1 /*
2  * ADS7846 based touchscreen and sensor driver
3  *
4  * Copyright (c) 2005 David Brownell
5  * Copyright (c) 2006 Nokia Corporation
6  * Various changes: Imre Deak <imre.deak@nokia.com>
7  *
8  * Using code from:
9  *  - corgi_ts.c
10  *	Copyright (C) 2004-2005 Richard Purdie
11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
12  *	Copyright (C) 2002 MontaVista Software
13  *	Copyright (C) 2004 Texas Instruments
14  *	Copyright (C) 2005 Dirk Behme
15  *
16  *  This program is free software; you can redistribute it and/or modify
17  *  it under the terms of the GNU General Public License version 2 as
18  *  published by the Free Software Foundation.
19  */
20 #include <linux/types.h>
21 #include <linux/hwmon.h>
22 #include <linux/err.h>
23 #include <linux/sched.h>
24 #include <linux/delay.h>
25 #include <linux/input.h>
26 #include <linux/interrupt.h>
27 #include <linux/slab.h>
28 #include <linux/pm.h>
29 #include <linux/of.h>
30 #include <linux/of_gpio.h>
31 #include <linux/of_device.h>
32 #include <linux/gpio.h>
33 #include <linux/spi/spi.h>
34 #include <linux/spi/ads7846.h>
35 #include <linux/regulator/consumer.h>
36 #include <linux/module.h>
37 #include <asm/irq.h>
38 
39 /*
40  * This code has been heavily tested on a Nokia 770, and lightly
41  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
42  * TSC2046 is just newer ads7846 silicon.
43  * Support for ads7843 tested on Atmel at91sam926x-EK.
44  * Support for ads7845 has only been stubbed in.
45  * Support for Analog Devices AD7873 and AD7843 tested.
46  *
47  * IRQ handling needs a workaround because of a shortcoming in handling
48  * edge triggered IRQs on some platforms like the OMAP1/2. These
49  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
50  * have to maintain our own SW IRQ disabled status. This should be
51  * removed as soon as the affected platform's IRQ handling is fixed.
52  *
53  * App note sbaa036 talks in more detail about accurate sampling...
54  * that ought to help in situations like LCDs inducing noise (which
55  * can also be helped by using synch signals) and more generally.
56  * This driver tries to utilize the measures described in the app
57  * note. The strength of filtering can be set in the board-* specific
58  * files.
59  */
60 
61 #define TS_POLL_DELAY	1	/* ms delay before the first sample */
62 #define TS_POLL_PERIOD	5	/* ms delay between samples */
63 
64 /* this driver doesn't aim at the peak continuous sample rate */
65 #define	SAMPLE_BITS	(8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
66 
67 struct ts_event {
68 	/*
69 	 * For portability, we can't read 12 bit values using SPI (which
70 	 * would make the controller deliver them as native byte order u16
71 	 * with msbs zeroed).  Instead, we read them as two 8-bit values,
72 	 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
73 	 */
74 	u16	x;
75 	u16	y;
76 	u16	z1, z2;
77 	bool	ignore;
78 	u8	x_buf[3];
79 	u8	y_buf[3];
80 };
81 
82 /*
83  * We allocate this separately to avoid cache line sharing issues when
84  * driver is used with DMA-based SPI controllers (like atmel_spi) on
85  * systems where main memory is not DMA-coherent (most non-x86 boards).
86  */
87 struct ads7846_packet {
88 	u8			read_x, read_y, read_z1, read_z2, pwrdown;
89 	u16			dummy;		/* for the pwrdown read */
90 	struct ts_event		tc;
91 	/* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
92 	u8			read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
93 };
94 
95 struct ads7846 {
96 	struct input_dev	*input;
97 	char			phys[32];
98 	char			name[32];
99 
100 	struct spi_device	*spi;
101 	struct regulator	*reg;
102 
103 #if IS_ENABLED(CONFIG_HWMON)
104 	struct device		*hwmon;
105 #endif
106 
107 	u16			model;
108 	u16			vref_mv;
109 	u16			vref_delay_usecs;
110 	u16			x_plate_ohms;
111 	u16			pressure_max;
112 
113 	bool			swap_xy;
114 	bool			use_internal;
115 
116 	struct ads7846_packet	*packet;
117 
118 	struct spi_transfer	xfer[18];
119 	struct spi_message	msg[5];
120 	int			msg_count;
121 	wait_queue_head_t	wait;
122 
123 	bool			pendown;
124 
125 	int			read_cnt;
126 	int			read_rep;
127 	int			last_read;
128 
129 	u16			debounce_max;
130 	u16			debounce_tol;
131 	u16			debounce_rep;
132 
133 	u16			penirq_recheck_delay_usecs;
134 
135 	struct mutex		lock;
136 	bool			stopped;	/* P: lock */
137 	bool			disabled;	/* P: lock */
138 	bool			suspended;	/* P: lock */
139 
140 	int			(*filter)(void *data, int data_idx, int *val);
141 	void			*filter_data;
142 	void			(*filter_cleanup)(void *data);
143 	int			(*get_pendown_state)(void);
144 	int			gpio_pendown;
145 
146 	void			(*wait_for_sync)(void);
147 };
148 
149 /* leave chip selected when we're done, for quicker re-select? */
150 #if	0
151 #define	CS_CHANGE(xfer)	((xfer).cs_change = 1)
152 #else
153 #define	CS_CHANGE(xfer)	((xfer).cs_change = 0)
154 #endif
155 
156 /*--------------------------------------------------------------------------*/
157 
158 /* The ADS7846 has touchscreen and other sensors.
