summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/tsc2007_core.c
blob: 8342e0c48a534d5554522a136cb46550e1a06461 (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
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
/*
 * 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/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_data/tsc2007.h>
#include "tsc2007.h"

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);
}

u32 tsc2007_calculate_resistance(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 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;
}

bool tsc2007_is_pen_down(struct tsc2007 *ts)
{
	/*
	 * 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 assume that the pen is down and expect caller
	 * to fall back on the pressure reading.
	 */

	if (!ts->get_pendown_state)
		return true;

	return ts->get_pendown_state(&ts->client->dev);
}

static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
{
	struct tsc2007 *ts = handle;
	struct input_dev *input = ts->input;
	struct ts_event tc;
	u32 rt;

	while (!ts->stopped && tsc2007_is_pen_down(ts)) {

		/* pen is down, continue with the measurement */

		mutex_lock(&ts->mlock);
		tsc2007_read_values(ts, &tc);
		mutex_unlock(&ts->mlock);

		rt = tsc2007_calculate_resistance(ts, &tc);

		if (!rt && !ts->get_pendown_state) {
			/*
			 * If pressure reported is 0 and we don't have
			 * callback to check pendown state, we have to
			 * assume that pen was lifted up.
			 */
			break;
		}

		if (rt <= ts->max_rt) {
			dev_dbg(&ts->client->dev,
				"DOWN point(%4d,%4d), resistance (%4u)\n",
				tc.x, tc.y, rt);

			rt = ts->max_rt - rt;

			input_report_key(input, BTN_TOUCH, 1);
			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);

		} else {
			/*
			 * 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);
		}

		wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
	}

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

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

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

	return IRQ_HANDLED;
}

static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
{
	struct tsc2007 *ts = handle;

	if (tsc2007_is_pen_down(ts))
		return IRQ_WAKE_THREAD;

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

	return IRQ_HANDLED;
}

static void tsc2007_stop(struct tsc2007 *ts)
{
	ts->stopped = true;
	mb();
	wake_up(&ts->wait);

	disable_irq(ts->irq);
}

static int tsc2007_open(struct input_dev *input_dev)
{
	struct tsc2007 *ts = input_get_drvdata(input_dev);
	int err;

	ts->stopped = false;
	mb();

	enable_irq(ts->irq);

	/* Prepare for touch readings - power down ADC and enable PENIRQ */
	err = tsc2007_xfer(ts, PWRDOWN);
	if (err < 0) {
		tsc2007_stop(ts);
		return err;
	}

	return 0;
}

static void tsc2007_close(struct input_dev *input_dev)
{
	struct tsc2007 *ts = input_get_drvdata(input_dev);

	tsc2007_stop(ts);
}

#ifdef CONFIG_OF
static int tsc2007_get_pendown_state_gpio(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tsc2007 *ts = i2c_get_clientdata(client);

	return !gpio_get_value(ts->gpio);
}

static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
{
	struct device_node *np = client->dev.of_node;
	u32 val32;
	u64 val64;

	if (!np) {
		dev_err(&client->dev, "missing device tree data\n");
		return -EINVAL;
	}

	if (!of_property_read_u32(np, "ti,max-rt", &val32))
		ts->max_rt = val32;
	else
		ts->max_rt = MAX_12BIT;

	if (!of_property_read_u32(np, "ti,fuzzx", &val32))
		ts->fuzzx = val32;

	if (!of_property_read_u32(np, "ti,fuzzy", &val32))
		ts->fuzzy = val32;

	if (!of_property_read_u32(np, "ti,fuzzz", &val32))
		ts->fuzzz = val32;

	if (!of_property_read_u64(np, "ti,poll-period", &val64))
		ts->poll_period = msecs_to_jiffies(val64);
	else
		ts->poll_period = msecs_to_jiffies(1);

	if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
		ts->x_plate_ohms = val32;
	} else {
		dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
		return -EINVAL;
	}

	ts->gpio = of_get_gpio(np, 0);
	if (gpio_is_valid(ts->gpio))
		ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
	else
		dev_warn(&client->dev,
			 "GPIO not specified in DT (of_get_gpio returned %d)\n",
			 ts->gpio);

	return 0;
}
#else
static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
{
	dev_err(&client->dev, "platform data is required!\n");
	return -EINVAL;
}
#endif

static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
			      const struct tsc2007_platform_data *pdata,
			      const struct i2c_device_id *id)
{
	ts->model             = pdata->model;
	ts->x_plate_ohms      = pdata->x_plate_ohms;
	ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
	ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
	ts->get_pendown_state = pdata->get_pendown_state;
	ts->clear_penirq      = pdata->clear_penirq;
	ts->fuzzx             = pdata->fuzzx;
	ts->fuzzy             = pdata->fuzzy;
	ts->fuzzz             = pdata->fuzzz;

	if (pdata->x_plate_ohms == 0) {
		dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
		return -EINVAL;
	}

	return 0;
}

static void tsc2007_call_exit_platform_hw(void *data)
{
	struct device *dev = data;
	const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);

	pdata->exit_platform_hw();
}

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

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

	ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
	if (!ts)
		return -ENOMEM;

	if (pdata)
		err = tsc2007_probe_pdev(client, ts, pdata, id);
	else
		err = tsc2007_probe_dt(client, ts);
	if (err)
		return err;

	input_dev = devm_input_allocate_device(&client->dev);
	if (!input_dev)
		return -ENOMEM;

	i2c_set_clientdata(client, ts);

	ts->client = client;
	ts->irq = client->irq;
	ts->input = input_dev;

	init_waitqueue_head(&ts->wait);
	mutex_init(&ts->mlock);

	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->open = tsc2007_open;
	input_dev->close = tsc2007_close;

	input_set_drvdata(input_dev, ts);

	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

	input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
			     ts->fuzzz, 0);

	if (pdata) {
		if (pdata->exit_platform_hw) {
			err = devm_add_action(&client->dev,
					      tsc2007_call_exit_platform_hw,
					      &client->dev);
			if (err) {
				dev_err(&client->dev,
					"Failed to register exit_platform_hw action, %d\n",
					err);
				return err;
			}
		}

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

	err = devm_request_threaded_irq(&client->dev, ts->irq,
					tsc2007_hard_irq, tsc2007_soft_irq,
					IRQF_ONESHOT,
					client->dev.driver->name, ts);
	if (err) {
		dev_err(&client->dev, "Failed to request irq %d: %d\n",
			ts->irq, err);
		return err;
	}

	tsc2007_stop(ts);

	/* power down the chip (TSC2007_SETUP does not ACK on I2C) */
	err = tsc2007_xfer(ts, PWRDOWN);
	if (err < 0) {
		dev_err(&client->dev,
			"Failed to setup chip: %d\n", err);
		return err;	/* chip does not respond */
	}

	err = input_register_device(input_dev);
	if (err) {
		dev_err(&client->dev,
			"Failed to register input device: %d\n", err);
		return err;
	}

	err =  tsc2007_iio_configure(ts);
	if (err) {
		dev_err(&client->dev,
			"Failed to register with IIO: %d\n", err);
		return err;
	}

	return 0;
}

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

MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);

#ifdef CONFIG_OF
static const struct of_device_id tsc2007_of_match[] = {
	{ .compatible = "ti,tsc2007" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, tsc2007_of_match);
#endif

static struct i2c_driver tsc2007_driver = {
	.driver = {
		.name	= "tsc2007",
		.of_match_table = of_match_ptr(tsc2007_of_match),
	},
	.id_table	= tsc2007_idtable,
	.probe		= tsc2007_probe,
};

module_i2c_driver(tsc2007_driver);

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