1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Semtech SX8654 I2C touchscreen controller.
4  *
5  * Copyright (c) 2015 Armadeus Systems
6  *	Sébastien Szymanski <sebastien.szymanski@armadeus.com>
7  *
8  * Using code from:
9  *  - sx865x.c
10  *	Copyright (c) 2013 U-MoBo Srl
11  *	Pierluigi Passaro <p.passaro@u-mobo.com>
12  *  - sx8650.c
13  *      Copyright (c) 2009 Wayne Roberts
14  *  - tsc2007.c
15  *      Copyright (c) 2008 Kwangwoo Lee
16  *  - ads7846.c
17  *      Copyright (c) 2005 David Brownell
18  *      Copyright (c) 2006 Nokia Corporation
19  *  - corgi_ts.c
20  *      Copyright (C) 2004-2005 Richard Purdie
21  *  - omap_ts.[hc], ads7846.h, ts_osk.c
22  *      Copyright (C) 2002 MontaVista Software
23  *      Copyright (C) 2004 Texas Instruments
24  *      Copyright (C) 2005 Dirk Behme
25  */
26 
27 #include <linux/bitops.h>
28 #include <linux/delay.h>
29 #include <linux/gpio/consumer.h>
30 #include <linux/i2c.h>
31 #include <linux/input.h>
32 #include <linux/input/touchscreen.h>
33 #include <linux/interrupt.h>
34 #include <linux/irq.h>
35 #include <linux/module.h>
36 #include <linux/of.h>
37 
38 /* register addresses */
39 #define I2C_REG_TOUCH0			0x00
40 #define I2C_REG_TOUCH1			0x01
41 #define I2C_REG_CHANMASK		0x04
42 #define I2C_REG_IRQMASK			0x22
43 #define I2C_REG_IRQSRC			0x23
44 #define I2C_REG_SOFTRESET		0x3f
45 
46 #define I2C_REG_SX8650_STAT		0x05
47 #define SX8650_STAT_CONVIRQ		BIT(7)
48 
49 /* commands */
50 #define CMD_READ_REGISTER		0x40
51 #define CMD_PENTRG			0xe0
52 
53 /* value for I2C_REG_SOFTRESET */
54 #define SOFTRESET_VALUE			0xde
55 
56 /* bits for I2C_REG_IRQSRC */
57 #define IRQ_PENTOUCH_TOUCHCONVDONE	BIT(3)
58 #define IRQ_PENRELEASE			BIT(2)
59 
60 /* bits for RegTouch1 */
61 #define CONDIRQ				0x20
62 #define RPDNT_100K			0x00
63 #define FILT_7SA			0x03
64 
65 /* bits for I2C_REG_CHANMASK */
66 #define CONV_X				BIT(7)
67 #define CONV_Y				BIT(6)
68 
69 /* coordinates rate: higher nibble of CTRL0 register */
70 #define RATE_MANUAL			0x00
71 #define RATE_5000CPS			0xf0
72 
73 /* power delay: lower nibble of CTRL0 register */
74 #define POWDLY_1_1MS			0x0b
75 
76 /* for sx8650, as we have no pen release IRQ there: timeout in ns following the
77  * last PENIRQ after which we assume the pen is lifted.
78  */
79 #define SX8650_PENIRQ_TIMEOUT		msecs_to_jiffies(10)
80 
81 #define MAX_12BIT			((1 << 12) - 1)
82 #define MAX_I2C_READ_LEN		10 /* see datasheet section 5.1.5 */
83 
84 /* channel definition */
85 #define CH_X				0x00
86 #define CH_Y				0x01
87 
88 struct sx865x_data {
89 	u8 cmd_manual;
90 	u8 chan_mask;
91 	bool has_irq_penrelease;
92 	bool has_reg_irqmask;
93 	irq_handler_t irqh;
94 };
95 
96 struct sx8654 {
97 	struct input_dev *input;
98 	struct i2c_client *client;
99 	struct gpio_desc *gpio_reset;
100 
101 	spinlock_t lock;	/* for input reporting from irq/timer */
102 	struct timer_list timer;
103 
104 	struct touchscreen_properties props;
105 
106 	const struct sx865x_data *data;
107 };
108 
sx865x_penrelease(struct sx8654 * ts)109 static inline void sx865x_penrelease(struct sx8654 *ts)
110 {
111 	struct input_dev *input_dev = ts->input;
112 
113 	input_report_key(input_dev, BTN_TOUCH, 0);
114 	input_sync(input_dev);
115 }
116 
sx865x_penrelease_timer_handler(struct timer_list * t)117 static void sx865x_penrelease_timer_handler(struct timer_list *t)
118 {
119 	struct sx8654 *ts = from_timer(ts, t, timer);
120 	unsigned long flags;
121 
122 	spin_lock_irqsave(&ts->lock, flags);