159  * Earlier ads784x chips are somewhat compatible.
160  */
161 #define	ADS_START		(1 << 7)
162 #define	ADS_A2A1A0_d_y		(1 << 4)	/* differential */
163 #define	ADS_A2A1A0_d_z1		(3 << 4)	/* differential */
164 #define	ADS_A2A1A0_d_z2		(4 << 4)	/* differential */
165 #define	ADS_A2A1A0_d_x		(5 << 4)	/* differential */
166 #define	ADS_A2A1A0_temp0	(0 << 4)	/* non-differential */
167 #define	ADS_A2A1A0_vbatt	(2 << 4)	/* non-differential */
168 #define	ADS_A2A1A0_vaux		(6 << 4)	/* non-differential */
169 #define	ADS_A2A1A0_temp1	(7 << 4)	/* non-differential */
170 #define	ADS_8_BIT		(1 << 3)
171 #define	ADS_12_BIT		(0 << 3)
172 #define	ADS_SER			(1 << 2)	/* non-differential */
173 #define	ADS_DFR			(0 << 2)	/* differential */
174 #define	ADS_PD10_PDOWN		(0 << 0)	/* low power mode + penirq */
175 #define	ADS_PD10_ADC_ON		(1 << 0)	/* ADC on */
176 #define	ADS_PD10_REF_ON		(2 << 0)	/* vREF on + penirq */
177 #define	ADS_PD10_ALL_ON		(3 << 0)	/* ADC + vREF on */
178 
179 #define	MAX_12BIT	((1<<12)-1)
180 
181 /* leave ADC powered up (disables penirq) between differential samples */
182 #define	READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
183 	| ADS_12_BIT | ADS_DFR | \
184 	(adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
185 
186 #define	READ_Y(vref)	(READ_12BIT_DFR(y,  1, vref))
187 #define	READ_Z1(vref)	(READ_12BIT_DFR(z1, 1, vref))
188 #define	READ_Z2(vref)	(READ_12BIT_DFR(z2, 1, vref))
189 
190 #define	READ_X(vref)	(READ_12BIT_DFR(x,  1, vref))
191 #define	PWRDOWN		(READ_12BIT_DFR(y,  0, 0))	/* LAST */
192 
193 /* single-ended samples need to first power up reference voltage;
194  * we leave both ADC and VREF powered
195  */
196 #define	READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
197 	| ADS_12_BIT | ADS_SER)
198 
199 #define	REF_ON	(READ_12BIT_DFR(x, 1, 1))
200 #define	REF_OFF	(READ_12BIT_DFR(y, 0, 0))
201 
202 /* Must be called with ts->lock held */
203 static void ads7846_stop(struct ads7846 *ts)
204 {
205 	if (!ts->disabled && !ts->suspended) {
206 		/* Signal IRQ thread to stop polling and disable the handler. */
207 		ts->stopped = true;
208 		mb();
209 		wake_up(&ts->wait);
210 		disable_irq(ts->spi->irq);
211 	}
212 }
213 
214 /* Must be called with ts->lock held */
215 static void ads7846_restart(struct ads7846 *ts)
216 {
217 	if (!ts->disabled && !ts->suspended) {
218 		/* Tell IRQ thread that it may poll the device. */
219 		ts->stopped = false;
220 		mb();
221 		enable_irq(ts->spi->irq);
222 	}
223 }
224 
225 /* Must be called with ts->lock held */
226 static void __ads7846_disable(struct ads7846 *ts)
227 {
228 	ads7846_stop(ts);
229 	regulator_disable(ts->reg);
230 
231 	/*
232 	 * We know the chip's in low power mode since we always
233 	 * leave it that way after every request
234 	 */
235 }
236 
237 /* Must be called with ts->lock held */
238 static void __ads7846_enable(struct ads7846 *ts)
239 {
240 	int error;
241 
242 	error = regulator_enable(ts->reg);
243 	if (error != 0)
244 		dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
245 
246 	ads7846_restart(ts);
247 }
248 
249 static void ads7846_disable(struct ads7846 *ts)
250 {
251 	mutex_lock(&ts->lock);
252 
253 	if (!ts->disabled) {
254 
255 		if  (!ts->suspended)
256 			__ads7846_disable(ts);
257 
258 		ts->disabled = true;
259 	}
260 
261 	mutex_unlock(&ts->lock);
262 }
263 
264 static void ads7846_enable(struct ads7846 *ts)
265 {
266 	mutex_lock(&ts->lock);
267 
268 	if (ts->disabled) {
269 
270 		ts->disabled = false;
271 
272 		if (!ts->suspended)
273 			__ads7846_enable(ts);
274 	}
275 
276 	mutex_unlock(&ts->lock);
277 }
278 
279 /*--------------------------------------------------------------------------*/
280 
281 /*
282  * Non-touchscreen sensors only use single-ended conversions.
