1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for MStar msg2638 touchscreens
4 *
5 * Copyright (c) 2021 Vincent Knecht <vincent.knecht@mailoo.org>
6 *
7 * Checksum and IRQ handler based on mstar_drv_common.c and
8 * mstar_drv_mutual_fw_control.c
9 * Copyright (c) 2006-2012 MStar Semiconductor, Inc.
10 *
11 * Driver structure based on zinitix.c by Michael Srba <Michael.Srba@seznam.cz>
12 */
13
14 #include <linux/delay.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/i2c.h>
17 #include <linux/input.h>
18 #include <linux/input/mt.h>
19 #include <linux/input/touchscreen.h>
20 #include <linux/interrupt.h>
21 #include <linux/kernel.h>
22 #include <linux/mod_devicetable.h>
23 #include <linux/module.h>
24 #include <linux/property.h>
25 #include <linux/regulator/consumer.h>
26 #include <linux/slab.h>
27
28 #define MODE_DATA_RAW 0x5A
29
30 #define MSG2138_MAX_FINGERS 2
31 #define MSG2638_MAX_FINGERS 5
32
33 #define MAX_BUTTONS 4
34
35 #define CHIP_ON_DELAY_MS 15
36 #define FIRMWARE_ON_DELAY_MS 50
37 #define RESET_DELAY_MIN_US 10000
38 #define RESET_DELAY_MAX_US 11000
39
40 struct msg_chip_data {
41 irq_handler_t irq_handler;
42 unsigned int max_fingers;
43 };
44
45 struct msg2138_packet {
46 u8 xy_hi; /* higher bits of x and y coordinates */
47 u8 x_low;
48 u8 y_low;
49 };
50
51 struct msg2138_touch_event {
52 u8 magic;
53 struct msg2138_packet pkt[MSG2138_MAX_FINGERS];
54 u8 checksum;
55 };
56
57 struct msg2638_packet {
58 u8 xy_hi; /* higher bits of x and y coordinates */
59 u8 x_low;
60 u8 y_low;
61 u8 pressure;
62 };
63
64 struct msg2638_touch_event {
65 u8 mode;
66 struct msg2638_packet pkt[MSG2638_MAX_FINGERS];
67 u8 proximity;
68 u8 checksum;
69 };
70
71 struct msg2638_ts_data {
72 struct i2c_client *client;
73 struct input_dev *input_dev;
74 struct touchscreen_properties prop;
75 struct regulator_bulk_data supplies[2];
76 struct gpio_desc *reset_gpiod;
77 int max_fingers;
78 u32 keycodes[MAX_BUTTONS];
79 int num_keycodes;
80 };
81
msg2638_checksum(u8 * data,u32 length)82 static u8 msg2638_checksum(u8 *data, u32 length)
83 {
84 s32 sum = 0;
85 u32 i;
86
87 for (i = 0; i < length; i++)
88 sum += data[i];
89
90 return (u8)((-sum) & 0xFF);
91 }
92
msg2138_report_keys(struct msg2638_ts_data * msg2638,u8 keys)93 static void msg2138_report_keys(struct msg2638_ts_data *msg2638, u8 keys)
94 {
95 int i;
96
97 /* keys can be 0x00 or 0xff when all keys have been released */
98 if (keys == 0xff)
99 keys = 0;
100
101 for (i = 0; i < msg2638->num_keycodes; ++i)
102 input_report_key(msg2638->input_dev, msg2638->keycodes[i],
103 keys & BIT(i));
104 }
105
msg2138_ts_irq_handler(int irq,void * msg2638_handler)106 static irqreturn_t msg2138_ts_irq_handler(int irq, void *msg2638_handler)
107 {
108 struct msg2638_ts_data *msg2638 = msg2638_handler;
109 struct i2c_client *client = msg2638->client;
110 struct input_dev *input = msg2638->input_dev;
111 struct msg2138_touch_event touch_event;
112 u32 len = sizeof(touch_event);
113 struct i2c_msg msg[] = {
114 {
115 .addr = client->addr,
116 .flags = I2C_M_RD,
117 .len = sizeof(touch_event),
118 .buf = (u8 *)&touch_event,
119 },
120 };
121 struct msg2138_packet *p0, *p1;
122 u16 x, y, delta_x, delta_y;
123 int ret;
124
125 ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
126 if (ret != ARRAY_SIZE(msg)) {
127 dev_err(&client->dev,
128 "Failed I2C transfer in irq handler: %d\n",
129 ret < 0 ? ret : -EIO);
130 goto out;
131 }
132
133 if (msg2638_checksum((u8 *)&touch_event, len - 1) !=
134 touch_event.checksum) {
135 dev_err(&client->dev, "Failed checksum!\n");
136 goto out;
137 }
138
139 p0 = &touch_event.pkt[0];
140 p1 = &touch_event.pkt[1];
