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1/*
2 * Touch Screen driver for SiS 9200 family I2C Touch panels
3 *
4 * Copyright (C) 2015 SiS, Inc.
5 * Copyright (C) 2016 Nextfour Group
6 *
7 * This software is licensed under the terms of the GNU General Public
8 * License version 2, as published by the Free Software Foundation, and
9 * may be copied, distributed, and modified under those terms.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/crc-itu-t.h>
18#include <linux/delay.h>
19#include <linux/i2c.h>
20#include <linux/input.h>
21#include <linux/input/mt.h>
22#include <linux/interrupt.h>
23#include <linux/gpio/consumer.h>
24#include <linux/module.h>
25#include <linux/slab.h>
26#include <asm/unaligned.h>
27
28#define SIS_I2C_NAME "sis_i2c_ts"
29
30/*
31 * The I2C packet format:
32 * le16 byte count
33 * u8 Report ID
34 * <contact data - variable length>
35 * u8 Number of contacts
36 * le16 Scan Time (optional)
37 * le16 CRC
38 *
39 * One touch point information consists of 6+ bytes, the order is:
40 * u8 contact state
41 * u8 finger id
42 * le16 x axis
43 * le16 y axis
44 * u8 contact width (optional)
45 * u8 contact height (optional)
46 * u8 pressure (optional)
47 *
48 * Maximum amount of data transmitted in one shot is 64 bytes, if controller
49 * needs to report more contacts than fit in one packet it will send true
50 * number of contacts in first packet and 0 as number of contacts in second
51 * packet.
52 */
53
54#define SIS_MAX_PACKET_SIZE 64
55
56#define SIS_PKT_LEN_OFFSET 0
57#define SIS_PKT_REPORT_OFFSET 2 /* Report ID/type */
58#define SIS_PKT_CONTACT_OFFSET 3 /* First contact */
59
60#define SIS_SCAN_TIME_LEN 2
61
62/* Supported report types */
63#define SIS_ALL_IN_ONE_PACKAGE 0x10
64#define SIS_PKT_IS_TOUCH(x) (((x) & 0x0f) == 0x01)
65#define SIS_PKT_IS_HIDI2C(x) (((x) & 0x0f) == 0x06)
66
67/* Contact properties within report */
68#define SIS_PKT_HAS_AREA(x) ((x) & BIT(4))
69#define SIS_PKT_HAS_PRESSURE(x) ((x) & BIT(5))
70#define SIS_PKT_HAS_SCANTIME(x) ((x) & BIT(6))
71
72/* Contact size */
73#define SIS_BASE_LEN_PER_CONTACT 6
74#define SIS_AREA_LEN_PER_CONTACT 2
75#define SIS_PRESSURE_LEN_PER_CONTACT 1
76
77/* Offsets within contact data */
78#define SIS_CONTACT_STATUS_OFFSET 0
79#define SIS_CONTACT_ID_OFFSET 1 /* Contact ID */
80#define SIS_CONTACT_X_OFFSET 2
81#define SIS_CONTACT_Y_OFFSET 4
82#define SIS_CONTACT_WIDTH_OFFSET 6
83#define SIS_CONTACT_HEIGHT_OFFSET 7
84#define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6)
85
86/* Individual contact state */
87#define SIS_STATUS_UP 0x0
88#define SIS_STATUS_DOWN 0x3
89
90/* Touchscreen parameters */
91#define SIS_MAX_FINGERS 10
92#define SIS_MAX_X 4095
93#define SIS_MAX_Y 4095
94#define SIS_MAX_PRESSURE 255
95
96/* Resolution diagonal */
97#define SIS_AREA_LENGTH_LONGER 5792
98/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
99#define SIS_AREA_LENGTH_SHORT 5792
100#define SIS_AREA_UNIT (5792 / 32)
101
102struct sis_ts_data {
103 struct i2c_client *client;
104 struct input_dev *input;
105
106 struct gpio_desc *attn_gpio;
107 struct gpio_desc *reset_gpio;
108
109 u8 packet[SIS_MAX_PACKET_SIZE];
110};
111
112static int sis_read_packet(struct i2c_client *client, u8 *buf,
113 unsigned int *num_contacts,
114 unsigned int *contact_size)
115{
116 int count_idx;
117 int ret;
118 u16 len;
119 u16 crc, pkg_crc;
120 u8 report_id;
121
122 ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
123 if (ret <= 0)
124 return -EIO;
125
126 len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
127 if (len > SIS_MAX_PACKET_SIZE) {
128 dev_err(&client->dev,
129 "%s: invalid packet length (%d vs %d)\n",
130 __func__, len, SIS_MAX_PACKET_SIZE);
131 return -E2BIG;
132 }
133
134 if (len < 10)
135 return -EINVAL;
136
137 report_id = buf[SIS_PKT_REPORT_OFFSET];
138 count_idx = len - 1;
139 *contact_size = SIS_BASE_LEN_PER_CONTACT;
140
141 if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
142 if (SIS_PKT_IS_TOUCH(report_id)) {
143 /*
144 * Calculate CRC ignoring packet length
145 * in the beginning and CRC transmitted
146 * at the end of the packet.
