1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Touch Screen driver for SiS 9200 family I2C Touch panels
4 *
5 * Copyright (C) 2015 SiS, Inc.
6 * Copyright (C) 2016 Nextfour Group
7 */
8
9 #include <linux/crc-itu-t.h>
10 #include <linux/delay.h>
11 #include <linux/i2c.h>
12 #include <linux/input.h>
13 #include <linux/input/mt.h>
14 #include <linux/interrupt.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <asm/unaligned.h>
19
20 #define SIS_I2C_NAME "sis_i2c_ts"
21
22 /*
23 * The I2C packet format:
24 * le16 byte count
25 * u8 Report ID
26 * <contact data - variable length>
27 * u8 Number of contacts
28 * le16 Scan Time (optional)
29 * le16 CRC
30 *
31 * One touch point information consists of 6+ bytes, the order is:
32 * u8 contact state
33 * u8 finger id
34 * le16 x axis
35 * le16 y axis
36 * u8 contact width (optional)
37 * u8 contact height (optional)
38 * u8 pressure (optional)
39 *
40 * Maximum amount of data transmitted in one shot is 64 bytes, if controller
41 * needs to report more contacts than fit in one packet it will send true
42 * number of contacts in first packet and 0 as number of contacts in second
43 * packet.
44 */
45
46 #define SIS_MAX_PACKET_SIZE 64
47
48 #define SIS_PKT_LEN_OFFSET 0
49 #define SIS_PKT_REPORT_OFFSET 2 /* Report ID/type */
50 #define SIS_PKT_CONTACT_OFFSET 3 /* First contact */
51
52 #define SIS_SCAN_TIME_LEN 2
53
54 /* Supported report types */
55 #define SIS_ALL_IN_ONE_PACKAGE 0x10
56 #define SIS_PKT_IS_TOUCH(x) (((x) & 0x0f) == 0x01)
57 #define SIS_PKT_IS_HIDI2C(x) (((x) & 0x0f) == 0x06)
58
59 /* Contact properties within report */
60 #define SIS_PKT_HAS_AREA(x) ((x) & BIT(4))
61 #define SIS_PKT_HAS_PRESSURE(x) ((x) & BIT(5))
62 #define SIS_PKT_HAS_SCANTIME(x) ((x) & BIT(6))
63
64 /* Contact size */
65 #define SIS_BASE_LEN_PER_CONTACT 6
66 #define SIS_AREA_LEN_PER_CONTACT 2
67 #define SIS_PRESSURE_LEN_PER_CONTACT 1
68
69 /* Offsets within contact data */
70 #define SIS_CONTACT_STATUS_OFFSET 0
71 #define SIS_CONTACT_ID_OFFSET 1 /* Contact ID */
72 #define SIS_CONTACT_X_OFFSET 2
73 #define SIS_CONTACT_Y_OFFSET 4
74 #define SIS_CONTACT_WIDTH_OFFSET 6
75 #define SIS_CONTACT_HEIGHT_OFFSET 7
76 #define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6)
77
78 /* Individual contact state */
79 #define SIS_STATUS_UP 0x0
80 #define SIS_STATUS_DOWN 0x3
81
82 /* Touchscreen parameters */
83 #define SIS_MAX_FINGERS 10
84 #define SIS_MAX_X 4095
85 #define SIS_MAX_Y 4095
86 #define SIS_MAX_PRESSURE 255
87
88 /* Resolution diagonal */
89 #define SIS_AREA_LENGTH_LONGER 5792
90 /*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
91 #define SIS_AREA_LENGTH_SHORT 5792
92 #define SIS_AREA_UNIT (5792 / 32)
93
94 struct sis_ts_data {
95 struct i2c_client *client;
96 struct input_dev *input;
97
98 struct gpio_desc *attn_gpio;
99 struct gpio_desc *reset_gpio;
100
101 u8 packet[SIS_MAX_PACKET_SIZE];
102 };
103
sis_read_packet(struct i2c_client * client,u8 * buf,unsigned int * num_contacts,unsigned int * contact_size)104 static int sis_read_packet(struct i2c_client *client, u8 *buf,
105 unsigned int *num_contacts,
106 unsigned int *contact_size)
107 {
108 int count_idx;
109 int ret;
110 u16 len;
111 u16 crc, pkg_crc;
112 u8 report_id;
113
114 ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
115 if (ret <= 0)
116 return -EIO;
117
118 len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
119 if (len > SIS_MAX_PACKET_SIZE) {
120 dev_err(&client->dev,
121 "%s: invalid packet length (%d vs %d)\n",
122 __func__, len, SIS_MAX_PACKET_SIZE);
123 return -E2BIG;
124 }
125
126 if (len < 10)
127 return -EINVAL;
128
129 report_id = buf[SIS_PKT_REPORT_OFFSET];
130 count_idx = len - 1;
131 *contact_size = SIS_BASE_LEN_PER_CONTACT;
132
133 if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
134 if (SIS_PKT_IS_TOUCH(report_id)) {
135 /*
136 * Calculate CRC ignoring packet length
137 * in the beginning and CRC transmitted
138 * at the end of the packet.
