1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  Microchip AT42QT1050 QTouch Sensor Controller
4 *
5 *  Copyright (C) 2019 Pengutronix, Marco Felsch <kernel@pengutronix.de>
6 *
7 *  Base on AT42QT1070 driver by:
8 *  Bo Shen <voice.shen@atmel.com>
9 *  Copyright (C) 2011 Atmel
10 */
11
12#include <linux/delay.h>
13#include <linux/i2c.h>
14#include <linux/input.h>
15#include <linux/interrupt.h>
16#include <linux/kernel.h>
17#include <linux/log2.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/regmap.h>
21
22/* Chip ID */
23#define QT1050_CHIP_ID		0x00
24#define QT1050_CHIP_ID_VER	0x46
25
26/* Firmware version */
27#define QT1050_FW_VERSION	0x01
28
29/* Detection status */
30#define QT1050_DET_STATUS	0x02
31
32/* Key status */
33#define QT1050_KEY_STATUS	0x03
34
35/* Key Signals */
36#define QT1050_KEY_SIGNAL_0_MSB	0x06
37#define QT1050_KEY_SIGNAL_0_LSB	0x07
38#define QT1050_KEY_SIGNAL_1_MSB	0x08
39#define QT1050_KEY_SIGNAL_1_LSB	0x09
40#define QT1050_KEY_SIGNAL_2_MSB	0x0c
41#define QT1050_KEY_SIGNAL_2_LSB	0x0d
42#define QT1050_KEY_SIGNAL_3_MSB	0x0e
43#define QT1050_KEY_SIGNAL_3_LSB	0x0f
44#define QT1050_KEY_SIGNAL_4_MSB	0x10
45#define QT1050_KEY_SIGNAL_4_LSB	0x11
46
47/* Reference data */
48#define QT1050_REF_DATA_0_MSB	0x14
49#define QT1050_REF_DATA_0_LSB	0x15
50#define QT1050_REF_DATA_1_MSB	0x16
51#define QT1050_REF_DATA_1_LSB	0x17
52#define QT1050_REF_DATA_2_MSB	0x1a
53#define QT1050_REF_DATA_2_LSB	0x1b
54#define QT1050_REF_DATA_3_MSB	0x1c
55#define QT1050_REF_DATA_3_LSB	0x1d
56#define QT1050_REF_DATA_4_MSB	0x1e
57#define QT1050_REF_DATA_4_LSB	0x1f
58
59/* Negative threshold level */
60#define QT1050_NTHR_0		0x21
61#define QT1050_NTHR_1		0x22
62#define QT1050_NTHR_2		0x24
63#define QT1050_NTHR_3		0x25
64#define QT1050_NTHR_4		0x26
65
66/* Pulse / Scale  */
67#define QT1050_PULSE_SCALE_0	0x28
68#define QT1050_PULSE_SCALE_1	0x29
69#define QT1050_PULSE_SCALE_2	0x2b
70#define QT1050_PULSE_SCALE_3	0x2c
71#define QT1050_PULSE_SCALE_4	0x2d
72
73/* Detection integrator counter / AKS */
74#define QT1050_DI_AKS_0		0x2f
75#define QT1050_DI_AKS_1		0x30
76#define QT1050_DI_AKS_2		0x32
77#define QT1050_DI_AKS_3		0x33
78#define QT1050_DI_AKS_4		0x34
79
80/* Charge Share Delay */
81#define QT1050_CSD_0		0x36
82#define QT1050_CSD_1		0x37
83#define QT1050_CSD_2		0x39
84#define QT1050_CSD_3		0x3a
85#define QT1050_CSD_4		0x3b
86
87/* Low Power Mode */
88#define QT1050_LPMODE		0x3d
89
90/* Calibration and Reset */
91#define QT1050_RES_CAL		0x3f
92#define QT1050_RES_CAL_RESET		BIT(7)
93#define QT1050_RES_CAL_CALIBRATE	BIT(1)
94
95#define QT1050_MAX_KEYS		5
96#define QT1050_RESET_TIME	255
97
98struct qt1050_key_regs {
99	unsigned int nthr;
100	unsigned int pulse_scale;
101	unsigned int di_aks;
102	unsigned int csd;
103};
104
105struct qt1050_key {
106	u32 num;
107	u32 charge_delay;
108	u32 thr_cnt;
109	u32 samples;
110	u32 scale;
111	u32 keycode;
112};
113
114struct qt1050_priv {
115	struct i2c_client	*client;
116	struct input_dev	*input;
117	struct regmap		*regmap;
118	struct qt1050_key	keys[QT1050_MAX_KEYS];
119	unsigned short		keycodes[QT1050_MAX_KEYS];
120	u8			reg_keys;
121	u8			last_keys;
122};
123
124static const struct qt1050_key_regs qt1050_key_regs_data[] = {
125	{
126		.nthr = QT1050_NTHR_0,
127		.pulse_scale = QT1050_PULSE_SCALE_0,
128		.di_aks = QT1050_DI_AKS_0,