283  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
284  * ads7846 lets that pin be unconnected, to use internal vREF.
285  */
286 
287 struct ser_req {
288 	u8			ref_on;
289 	u8			command;
290 	u8			ref_off;
291 	u16			scratch;
292 	struct spi_message	msg;
293 	struct spi_transfer	xfer[6];
294 	/*
295 	 * DMA (thus cache coherency maintenance) requires the
296 	 * transfer buffers to live in their own cache lines.
297 	 */
298 	__be16 sample ____cacheline_aligned;
299 };
300 
301 struct ads7845_ser_req {
302 	u8			command[3];
303 	struct spi_message	msg;
304 	struct spi_transfer	xfer[2];
305 	/*
306 	 * DMA (thus cache coherency maintenance) requires the
307 	 * transfer buffers to live in their own cache lines.
308 	 */
309 	u8 sample[3] ____cacheline_aligned;
310 };
311 
312 static int ads7846_read12_ser(struct device *dev, unsigned command)
313 {
314 	struct spi_device *spi = to_spi_device(dev);
315 	struct ads7846 *ts = dev_get_drvdata(dev);
316 	struct ser_req *req;
317 	int status;
318 
319 	req = kzalloc(sizeof *req, GFP_KERNEL);
320 	if (!req)
321 		return -ENOMEM;
322 
323 	spi_message_init(&req->msg);
324 
325 	/* maybe turn on internal vREF, and let it settle */
326 	if (ts->use_internal) {
327 		req->ref_on = REF_ON;
328 		req->xfer[0].tx_buf = &req->ref_on;
329 		req->xfer[0].len = 1;
330 		spi_message_add_tail(&req->xfer[0], &req->msg);
331 
332 		req->xfer[1].rx_buf = &req->scratch;
333 		req->xfer[1].len = 2;
334 
335 		/* for 1uF, settle for 800 usec; no cap, 100 usec.  */
336 		req->xfer[1].delay_usecs = ts->vref_delay_usecs;
337 		spi_message_add_tail(&req->xfer[1], &req->msg);
338 
339 		/* Enable reference voltage */
340 		command |= ADS_PD10_REF_ON;
341 	}
342 
343 	/* Enable ADC in every case */
344 	command |= ADS_PD10_ADC_ON;
345 
346 	/* take sample */
347 	req->command = (u8) command;
348 	req->xfer[2].tx_buf = &req->command;
349 	req->xfer[2].len = 1;
350 	spi_message_add_tail(&req->xfer[2], &req->msg);
351 
352 	req->xfer[3].rx_buf = &req->sample;
353 	req->xfer[3].len = 2;
354 	spi_message_add_tail(&req->xfer[3], &req->msg);
355 
356 	/* REVISIT:  take a few more samples, and compare ... */
357 
358 	/* converter in low power mode & enable PENIRQ */
359 	req->ref_off = PWRDOWN;
360 	req->xfer[4].tx_buf = &req->ref_off;
361 	req->xfer[4].len = 1;
362 	spi_message_add_tail(&req->xfer[4], &req->msg);
363 
364 	req->xfer[5].rx_buf = &req->scratch;
365 	req->xfer[5].len = 2;
366 	CS_CHANGE(req->xfer[5]);
367 	spi_message_add_tail(&req->xfer[5], &req->msg);
368 
369 	mutex_lock(&ts->lock);
370 	ads7846_stop(ts);
371 	status = spi_sync(spi, &req->msg);
372 	ads7846_restart(ts);
373 	mutex_unlock(&ts->lock);
374 
375 	if (status == 0) {
376 		/* on-wire is a must-ignore bit, a BE12 value, then padding */
377 		status = be16_to_cpu(req->sample);
378 		status = status >> 3;
379 		status &= 0x0fff;
380 	}
381 
382 	kfree(req);
383 	return status;
384 }
385 
386 static int ads7845_read12_ser(struct device *dev, unsigned command)
387 {
388 	struct spi_device *spi = to_spi_device(dev);
389 	struct ads7846 *ts = dev_get_drvdata(dev);
390 	struct ads7845_ser_req *req;
391 	int status;
392 
393 	req = kzalloc(sizeof *req, GFP_KERNEL);
394 	if (!req)
395 		return -ENOMEM;
396 
397 	spi_message_init(&req->msg);
398 
399 	req->command[0] = (u8) command;
400 	req->xfer[0].tx_buf = req->command;
401 	req->xfer[0].rx_buf = req->sample;
402 	req->xfer[0].len = 3;
403 	spi_message_add_tail(&req->xfer[0], &req->msg);
404 
405 	mutex_lock(&ts->lock);
406 	ads7846_stop(ts);
407 	status = spi_sync(spi, &req->msg);
408 	ads7846_restart(ts);
409 	mutex_unlock(&ts->lock);
410 
411 	if (status == 0) {
412 		/* BE12 value, then padding */
413 		status = be16_to_cpu(*((u16 *)&req->sample[1]));
414 		status = status >> 3;
415 		status &= 0x0fff;
416 	}
417 
418 	kfree(req);
419 	return status;
420 }
421 
422 #if IS_ENABLED(CONFIG_HWMON)
423 
424 #define SHOW(name, var, adjust) static ssize_t \
425 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
426 { \
427 	struct ads7846 *ts = dev_get_drvdata(dev); \
428 	ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
429 			READ_12BIT_SER(var)); \
430 	if (v < 0) \
431 		return v; \
432 	return sprintf(buf, "%u\n", adjust(ts, v)); \
433 } \
434 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
435 
436 
437 /* Sysfs conventions report temperatures in millidegrees Celsius.
