1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Pixcir I2C touchscreen controllers.
4  *
5  * Copyright (C) 2010-2011 Pixcir, Inc.
6  */
7 
8 #include <asm/unaligned.h>
9 #include <linux/delay.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/i2c.h>
12 #include <linux/input.h>
13 #include <linux/input/mt.h>
14 #include <linux/input/touchscreen.h>
15 #include <linux/interrupt.h>
16 #include <linux/of_device.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 
20 #define PIXCIR_MAX_SLOTS       5 /* Max fingers supported by driver */
21 
22 /*
23  * Register map
24  */
25 #define PIXCIR_REG_POWER_MODE	51
26 #define PIXCIR_REG_INT_MODE	52
27 
28 /*
29  * Power modes:
30  * active: max scan speed
31  * idle: lower scan speed with automatic transition to active on touch
32  * halt: datasheet says sleep but this is more like halt as the chip
33  *       clocks are cut and it can only be brought out of this mode
34  *	 using the RESET pin.
35  */
36 enum pixcir_power_mode {
37 	PIXCIR_POWER_ACTIVE,
38 	PIXCIR_POWER_IDLE,
39 	PIXCIR_POWER_HALT,
40 };
41 
42 #define PIXCIR_POWER_MODE_MASK	0x03
43 #define PIXCIR_POWER_ALLOW_IDLE (1UL << 2)
44 
45 /*
46  * Interrupt modes:
47  * periodical: interrupt is asserted periodicaly
48  * diff coordinates: interrupt is asserted when coordinates change
49  * level on touch: interrupt level asserted during touch
50  * pulse on touch: interrupt pulse asserted during touch
51  *
52  */
53 enum pixcir_int_mode {
54 	PIXCIR_INT_PERIODICAL,
55 	PIXCIR_INT_DIFF_COORD,
56 	PIXCIR_INT_LEVEL_TOUCH,
57 	PIXCIR_INT_PULSE_TOUCH,
58 };
59 
60 #define PIXCIR_INT_MODE_MASK	0x03
61 #define PIXCIR_INT_ENABLE	(1UL << 3)
62 #define PIXCIR_INT_POL_HIGH	(1UL << 2)
63 
64 /**
65  * struct pixcir_i2c_chip_data - chip related data
66  * @max_fingers:	Max number of fingers reported simultaneously by h/w
67  * @has_hw_ids:		Hardware supports finger tracking IDs
68  *
69  */
70 struct pixcir_i2c_chip_data {
71 	u8 max_fingers;
72 	bool has_hw_ids;
73 };
74 
75 struct pixcir_i2c_ts_data {
76 	struct i2c_client *client;
77 	struct input_dev *input;
78 	struct gpio_desc *gpio_attb;
79 	struct gpio_desc *gpio_reset;
80 	struct gpio_desc *gpio_enable;
81 	struct gpio_desc *gpio_wake;
82 	const struct pixcir_i2c_chip_data *chip;
83 	struct touchscreen_properties prop;
84 	bool running;
85 };
86 
87 struct pixcir_report_data {
88 	int num_touches;
89 	struct input_mt_pos pos[PIXCIR_MAX_SLOTS];
90 	int ids[PIXCIR_MAX_SLOTS];
91 };
92 
93 static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
94 			    struct pixcir_report_data *report)
95 {
96 	u8 rdbuf[2 + PIXCIR_MAX_SLOTS * 5];
97 	u8 wrbuf[1] = { 0 };
98 	u8 *bufptr;
99 	u8 touch;
100 	int ret, i;
101 	int readsize;
102 	const struct pixcir_i2c_chip_data *chip = tsdata->chip;
103 
104 	memset(report, 0, sizeof(struct pixcir_report_data));
105 
106 	i = chip->has_hw_ids ? 1 : 0;
107 	readsize = 2 + tsdata->chip->max_fingers * (4 + i);
108 	if (readsize > sizeof(rdbuf))
109 		readsize = sizeof(rdbuf);
110 
111 	ret = i2c_master_send(tsdata->client, wrbuf, sizeof(wrbuf));
112 	if (ret != sizeof(wrbuf)) {
113 		dev_err(&tsdata->client->dev,
114 			"%s: i2c_master_send failed(), ret=%d\n",
115 			__func__, ret);
116 		return;
117 	}
118 
119 	ret = i2c_master_recv(tsdata->client, rdbuf, readsize);
120 	if (ret != readsize) {
121 		dev_err(&tsdata->client->dev,
122 			"%s: i2c_master_recv failed(), ret=%d\n",
123 			__func__, ret);
124 		return;
125 	}
126 
127 	touch = rdbuf[0] & 0x7;
128 	if (touch > tsdata->chip->max_fingers)
129 		touch = tsdata->chip->max_fingers;
130 
131 	report->num_touches = touch;
132 	bufptr = &rdbuf[2];
133 
134 	for (i = 0; i < touch; i++) {
135 		touchscreen_set_mt_pos(&report->pos[i], &tsdata->prop,
