summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/bu21029_ts.c
blob: 686d0a6b1570b1e52a42dd237edf2becd5b9881c (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
459
460
461
462
463
464
465
466
467
468
469
470
// SPDX-License-Identifier: GPL-2.0
/*
 * Rohm BU21029 touchscreen controller driver
 *
 * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH
 *
 * 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/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/timer.h>

/*
 * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |                                 HW_IDH                                |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |                                 HW_IDL                                |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * HW_IDH: high 8bits of IC's ID
 * HW_IDL: low  8bits of IC's ID
 */
#define BU21029_HWID_REG	(0x0E << 3)
#define SUPPORTED_HWID		0x0229

/*
 * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   0    |   0    |  CALIB |  INTRM |   0    |   0    |   0    |   0    |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * CALIB: 0 = not to use calibration result (*)
 *        1 = use calibration result
 * INTRM: 0 = INT output depend on "pen down" (*)
 *        1 = INT output always "0"
 */
#define BU21029_CFR0_REG	(0x00 << 3)
#define CFR0_VALUE		0x00

/*
 * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |  MAV   |         AVE[2:0]         |   0    |         SMPL[2:0]        |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * MAV:  0 = median average filter off
 *       1 = median average filter on (*)
 * AVE:  AVE+1 = number of average samples for MAV,
 *               if AVE>SMPL, then AVE=SMPL (=3)
 * SMPL: SMPL+1 = number of conversion samples for MAV (=7)
 */
#define BU21029_CFR1_REG	(0x01 << 3)
#define CFR1_VALUE		0xA6

/*
 * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |          INTVL_TIME[3:0]          |          TIME_ST_ADC[3:0]         |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * INTVL_TIME: waiting time between completion of conversion
 *             and start of next conversion, only usable in
 *             autoscan mode (=20.480ms)
 * TIME_ST_ADC: waiting time between application of voltage
 *              to panel and start of A/D conversion (=100us)
 */
#define BU21029_CFR2_REG	(0x02 << 3)
#define CFR2_VALUE		0xC9

/*
 * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |  RM8   | STRETCH|  PU90K |  DUAL  |           PIDAC_OFS[3:0]          |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * RM8: 0 = coordinate resolution is 12bit (*)
 *      1 = coordinate resolution is 8bit
 * STRETCH: 0 = SCL_STRETCH function off
 *          1 = SCL_STRETCH function on (*)
 * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*)
 *        1 = internal pull-up resistance for touch detection is ~90kohms
 * DUAL: 0 = dual touch detection off (*)
 *       1 = dual touch detection on
 * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary
 *            to change this from initial value
 */
#define BU21029_CFR3_REG	(0x0B << 3)
#define CFR3_VALUE		0x42

/*
 * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   0    |         PVDD[2:0]        |   0    |         AVDD[2:0]        |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * PVDD: output voltage of panel output regulator (=2.000V)
 * AVDD: output voltage of analog circuit regulator (=2.000V)
 */
#define BU21029_LDO_REG		(0x0C << 3)
#define LDO_VALUE		0x77

/*
 * Serial Interface Command Byte 1 (CID=1)
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * |   1    |                 CF                |  CMSK  |  PDM   |  STP   |
 * +--------+--------+--------+--------+--------+--------+--------+--------+
 * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan)
 * CMSK: 0 = executes convert function (*)
 *       1 = reads the convert result
 * PDM: 0 = power down after convert function stops (*)
 *      1 = keep power on after convert function stops
 * STP: 1 = abort current conversion and power down, set to "0" automatically
 */
#define BU21029_AUTOSCAN	0x80

/*
 * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and
 * conversion time), where tConv4 is calculated by formula:
 * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3
 * see figure 8 in datasheet p15 for details of each field.
 */
#define PEN_UP_TIMEOUT_MS	50

#define STOP_DELAY_MIN_US	50
#define STOP_DELAY_MAX_US	1000
#define START_DELAY_MS		2
#define BUF_LEN			8
#define SCALE_12BIT		(1 << 12)
#define MAX_12BIT		((1 << 12) - 1)
#define DRIVER_NAME		"bu21029"

struct bu21029_ts_data {
	struct i2c_client		*client;
	struct input_dev		*in_dev;
	struct timer_list		timer;
	struct regulator		*vdd;
	struct gpio_desc		*reset_gpios;
	u32				x_plate_ohms;
	struct touchscreen_properties	prop;
};

static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf)
{
	u16 x, y, z1, z2;
	u32 rz;
	s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE);