438  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
439  * accuracy scheme without calibration data.  For now we won't try either;
440  * userspace sees raw sensor values, and must scale/calibrate appropriately.
441  */
442 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
443 {
444 	return v;
445 }
446 
447 SHOW(temp0, temp0, null_adjust)		/* temp1_input */
448 SHOW(temp1, temp1, null_adjust)		/* temp2_input */
449 
450 
451 /* sysfs conventions report voltages in millivolts.  We can convert voltages
452  * if we know vREF.  userspace may need to scale vAUX to match the board's
453  * external resistors; we assume that vBATT only uses the internal ones.
454  */
455 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
456 {
457 	unsigned retval = v;
458 
459 	/* external resistors may scale vAUX into 0..vREF */
460 	retval *= ts->vref_mv;
461 	retval = retval >> 12;
462 
463 	return retval;
464 }
465 
466 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
467 {
468 	unsigned retval = vaux_adjust(ts, v);
469 
470 	/* ads7846 has a resistor ladder to scale this signal down */
471 	if (ts->model == 7846)
472 		retval *= 4;
473 
474 	return retval;
475 }
476 
477 SHOW(in0_input, vaux, vaux_adjust)
478 SHOW(in1_input, vbatt, vbatt_adjust)
479 
480 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
481 				  int index)
482 {
483 	struct device *dev = container_of(kobj, struct device, kobj);
484 	struct ads7846 *ts = dev_get_drvdata(dev);
485 
486 	if (ts->model == 7843 && index < 2)	/* in0, in1 */
487 		return 0;
488 	if (ts->model == 7845 && index != 2)	/* in0 */
489 		return 0;
490 
491 	return attr->mode;
492 }
493 
494 static struct attribute *ads7846_attributes[] = {
495 	&dev_attr_temp0.attr,		/* 0 */
496 	&dev_attr_temp1.attr,		/* 1 */
497 	&dev_attr_in0_input.attr,	/* 2 */
498 	&dev_attr_in1_input.attr,	/* 3 */
499 	NULL,
500 };
501 
502 static struct attribute_group ads7846_attr_group = {
503 	.attrs = ads7846_attributes,
504 	.is_visible = ads7846_is_visible,
505 };
506 __ATTRIBUTE_GROUPS(ads7846_attr);
507 
508 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
509 {
510 	/* hwmon sensors need a reference voltage */
511 	switch (ts->model) {
512 	case 7846:
513 		if (!ts->vref_mv) {
514 			dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
515 			ts->vref_mv = 2500;
516 			ts->use_internal = true;
517 		}
518 		break;
519 	case 7845:
520 	case 7843:
521 		if (!ts->vref_mv) {
522 			dev_warn(&spi->dev,
523 				"external vREF for ADS%d not specified\n",
524 				ts->model);
525 			return 0;
526 		}
527 		break;
528 	}
529 
530 	ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
531 						      ts, ads7846_attr_groups);
532 	if (IS_ERR(ts->hwmon))
533 		return PTR_ERR(ts->hwmon);
534 
535 	return 0;
536 }
537 
538 static void ads784x_hwmon_unregister(struct spi_device *spi,
539 				     struct ads7846 *ts)
540 {
541 	if (ts->hwmon)
542 		hwmon_device_unregister(ts->hwmon);
543 }
544 
545 #else
546 static inline int ads784x_hwmon_register(struct spi_device *spi,
547 					 struct ads7846 *ts)
548 {
549 	return 0;
550 }
551 
552 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
553 					    struct ads7846 *ts)
554 {
555 }
556 #endif
557 
558 static ssize_t ads7846_pen_down_show(struct device *dev,
559 				     struct device_attribute *attr, char *buf)
560 {
561 	struct ads7846 *ts = dev_get_drvdata(dev);
562 
563 	return sprintf(buf, "%u\n", ts->pendown);
564 }
565 
566 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
567 
568 static ssize_t ads7846_disable_show(struct device *dev,
569 				     struct device_attribute *attr, char *buf)
570 {
571 	struct ads7846 *ts = dev_get_drvdata(dev);
572 
573 	return sprintf(buf, "%u\n", ts->disabled);
574 }
575 
576 static ssize_t ads7846_disable_store(struct device *dev,
577 				     struct device_attribute *attr,
578 				     const char *buf, size_t count)
579 {
580 	struct ads7846 *ts = dev_get_drvdata(dev);
581 	unsigned int i;
582 	int err;
583 
584 	err = kstrtouint(buf, 10, &i);
585 	if (err)
586 		return err;
587 
588 	if (i)
589 		ads7846_disable(ts);
590 	else
591 		ads7846_enable(ts);
592 
593 	return count;
594 }
595 
