summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/sis_i2c.c
blob: 6274555f167360ec7bcf6d21a93fe50978a59acc (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Touch Screen driver for SiS 9200 family I2C Touch panels
 *
 * Copyright (C) 2015 SiS, Inc.
 * Copyright (C) 2016 Nextfour Group
 */

#include <linux/crc-itu-t.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/interrupt.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

#define SIS_I2C_NAME		"sis_i2c_ts"

/*
 * The I2C packet format:
 * le16		byte count
 * u8		Report ID
 * <contact data - variable length>
 * u8		Number of contacts
 * le16		Scan Time (optional)
 * le16		CRC
 *
 * One touch point information consists of 6+ bytes, the order is:
 * u8		contact state
 * u8		finger id
 * le16		x axis
 * le16		y axis
 * u8		contact width (optional)
 * u8		contact height (optional)
 * u8		pressure (optional)
 *
 * Maximum amount of data transmitted in one shot is 64 bytes, if controller
 * needs to report more contacts than fit in one packet it will send true
 * number of contacts in first packet and 0 as number of contacts in second
 * packet.
 */

#define SIS_MAX_PACKET_SIZE		64

#define SIS_PKT_LEN_OFFSET		0
#define SIS_PKT_REPORT_OFFSET		2 /* Report ID/type */
#define SIS_PKT_CONTACT_OFFSET		3 /* First contact */

#define SIS_SCAN_TIME_LEN		2

/* Supported report types */
#define SIS_ALL_IN_ONE_PACKAGE		0x10
#define SIS_PKT_IS_TOUCH(x)		(((x) & 0x0f) == 0x01)
#define SIS_PKT_IS_HIDI2C(x)		(((x) & 0x0f) == 0x06)

/* Contact properties within report */
#define SIS_PKT_HAS_AREA(x)		((x) & BIT(4))
#define SIS_PKT_HAS_PRESSURE(x)		((x) & BIT(5))
#define SIS_PKT_HAS_SCANTIME(x)		((x) & BIT(6))

/* Contact size */
#define SIS_BASE_LEN_PER_CONTACT	6
#define SIS_AREA_LEN_PER_CONTACT	2
#define SIS_PRESSURE_LEN_PER_CONTACT	1

/* Offsets within contact data */
#define SIS_CONTACT_STATUS_OFFSET	0
#define SIS_CONTACT_ID_OFFSET		1 /* Contact ID */
#define SIS_CONTACT_X_OFFSET		2
#define SIS_CONTACT_Y_OFFSET		4
#define SIS_CONTACT_WIDTH_OFFSET	6
#define SIS_CONTACT_HEIGHT_OFFSET	7
#define SIS_CONTACT_PRESSURE_OFFSET(id)	(SIS_PKT_HAS_AREA(id) ? 8 : 6)

/* Individual contact state */
#define SIS_STATUS_UP			0x0
#define SIS_STATUS_DOWN			0x3

/* Touchscreen parameters */
#define SIS_MAX_FINGERS			10
#define SIS_MAX_X			4095
#define SIS_MAX_Y			4095
#define SIS_MAX_PRESSURE		255

/* Resolution diagonal */
#define SIS_AREA_LENGTH_LONGER		5792
/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
#define SIS_AREA_LENGTH_SHORT		5792
#define SIS_AREA_UNIT			(5792 / 32)

struct sis_ts_data {
	struct i2c_client *client;
	struct input_dev *input;

	struct gpio_desc *attn_gpio;
	struct gpio_desc *reset_gpio;

	u8 packet[SIS_MAX_PACKET_SIZE];
};

static int sis_read_packet(struct i2c_client *client, u8 *buf,
			   unsigned int *num_contacts,
			   unsigned int *contact_size)
{
	int count_idx;
	int ret;
	u16 len;
	u16 crc, pkg_crc;
	u8 report_id;

	ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
	if (ret <= 0)
		return -EIO;

	len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
	if (len > SIS_MAX_PACKET_SIZE) {
		dev_err(&client->dev,
			"%s: invalid packet length (%d vs %d)\n",
			__func__, len, SIS_MAX_PACKET_SIZE);
		return -E2BIG;
	}

	if (len < 10)
		return -EINVAL;

	report_id = buf[SIS_PKT_REPORT_OFFSET];
	count_idx  = len - 1;
	*contact_size = SIS_BASE_LEN_PER_CONTACT;

	if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
		if (SIS_PKT_IS_TOUCH(report_id)) {
			/*
			 * Calculate CRC ignoring packet length
			 * in the beginning and CRC transmitted
			 * at the end of the packet.
			 */
			crc = crc_itu_t(0, buf + 2, len - 2 - 2);
			pkg_crc = get_unaligned_le16(&buf[len - 2]);

			if (crc != pkg_crc) {
				dev_err(&client->dev,
					"%s: CRC Error (%d vs %d)\n",
					__func__, crc, pkg_crc);
				return -EINVAL;
			}

			count_idx -= 2;

		} else if (!SIS_PKT_IS_HIDI2C(report_id)) {
			dev_err(&client->dev,
				"%s: invalid packet ID %#02x\n",
				__func__, report_id);
			return -EINVAL;
		}

		if (SIS_PKT_HAS_SCANTIME(report_id))
			count_idx -= SIS_SCAN_TIME_LEN;

		if (SIS_PKT_HAS_AREA(report_id))
			*contact_size += SIS_AREA_LEN_PER_CONTACT;
		if (SIS_PKT_HAS_PRESSURE(report_id))
			*contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
	}