136 				       get_unaligned_le16(bufptr),
137 				       get_unaligned_le16(bufptr + 2));
138 		if (chip->has_hw_ids) {
139 			report->ids[i] = bufptr[4];
140 			bufptr = bufptr + 5;
141 		} else {
142 			bufptr = bufptr + 4;
143 		}
144 	}
145 }
146 
147 static void pixcir_ts_report(struct pixcir_i2c_ts_data *ts,
148 			     struct pixcir_report_data *report)
149 {
150 	int slots[PIXCIR_MAX_SLOTS];
151 	int n, i, slot;
152 	struct device *dev = &ts->client->dev;
153 	const struct pixcir_i2c_chip_data *chip = ts->chip;
154 
155 	n = report->num_touches;
156 	if (n > PIXCIR_MAX_SLOTS)
157 		n = PIXCIR_MAX_SLOTS;
158 
159 	if (!ts->chip->has_hw_ids)
160 		input_mt_assign_slots(ts->input, slots, report->pos, n, 0);
161 
162 	for (i = 0; i < n; i++) {
163 		if (chip->has_hw_ids) {
164 			slot = input_mt_get_slot_by_key(ts->input,
165 							report->ids[i]);
166 			if (slot < 0) {
167 				dev_dbg(dev, "no free slot for id 0x%x\n",
168 					report->ids[i]);
169 				continue;
170 			}
171 		} else {
172 			slot = slots[i];
173 		}
174 
175 		input_mt_slot(ts->input, slot);
176 		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
177 
178 		input_report_abs(ts->input, ABS_MT_POSITION_X,
179 				 report->pos[i].x);
180 		input_report_abs(ts->input, ABS_MT_POSITION_Y,
181 				 report->pos[i].y);
182 
183 		dev_dbg(dev, "%d: slot %d, x %d, y %d\n",
184 			i, slot, report->pos[i].x, report->pos[i].y);
185 	}
186 
187 	input_mt_sync_frame(ts->input);
188 	input_sync(ts->input);
189 }
190 
191 static irqreturn_t pixcir_ts_isr(int irq, void *dev_id)
192 {
193 	struct pixcir_i2c_ts_data *tsdata = dev_id;
194 	struct pixcir_report_data report;
195 
196 	while (tsdata->running) {
197 		/* parse packet */
198 		pixcir_ts_parse(tsdata, &report);
199 
200 		/* report it */
201 		pixcir_ts_report(tsdata, &report);
202 
203 		if (gpiod_get_value_cansleep(tsdata->gpio_attb)) {
204 			if (report.num_touches) {
205 				/*
206 				 * Last report with no finger up?
207 				 * Do it now then.
208 				 */
209 				input_mt_sync_frame(tsdata->input);
210 				input_sync(tsdata->input);
211 			}
212 			break;
213 		}
214 
215 		msleep(20);
216 	}
217 
218 	return IRQ_HANDLED;
219 }
220 
221 static void pixcir_reset(struct pixcir_i2c_ts_data *tsdata)
222 {
223 	if (!IS_ERR_OR_NULL(tsdata->gpio_reset)) {
224 		gpiod_set_value_cansleep(tsdata->gpio_reset, 1);
225 		ndelay(100);	/* datasheet section 1.2.3 says 80ns min. */
226 		gpiod_set_value_cansleep(tsdata->gpio_reset, 0);
227 		/* wait for controller ready. 100ms guess. */
228 		msleep(100);
229 	}
230 }
231 
232 static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts,
233 				 enum pixcir_power_mode mode)
234 {
235 	struct device *dev = &ts->client->dev;
236 	int ret;
237 
238 	if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) {
239 		if (ts->gpio_wake)
240 			gpiod_set_value_cansleep(ts->gpio_wake, 1);
241 	}
242 
243 	ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE);
244 	if (ret < 0) {
245 		dev_err(dev, "%s: can't read reg %d : %d\n",
246 			__func__, PIXCIR_REG_POWER_MODE, ret);
247 		return ret;
248 	}
249 
250 	ret &= ~PIXCIR_POWER_MODE_MASK;
251 	ret |= mode;
252 
253 	/* Always AUTO_IDLE */
254 	ret |= PIXCIR_POWER_ALLOW_IDLE;
255 
256 	ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_POWER_MODE, ret);
257 	if (ret < 0) {
258 		dev_err(dev, "%s: can't write reg %d : %d\n",
259 			__func__, PIXCIR_REG_POWER_MODE, ret);
260 		return ret;
261 	}
262 
263 	if (mode == PIXCIR_POWER_HALT) {
264 		if (ts->gpio_wake)
265 			gpiod_set_value_cansleep(ts->gpio_wake, 0);
266 	}
267 
268 	return 0;
269 }
270 
271 /*
272  * Set the interrupt mode for the device i.e. ATTB line behaviour
273  *
274  * @polarity : 1 for active high, 0 for active low.