596 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
597 
598 static struct attribute *ads784x_attributes[] = {
599 	&dev_attr_pen_down.attr,
600 	&dev_attr_disable.attr,
601 	NULL,
602 };
603 
604 static struct attribute_group ads784x_attr_group = {
605 	.attrs = ads784x_attributes,
606 };
607 
608 /*--------------------------------------------------------------------------*/
609 
610 static int get_pendown_state(struct ads7846 *ts)
611 {
612 	if (ts->get_pendown_state)
613 		return ts->get_pendown_state();
614 
615 	return !gpio_get_value(ts->gpio_pendown);
616 }
617 
618 static void null_wait_for_sync(void)
619 {
620 }
621 
622 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
623 {
624 	struct ads7846 *ts = ads;
625 
626 	if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
627 		/* Start over collecting consistent readings. */
628 		ts->read_rep = 0;
629 		/*
630 		 * Repeat it, if this was the first read or the read
631 		 * wasn't consistent enough.
632 		 */
633 		if (ts->read_cnt < ts->debounce_max) {
634 			ts->last_read = *val;
635 			ts->read_cnt++;
636 			return ADS7846_FILTER_REPEAT;
637 		} else {
638 			/*
639 			 * Maximum number of debouncing reached and still
640 			 * not enough number of consistent readings. Abort
641 			 * the whole sample, repeat it in the next sampling
642 			 * period.
643 			 */
644 			ts->read_cnt = 0;
645 			return ADS7846_FILTER_IGNORE;
646 		}
647 	} else {
648 		if (++ts->read_rep > ts->debounce_rep) {
649 			/*
650 			 * Got a good reading for this coordinate,
651 			 * go for the next one.
652 			 */
653 			ts->read_cnt = 0;
654 			ts->read_rep = 0;
655 			return ADS7846_FILTER_OK;
656 		} else {
657 			/* Read more values that are consistent. */
658 			ts->read_cnt++;
659 			return ADS7846_FILTER_REPEAT;
660 		}
661 	}
662 }
663 
664 static int ads7846_no_filter(void *ads, int data_idx, int *val)
665 {
666 	return ADS7846_FILTER_OK;
667 }
668 
669 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
670 {
671 	struct spi_transfer *t =
672 		list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
673 
674 	if (ts->model == 7845) {
675 		return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
676 	} else {
677 		/*
678 		 * adjust:  on-wire is a must-ignore bit, a BE12 value, then
679 		 * padding; built from two 8 bit values written msb-first.
680 		 */
681 		return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
682 	}
683 }
684 
685 static void ads7846_update_value(struct spi_message *m, int val)
686 {
687 	struct spi_transfer *t =
688 		list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
689 
690 	*(u16 *)t->rx_buf = val;
691 }
692 
693 static void ads7846_read_state(struct ads7846 *ts)
694 {
695 	struct ads7846_packet *packet = ts->packet;
696 	struct spi_message *m;
697 	int msg_idx = 0;
698 	int val;
699 	int action;
700 	int error;
701 
702 	while (msg_idx < ts->msg_count) {
703 
704 		ts->wait_for_sync();
705 
706 		m = &ts->msg[msg_idx];
707 		error = spi_sync(ts->spi, m);
708 		if (error) {
709 			dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
710 			packet->tc.ignore = true;
711 			return;
712 		}
713 
714 		/*
715 		 * Last message is power down request, no need to convert
716 		 * or filter the value.
717 		 */
718 		if (msg_idx < ts->msg_count - 1) {
719 
720 			val = ads7846_get_value(ts, m);
721 
722 			action = ts->filter(ts->filter_data, msg_idx, &val);
723 			switch (action) {
724 			case ADS7846_FILTER_REPEAT:
725 				continue;
726 
727 			case ADS7846_FILTER_IGNORE:
728 				packet->tc.ignore = true;
729 				msg_idx = ts->msg_count - 1;
730 				continue;
731 
732 			case ADS7846_FILTER_OK:
733 				ads7846_update_value(m, val);
734 				packet->tc.ignore = false;
735 				msg_idx++;
736 				break;
737 
738 			default:
739 				BUG();
740 			}
741 		} else {
742 			msg_idx++;
743 		}
744 	}
745 }
746 
747 static void ads7846_report_state(struct ads7846 *ts)
748 {
749 	struct ads7846_packet *packet = ts->packet;
750 	unsigned int Rt;
751 	u16 x, y, z1, z2;
752 
753 	/*
754 	 * ads7846_get_value() does in-place conversion (including byte swap)
755 	 * from on-the-wire format as part of debouncing to get stable
756 	 * readings.