123 	sx865x_penrelease(ts);
124 	spin_unlock_irqrestore(&ts->lock, flags);
125 	dev_dbg(&ts->client->dev, "penrelease by timer\n");
126 }
127 
sx8650_irq(int irq,void * handle)128 static irqreturn_t sx8650_irq(int irq, void *handle)
129 {
130 	struct sx8654 *ts = handle;
131 	struct device *dev = &ts->client->dev;
132 	int len, i;
133 	unsigned long flags;
134 	u8 stat;
135 	u16 x, y;
136 	u16 ch;
137 	u16 chdata;
138 	__be16 data[MAX_I2C_READ_LEN / sizeof(__be16)];
139 	u8 nchan = hweight32(ts->data->chan_mask);
140 	u8 readlen = nchan * sizeof(*data);
141 
142 	stat = i2c_smbus_read_byte_data(ts->client, CMD_READ_REGISTER
143 						    | I2C_REG_SX8650_STAT);
144 
145 	if (!(stat & SX8650_STAT_CONVIRQ)) {
146 		dev_dbg(dev, "%s ignore stat [0x%02x]", __func__, stat);
147 		return IRQ_HANDLED;
148 	}
149 
150 	len = i2c_master_recv(ts->client, (u8 *)data, readlen);
151 	if (len != readlen) {
152 		dev_dbg(dev, "ignore short recv (%d)\n", len);
153 		return IRQ_HANDLED;
154 	}
155 
156 	spin_lock_irqsave(&ts->lock, flags);
157 
158 	x = 0;
159 	y = 0;
160 	for (i = 0; i < nchan; i++) {
161 		chdata = be16_to_cpu(data[i]);
162 
163 		if (unlikely(chdata == 0xFFFF)) {
164 			dev_dbg(dev, "invalid qualified data @ %d\n", i);
165 			continue;
166 		} else if (unlikely(chdata & 0x8000)) {
167 			dev_warn(dev, "hibit @ %d [0x%04x]\n", i, chdata);
168 			continue;
169 		}
170 
171 		ch = chdata >> 12;
172 		if (ch == CH_X)
173 			x = chdata & MAX_12BIT;
174 		else if (ch == CH_Y)
175 			y = chdata & MAX_12BIT;
176 		else
177 			dev_warn(dev, "unknown channel %d [0x%04x]\n", ch,
178 				 chdata);
179 	}
180 
181 	touchscreen_report_pos(ts->input, &ts->props, x, y, false);
182 	input_report_key(ts->input, BTN_TOUCH, 1);
183 	input_sync(ts->input);
184 	dev_dbg(dev, "point(%4d,%4d)\n", x, y);
185 
186 	mod_timer(&ts->timer, jiffies + SX8650_PENIRQ_TIMEOUT);
187 	spin_unlock_irqrestore(&ts->lock, flags);
188 
189 	return IRQ_HANDLED;
190 }
191 
sx8654_irq(int irq,void * handle)192 static irqreturn_t sx8654_irq(int irq, void *handle)
193 {
194 	struct sx8654 *sx8654 = handle;
195 	int irqsrc;
196 	u8 data[4];
197 	unsigned int x, y;
198 	int retval;
199 
200 	irqsrc = i2c_smbus_read_byte_data(sx8654->client,
201 					  CMD_READ_REGISTER | I2C_REG_IRQSRC);
202 	dev_dbg(&sx8654->client->dev, "irqsrc = 0x%x", irqsrc);
203 
204 	if (irqsrc < 0)
205 		goto out;
206 
207 	if (irqsrc & IRQ_PENRELEASE) {
208 		dev_dbg(&sx8654->client->dev, "pen release interrupt");
209 
210 		input_report_key(sx8654->input, BTN_TOUCH, 0);
211 		input_sync(sx8654->input);
212 	}
213 
214 	if (irqsrc & IRQ_PENTOUCH_TOUCHCONVDONE) {
215 		dev_dbg(&sx8654->client->dev, "pen touch interrupt");
216 
217 		retval = i2c_master_recv(sx8654->client, data, sizeof(data));
218 		if (retval != sizeof(data))
219 			goto out;
220 
221 		/* invalid data */
222 		if (unlikely(data[0] & 0x80 || data[2] & 0x80))
223 			goto out;
224 
225 		x = ((data[0] & 0xf) << 8) | (data[1]);
226 		y = ((data[2] & 0xf) << 8) | (data[3]);
227 
228 		touchscreen_report_pos(sx8654->input, &sx8654->props, x, y,
229 				       false);
230 		input_report_key(sx8654->input, BTN_TOUCH, 1);
231 		input_sync(sx8654->input);
232 
233 		dev_dbg(&sx8654->client->dev, "point(%4d,%4d)\n", x, y);
234 	}
235 
236 out:
237 	return IRQ_HANDLED;
238 }
239 
sx8654_reset(struct sx8654 * ts)240 static int sx8654_reset(struct sx8654 *ts)
241 {
242 	int err;
243 
244 	if (ts->gpio_reset) {
