->irq_gpio);
243 err1:
244 	input_free_device(input);
245 	kfree(priv);
246 err0:
247 	return err;
248 }
249 
250 static 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
268 static 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 
287 static 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 
306 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
307 #endif
308 
309 static const struct i2c_device_id eeti_ts_id[] = {
310 	{ "eeti_ts", 0 },
311 	{ }
312 };
313 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
314 
315 static struct i2c_driver eeti_ts_driver = {
316 	.driver = {
317 		.name = "eeti_ts",
318 #ifdef CONFIG_PM
319 		.pm = &eeti_ts_pm,
320 #endif
321 	},
322 	.probe = eeti_ts_probe,
323 	.remove = eeti_ts_remove,
324 	.id_table = eeti_ts_id,
325 };
326 
327 module_i2c_driver(eeti_ts_driver);
328 
329 MODULE_DESCRIPTION("EETI Touchscreen driver");
330 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
331 MODULE_LICENSE("GPL");
332