147 */
148 crc = crc_itu_t(0, buf + 2, len - 2 - 2);
149 pkg_crc = get_unaligned_le16(&buf[len - 2]);
150
151 if (crc != pkg_crc) {
152 dev_err(&client->dev,
153 "%s: CRC Error (%d vs %d)\n",
154 __func__, crc, pkg_crc);
155 return -EINVAL;
156 }
157
158 count_idx -= 2;
159
160 } else if (!SIS_PKT_IS_HIDI2C(report_id)) {
161 dev_err(&client->dev,
162 "%s: invalid packet ID %#02x\n",
163 __func__, report_id);
164 return -EINVAL;
165 }
166
167 if (SIS_PKT_HAS_SCANTIME(report_id))
168 count_idx -= SIS_SCAN_TIME_LEN;
169
170 if (SIS_PKT_HAS_AREA(report_id))
171 *contact_size += SIS_AREA_LEN_PER_CONTACT;
172 if (SIS_PKT_HAS_PRESSURE(report_id))
173 *contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
174 }
175
176 *num_contacts = buf[count_idx];
177 return 0;
178}
179
180static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
181{
182 struct input_dev *input = ts->input;
183 int slot;
184 u8 status = data[SIS_CONTACT_STATUS_OFFSET];
185 u8 pressure;
186 u8 height, width;
187 u16 x, y;
188
189 if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
190 dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
191 data[SIS_CONTACT_STATUS_OFFSET]);
192 return -EINVAL;
193 }
194
195 slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
196 if (slot < 0)
197 return -ENOENT;
198
199 input_mt_slot(input, slot);
200 input_mt_report_slot_state(input, MT_TOOL_FINGER,
201 status == SIS_STATUS_DOWN);
202
203 if (status == SIS_STATUS_DOWN) {
204 pressure = height = width = 1;
205 if (id != SIS_ALL_IN_ONE_PACKAGE) {
206 if (SIS_PKT_HAS_AREA(id)) {
207 width = data[SIS_CONTACT_WIDTH_OFFSET];
208 height = data[SIS_CONTACT_HEIGHT_OFFSET];
209 }
210
211 if (SIS_PKT_HAS_PRESSURE(id))
212 pressure =
213 data[SIS_CONTACT_PRESSURE_OFFSET(id)];
214 }
215
216 x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
217 y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);
218
219 input_report_abs(input, ABS_MT_TOUCH_MAJOR,
220 width * SIS_AREA_UNIT);
221 input_report_abs(input, ABS_MT_TOUCH_MINOR,
222 height * SIS_AREA_UNIT);
223 input_report_abs(input, ABS_MT_PRESSURE, pressure);
224 input_report_abs(input, ABS_MT_POSITION_X, x);
225 input_report_abs(input, ABS_MT_POSITION_Y, y);
226 }
227
228 return 0;
229}
230
231static void sis_ts_handle_packet(struct sis_ts_data *ts)
232{
233 const u8 *contact;
234 unsigned int num_to_report = 0;
235 unsigned int num_contacts;
236 unsigned int num_reported;
237 unsigned int contact_size;
238 int error;
239 u8 report_id;
240
241 do {
242 error = sis_read_packet(ts->client, ts->packet,
243 &num_contacts, &contact_size);
244 if (error)
245 break;
246
247 if (num_to_report == 0) {
248 num_to_report = num_contacts;
249 } else if (num_contacts != 0) {
250 dev_err(&ts->client->dev,
251 "%s: nonzero (%d) point count in tail packet\n",
252 __func__, num_contacts);
253 break;
254 }
255
256 report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
257 contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
258 num_reported = 0;
259
260 while (num_to_report > 0) {
261 error = sis_ts_report_contact(ts, contact, report_id);
262 if (error)
263 break;
264
265 contact += contact_size;
266 num_to_report--;
267 num_reported++;
268
269 if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
270 num_reported >= 5) {
271 /*
272 * The remainder of contacts is sent
273 * in the 2nd packet.