139 */
140 crc = crc_itu_t(0, buf + 2, len - 2 - 2);
141 pkg_crc = get_unaligned_le16(&buf[len - 2]);
142
143 if (crc != pkg_crc) {
144 dev_err(&client->dev,
145 "%s: CRC Error (%d vs %d)\n",
146 __func__, crc, pkg_crc);
147 return -EINVAL;
148 }
149
150 count_idx -= 2;
151
152 } else if (!SIS_PKT_IS_HIDI2C(report_id)) {
153 dev_err(&client->dev,
154 "%s: invalid packet ID %#02x\n",
155 __func__, report_id);
156 return -EINVAL;
157 }
158
159 if (SIS_PKT_HAS_SCANTIME(report_id))
160 count_idx -= SIS_SCAN_TIME_LEN;
161
162 if (SIS_PKT_HAS_AREA(report_id))
163 *contact_size += SIS_AREA_LEN_PER_CONTACT;
164 if (SIS_PKT_HAS_PRESSURE(report_id))
165 *contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
166 }
167
168 *num_contacts = buf[count_idx];
169 return 0;
170 }
171
sis_ts_report_contact(struct sis_ts_data * ts,const u8 * data,u8 id)172 static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
173 {
174 struct input_dev *input = ts->input;
175 int slot;
176 u8 status = data[SIS_CONTACT_STATUS_OFFSET];
177 u8 pressure;
178 u8 height, width;
179 u16 x, y;
180
181 if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
182 dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
183 data[SIS_CONTACT_STATUS_OFFSET]);
184 return -EINVAL;
185 }
186
187 slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
188 if (slot < 0)
189 return -ENOENT;
190
191 input_mt_slot(input, slot);
192 input_mt_report_slot_state(input, MT_TOOL_FINGER,
193 status == SIS_STATUS_DOWN);
194
195 if (status == SIS_STATUS_DOWN) {
196 pressure = height = width = 1;
197 if (id != SIS_ALL_IN_ONE_PACKAGE) {
198 if (SIS_PKT_HAS_AREA(id)) {
199 width = data[SIS_CONTACT_WIDTH_OFFSET];
200 height = data[SIS_CONTACT_HEIGHT_OFFSET];
201 }
202
203 if (SIS_PKT_HAS_PRESSURE(id))
204 pressure =
205 data[SIS_CONTACT_PRESSURE_OFFSET(id)];
206 }
207
208 x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
209 y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);
210
211 input_report_abs(input, ABS_MT_TOUCH_MAJOR,
212 width * SIS_AREA_UNIT);
213 input_report_abs(input, ABS_MT_TOUCH_MINOR,
214 height * SIS_AREA_UNIT);
215 input_report_abs(input, ABS_MT_PRESSURE, pressure);
216 input_report_abs(input, ABS_MT_POSITION_X, x);
217 input_report_abs(input, ABS_MT_POSITION_Y, y);
218 }
219
220 return 0;
221 }
222
sis_ts_handle_packet(struct sis_ts_data * ts)223 static void sis_ts_handle_packet(struct sis_ts_data *ts)
224 {
225 const u8 *contact;
226 unsigned int num_to_report = 0;
227 unsigned int num_contacts;
228 unsigned int num_reported;
229 unsigned int contact_size;
230 int error;
231 u8 report_id;
232
233 do {
234 error = sis_read_packet(ts->client, ts->packet,
235 &num_contacts, &contact_size);
236 if (error)
237 break;
238
239 if (num_to_report == 0) {
240 num_to_report = num_contacts;
241 } else if (num_contacts != 0) {
242 dev_err(&ts->client->dev,
243 "%s: nonzero (%d) point count in tail packet\n",
244 __func__, num_contacts);
245 break;
246 }
247
248 report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
249 contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
250 num_reported = 0;
251
252 while (num_to_report > 0) {
253 error = sis_ts_report_contact(ts, contact, report_id);
254 if (error)
255 break;
256
257 contact += contact_size;
258 num_to_report--;
259 num_reported++;
260
261 if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
262 num_reported >= 5) {
263 /*
264 * The remainder of contacts is sent
265 * in the 2nd packet.