141
142 /* Ignore non-pressed finger data, but check for key code */
143 if (p0->xy_hi == 0xFF && p0->x_low == 0xFF && p0->y_low == 0xFF) {
144 if (p1->xy_hi == 0xFF && p1->y_low == 0xFF)
145 msg2138_report_keys(msg2638, p1->x_low);
146 goto report;
147 }
148
149 x = ((p0->xy_hi & 0xF0) << 4) | p0->x_low;
150 y = ((p0->xy_hi & 0x0F) << 8) | p0->y_low;
151
152 input_mt_slot(input, 0);
153 input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
154 touchscreen_report_pos(input, &msg2638->prop, x, y, true);
155
156 /* Ignore non-pressed finger data */
157 if (p1->xy_hi == 0xFF && p1->x_low == 0xFF && p1->y_low == 0xFF)
158 goto report;
159
160 /* Second finger is reported as a delta position */
161 delta_x = ((p1->xy_hi & 0xF0) << 4) | p1->x_low;
162 delta_y = ((p1->xy_hi & 0x0F) << 8) | p1->y_low;
163
164 /* Ignore second finger if both deltas equal 0 */
165 if (delta_x == 0 && delta_y == 0)
166 goto report;
167
168 x += delta_x;
169 y += delta_y;
170
171 input_mt_slot(input, 1);
172 input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
173 touchscreen_report_pos(input, &msg2638->prop, x, y, true);
174
175 report:
176 input_mt_sync_frame(msg2638->input_dev);
177 input_sync(msg2638->input_dev);
178
179 out:
180 return IRQ_HANDLED;
181 }
182
msg2638_ts_irq_handler(int irq,void * msg2638_handler)183 static irqreturn_t msg2638_ts_irq_handler(int irq, void *msg2638_handler)
184 {
185 struct msg2638_ts_data *msg2638 = msg2638_handler;
186 struct i2c_client *client = msg2638->client;
187 struct input_dev *input = msg2638->input_dev;
188 struct msg2638_touch_event touch_event;
189 u32 len = sizeof(touch_event);
190 struct i2c_msg msg[] = {
191 {
192 .addr = client->addr,
193 .flags = I2C_M_RD,
194 .len = sizeof(touch_event),
195 .buf = (u8 *)&touch_event,
196 },
197 };
198 struct msg2638_packet *p;
199 u16 x, y;
200 int ret;
201 int i;
202
203 ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
204 if (ret != ARRAY_SIZE(msg)) {
205 dev_err(&client->dev,
206 "Failed I2C transfer in irq handler: %d\n",
207 ret < 0 ? ret : -EIO);
208 goto out;
209 }
210
211 if (touch_event.mode != MODE_DATA_RAW)
212 goto out;
213
214 if (msg2638_checksum((u8 *)&touch_event, len - 1) !=
215 touch_event.checksum) {
216 dev_err(&client->dev, "Failed checksum!\n");
217 goto out;
218 }
219
220 for (i = 0; i < msg2638->max_fingers; i++) {
221 p = &touch_event.pkt[i];
222
223 /* Ignore non-pressed finger data */
224 if (p->xy_hi == 0xFF && p->x_low == 0xFF && p->y_low == 0xFF)
225 continue;
226
227 x = (((p->xy_hi & 0xF0) << 4) | p->x_low);
228 y = (((p->xy_hi & 0x0F) << 8) | p->y_low);
229
230 input_mt_slot(input, i);
231 input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
232 touchscreen_report_pos(input, &msg2638->prop, x, y, true);
233 }
234
235 input_mt_sync_frame(msg2638->input_dev);
236 input_sync(msg2638->input_dev);
237
238 out:
239 return IRQ_HANDLED;
240 }
241
msg2638_reset(struct msg2638_ts_data * msg2638)242 static void msg2638_reset(struct msg2638_ts_data *msg2638)
243 {
244 gpiod_set_value_cansleep(msg2638->reset_gpiod, 1);
245 usleep_range(RESET_DELAY_MIN_US, RESET_DELAY_MAX_US);
246 gpiod_set_value_cansleep(msg2638->reset_gpiod, 0);
247 msleep(FIRMWARE_ON_DELAY_MS);
248 }
249
msg2638_start(struct msg2638_ts_data * msg2638)250 static int msg2638_start(struct msg2638_ts_data *msg2638)
251 {
252 int error;
253
254 error = regulator_bulk_enable(ARRAY_SIZE(msg2638->supplies),
255 msg2638->supplies);
256 if (error) {
257 dev_err(&msg2638->client->dev,
258 "Failed to enable regulators: %d\n", error);
259 return error;
260 }
261
262 msleep(CHIP_ON_DELAY_MS);
263
264 msg2638_reset(msg2638);