	/*
	 * compose upper 8 and lower 4 bits into a 12bit value:
	 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	 * |            ByteH              |            ByteL              |
	 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	 * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00|
	 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	 * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 |
	 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	 */
	x  = (buf[0] << 4) | (buf[1] >> 4);
	y  = (buf[2] << 4) | (buf[3] >> 4);
	z1 = (buf[4] << 4) | (buf[5] >> 4);
	z2 = (buf[6] << 4) | (buf[7] >> 4);

	if (z1 && z2) {
		/*
		 * calculate Rz (pressure resistance value) by equation:
		 * Rz = Rx * (x/Q) * ((z2/z1) - 1), where
		 * Rx is x-plate resistance,
		 * Q  is the touch screen resolution (8bit = 256, 12bit = 4096)
		 * x, z1, z2 are the measured positions.
		 */
		rz  = z2 - z1;
		rz *= x;
		rz *= bu21029->x_plate_ohms;
		rz /= z1;
		rz  = DIV_ROUND_CLOSEST(rz, SCALE_12BIT);
		if (rz <= max_pressure) {
			touchscreen_report_pos(bu21029->in_dev, &bu21029->prop,
					       x, y, false);
			input_report_abs(bu21029->in_dev, ABS_PRESSURE,
					 max_pressure - rz);
			input_report_key(bu21029->in_dev, BTN_TOUCH, 1);
			input_sync(bu21029->in_dev);
		}
	}
}

static void bu21029_touch_release(struct timer_list *t)
{
	struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer);

	input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0);
	input_report_key(bu21029->in_dev, BTN_TOUCH, 0);
	input_sync(bu21029->in_dev);
}

static irqreturn_t bu21029_touch_soft_irq(int irq, void *data)
{
	struct bu21029_ts_data *bu21029 = data;
	u8 buf[BUF_LEN];
	int error;

	/*
	 * Read touch data and deassert interrupt (will assert again after
	 * INTVL_TIME + tConv4 for continuous touch)
	 */
	error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN,
					      sizeof(buf), buf);
	if (error < 0)
		goto out;

	bu21029_touch_report(bu21029, buf);

	/* reset timer for pen up detection */
	mod_timer(&bu21029->timer,
		  jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS));

out:
	return IRQ_HANDLED;
}

static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029)
{
	if (bu21029->reset_gpios) {
		gpiod_set_value_cansleep(bu21029->reset_gpios, 1);
		usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US);
	}
}

static int bu21029_start_chip(struct input_dev *dev)
{
	struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
	struct i2c_client *i2c = bu21029->client;
	struct {
		u8 reg;
		u8 value;
	} init_table[] = {
		{BU21029_CFR0_REG, CFR0_VALUE},
		{BU21029_CFR1_REG, CFR1_VALUE},
		{BU21029_CFR2_REG, CFR2_VALUE},
		{BU21029_CFR3_REG, CFR3_VALUE},
		{BU21029_LDO_REG,  LDO_VALUE}
	};
	int error, i;
	__be16 hwid;

	error = regulator_enable(bu21029->vdd);
	if (error) {
		dev_err(&i2c->dev, "failed to power up chip: %d", error);
		return error;
	}

	/* take chip out of reset */
	if (bu21029->reset_gpios) {
		gpiod_set_value_cansleep(bu21029->reset_gpios, 0);
		msleep(START_DELAY_MS);
	}

	error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG,
					      sizeof(hwid), (u8 *)&hwid);
	if (error < 0) {
		dev_err(&i2c->dev, "failed to read HW ID\n");
		goto err_out;
	}

	if (be16_to_cpu(hwid) != SUPPORTED_HWID) {
		dev_err(&i2c->dev,
			"unsupported HW ID 0x%x\n", be16_to_cpu(hwid));
		error = -ENODEV;
		goto err_out;
	}

	for (i = 0; i < ARRAY_SIZE(init_table); ++i) {
		error = i2c_smbus_write_byte_data(i2c,
						  init_table[i].reg,
						  init_table[i].value);
		if (error < 0) {
			dev_err(&i2c->dev,
				"failed to write %#02x to register %#02x: %d\n",
				init_table[i].value, init_table[i].reg,
				error);
			goto err_out;
		}
	}

	error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN);
	if (error < 0) {
		dev_err(&i2c->dev, "failed to start autoscan\n");
		goto err_out;
	}