274 */
275 break;
276 }
277 }
278 } while (num_to_report > 0);
279
280 input_mt_sync_frame(ts->input);
281 input_sync(ts->input);
282}
283
284static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
285{
286 struct sis_ts_data *ts = dev_id;
287
288 do {
289 sis_ts_handle_packet(ts);
290 } while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));
291
292 return IRQ_HANDLED;
293}
294
295static void sis_ts_reset(struct sis_ts_data *ts)
296{
297 if (ts->reset_gpio) {
298 /* Get out of reset */
299 usleep_range(1000, 2000);
300 gpiod_set_value(ts->reset_gpio, 1);
301 usleep_range(1000, 2000);
302 gpiod_set_value(ts->reset_gpio, 0);
303 msleep(100);
304 }
305}
306
307static int sis_ts_probe(struct i2c_client *client,
308 const struct i2c_device_id *id)
309{
310 struct sis_ts_data *ts;
311 struct input_dev *input;
312 int error;
313
314 ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
315 if (!ts)
316 return -ENOMEM;
317
318 ts->client = client;
319 i2c_set_clientdata(client, ts);
320
321 ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
322 "attn", GPIOD_IN);
323 if (IS_ERR(ts->attn_gpio)) {
324 error = PTR_ERR(ts->attn_gpio);
325 if (error != -EPROBE_DEFER)
326 dev_err(&client->dev,
327 "Failed to get attention GPIO: %d\n", error);
328 return error;
329 }
330
331 ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
332 "reset", GPIOD_OUT_LOW);
333 if (IS_ERR(ts->reset_gpio)) {
334 error = PTR_ERR(ts->reset_gpio);
335 if (error != -EPROBE_DEFER)
336 dev_err(&client->dev,
337 "Failed to get reset GPIO: %d\n", error);
338 return error;
339 }
340
341 sis_ts_reset(ts);
342
343 ts->input = input = devm_input_allocate_device(&client->dev);
344 if (!input) {
345 dev_err(&client->dev, "Failed to allocate input device\n");
346 return -ENOMEM;
347 }
348
349 input->name = "SiS Touchscreen";
350 input->id.bustype = BUS_I2C;
351
352 input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
353 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
354 input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
355 input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
356 0, SIS_AREA_LENGTH_LONGER, 0, 0);
357 input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
358 0, SIS_AREA_LENGTH_SHORT, 0, 0);
359
360 error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
361 if (error) {
362 dev_err(&client->dev,
363 "Failed to initialize MT slots: %d\n", error);
364 return error;
365 }
366
367 error = devm_request_threaded_irq(&client->dev, client->irq,
368 NULL, sis_ts_irq_handler,
369 IRQF_ONESHOT,
370 client->name, ts);
371 if (error) {
372 dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
373 return error;
374 }
375
376 error = input_register_device(ts->input);
377 if (error) {
378 dev_err(&client->dev,
379 "Failed to register input device: %d\n", error);
380 return error;
381 }
382
383 return 0;
384}
385
386#ifdef CONFIG_OF
387static const struct of_device_id sis_ts_dt_ids[] = {
388 { .compatible = "sis,9200-ts" },
389 { /* sentinel */ }
390};
391MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
392#endif
393
394static const struct i2c_device_id sis_ts_id[] = {
395 { SIS_I2C_NAME, 0 },
396 { "9200-ts", 0 },
397 { /* sentinel */ }
398};
399MODULE_DEVICE_TABLE(i2c, sis_ts_id);
400
401static struct i2c_driver sis_ts_driver = {
402 .driver = {
403 .name = SIS_I2C_NAME,
404 .of_match_table = of_match_ptr(sis_ts_dt_ids),
405 },
406 .probe = sis_ts_probe,
407 .id_table = sis_ts_id,
408};
409module_i2c_driver(sis_ts_driver);
410
411MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
412MODULE_LICENSE("GPL v2");
413MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");