129		.csd = QT1050_CSD_0,
130	}, {
131		.nthr = QT1050_NTHR_1,
132		.pulse_scale = QT1050_PULSE_SCALE_1,
133		.di_aks = QT1050_DI_AKS_1,
134		.csd = QT1050_CSD_1,
135	}, {
136		.nthr = QT1050_NTHR_2,
137		.pulse_scale = QT1050_PULSE_SCALE_2,
138		.di_aks = QT1050_DI_AKS_2,
139		.csd = QT1050_CSD_2,
140	}, {
141		.nthr = QT1050_NTHR_3,
142		.pulse_scale = QT1050_PULSE_SCALE_3,
143		.di_aks = QT1050_DI_AKS_3,
144		.csd = QT1050_CSD_3,
145	}, {
146		.nthr = QT1050_NTHR_4,
147		.pulse_scale = QT1050_PULSE_SCALE_4,
148		.di_aks = QT1050_DI_AKS_4,
149		.csd = QT1050_CSD_4,
150	}
151};
152
153static bool qt1050_volatile_reg(struct device *dev, unsigned int reg)
154{
155	switch (reg) {
156	case QT1050_DET_STATUS:
157	case QT1050_KEY_STATUS:
158	case QT1050_KEY_SIGNAL_0_MSB:
159	case QT1050_KEY_SIGNAL_0_LSB:
160	case QT1050_KEY_SIGNAL_1_MSB:
161	case QT1050_KEY_SIGNAL_1_LSB:
162	case QT1050_KEY_SIGNAL_2_MSB:
163	case QT1050_KEY_SIGNAL_2_LSB:
164	case QT1050_KEY_SIGNAL_3_MSB:
165	case QT1050_KEY_SIGNAL_3_LSB:
166	case QT1050_KEY_SIGNAL_4_MSB:
167	case QT1050_KEY_SIGNAL_4_LSB:
168		return true;
169	default:
170		return false;
171	}
172}
173
174static const struct regmap_range qt1050_readable_ranges[] = {
175	regmap_reg_range(QT1050_CHIP_ID, QT1050_KEY_STATUS),
176	regmap_reg_range(QT1050_KEY_SIGNAL_0_MSB, QT1050_KEY_SIGNAL_1_LSB),
177	regmap_reg_range(QT1050_KEY_SIGNAL_2_MSB, QT1050_KEY_SIGNAL_4_LSB),
178	regmap_reg_range(QT1050_REF_DATA_0_MSB, QT1050_REF_DATA_1_LSB),
179	regmap_reg_range(QT1050_REF_DATA_2_MSB, QT1050_REF_DATA_4_LSB),
180	regmap_reg_range(QT1050_NTHR_0, QT1050_NTHR_1),
181	regmap_reg_range(QT1050_NTHR_2, QT1050_NTHR_4),
182	regmap_reg_range(QT1050_PULSE_SCALE_0, QT1050_PULSE_SCALE_1),
183	regmap_reg_range(QT1050_PULSE_SCALE_2, QT1050_PULSE_SCALE_4),
184	regmap_reg_range(QT1050_DI_AKS_0, QT1050_DI_AKS_1),
185	regmap_reg_range(QT1050_DI_AKS_2, QT1050_DI_AKS_4),
186	regmap_reg_range(QT1050_CSD_0, QT1050_CSD_1),
187	regmap_reg_range(QT1050_CSD_2, QT1050_RES_CAL),
188};
189
190static const struct regmap_access_table qt1050_readable_table = {
191	.yes_ranges = qt1050_readable_ranges,
192	.n_yes_ranges = ARRAY_SIZE(qt1050_readable_ranges),
193};
194
195static const struct regmap_range qt1050_writeable_ranges[] = {
196	regmap_reg_range(QT1050_NTHR_0, QT1050_NTHR_1),
197	regmap_reg_range(QT1050_NTHR_2, QT1050_NTHR_4),
198	regmap_reg_range(QT1050_PULSE_SCALE_0, QT1050_PULSE_SCALE_1),
199	regmap_reg_range(QT1050_PULSE_SCALE_2, QT1050_PULSE_SCALE_4),
200	regmap_reg_range(QT1050_DI_AKS_0, QT1050_DI_AKS_1),
201	regmap_reg_range(QT1050_DI_AKS_2, QT1050_DI_AKS_4),
202	regmap_reg_range(QT1050_CSD_0, QT1050_CSD_1),
203	regmap_reg_range(QT1050_CSD_2, QT1050_RES_CAL),
204};
205
206static const struct regmap_access_table qt1050_writeable_table = {
207	.yes_ranges = qt1050_writeable_ranges,
208	.n_yes_ranges = ARRAY_SIZE(qt1050_writeable_ranges),
209};
210
211static struct regmap_config qt1050_regmap_config = {
212	.reg_bits = 8,
213	.val_bits = 8,
214	.max_register = QT1050_RES_CAL,
215
216	.cache_type = REGCACHE_MAPLE,
217
218	.wr_table = &qt1050_writeable_table,
219	.rd_table = &qt1050_readable_table,
220	.volatile_reg = qt1050_volatile_reg,
221};
222
223static bool qt1050_identify(struct qt1050_priv *ts)
224{
225	unsigned int val;
226	int err;
227
228	/* Read Chip ID */
229	regmap_read(ts->regmap, QT1050_CHIP_ID, &val);