	*num_contacts = buf[count_idx];
	return 0;
}

static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
{
	struct input_dev *input = ts->input;
	int slot;
	u8 status = data[SIS_CONTACT_STATUS_OFFSET];
	u8 pressure;
	u8 height, width;
	u16 x, y;

	if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
		dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
			data[SIS_CONTACT_STATUS_OFFSET]);
		return -EINVAL;
	}

	slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
	if (slot < 0)
		return -ENOENT;

	input_mt_slot(input, slot);
	input_mt_report_slot_state(input, MT_TOOL_FINGER,
				   status == SIS_STATUS_DOWN);

	if (status == SIS_STATUS_DOWN) {
		pressure = height = width = 1;
		if (id != SIS_ALL_IN_ONE_PACKAGE) {
			if (SIS_PKT_HAS_AREA(id)) {
				width = data[SIS_CONTACT_WIDTH_OFFSET];
				height = data[SIS_CONTACT_HEIGHT_OFFSET];
			}

			if (SIS_PKT_HAS_PRESSURE(id))
				pressure =
					data[SIS_CONTACT_PRESSURE_OFFSET(id)];
		}

		x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
		y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);

		input_report_abs(input, ABS_MT_TOUCH_MAJOR,
				 width * SIS_AREA_UNIT);
		input_report_abs(input, ABS_MT_TOUCH_MINOR,
				 height * SIS_AREA_UNIT);
		input_report_abs(input, ABS_MT_PRESSURE, pressure);
		input_report_abs(input, ABS_MT_POSITION_X, x);
		input_report_abs(input, ABS_MT_POSITION_Y, y);
	}

	return 0;
}

static void sis_ts_handle_packet(struct sis_ts_data *ts)
{
	const u8 *contact;
	unsigned int num_to_report = 0;
	unsigned int num_contacts;
	unsigned int num_reported;
	unsigned int contact_size;
	int error;
	u8 report_id;

	do {
		error = sis_read_packet(ts->client, ts->packet,
					&num_contacts, &contact_size);
		if (error)
			break;

		if (num_to_report == 0) {
			num_to_report = num_contacts;
		} else if (num_contacts != 0) {
			dev_err(&ts->client->dev,
				"%s: nonzero (%d) point count in tail packet\n",
				__func__, num_contacts);
			break;
		}

		report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
		contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
		num_reported = 0;

		while (num_to_report > 0) {
			error = sis_ts_report_contact(ts, contact, report_id);
			if (error)
				break;

			contact += contact_size;
			num_to_report--;
			num_reported++;

			if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
			    num_reported >= 5) {
				/*
				 * The remainder of contacts is sent
				 * in the 2nd packet.
				 */
				break;
			}
		}
	} while (num_to_report > 0);

	input_mt_sync_frame(ts->input);
	input_sync(ts->input);
}

static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
{
	struct sis_ts_data *ts = dev_id;

	do {
		sis_ts_handle_packet(ts);
	} while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));

	return IRQ_HANDLED;
}

static void sis_ts_reset(struct sis_ts_data *ts)
{
	if (ts->reset_gpio) {
		/* Get out of reset */
		usleep_range(1000, 2000);
		gpiod_set_value(ts->reset_gpio, 1);
		usleep_range(1000, 2000);
		gpiod_set_value(ts->reset_gpio, 0);
		msleep(100);
	}
}

static int sis_ts_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct sis_ts_data *ts;
	struct input_dev *input;
	int error;

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

	ts->client = client;

	ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
						"attn", GPIOD_IN);
	if (IS_ERR(ts->attn_gpio)) {
		error = PTR_ERR(ts->attn_gpio);
		if (error != -EPROBE_DEFER)
			dev_err(&client->dev,
				"Failed to get attention GPIO: %d\n", error);
		return error;
	}

	ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
						 "reset", GPIOD_OUT_LOW);
	if (IS_ERR(ts->reset_gpio)) {
		error = PTR_ERR(ts->reset_gpio);
		if (error != -EPROBE_DEFER)
			dev_err(&client->dev,
				"Failed to get reset GPIO: %d\n", error);
		return error;
	}

	sis_ts_reset(ts);

	ts->input = input = devm_input_allocate_device(&client->dev);
	if (!input) {
		dev_err(&client->dev, "Failed to allocate input device\n");
		return -ENOMEM;
	}

	input->name = "SiS Touchscreen";
	input->id.bustype = BUS_I2C;

	input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
	input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
			     0, SIS_AREA_LENGTH_LONGER, 0, 0);
	input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
			     0, SIS_AREA_LENGTH_SHORT, 0, 0);

	error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
	if (error) {
		dev_err(&client->dev,
			"Failed to initialize MT slots: %d\n", error);
		return error;
	}

	error = devm_request_threaded_irq(&client->dev, client->irq,
					  NULL, sis_ts_irq_handler,
					  IRQF_ONESHOT,
					  client->name, ts);
	if (error) {
		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
		return error;
	}

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

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id sis_ts_dt_ids[] = {
	{ .compatible = "sis,9200-ts" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
#endif

static const struct i2c_device_id sis_ts_id[] = {
	{ SIS_I2C_NAME,	0 },
	{ "9200-ts",	0 },
	{ /* sentinel */  }
};
MODULE_DEVICE_TABLE(i2c, sis_ts_id);

static struct i2c_driver sis_ts_driver = {
	.driver = {
		.name	= SIS_I2C_NAME,
		.of_match_table = of_match_ptr(sis_ts_dt_ids),
	},
	.probe		= sis_ts_probe,
	.id_table	= sis_ts_id,
};
module_i2c_driver(sis_ts_driver);

MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");