245 		gpiod_set_value_cansleep(ts->gpio_reset, 1);
246 		udelay(2); /* Tpulse > 1µs */
247 		gpiod_set_value_cansleep(ts->gpio_reset, 0);
248 	} else {
249 		dev_dbg(&ts->client->dev, "NRST unavailable, try softreset\n");
250 		err = i2c_smbus_write_byte_data(ts->client, I2C_REG_SOFTRESET,
251 						SOFTRESET_VALUE);
252 		if (err)
253 			return err;
254 	}
255 
256 	return 0;
257 }
258 
sx8654_open(struct input_dev * dev)259 static int sx8654_open(struct input_dev *dev)
260 {
261 	struct sx8654 *sx8654 = input_get_drvdata(dev);
262 	struct i2c_client *client = sx8654->client;
263 	int error;
264 
265 	/* enable pen trigger mode */
266 	error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH0,
267 					  RATE_5000CPS | POWDLY_1_1MS);
268 	if (error) {
269 		dev_err(&client->dev, "writing to I2C_REG_TOUCH0 failed");
270 		return error;
271 	}
272 
273 	error = i2c_smbus_write_byte(client, CMD_PENTRG);
274 	if (error) {
275 		dev_err(&client->dev, "writing command CMD_PENTRG failed");
276 		return error;
277 	}
278 
279 	enable_irq(client->irq);
280 
281 	return 0;
282 }
283 
sx8654_close(struct input_dev * dev)284 static void sx8654_close(struct input_dev *dev)
285 {
286 	struct sx8654 *sx8654 = input_get_drvdata(dev);
287 	struct i2c_client *client = sx8654->client;
288 	int error;
289 
290 	disable_irq(client->irq);
291 
292 	if (!sx8654->data->has_irq_penrelease)
293 		del_timer_sync(&sx8654->timer);
294 
295 	/* enable manual mode mode */
296 	error = i2c_smbus_write_byte(client, sx8654->data->cmd_manual);
297 	if (error) {
298 		dev_err(&client->dev, "writing command CMD_MANUAL failed");
299 		return;
300 	}
301 
302 	error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH0, RATE_MANUAL);
303 	if (error) {
304 		dev_err(&client->dev, "writing to I2C_REG_TOUCH0 failed");
305 		return;
306 	}
307 }
308 
sx8654_probe(struct i2c_client * client)309 static int sx8654_probe(struct i2c_client *client)
310 {
311 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
312 	struct sx8654 *sx8654;
313 	struct input_dev *input;
314 	int error;
315 
316 	if (!i2c_check_functionality(client->adapter,
317 				     I2C_FUNC_SMBUS_READ_WORD_DATA))
318 		return -ENXIO;
319 
320 	sx8654 = devm_kzalloc(&client->dev, sizeof(*sx8654), GFP_KERNEL);
321 	if (!sx8654)
322 		return -ENOMEM;
323 
324 	sx8654->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
325 						     GPIOD_OUT_HIGH);
326 	if (IS_ERR(sx8654->gpio_reset))
327 		return dev_err_probe(&client->dev, PTR_ERR(sx8654->gpio_reset),
328 				     "unable to get reset-gpio\n");
329 	dev_dbg(&client->dev, "got GPIO reset pin\n");
330 
331 	sx8654->data = device_get_match_data(&client->dev);
332 	if (!sx8654->data)
333 		sx8654->data = (const struct sx865x_data *)id->driver_data;
334 	if (!sx8654->data) {
335 		dev_err(&client->dev, "invalid or missing device data\n");
336 		return -EINVAL;
337 	}
338 
339 	if (!sx8654->data->has_irq_penrelease) {
340 		dev_dbg(&client->dev, "use timer for penrelease\n");
341 		timer_setup(&sx8654->timer, sx865x_penrelease_timer_handler, 0);
342 		spin_lock_init(&sx8654->lock);
343 	}
344 
345 	input = devm_input_allocate_device(&client->dev);
346 	if (!input)
347 		return -ENOMEM;
348 
349 	input->name = "SX8654 I2C Touchscreen";
350 	input->id.bustype = BUS_I2C;
351 	input->dev.parent = &client->dev;
352 	input->open = sx8654_open;
353 	input->close = sx8654_close;
354 
355 	__set_bit(INPUT_PROP_DIRECT, input->propbit);
356 	input_set_capability(input, EV_KEY, BTN_TOUCH);