230	if (val != QT1050_CHIP_ID_VER) {
231		dev_err(&ts->client->dev, "ID %d not supported\n", val);
232		return false;
233	}
234
235	/* Read firmware version */
236	err = regmap_read(ts->regmap, QT1050_FW_VERSION, &val);
237	if (err) {
238		dev_err(&ts->client->dev, "could not read the firmware version\n");
239		return false;
240	}
241
242	dev_info(&ts->client->dev, "AT42QT1050 firmware version %1d.%1d\n",
243		 val >> 4, val & 0xf);
244
245	return true;
246}
247
248static irqreturn_t qt1050_irq_threaded(int irq, void *dev_id)
249{
250	struct qt1050_priv *ts = dev_id;
251	struct input_dev *input = ts->input;
252	unsigned long new_keys, changed;
253	unsigned int val;
254	int i, err;
255
256	/* Read the detected status register, thus clearing interrupt */
257	err = regmap_read(ts->regmap, QT1050_DET_STATUS, &val);
258	if (err) {
259		dev_err(&ts->client->dev, "Fail to read detection status: %d\n",
260			err);
261		return IRQ_NONE;
262	}
263
264	/* Read which key changed, keys are not continuous */
265	err = regmap_read(ts->regmap, QT1050_KEY_STATUS, &val);
266	if (err) {
267		dev_err(&ts->client->dev,
268			"Fail to determine the key status: %d\n", err);
269		return IRQ_NONE;
270	}
271	new_keys = (val & 0x70) >> 2 | (val & 0x6) >> 1;
272	changed = ts->last_keys ^ new_keys;
273	/* Report registered keys only */
274	changed &= ts->reg_keys;
275
276	for_each_set_bit(i, &changed, QT1050_MAX_KEYS)
277		input_report_key(input, ts->keys[i].keycode,
278				 test_bit(i, &new_keys));
279
280	ts->last_keys = new_keys;
281	input_sync(input);
282
283	return IRQ_HANDLED;
284}
285
286static const struct qt1050_key_regs *qt1050_get_key_regs(int key_num)
287{
288	return &qt1050_key_regs_data[key_num];
289}
290
291static int qt1050_set_key(struct regmap *map, int number, int on)
292{
293	const struct qt1050_key_regs *key_regs;
294
295	key_regs = qt1050_get_key_regs(number);
296
297	return regmap_update_bits(map, key_regs->di_aks, 0xfc,
298				  on ? BIT(4) : 0x00);
299}
300
301static int qt1050_apply_fw_data(struct qt1050_priv *ts)
302{
303	struct regmap *map = ts->regmap;
304	struct qt1050_key *button = &ts->keys[0];
305	const struct qt1050_key_regs *key_regs;
306	int i, err;
307
308	/* Disable all keys and enable only the specified ones */
309	for (i = 0; i < QT1050_MAX_KEYS; i++) {
310		err = qt1050_set_key(map, i, 0);
311		if (err)
312			return err;
313	}
314
315	for (i = 0; i < QT1050_MAX_KEYS; i++, button++) {
316		/* Keep KEY_RESERVED keys off */
317		if (button->keycode == KEY_RESERVED)
318			continue;
319
320		err = qt1050_set_key(map, button->num, 1);
321		if (err)
322			return err;
323
324		key_regs = qt1050_get_key_regs(button->num);
325
326		err = regmap_write(map, key_regs->pulse_scale,
327				   (button->samples << 4) | (button->scale));
328		if (err)
329			return err;
330		err = regmap_write(map, key_regs->csd, button->charge_delay);
331		if (err)
332			return err;
333		err = regmap_write(map, key_regs->nthr, button->thr_cnt);
334		if (err)
335			return err;
336	}
337
338	return 0;
339}
340
341static int qt1050_parse_fw(struct qt1050_priv *ts)
342{
343	struct device *dev = &ts->client->dev;
344	struct fwnode_handle *child;
345	int nbuttons;
346
347	nbuttons = device_get_child_node_count(dev);
348	if (nbuttons == 0 || nbuttons > QT1050_MAX_KEYS)
349		return -ENODEV;