275  */
276 static int pixcir_set_int_mode(struct pixcir_i2c_ts_data *ts,
277 			       enum pixcir_int_mode mode, bool polarity)
278 {
279 	struct device *dev = &ts->client->dev;
280 	int ret;
281 
282 	ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_INT_MODE);
283 	if (ret < 0) {
284 		dev_err(dev, "%s: can't read reg %d : %d\n",
285 			__func__, PIXCIR_REG_INT_MODE, ret);
286 		return ret;
287 	}
288 
289 	ret &= ~PIXCIR_INT_MODE_MASK;
290 	ret |= mode;
291 
292 	if (polarity)
293 		ret |= PIXCIR_INT_POL_HIGH;
294 	else
295 		ret &= ~PIXCIR_INT_POL_HIGH;
296 
297 	ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_INT_MODE, ret);
298 	if (ret < 0) {
299 		dev_err(dev, "%s: can't write reg %d : %d\n",
300 			__func__, PIXCIR_REG_INT_MODE, ret);
301 		return ret;
302 	}
303 
304 	return 0;
305 }
306 
307 /*
308  * Enable/disable interrupt generation
309  */
310 static int pixcir_int_enable(struct pixcir_i2c_ts_data *ts, bool enable)
311 {
312 	struct device *dev = &ts->client->dev;
313 	int ret;
314 
315 	ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_INT_MODE);
316 	if (ret < 0) {
317 		dev_err(dev, "%s: can't read reg %d : %d\n",
318 			__func__, PIXCIR_REG_INT_MODE, ret);
319 		return ret;
320 	}
321 
322 	if (enable)
323 		ret |= PIXCIR_INT_ENABLE;
324 	else
325 		ret &= ~PIXCIR_INT_ENABLE;
326 
327 	ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_INT_MODE, ret);
328 	if (ret < 0) {
329 		dev_err(dev, "%s: can't write reg %d : %d\n",
330 			__func__, PIXCIR_REG_INT_MODE, ret);
331 		return ret;
332 	}
333 
334 	return 0;
335 }
336 
337 static int pixcir_start(struct pixcir_i2c_ts_data *ts)
338 {
339 	struct device *dev = &ts->client->dev;
340 	int error;
341 
342 	if (ts->gpio_enable) {
343 		gpiod_set_value_cansleep(ts->gpio_enable, 1);
344 		msleep(100);
345 	}
346 
347 	/* LEVEL_TOUCH interrupt with active low polarity */
348 	error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0);
349 	if (error) {
350 		dev_err(dev, "Failed to set interrupt mode: %d\n", error);
351 		return error;
352 	}
353 
354 	ts->running = true;
355 	mb();	/* Update status before IRQ can fire */
356 
357 	/* enable interrupt generation */
358 	error = pixcir_int_enable(ts, true);
359 	if (error) {
360 		dev_err(dev, "Failed to enable interrupt generation: %d\n",
361 			error);
362 		return error;
363 	}
364 
365 	return 0;
366 }
367 
368 static int pixcir_stop(struct pixcir_i2c_ts_data *ts)
369 {
370 	int error;
371 
372 	/* Disable interrupt generation */
373 	error = pixcir_int_enable(ts, false);
374 	if (error) {
375 		dev_err(&ts->client->dev,
376 			"Failed to disable interrupt generation: %d\n",
377 			error);
378 		return error;
379 	}
380 
381 	/* Exit ISR if running, no more report parsing */
382 	ts->running = false;
383 	mb();	/* update status before we synchronize irq */
384 
385 	/* Wait till running ISR is complete */
386 	synchronize_irq(ts->client->irq);
387 
388 	if (ts->gpio_enable)
389 		gpiod_set_value_cansleep(ts->gpio_enable, 0);
390 
391 	return 0;
392 }
393 
394 static int pixcir_input_open(struct input_dev *dev)
395 {
396 	struct pixcir_i2c_ts_data *ts = input_get_drvdata(dev);
397 
398 	return pixcir_start(ts);
399 }
400 
401 static void pixcir_input_close(struct input_dev *dev)
402 {