757 	 */
758 	if (ts->model == 7845) {
759 		x = *(u16 *)packet->tc.x_buf;
760 		y = *(u16 *)packet->tc.y_buf;
761 		z1 = 0;
762 		z2 = 0;
763 	} else {
764 		x = packet->tc.x;
765 		y = packet->tc.y;
766 		z1 = packet->tc.z1;
767 		z2 = packet->tc.z2;
768 	}
769 
770 	/* range filtering */
771 	if (x == MAX_12BIT)
772 		x = 0;
773 
774 	if (ts->model == 7843) {
775 		Rt = ts->pressure_max / 2;
776 	} else if (ts->model == 7845) {
777 		if (get_pendown_state(ts))
778 			Rt = ts->pressure_max / 2;
779 		else
780 			Rt = 0;
781 		dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
782 	} else if (likely(x && z1)) {
783 		/* compute touch pressure resistance using equation #2 */
784 		Rt = z2;
785 		Rt -= z1;
786 		Rt *= x;
787 		Rt *= ts->x_plate_ohms;
788 		Rt /= z1;
789 		Rt = (Rt + 2047) >> 12;
790 	} else {
791 		Rt = 0;
792 	}
793 
794 	/*
795 	 * Sample found inconsistent by debouncing or pressure is beyond
796 	 * the maximum. Don't report it to user space, repeat at least
797 	 * once more the measurement
798 	 */
799 	if (packet->tc.ignore || Rt > ts->pressure_max) {
800 		dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
801 			 packet->tc.ignore, Rt);
802 		return;
803 	}
804 
805 	/*
806 	 * Maybe check the pendown state before reporting. This discards
807 	 * false readings when the pen is lifted.
808 	 */
809 	if (ts->penirq_recheck_delay_usecs) {
810 		udelay(ts->penirq_recheck_delay_usecs);
811 		if (!get_pendown_state(ts))
812 			Rt = 0;
813 	}
814 
815 	/*
816 	 * NOTE: We can't rely on the pressure to determine the pen down
817 	 * state, even this controller has a pressure sensor. The pressure
818 	 * value can fluctuate for quite a while after lifting the pen and
819 	 * in some cases may not even settle at the expected value.
820 	 *
821 	 * The only safe way to check for the pen up condition is in the
822 	 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
823 	 */
824 	if (Rt) {
825 		struct input_dev *input = ts->input;
826 
827 		if (ts->swap_xy)
828 			swap(x, y);
829 
830 		if (!ts->pendown) {
831 			input_report_key(input, BTN_TOUCH, 1);
832 			ts->pendown = true;
833 			dev_vdbg(&ts->spi->dev, "DOWN\n");
834 		}
835 
836 		input_report_abs(input, ABS_X, x);
837 		input_report_abs(input, ABS_Y, y);
838 		input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
839 
840 		input_sync(input);
841 		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
842 	}
843 }
844 
845 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
846 {
847 	struct ads7846 *ts = handle;
848 
849 	return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
850 }
851 
852 
853 static irqreturn_t ads7846_irq(int irq, void *handle)
854 {
855 	struct ads7846 *ts = handle;
856 
857 	/* Start with a small delay before checking pendown state */
858 	msleep(TS_POLL_DELAY);
859 
860 	while (!ts->stopped && get_pendown_state(ts)) {
861 
862 		/* pen is down, continue with the measurement */
863 		ads7846_read_state(ts);
864 
865 		if (!ts->stopped)
866 			ads7846_report_state(ts);
867 
868 		wait_event_timeout(ts->wait, ts->stopped,
869 				   msecs_to_jiffies(TS_POLL_PERIOD));
870 	}
871 
872 	if (ts->pendown) {
873 		struct input_dev *input = ts->input;
874 
875 		input_report_key(input, BTN_TOUCH, 0);
876 		input_report_abs(input, ABS_PRESSURE, 0);
877 		input_sync(input);
878 
879 		ts->pendown = false;
880 		dev_vdbg(&ts->spi->dev, "UP\n");
881 	}
882 
883 	return IRQ_HANDLED;
884 }
885 
886 static int __maybe_unused ads7846_suspend(struct device *dev)
887 {
888 	struct ads7846 *ts = dev_get_drvdata(dev);
889 
890 	mutex_lock(&ts->lock);
891 
892 	if (!ts->suspended) {
893 
894 		if (!ts->disabled)
895 			__ads7846_disable(ts);
896 
897 		if (device_may_wakeup(&ts->spi->dev))
898 			enable_irq_wake(ts->spi->irq);
899 
900 		ts->suspended = true;
901 	}
902 
903 	mutex_unlock(&ts->lock);
904 
905 	return 0;
906 }
907 
908 static int __maybe_unused ads7846_resume(struct device *dev)
909 {
910 	struct ads7846 *ts = dev_get_drvdata(dev);
911 
912 	mutex_lock(&ts->lock);
913 
914 	if (ts->suspended) {
915 
916 		ts->suspended = false;
917 
918 		if (device_may_wakeup(&ts->spi->dev))
919 			disable_irq_wake(ts->spi->irq);
920 
921 		if (!ts->disabled)
922 			__ads7846_enable(ts);
923 	}
924 
925 	mutex_unlock(&ts->lock);
926 
927 	return 0;
928 }
929 
930 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
931 
932 static int ads7846_setup_pendown(struct spi_device *spi,
933 				 struct ads7846 *ts,
934 				 const struct ads7846_platform_data *pdata)
935 {
936 	int err;
937 
938 	/*
939 	 * REVISIT when the irq can be triggered active-low, or if for some
940 	 * reason the touchscreen isn't hooked up, we don't need to access
941 	 * the pendown state.