	enable_irq(bu21029->client->irq);
	return 0;

err_out:
	bu21029_put_chip_in_reset(bu21029);
	regulator_disable(bu21029->vdd);
	return error;
}

static void bu21029_stop_chip(struct input_dev *dev)
{
	struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);

	disable_irq(bu21029->client->irq);
	del_timer_sync(&bu21029->timer);

	bu21029_put_chip_in_reset(bu21029);
	regulator_disable(bu21029->vdd);
}

static int bu21029_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct bu21029_ts_data *bu21029;
	struct input_dev *in_dev;
	int error;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_WRITE_BYTE |
				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
		dev_err(dev, "i2c functionality support is not sufficient\n");
		return -EIO;
	}

	bu21029 = devm_kzalloc(dev, sizeof(*bu21029), GFP_KERNEL);
	if (!bu21029)
		return -ENOMEM;

	error = device_property_read_u32(dev, "rohm,x-plate-ohms", &bu21029->x_plate_ohms);
	if (error) {
		dev_err(dev, "invalid 'x-plate-ohms' supplied: %d\n", error);
		return error;
	}

	bu21029->vdd = devm_regulator_get(dev, "vdd");
	if (IS_ERR(bu21029->vdd))
		return dev_err_probe(dev, PTR_ERR(bu21029->vdd),
				     "failed to acquire 'vdd' supply\n");

	bu21029->reset_gpios = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(bu21029->reset_gpios))
		return dev_err_probe(dev, PTR_ERR(bu21029->reset_gpios),
				     "failed to acquire 'reset' gpio\n");

	in_dev = devm_input_allocate_device(dev);
	if (!in_dev) {
		dev_err(dev, "unable to allocate input device\n");
		return -ENOMEM;
	}

	bu21029->client = client;
	bu21029->in_dev = in_dev;
	timer_setup(&bu21029->timer, bu21029_touch_release, 0);

	in_dev->name		= DRIVER_NAME;
	in_dev->id.bustype	= BUS_I2C;
	in_dev->open		= bu21029_start_chip;
	in_dev->close		= bu21029_stop_chip;

	input_set_capability(in_dev, EV_KEY, BTN_TOUCH);
	input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
	touchscreen_parse_properties(in_dev, false, &bu21029->prop);

	input_set_drvdata(in_dev, bu21029);

	error = devm_request_threaded_irq(dev, client->irq, NULL,
					  bu21029_touch_soft_irq,
					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
					  DRIVER_NAME, bu21029);
	if (error) {
		dev_err(dev, "unable to request touch irq: %d\n", error);
		return error;
	}

	error = input_register_device(in_dev);
	if (error) {
		dev_err(dev, "unable to register input device: %d\n", error);
		return error;
	}

	i2c_set_clientdata(client, bu21029);

	return 0;
}

static int bu21029_suspend(struct device *dev)
{
	struct i2c_client *i2c = to_i2c_client(dev);
	struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);

	if (!device_may_wakeup(dev)) {
		mutex_lock(&bu21029->in_dev->mutex);
		if (input_device_enabled(bu21029->in_dev))
			bu21029_stop_chip(bu21029->in_dev);
		mutex_unlock(&bu21029->in_dev->mutex);
	}

	return 0;
}

static int bu21029_resume(struct device *dev)
{
	struct i2c_client *i2c = to_i2c_client(dev);
	struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);

	if (!device_may_wakeup(dev)) {
		mutex_lock(&bu21029->in_dev->mutex);
		if (input_device_enabled(bu21029->in_dev))
			bu21029_start_chip(bu21029->in_dev);
		mutex_unlock(&bu21029->in_dev->mutex);
	}

	return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume);

static const struct i2c_device_id bu21029_ids[] = {
	{ DRIVER_NAME },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, bu21029_ids);

#ifdef CONFIG_OF
static const struct of_device_id bu21029_of_ids[] = {
	{ .compatible = "rohm,bu21029" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, bu21029_of_ids);
#endif

static struct i2c_driver bu21029_driver = {
	.driver	= {
		.name		= DRIVER_NAME,
		.of_match_table	= of_match_ptr(bu21029_of_ids),
		.pm		= pm_sleep_ptr(&bu21029_pm_ops),
	},
	.id_table	= bu21029_ids,
	.probe		= bu21029_probe,
};
module_i2c_driver(bu21029_driver);

MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>");
MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
MODULE_LICENSE("GPL v2");