403 	struct pixcir_i2c_ts_data *ts = input_get_drvdata(dev);
404 
405 	pixcir_stop(ts);
406 }
407 
408 static int pixcir_i2c_ts_suspend(struct device *dev)
409 {
410 	struct i2c_client *client = to_i2c_client(dev);
411 	struct pixcir_i2c_ts_data *ts = i2c_get_clientdata(client);
412 	struct input_dev *input = ts->input;
413 	int ret = 0;
414 
415 	mutex_lock(&input->mutex);
416 
417 	if (device_may_wakeup(&client->dev)) {
418 		if (!input_device_enabled(input)) {
419 			ret = pixcir_start(ts);
420 			if (ret) {
421 				dev_err(dev, "Failed to start\n");
422 				goto unlock;
423 			}
424 		}
425 	} else if (input_device_enabled(input)) {
426 		ret = pixcir_stop(ts);
427 	}
428 
429 unlock:
430 	mutex_unlock(&input->mutex);
431 
432 	return ret;
433 }
434 
435 static int pixcir_i2c_ts_resume(struct device *dev)
436 {
437 	struct i2c_client *client = to_i2c_client(dev);
438 	struct pixcir_i2c_ts_data *ts = i2c_get_clientdata(client);
439 	struct input_dev *input = ts->input;
440 	int ret = 0;
441 
442 	mutex_lock(&input->mutex);
443 
444 	if (device_may_wakeup(&client->dev)) {
445 		if (!input_device_enabled(input)) {
446 			ret = pixcir_stop(ts);
447 			if (ret) {
448 				dev_err(dev, "Failed to stop\n");
449 				goto unlock;
450 			}
451 		}
452 	} else if (input_device_enabled(input)) {
453 		ret = pixcir_start(ts);
454 	}
455 
456 unlock:
457 	mutex_unlock(&input->mutex);
458 
459 	return ret;
460 }
461 
462 static DEFINE_SIMPLE_DEV_PM_OPS(pixcir_dev_pm_ops,
463 				pixcir_i2c_ts_suspend, pixcir_i2c_ts_resume);
464 
465 static int pixcir_i2c_ts_probe(struct i2c_client *client)
466 {
467 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
468 	struct device *dev = &client->dev;
469 	struct pixcir_i2c_ts_data *tsdata;
470 	struct input_dev *input;
471 	int error;
472 
473 	tsdata = devm_kzalloc(dev, sizeof(*tsdata), GFP_KERNEL);
474 	if (!tsdata)
475 		return -ENOMEM;
476 
477 	tsdata->chip = device_get_match_data(dev);
478 	if (!tsdata->chip && id)
479 		tsdata->chip = (const void *)id->driver_data;
480 	if (!tsdata->chip) {
481 		dev_err(dev, "can't locate chip data\n");
482 		return -EINVAL;
483 	}
484 
485 	input = devm_input_allocate_device(dev);
486 	if (!input) {
487 		dev_err(dev, "Failed to allocate input device\n");
488 		return -ENOMEM;
489 	}
490 
491 	tsdata->client = client;
492 	tsdata->input = input;
493 
494 	input->name = client->name;
495 	input->id.bustype = BUS_I2C;
496 	input->open = pixcir_input_open;
497 	input->close = pixcir_input_close;
498 
499 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
500 	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
501 	touchscreen_parse_properties(input, true, &tsdata->prop);
502 	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
503 	    !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
504 		dev_err(dev, "Touchscreen size is not specified\n");
505 		return -EINVAL;
506 	}
507 
508 	error = input_mt_init_slots(input, tsdata->chip->max_fingers,
509 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
510 	if (error) {
511 		dev_err(dev, "Error initializing Multi-Touch slots\n");
512 		return error;
513 	}
514 
515 	input_set_drvdata(input, tsdata);
516 
517 	tsdata->gpio_attb = devm_gpiod_get(dev, "attb", GPIOD_IN);
518 	if (IS_ERR(tsdata->gpio_attb)) {
