aboutsummaryrefslogtreecommitdiff
path: root/drivers/input/touchscreen/tsc2007.c
blob: be23780e8a3e3b81be9df7b7cd0f8aab86d87e61 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
/*
 * drivers/input/touchscreen/tsc2007.c
 *
 * Copyright (c) 2008 MtekVision Co., Ltd.
 *	Kwangwoo Lee <kwlee@mtekvision.com>
 *
 * Using code from:
 *  - ads7846.c
 *	Copyright (c) 2005 David Brownell
 *	Copyright (c) 2006 Nokia Corporation
 *  - corgi_ts.c
 *	Copyright (C) 2004-2005 Richard Purdie
 *  - omap_ts.[hc], ads7846.h, ts_osk.c
 *	Copyright (C) 2002 MontaVista Software
 *	Copyright (C) 2004 Texas Instruments
 *	Copyright (C) 2005 Dirk Behme
 *
 *  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/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/i2c/tsc2007.h>

#define TS_POLL_DELAY			1 /* ms delay between samples */
#define TS_POLL_PERIOD			1 /* ms delay between samples */

#define TSC2007_MEASURE_TEMP0		(0x0 << 4)
#define TSC2007_MEASURE_AUX		(0x2 << 4)
#define TSC2007_MEASURE_TEMP1		(0x4 << 4)
#define TSC2007_ACTIVATE_XN		(0x8 << 4)
#define TSC2007_ACTIVATE_YN		(0x9 << 4)
#define TSC2007_ACTIVATE_YP_XN		(0xa << 4)
#define TSC2007_SETUP			(0xb << 4)
#define TSC2007_MEASURE_X		(0xc << 4)
#define TSC2007_MEASURE_Y		(0xd << 4)
#define TSC2007_MEASURE_Z1		(0xe << 4)
#define TSC2007_MEASURE_Z2		(0xf << 4)

#define TSC2007_POWER_OFF_IRQ_EN	(0x0 << 2)
#define TSC2007_ADC_ON_IRQ_DIS0		(0x1 << 2)
#define TSC2007_ADC_OFF_IRQ_EN		(0x2 << 2)
#define TSC2007_ADC_ON_IRQ_DIS1		(0x3 << 2)

#define TSC2007_12BIT			(0x0 << 1)
#define TSC2007_8BIT			(0x1 << 1)

#define	MAX_12BIT			((1 << 12) - 1)

#define ADC_ON_12BIT	(TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)

#define READ_Y		(ADC_ON_12BIT | TSC2007_MEASURE_Y)
#define READ_Z1		(ADC_ON_12BIT | TSC2007_MEASURE_Z1)
#define READ_Z2		(ADC_ON_12BIT | TSC2007_MEASURE_Z2)
#define READ_X		(ADC_ON_12BIT | TSC2007_MEASURE_X)
#define PWRDOWN		(TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)

struct ts_event {
	u16	x;
	u16	y;
	u16	z1, z2;
};

struct tsc2007 {
	struct input_dev	*input;
	char			phys[32];
	struct delayed_work	work;

	struct i2c_client	*client;

	u16			model;
	u16			x_plate_ohms;

	bool			pendown;
	int			irq;

	int			(*get_pendown_state)(void);
	void			(*clear_penirq)(void);
};

static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
{
	s32 data;
	u16 val;

	data = i2c_smbus_read_word_data(tsc->client, cmd);
	if (data < 0) {
		dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
		return data;
	}

	/* The protocol and raw data format from i2c interface:
	 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
	 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
	 */
	val = swab16(data) >> 4;

	dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);

	return val;
}

static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
{
	/* y- still on; turn on only y+ (and ADC) */
	tc->y = tsc2007_xfer(tsc, READ_Y);

	/* turn y- off, x+ on, then leave in lowpower */
	tc->x = tsc2007_xfer(tsc, READ_X);

	/* turn y+ off, x- on; we'll use formula #1 */
	tc->z1 = tsc2007_xfer(tsc, READ_Z1);
	tc->z2 = tsc2007_xfer(tsc, READ_Z2);

	/* Prepare for next touch reading - power down ADC, enable PENIRQ */
	tsc2007_xfer(tsc, PWRDOWN);
}

static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
{
	u32 rt = 0;

	/* range filtering */
	if (tc->x == MAX_12BIT)
		tc->x = 0;

	if (likely(tc->x && tc->z1)) {
		/* compute touch pressure resistance using equation #1 */
		rt = tc->z2 - tc->z1;
		rt *= tc->x;
		rt *= tsc->x_plate_ohms;
		rt /= tc->z1;
		rt = (rt + 2047) >> 12;
	}

	return rt;
}

static void tsc2007_send_up_event(struct tsc2007 *tsc)
{
	struct input_dev *input = tsc->input;

	dev_dbg(&tsc->client->dev, "UP\n");

	input_report_key(input, BTN_TOUCH, 0);
	input_report_abs(input, ABS_PRESSURE, 0);
	input_sync(input);
}

static void tsc2007_work(struct work_struct *work)
{
	struct tsc2007 *ts =
		container_of(to_delayed_work(work), struct tsc2007, work);
	struct ts_event tc;
	u32 rt;