942 	 */
943 
944 	if (pdata->get_pendown_state) {
945 		ts->get_pendown_state = pdata->get_pendown_state;
946 	} else if (gpio_is_valid(pdata->gpio_pendown)) {
947 
948 		err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
949 				       "ads7846_pendown");
950 		if (err) {
951 			dev_err(&spi->dev,
952 				"failed to request/setup pendown GPIO%d: %d\n",
953 				pdata->gpio_pendown, err);
954 			return err;
955 		}
956 
957 		ts->gpio_pendown = pdata->gpio_pendown;
958 
959 		if (pdata->gpio_pendown_debounce)
960 			gpio_set_debounce(pdata->gpio_pendown,
961 					  pdata->gpio_pendown_debounce);
962 	} else {
963 		dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
964 		return -EINVAL;
965 	}
966 
967 	return 0;
968 }
969 
970 /*
971  * Set up the transfers to read touchscreen state; this assumes we
972  * use formula #2 for pressure, not #3.
973  */
974 static void ads7846_setup_spi_msg(struct ads7846 *ts,
975 				  const struct ads7846_platform_data *pdata)
976 {
977 	struct spi_message *m = &ts->msg[0];
978 	struct spi_transfer *x = ts->xfer;
979 	struct ads7846_packet *packet = ts->packet;
980 	int vref = pdata->keep_vref_on;
981 
982 	if (ts->model == 7873) {
983 		/*
984 		 * The AD7873 is almost identical to the ADS7846
985 		 * keep VREF off during differential/ratiometric
986 		 * conversion modes.
987 		 */
988 		ts->model = 7846;
989 		vref = 0;
990 	}
991 
992 	ts->msg_count = 1;
993 	spi_message_init(m);
994 	m->context = ts;
995 
996 	if (ts->model == 7845) {
997 		packet->read_y_cmd[0] = READ_Y(vref);
998 		packet->read_y_cmd[1] = 0;
999 		packet->read_y_cmd[2] = 0;
1000 		x->tx_buf = &packet->read_y_cmd[0];
1001 		x->rx_buf = &packet->tc.y_buf[0];
1002 		x->len = 3;
1003 		spi_message_add_tail(x, m);
1004 	} else {
1005 		/* y- still on; turn on only y+ (and ADC) */
1006 		packet->read_y = READ_Y(vref);
1007 		x->tx_buf = &packet->read_y;
1008 		x->len = 1;
1009 		spi_message_add_tail(x, m);
1010 
1011 		x++;
1012 		x->rx_buf = &packet->tc.y;
1013 		x->len = 2;
1014 		spi_message_add_tail(x, m);
1015 	}
1016 
1017 	/*
1018 	 * The first sample after switching drivers can be low quality;
1019 	 * optionally discard it, using a second one after the signals
1020 	 * have had enough time to stabilize.