265
266 enable_irq(msg2638->client->irq);
267
268 return 0;
269 }
270
msg2638_stop(struct msg2638_ts_data * msg2638)271 static int msg2638_stop(struct msg2638_ts_data *msg2638)
272 {
273 int error;
274
275 disable_irq(msg2638->client->irq);
276
277 error = regulator_bulk_disable(ARRAY_SIZE(msg2638->supplies),
278 msg2638->supplies);
279 if (error) {
280 dev_err(&msg2638->client->dev,
281 "Failed to disable regulators: %d\n", error);
282 return error;
283 }
284
285 return 0;
286 }
287
msg2638_input_open(struct input_dev * dev)288 static int msg2638_input_open(struct input_dev *dev)
289 {
290 struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
291
292 return msg2638_start(msg2638);
293 }
294
msg2638_input_close(struct input_dev * dev)295 static void msg2638_input_close(struct input_dev *dev)
296 {
297 struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
298
299 msg2638_stop(msg2638);
300 }
301
msg2638_init_input_dev(struct msg2638_ts_data * msg2638)302 static int msg2638_init_input_dev(struct msg2638_ts_data *msg2638)
303 {
304 struct device *dev = &msg2638->client->dev;
305 struct input_dev *input_dev;
306 int error;
307 int i;
308
309 input_dev = devm_input_allocate_device(dev);
310 if (!input_dev) {
311 dev_err(dev, "Failed to allocate input device.\n");
312 return -ENOMEM;
313 }
314
315 input_set_drvdata(input_dev, msg2638);
316 msg2638->input_dev = input_dev;
317
318 input_dev->name = "MStar TouchScreen";
319 input_dev->phys = "input/ts";
320 input_dev->id.bustype = BUS_I2C;
321 input_dev->open = msg2638_input_open;
322 input_dev->close = msg2638_input_close;
323
324 if (msg2638->num_keycodes) {
325 input_dev->keycode = msg2638->keycodes;
326 input_dev->keycodemax = msg2638->num_keycodes;
327 input_dev->keycodesize = sizeof(msg2638->keycodes[0]);
328 for (i = 0; i < msg2638->num_keycodes; i++)
329 input_set_capability(input_dev,
330 EV_KEY, msg2638->keycodes[i]);
331 }
332
333 input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
334 input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
335
336 touchscreen_parse_properties(input_dev, true, &msg2638->prop);
337 if (!msg2638->prop.max_x || !msg2638->prop.max_y) {
338 dev_err(dev, "touchscreen-size-x and/or touchscreen-size-y not set in properties\n");
339 return -EINVAL;
340 }
341
342 error = input_mt_init_slots(input_dev, msg2638->max_fingers,
343 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
344 if (error) {
345 dev_err(dev, "Failed to initialize MT slots: %d\n", error);
346 return error;
347 }
348
349 error = input_register_device(input_dev);
350 if (error) {
351 dev_err(dev, "Failed to register input device: %d\n", error);
352 return error;
353 }
354
355 return 0;
356 }
357
msg2638_ts_probe(struct i2c_client * client)358 static int msg2638_ts_probe(struct i2c_client *client)
359 {
360 const struct msg_chip_data *chip_data;
361 struct device *dev = &client->dev;
362 struct msg2638_ts_data *msg2638;
363 int error;
364
365 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
366 dev_err(dev, "Failed to assert adapter's support for plain I2C.\n");
367 return -ENXIO;
368 }
369
370 msg2638 = devm_kzalloc(dev, sizeof(*msg2638), GFP_KERNEL);
371 if (!msg2638)
372 return -ENOMEM;
373
374 msg2638->client = client;
375 i2c_set_clientdata(client, msg2638);
376
377 chip_data = device_get_match_data(&client->dev);
378 if (!chip_data || !chip_data->max_fingers) {
379 dev_err(dev, "Invalid or missing chip data\n");
380 return -EINVAL;
381 }
382
383 msg2638->max_fingers = chip_data->max_fingers;
384
385 msg2638->supplies[0].supply = "vdd";
386 msg2638->supplies[1].supply = "vddio";
