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/module.h>
17#include <linux/of.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 */
36enum 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 */
53enum 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 */
70struct pixcir_i2c_chip_data {
71	u8 max_fingers;
72	bool has_hw_ids;
73};
74
75struct 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
87struct pixcir_report_data {
88	int num_touches;
89	struct input_mt_pos pos[PIXCIR_MAX_SLOTS];
90	int ids[PIXCIR_MAX_SLOTS];
91};
92
93static 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
147static 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
191static 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
221static 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
232static 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 */
276static 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 */
310static 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
337static 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
368static 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
394static 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
401static 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
408static 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
429unlock:
430	mutex_unlock(&input->mutex);
431
432	return ret;
433}
434
435static 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
456unlock:
457	mutex_unlock(&input->mutex);
458
459	return ret;
460}
461
462static DEFINE_SIMPLE_DEV_PM_OPS(pixcir_dev_pm_ops,
463				pixcir_i2c_ts_suspend, pixcir_i2c_ts_resume);
464
465static 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		return dev_err_probe(dev, PTR_ERR(tsdata->gpio_attb),
520				     "Failed to request ATTB gpio\n");
521
522	tsdata->gpio_reset = devm_gpiod_get_optional(dev, "reset",
523						     GPIOD_OUT_LOW);
524	if (IS_ERR(tsdata->gpio_reset))
525		return dev_err_probe(dev, PTR_ERR(tsdata->gpio_reset),
526				     "Failed to request RESET gpio\n");
527
528	tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake",
529						    GPIOD_OUT_HIGH);
530	if (IS_ERR(tsdata->gpio_wake))
531		return dev_err_probe(dev, PTR_ERR(tsdata->gpio_wake),
532				     "Failed to get wake gpio\n");
533
534	tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable",
535						      GPIOD_OUT_HIGH);
536	if (IS_ERR(tsdata->gpio_enable))
537		return dev_err_probe(dev, PTR_ERR(tsdata->gpio_enable),
538				     "Failed to get enable gpio\n");
539
540	if (tsdata->gpio_enable)
541		msleep(100);
542
543	error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr,
544					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
545					  client->name, tsdata);
546	if (error) {
547		dev_err(dev, "failed to request irq %d\n", client->irq);
548		return error;
549	}
550
551	pixcir_reset(tsdata);
552
553	/* Always be in IDLE mode to save power, device supports auto wake */
554	error = pixcir_set_power_mode(tsdata, PIXCIR_POWER_IDLE);
555	if (error) {
556		dev_err(dev, "Failed to set IDLE mode\n");
557		return error;
558	}
559
560	/* Stop device till opened */
561	error = pixcir_stop(tsdata);
562	if (error)
563		return error;
564
565	error = input_register_device(input);
566	if (error)
567		return error;
568
569	i2c_set_clientdata(client, tsdata);
570
571	return 0;
572}
573
574static const struct pixcir_i2c_chip_data pixcir_ts_data = {
575	.max_fingers = 2,
576	/* no hw id support */
577};
578
579static const struct pixcir_i2c_chip_data pixcir_tangoc_data = {
580	.max_fingers = 5,
581	.has_hw_ids = true,
582};
583
584static const struct i2c_device_id pixcir_i2c_ts_id[] = {
585	{ "pixcir_ts", (unsigned long) &pixcir_ts_data },
586	{ "pixcir_tangoc", (unsigned long) &pixcir_tangoc_data },
587	{ }
588};
589MODULE_DEVICE_TABLE(i2c, pixcir_i2c_ts_id);
590
591#ifdef CONFIG_OF
592static const struct of_device_id pixcir_of_match[] = {
593	{ .compatible = "pixcir,pixcir_ts", .data = &pixcir_ts_data },
594	{ .compatible = "pixcir,pixcir_tangoc", .data = &pixcir_tangoc_data },
595	{ }
596};
597MODULE_DEVICE_TABLE(of, pixcir_of_match);
598#endif
599
600static struct i2c_driver pixcir_i2c_ts_driver = {
601	.driver = {
602		.name	= "pixcir_ts",
603		.pm	= pm_sleep_ptr(&pixcir_dev_pm_ops),
604		.of_match_table = of_match_ptr(pixcir_of_match),
605	},
606	.probe		= pixcir_i2c_ts_probe,
607	.id_table	= pixcir_i2c_ts_id,
608};
609
610module_i2c_driver(pixcir_i2c_ts_driver);
611
612MODULE_AUTHOR("Jianchun Bian <jcbian@pixcir.com.cn>, Dequan Meng <dqmeng@pixcir.com.cn>");
613MODULE_DESCRIPTION("Pixcir I2C Touchscreen Driver");
614MODULE_LICENSE("GPL");
615