350
351	device_for_each_child_node(dev, child) {
352		struct qt1050_key button;
353
354		/* Required properties */
355		if (fwnode_property_read_u32(child, "linux,code",
356					     &button.keycode)) {
357			dev_err(dev, "Button without keycode\n");
358			goto err;
359		}
360		if (button.keycode >= KEY_MAX) {
361			dev_err(dev, "Invalid keycode 0x%x\n",
362				button.keycode);
363			goto err;
364		}
365
366		if (fwnode_property_read_u32(child, "reg",
367					     &button.num)) {
368			dev_err(dev, "Button without pad number\n");
369			goto err;
370		}
371		if (button.num < 0 || button.num > QT1050_MAX_KEYS - 1)
372			goto err;
373
374		ts->reg_keys |= BIT(button.num);
375
376		/* Optional properties */
377		if (fwnode_property_read_u32(child,
378					     "microchip,pre-charge-time-ns",
379					     &button.charge_delay)) {
380			button.charge_delay = 0;
381		} else {
382			if (button.charge_delay % 2500 == 0)
383				button.charge_delay =
384					button.charge_delay / 2500;
385			else
386				button.charge_delay = 0;
387		}
388
389		if (fwnode_property_read_u32(child, "microchip,average-samples",
390					 &button.samples)) {
391			button.samples = 0;
392		} else {
393			if (is_power_of_2(button.samples))
394				button.samples = ilog2(button.samples);
395			else
396				button.samples = 0;
397		}
398
399		if (fwnode_property_read_u32(child, "microchip,average-scaling",
400					     &button.scale)) {
401			button.scale = 0;
402		} else {
403			if (is_power_of_2(button.scale))
404				button.scale = ilog2(button.scale);
405			else
406				button.scale = 0;
407
408		}
409
410		if (fwnode_property_read_u32(child, "microchip,threshold",
411					 &button.thr_cnt)) {
412			button.thr_cnt = 20;
413		} else {
414			if (button.thr_cnt > 255)
415				button.thr_cnt = 20;
416		}
417
418		ts->keys[button.num] = button;
419	}
420
421	return 0;
422
423err:
424	fwnode_handle_put(child);
425	return -EINVAL;
426}
427
428static int qt1050_probe(struct i2c_client *client)
429{
430	struct qt1050_priv *ts;
431	struct input_dev *input;
432	struct device *dev = &client->dev;
433	struct regmap *map;
434	unsigned int status, i;
435	int err;
436
437	/* Check basic functionality */
438	err = i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE);
439	if (!err) {
440		dev_err(&client->dev, "%s adapter not supported\n",
441			dev_driver_string(&client->adapter->dev));
442		return -ENODEV;
443	}
444
445	if (!client->irq) {
446		dev_err(dev, "assign a irq line to this device\n");
447		return -EINVAL;
448	}
449
450	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
451	if (!ts)
452		return -ENOMEM;
453
454	input = devm_input_allocate_device(dev);
455	if (!input)
456		return -ENOMEM;
457
458	map = devm_regmap_init_i2c(client, &qt1050_regmap_config);
459	if (IS_ERR(map))
460		return PTR_ERR(map);
461
462	ts->client = client;
463	ts->input = input;
464	ts->regmap = map;
465
466	i2c_set_clientdata(client, ts);
467
468	/* Identify the qt1050 chip */
469	if (!qt1050_identify(ts))
470		return -ENODEV;
471
472	/* Get pdata */
473	err = qt1050_parse_fw(ts);
474	if (err) {
475		dev_err(dev, "Failed to parse firmware: %d\n", err);
476		return err;
477	}
478
479	input->name = "AT42QT1050 QTouch Sensor";
480	input->dev.parent = &client->dev;
481	input->id.bustype = BUS_I2C;
482
483	/* Add the keycode */
484	input->keycode = ts->keycodes;