357 	input_set_abs_params(input, ABS_X, 0, MAX_12BIT, 0, 0);
358 	input_set_abs_params(input, ABS_Y, 0, MAX_12BIT, 0, 0);
359 
360 	touchscreen_parse_properties(input, false, &sx8654->props);
361 
362 	sx8654->client = client;
363 	sx8654->input = input;
364 
365 	input_set_drvdata(sx8654->input, sx8654);
366 
367 	error = sx8654_reset(sx8654);
368 	if (error) {
369 		dev_err(&client->dev, "reset failed");
370 		return error;
371 	}
372 
373 	error = i2c_smbus_write_byte_data(client, I2C_REG_CHANMASK,
374 					  sx8654->data->chan_mask);
375 	if (error) {
376 		dev_err(&client->dev, "writing to I2C_REG_CHANMASK failed");
377 		return error;
378 	}
379 
380 	if (sx8654->data->has_reg_irqmask) {
381 		error = i2c_smbus_write_byte_data(client, I2C_REG_IRQMASK,
382 						  IRQ_PENTOUCH_TOUCHCONVDONE |
383 							IRQ_PENRELEASE);
384 		if (error) {
385 			dev_err(&client->dev, "writing I2C_REG_IRQMASK failed");
386 			return error;
387 		}
388 	}
389 
390 	error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH1,
391 					  CONDIRQ | RPDNT_100K | FILT_7SA);
392 	if (error) {
393 		dev_err(&client->dev, "writing to I2C_REG_TOUCH1 failed");
394 		return error;
395 	}
396 
397 	error = devm_request_threaded_irq(&client->dev, client->irq,
398 					  NULL, sx8654->data->irqh,
399 					  IRQF_ONESHOT,
400 					  client->name, sx8654);
401 	if (error) {
402 		dev_err(&client->dev,
403 			"Failed to enable IRQ %d, error: %d\n",
404 			client->irq, error);
405 		return error;
406 	}
407 
408 	/* Disable the IRQ, we'll enable it in sx8654_open() */
409 	disable_irq(client->irq);
410 
411 	error = input_register_device(sx8654->input);
412 	if (error)
413 		return error;
414 
415 	return 0;
416 }
417 
418 static const struct sx865x_data sx8650_data = {
419 	.cmd_manual		= 0xb0,
420 	.has_irq_penrelease	= false,
421 	.has_reg_irqmask	= false,
422 	.chan_mask		= (CONV_X | CONV_Y),
423 	.irqh			= sx8650_irq,
424 };
425 
426 static const struct sx865x_data sx8654_data = {
427 	.cmd_manual		= 0xc0,
428 	.has_irq_penrelease	= true,
429 	.has_reg_irqmask	= true,
430 	.chan_mask		= (CONV_X | CONV_Y),
431 	.irqh			= sx8654_irq,
432 };
433 
434 #ifdef CONFIG_OF
435 static const struct of_device_id sx8654_of_match[] = {
436 	{
437 		.compatible = "semtech,sx8650",
438 		.data = &sx8650_data,
439 	}, {
440 		.compatible = "semtech,sx8654",
441 		.data = &sx8654_data,
442 	}, {
443 		.compatible = "semtech,sx8655",
444 		.data = &sx8654_data,
445 	}, {
446 		.compatible = "semtech,sx8656",
447 		.data = &sx8654_data,
448 	},
449 	{ }
450 };
451 MODULE_DEVICE_TABLE(of, sx8654_of_match);
452 #endif
453 
454 static const struct i2c_device_id sx8654_id_table[] = {
455 	{ .name = "semtech_sx8650", .driver_data = (long)&sx8650_data },
456 	{ .name = "semtech_sx8654", .driver_data = (long)&sx8654_data },
457 	{ .name = "semtech_sx8655", .driver_data = (long)&sx8654_data },
458 	{ .name = "semtech_sx8656", .driver_data = (long)&sx8654_data },
459 	{ }
460 };
461 MODULE_DEVICE_TABLE(i2c, sx8654_id_table);
462 
463 static struct i2c_driver sx8654_driver = {
464 	.driver = {
465 		.name = "sx8654",
466 		.of_match_table = of_match_ptr(sx8654_of_match),
467 	},
468 	.id_table = sx8654_id_table,
469 	.probe = sx8654_probe,
470 };
471 module_i2c_driver(sx8654_driver);
472 
473 MODULE_AUTHOR("Sébastien Szymanski <sebastien.szymanski@armadeus.com>");
474 MODULE_DESCRIPTION("Semtech SX8654 I2C Touchscreen Driver");
475 MODULE_LICENSE("GPL");
476