519 		error = PTR_ERR(tsdata->gpio_attb);
520 		if (error != -EPROBE_DEFER)
521 			dev_err(dev, "Failed to request ATTB gpio: %d\n",
522 				error);
523 		return error;
524 	}
525 
526 	tsdata->gpio_reset = devm_gpiod_get_optional(dev, "reset",
527 						     GPIOD_OUT_LOW);
528 	if (IS_ERR(tsdata->gpio_reset)) {
529 		error = PTR_ERR(tsdata->gpio_reset);
530 		if (error != -EPROBE_DEFER)
531 			dev_err(dev, "Failed to request RESET gpio: %d\n",
532 				error);
533 		return error;
534 	}
535 
536 	tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake",
537 						    GPIOD_OUT_HIGH);
538 	if (IS_ERR(tsdata->gpio_wake)) {
539 		error = PTR_ERR(tsdata->gpio_wake);
540 		if (error != -EPROBE_DEFER)
541 			dev_err(dev, "Failed to get wake gpio: %d\n", error);
542 		return error;
543 	}
544 
545 	tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable",
546 						      GPIOD_OUT_HIGH);
547 	if (IS_ERR(tsdata->gpio_enable)) {
548 		error = PTR_ERR(tsdata->gpio_enable);
549 		if (error != -EPROBE_DEFER)
550 			dev_err(dev, "Failed to get enable gpio: %d\n", error);
551 		return error;
552 	}
553 
554 	if (tsdata->gpio_enable)
555 		msleep(100);
556 
557 	error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr,
558 					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
559 					  client->name, tsdata);
560 	if (error) {
561 		dev_err(dev, "failed to request irq %d\n", client->irq);
562 		return error;
563 	}
564 
565 	pixcir_reset(tsdata);
566 
567 	/* Always be in IDLE mode to save power, device supports auto wake */
568 	error = pixcir_set_power_mode(tsdata, PIXCIR_POWER_IDLE);
569 	if (error) {
570 		dev_err(dev, "Failed to set IDLE mode\n");
571 		return error;
572 	}
573 
574 	/* Stop device till opened */
575 	error = pixcir_stop(tsdata);
576 	if (error)
577 		return error;
578 
579 	error = input_register_device(input);
580 	if (error)
581 		return error;
582 
583 	i2c_set_clientdata(client, tsdata);
584 
585 	return 0;
586 }
587 
588 static const struct pixcir_i2c_chip_data pixcir_ts_data = {
589 	.max_fingers = 2,
590 	/* no hw id support */
591 };
592 
593 static const struct pixcir_i2c_chip_data pixcir_tangoc_data = {
594 	.max_fingers = 5,
595 	.has_hw_ids = true,
596 };
597 
598 static const struct i2c_device_id pixcir_i2c_ts_id[] = {
599 	{ "pixcir_ts", (unsigned long) &pixcir_ts_data },
600 	{ "pixcir_tangoc", (unsigned long) &pixcir_tangoc_data },
601 	{ }
602 };
603 MODULE_DEVICE_TABLE(i2c, pixcir_i2c_ts_id);
604 
605 #ifdef CONFIG_OF
606 static const struct of_device_id pixcir_of_match[] = {
607 	{ .compatible = "pixcir,pixcir_ts", .data = &pixcir_ts_data },
608 	{ .compatible = "pixcir,pixcir_tangoc", .data = &pixcir_tangoc_data },
609 	{ }
610 };
611 MODULE_DEVICE_TABLE(of, pixcir_of_match);
612 #endif
613 
614 static struct i2c_driver pixcir_i2c_ts_driver = {
615 	.driver = {
616 		.name	= "pixcir_ts",
617 		.pm	= pm_sleep_ptr(&pixcir_dev_pm_ops),
618 		.of_match_table = of_match_ptr(pixcir_of_match),
619 	},
620 	.probe		= pixcir_i2c_ts_probe,
621 	.id_table	= pixcir_i2c_ts_id,
622 };
623 
624 module_i2c_driver(pixcir_i2c_ts_driver);
625 
626 MODULE_AUTHOR("Jianchun Bian <jcbian@pixcir.com.cn>, Dequan Meng <dqmeng@pixcir.com.cn>");
627 MODULE_DESCRIPTION("Pixcir I2C Touchscreen Driver");
628 MODULE_LICENSE("GPL");
629