485	input->keycodesize = sizeof(ts->keycodes[0]);
486	input->keycodemax = QT1050_MAX_KEYS;
487
488	__set_bit(EV_KEY, input->evbit);
489	for (i = 0; i < QT1050_MAX_KEYS; i++) {
490		ts->keycodes[i] = ts->keys[i].keycode;
491		__set_bit(ts->keycodes[i], input->keybit);
492	}
493
494	/* Trigger re-calibration */
495	err = regmap_update_bits(ts->regmap, QT1050_RES_CAL, 0x7f,
496				 QT1050_RES_CAL_CALIBRATE);
497	if (err) {
498		dev_err(dev, "Trigger calibration failed: %d\n", err);
499		return err;
500	}
501	err = regmap_read_poll_timeout(ts->regmap, QT1050_DET_STATUS, status,
502				 status >> 7 == 1, 10000, 200000);
503	if (err) {
504		dev_err(dev, "Calibration failed: %d\n", err);
505		return err;
506	}
507
508	/* Soft reset to set defaults */
509	err = regmap_update_bits(ts->regmap, QT1050_RES_CAL,
510				 QT1050_RES_CAL_RESET, QT1050_RES_CAL_RESET);
511	if (err) {
512		dev_err(dev, "Trigger soft reset failed: %d\n", err);
513		return err;
514	}
515	msleep(QT1050_RESET_TIME);
516
517	/* Set pdata */
518	err = qt1050_apply_fw_data(ts);
519	if (err) {
520		dev_err(dev, "Failed to set firmware data: %d\n", err);
521		return err;
522	}
523
524	err = devm_request_threaded_irq(dev, client->irq, NULL,
525					qt1050_irq_threaded, IRQF_ONESHOT,
526					"qt1050", ts);
527	if (err) {
528		dev_err(&client->dev, "Failed to request irq: %d\n", err);
529		return err;
530	}
531
532	/* Clear #CHANGE line */
533	err = regmap_read(ts->regmap, QT1050_DET_STATUS, &status);
534	if (err) {
535		dev_err(dev, "Failed to clear #CHANGE line level: %d\n", err);
536		return err;
537	}
538
539	/* Register the input device */
540	err = input_register_device(ts->input);
541	if (err) {
542		dev_err(&client->dev, "Failed to register input device: %d\n",
543			err);
544		return err;
545	}
546
547	return 0;
548}
549
550static int qt1050_suspend(struct device *dev)
551{
552	struct i2c_client *client = to_i2c_client(dev);
553	struct qt1050_priv *ts = i2c_get_clientdata(client);
554
555	disable_irq(client->irq);
556
557	/*
558	 * Set measurement interval to 1s (125 x 8ms) if wakeup is allowed
559	 * else turn off. The 1s interval seems to be a good compromise between
560	 * low power and response time.
561	 */
562	return regmap_write(ts->regmap, QT1050_LPMODE,
563			    device_may_wakeup(dev) ? 125 : 0);
564}
565
566static int qt1050_resume(struct device *dev)
567{
568	struct i2c_client *client = to_i2c_client(dev);
569	struct qt1050_priv *ts = i2c_get_clientdata(client);
570
571	enable_irq(client->irq);
572
573	/* Set measurement interval back to 16ms (2 x 8ms) */
574	return regmap_write(ts->regmap, QT1050_LPMODE, 2);
575}
576
577static DEFINE_SIMPLE_DEV_PM_OPS(qt1050_pm_ops, qt1050_suspend, qt1050_resume);
578
579static const struct of_device_id __maybe_unused qt1050_of_match[] = {
580	{ .compatible = "microchip,qt1050", },
581	{ },
582};
583MODULE_DEVICE_TABLE(of, qt1050_of_match);
584
585static struct i2c_driver qt1050_driver = {
586	.driver	= {
587		.name = "qt1050",
588		.of_match_table = of_match_ptr(qt1050_of_match),
589		.pm = pm_sleep_ptr(&qt1050_pm_ops),
590	},
591	.probe = qt1050_probe,
592};
593
594module_i2c_driver(qt1050_driver);
595
596MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de");
597MODULE_DESCRIPTION("Driver for AT42QT1050 QTouch sensor");
598MODULE_LICENSE("GPL v2");
599