266 */
267 break;
268 }
269 }
270 } while (num_to_report > 0);
271
272 input_mt_sync_frame(ts->input);
273 input_sync(ts->input);
274 }
275
sis_ts_irq_handler(int irq,void * dev_id)276 static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
277 {
278 struct sis_ts_data *ts = dev_id;
279
280 do {
281 sis_ts_handle_packet(ts);
282 } while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));
283
284 return IRQ_HANDLED;
285 }
286
sis_ts_reset(struct sis_ts_data * ts)287 static void sis_ts_reset(struct sis_ts_data *ts)
288 {
289 if (ts->reset_gpio) {
290 /* Get out of reset */
291 usleep_range(1000, 2000);
292 gpiod_set_value(ts->reset_gpio, 1);
293 usleep_range(1000, 2000);
294 gpiod_set_value(ts->reset_gpio, 0);
295 msleep(100);
296 }
297 }
298
sis_ts_probe(struct i2c_client * client,const struct i2c_device_id * id)299 static int sis_ts_probe(struct i2c_client *client,
300 const struct i2c_device_id *id)
301 {
302 struct sis_ts_data *ts;
303 struct input_dev *input;
304 int error;
305
306 ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
307 if (!ts)
308 return -ENOMEM;
309
310 ts->client = client;
311
312 ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
313 "attn", GPIOD_IN);
314 if (IS_ERR(ts->attn_gpio)) {
315 error = PTR_ERR(ts->attn_gpio);
316 if (error != -EPROBE_DEFER)
317 dev_err(&client->dev,
318 "Failed to get attention GPIO: %d\n", error);
319 return error;
320 }
321
322 ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
323 "reset", GPIOD_OUT_LOW);
324 if (IS_ERR(ts->reset_gpio)) {
325 error = PTR_ERR(ts->reset_gpio);
326 if (error != -EPROBE_DEFER)
327 dev_err(&client->dev,
328 "Failed to get reset GPIO: %d\n", error);
329 return error;
330 }
331
332 sis_ts_reset(ts);
333
334 ts->input = input = devm_input_allocate_device(&client->dev);
335 if (!input) {
336 dev_err(&client->dev, "Failed to allocate input device\n");
337 return -ENOMEM;
338 }
339
340 input->name = "SiS Touchscreen";
341 input->id.bustype = BUS_I2C;
342
343 input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
344 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
345 input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
346 input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
347 0, SIS_AREA_LENGTH_LONGER, 0, 0);
348 input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
349 0, SIS_AREA_LENGTH_SHORT, 0, 0);
350
351 error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
352 if (error) {
353 dev_err(&client->dev,
354 "Failed to initialize MT slots: %d\n", error);
355 return error;
356 }
357
358 error = devm_request_threaded_irq(&client->dev, client->irq,
359 NULL, sis_ts_irq_handler,
360 IRQF_ONESHOT,
361 client->name, ts);
362 if (error) {
363 dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
364 return error;
365 }
366
367 error = input_register_device(ts->input);
368 if (error) {
369 dev_err(&client->dev,
370 "Failed to register input device: %d\n", error);
371 return error;
372 }
373
374 return 0;
375 }
376
377 #ifdef CONFIG_OF
378 static const struct of_device_id sis_ts_dt_ids[] = {
379 { .compatible = "sis,9200-ts" },
380 { /* sentinel */ }
381 };
382 MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
383 #endif
384
385 static const struct i2c_device_id sis_ts_id[] = {
386 { SIS_I2C_NAME, 0 },
387 { "9200-ts", 0 },
388 { /* sentinel */ }
389 };
390 MODULE_DEVICE_TABLE(i2c, sis_ts_id);
391
392 static struct i2c_driver sis_ts_driver = {
393 .driver = {
394 .name = SIS_I2C_NAME,
395 .of_match_table = of_match_ptr(sis_ts_dt_ids),
396 },
397 .probe = sis_ts_probe,
398 .id_table = sis_ts_id,
399 };
400 module_i2c_driver(sis_ts_driver);
401
402 MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
403 MODULE_LICENSE("GPL v2");
404 MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");
405