387 error = devm_regulator_bulk_get(dev, ARRAY_SIZE(msg2638->supplies),
388 msg2638->supplies);
389 if (error) {
390 dev_err(dev, "Failed to get regulators: %d\n", error);
391 return error;
392 }
393
394 msg2638->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
395 if (IS_ERR(msg2638->reset_gpiod)) {
396 error = PTR_ERR(msg2638->reset_gpiod);
397 dev_err(dev, "Failed to request reset GPIO: %d\n", error);
398 return error;
399 }
400
401 msg2638->num_keycodes = device_property_count_u32(dev,
402 "linux,keycodes");
403 if (msg2638->num_keycodes == -EINVAL) {
404 msg2638->num_keycodes = 0;
405 } else if (msg2638->num_keycodes < 0) {
406 dev_err(dev, "Unable to parse linux,keycodes property: %d\n",
407 msg2638->num_keycodes);
408 return msg2638->num_keycodes;
409 } else if (msg2638->num_keycodes > ARRAY_SIZE(msg2638->keycodes)) {
410 dev_warn(dev, "Found %d linux,keycodes but max is %zd, ignoring the rest\n",
411 msg2638->num_keycodes, ARRAY_SIZE(msg2638->keycodes));
412 msg2638->num_keycodes = ARRAY_SIZE(msg2638->keycodes);
413 }
414
415 if (msg2638->num_keycodes > 0) {
416 error = device_property_read_u32_array(dev, "linux,keycodes",
417 msg2638->keycodes,
418 msg2638->num_keycodes);
419 if (error) {
420 dev_err(dev, "Unable to read linux,keycodes values: %d\n",
421 error);
422 return error;
423 }
424 }
425
426 error = devm_request_threaded_irq(dev, client->irq,
427 NULL, chip_data->irq_handler,
428 IRQF_ONESHOT | IRQF_NO_AUTOEN,
429 client->name, msg2638);
430 if (error) {
431 dev_err(dev, "Failed to request IRQ: %d\n", error);
432 return error;
433 }
434
435 error = msg2638_init_input_dev(msg2638);
436 if (error) {
437 dev_err(dev, "Failed to initialize input device: %d\n", error);
438 return error;
439 }
440
441 return 0;
442 }
443
msg2638_suspend(struct device * dev)444 static int msg2638_suspend(struct device *dev)
445 {
446 struct i2c_client *client = to_i2c_client(dev);
447 struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
448
449 mutex_lock(&msg2638->input_dev->mutex);
450
451 if (input_device_enabled(msg2638->input_dev))
452 msg2638_stop(msg2638);
453
454 mutex_unlock(&msg2638->input_dev->mutex);
455
456 return 0;
457 }
458
msg2638_resume(struct device * dev)459 static int msg2638_resume(struct device *dev)
460 {
461 struct i2c_client *client = to_i2c_client(dev);
462 struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
463 int ret = 0;
464
465 mutex_lock(&msg2638->input_dev->mutex);
466
467 if (input_device_enabled(msg2638->input_dev))
468 ret = msg2638_start(msg2638);
469
470 mutex_unlock(&msg2638->input_dev->mutex);
471
472 return ret;
473 }
474
475 static DEFINE_SIMPLE_DEV_PM_OPS(msg2638_pm_ops, msg2638_suspend, msg2638_resume);
476
477 static const struct msg_chip_data msg2138_data = {
478 .irq_handler = msg2138_ts_irq_handler,
479 .max_fingers = MSG2138_MAX_FINGERS,
480 };
481
482 static const struct msg_chip_data msg2638_data = {
483 .irq_handler = msg2638_ts_irq_handler,
484 .max_fingers = MSG2638_MAX_FINGERS,
485 };
486
487 static const struct of_device_id msg2638_of_match[] = {
488 { .compatible = "mstar,msg2138", .data = &msg2138_data },
489 { .compatible = "mstar,msg2638", .data = &msg2638_data },
490 { }
491 };
492 MODULE_DEVICE_TABLE(of, msg2638_of_match);
493
494 static struct i2c_driver msg2638_ts_driver = {
495 .probe = msg2638_ts_probe,
496 .driver = {
497 .name = "MStar-TS",
498 .pm = pm_sleep_ptr(&msg2638_pm_ops),
499 .of_match_table = msg2638_of_match,
500 },
501 };
502 module_i2c_driver(msg2638_ts_driver);
503
504 MODULE_AUTHOR("Vincent Knecht <vincent.knecht@mailoo.org>");
505 MODULE_DESCRIPTION("MStar MSG2638 touchscreen driver");
506 MODULE_LICENSE("GPL v2");
507