	/*
	 * NOTE: We can't rely on the pressure to determine the pen down
	 * state, even though this controller has a pressure sensor.
	 * The pressure value can fluctuate for quite a while after
	 * lifting the pen and in some cases may not even settle at the
	 * expected value.
	 *
	 * The only safe way to check for the pen up condition is in the
	 * work function by reading the pen signal state (it's a GPIO
	 * and IRQ). Unfortunately such callback is not always available,
	 * in that case we have rely on the pressure anyway.
	 */
	if (ts->get_pendown_state) {
		if (unlikely(!ts->get_pendown_state())) {
			tsc2007_send_up_event(ts);
			ts->pendown = false;
			goto out;
		}

		dev_dbg(&ts->client->dev, "pen is still down\n");
	}

	tsc2007_read_values(ts, &tc);

	rt = tsc2007_calculate_pressure(ts, &tc);
	if (rt > MAX_12BIT) {
		/*
		 * Sample found inconsistent by debouncing or pressure is
		 * beyond the maximum. Don't report it to user space,
		 * repeat at least once more the measurement.
		 */
		dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
		goto out;

	}

	if (rt) {
		struct input_dev *input = ts->input;

		if (!ts->pendown) {
			dev_dbg(&ts->client->dev, "DOWN\n");

			input_report_key(input, BTN_TOUCH, 1);
			ts->pendown = true;
		}

		input_report_abs(input, ABS_X, tc.x);
		input_report_abs(input, ABS_Y, tc.y);
		input_report_abs(input, ABS_PRESSURE, rt);

		input_sync(input);

		dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
			tc.x, tc.y, rt);

	} else if (!ts->get_pendown_state && ts->pendown) {
		/*
		 * We don't have callback to check pendown state, so we
		 * have to assume that since pressure reported is 0 the
		 * pen was lifted up.
		 */
		tsc2007_send_up_event(ts);
		ts->pendown = false;
	}

 out:
	if (ts->pendown)
		schedule_delayed_work(&ts->work,
				      msecs_to_jiffies(TS_POLL_PERIOD));
	else
		enable_irq(ts->irq);
}

static irqreturn_t tsc2007_irq(int irq, void *handle)
{
	struct tsc2007 *ts = handle;

	if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
		disable_irq_nosync(ts->irq);
		schedule_delayed_work(&ts->work,
				      msecs_to_jiffies(TS_POLL_DELAY));
	}

	if (ts->clear_penirq)
		ts->clear_penirq();

	return IRQ_HANDLED;
}

static void tsc2007_free_irq(struct tsc2007 *ts)
{
	free_irq(ts->irq, ts);
	if (cancel_delayed_work_sync(&ts->work)) {
		/*
		 * Work was pending, therefore we need to enable
		 * IRQ here to balance the disable_irq() done in the
		 * interrupt handler.
		 */
		enable_irq(ts->irq);
	}
}

static int __devinit tsc2007_probe(struct i2c_client *client,
				   const struct i2c_device_id *id)
{
	struct tsc2007 *ts;
	struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
	struct input_dev *input_dev;
	int err;

	if (!pdata) {
		dev_err(&client->dev, "platform data is required!\n");
		return -EINVAL;
	}

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -EIO;

	ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!ts || !input_dev) {
		err = -ENOMEM;
		goto err_free_mem;
	}

	ts->client = client;
	ts->irq = client->irq;
	ts->input = input_dev;
	INIT_DELAYED_WORK(&ts->work, tsc2007_work);

	ts->model             = pdata->model;
	ts->x_plate_ohms      = pdata->x_plate_ohms;
	ts->get_pendown_state = pdata->get_pendown_state;
	ts->clear_penirq      = pdata->clear_penirq;

	snprintf(ts->phys, sizeof(ts->phys),
		 "%s/input0", dev_name(&client->dev));

	input_dev->name = "TSC2007 Touchscreen";
	input_dev->phys = ts->phys;
	input_dev->id.bustype = BUS_I2C;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);

	if (pdata->init_platform_hw)
		pdata->init_platform_hw();

	err = request_irq(ts->irq, tsc2007_irq, 0,
			client->dev.driver->name, ts);
	if (err < 0) {
		dev_err(&client->dev, "irq %d busy?\n", ts->irq);
		goto err_free_mem;
	}

	/* Prepare for touch readings - power down ADC and enable PENIRQ */
	err = tsc2007_xfer(ts, PWRDOWN);
	if (err < 0)
		goto err_free_irq;

	err = input_register_device(input_dev);
	if (err)
		goto err_free_irq;

	i2c_set_clientdata(client, ts);

	return 0;

 err_free_irq:
	tsc2007_free_irq(ts);
	if (pdata->exit_platform_hw)
		pdata->exit_platform_hw();
 err_free_mem:
	input_free_device(input_dev);
	kfree(ts);
	return err;
}

static int __devexit tsc2007_remove(struct i2c_client *client)
{
	struct tsc2007	*ts = i2c_get_clientdata(client);
	struct tsc2007_platform_data *pdata = client->dev.platform_data;

	tsc2007_free_irq(ts);

	if (pdata->exit_platform_hw)
		pdata->exit_platform_hw();

	input_unregister_device(ts->input);
	kfree(ts);

	return 0;
}

static const struct i2c_device_id tsc2007_idtable[] = {
	{ "tsc2007", 0 },
	{ }
};

MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);

static struct i2c_driver tsc2007_driver = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "tsc2007"
	},
	.id_table	= tsc2007_idtable,
	.probe		= tsc2007_probe,
	.remove		= __devexit_p(tsc2007_remove),
};

static int __init tsc2007_init(void)
{
	return i2c_add_driver(&tsc2007_driver);
}

static void __exit tsc2007_exit(void)
{
	i2c_del_driver(&tsc2007_driver);
}

module_init(tsc2007_init);
module_exit(tsc2007_exit);

MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
MODULE_LICENSE("GPL");