1021 	 */
1022 	if (pdata->settle_delay_usecs) {
1023 		x->delay_usecs = pdata->settle_delay_usecs;
1024 
1025 		x++;
1026 		x->tx_buf = &packet->read_y;
1027 		x->len = 1;
1028 		spi_message_add_tail(x, m);
1029 
1030 		x++;
1031 		x->rx_buf = &packet->tc.y;
1032 		x->len = 2;
1033 		spi_message_add_tail(x, m);
1034 	}
1035 
1036 	ts->msg_count++;
1037 	m++;
1038 	spi_message_init(m);
1039 	m->context = ts;
1040 
1041 	if (ts->model == 7845) {
1042 		x++;
1043 		packet->read_x_cmd[0] = READ_X(vref);
1044 		packet->read_x_cmd[1] = 0;
1045 		packet->read_x_cmd[2] = 0;
1046 		x->tx_buf = &packet->read_x_cmd[0];
1047 		x->rx_buf = &packet->tc.x_buf[0];
1048 		x->len = 3;
1049 		spi_message_add_tail(x, m);
1050 	} else {
1051 		/* turn y- off, x+ on, then leave in lowpower */
1052 		x++;
1053 		packet->read_x = READ_X(vref);
1054 		x->tx_buf = &packet->read_x;
1055 		x->len = 1;
1056 		spi_message_add_tail(x, m);
1057 
1058 		x++;
1059 		x->rx_buf = &packet->tc.x;
1060 		x->len = 2;
1061 		spi_message_add_tail(x, m);
1062 	}
1063 
1064 	/* ... maybe discard first sample ... */
1065 	if (pdata->settle_delay_usecs) {
1066 		x->delay_usecs = pdata->settle_delay_usecs;
1067 
1068 		x++;
1069 		x->tx_buf = &packet->read_x;
1070 		x->len = 1;
1071 		spi_message_add_tail(x, m);
1072 
1073 		x++;
1074 		x->rx_buf = &packet->tc.x;
1075 		x->len = 2;
1076 		spi_message_add_tail(x, m);
1077 	}
1078 
1079 	/* turn y+ off, x- on; we'll use formula #2 */
1080 	if (ts->model == 7846) {
1081 		ts->msg_count++;
1082 		m++;
1083 		spi_message_init(m);
1084 		m->context = ts;
1085 
1086 		x++;
1087 		packet->read_z1 = READ_Z1(vref);
1088 		x->tx_buf = &packet->read_z1;
1089 		x->len = 1;
1090 		spi_message_add_tail(x, m);
1091 
1092 		x++;
1093 		x->rx_buf = &packet->tc.z1;
1094 		x->len = 2;
1095 		spi_message_add_tail(x, m);
1096 
1097 		/* ... maybe discard first sample ... */
1098 		if (pdata->settle_delay_usecs) {
1099 			x->delay_usecs = pdata->settle_delay_usecs;
1100 
1101 			x++;
1102 			x->tx_buf = &packet->read_z1;
1103 			x->len = 1;
1104 			spi_message_add_tail(x, m);
1105 
1106 			x++;
1107 			x->rx_buf = &packet->tc.z1;
1108 			x->len = 2;
1109 			spi_message_add_tail(x, m);
1110 		}
1111 
1112 		ts->msg_count++;
1113 		m++;
1114 		spi_message_init(m);
1115 		m->context = ts;
1116 
1117 		x++;
1118 		packet->read_z2 = READ_Z2(vref);
1119 		x->tx_buf = &packet->read_z2;
1120 		x->len = 1;
1121 		spi_message_add_tail(x, m);
1122 
1123 		x++;
1124 		x->rx_buf = &packet->tc.z2;
1125 		x->len = 2;
1126 		spi_message_add_tail(x, m);
1127 
1128 		/* ... maybe discard first sample ... */
1129 		if (pdata->settle_delay_usecs) {
1130 			x->delay_usecs = pdata->settle_delay_usecs;
1131 
1132 			x++;
1133 			x->tx_buf = &packet->read_z2;
1134 			x->len = 1;
1135 			spi_message_add_tail(x, m);
1136 
1137 			x++;
1138 			x->rx_buf = &packet->tc.z2;
1139 			x->len = 2;
1140 			spi_message_add_tail(x, m);
1141 		}
1142 	}
1143 
1144 	/* power down */
1145 	ts->msg_count++;
1146 	m++;
1147 	spi_message_init(m);
1148 	m->context = ts;
1149 
1150 	if (ts->model == 7845) {
1151 		x++;
1152 		packet->pwrdown_cmd[0] = PWRDOWN;
1153 		packet->pwrdown_cmd[1] = 0;
1154 		packet->pwrdown_cmd[2] = 0;
1155 		x->tx_buf = &packet->pwrdown_cmd[0];
1156 		x->len = 3;
1157 	} else {
1158 		x++;
1159 		packet->pwrdown = PWRDOWN;
1160 		x->tx_buf = &packet->pwrdown;
1161 		x->len = 1;
1162 		spi_message_add_tail(x, m);
1163 
1164 		x++;
1165 		x->rx_buf = &packet->dummy;
1166 		x->len = 2;
1167 	}
1168 
1169 	CS_CHANGE(*x);
1170 	spi_message_add_tail(x, m);
1171 }
1172 
1173 #ifdef CONFIG_OF
1174 static const struct of_device_id ads7846_dt_ids[] = {
1175 	{ .compatible = "ti,tsc2046",	.data = (void *) 7846 },
1176 	{ .compatible = "ti,ads7843",	.data = (void *) 7843 },
1177 	{ .compatible = "ti,ads7845",	.data = (void *) 7845 },
1178 	{ .compatible = "ti,ads7846",	.data = (void *) 7846 },
1179 	{ .compatible = "ti,ads7873",	.data = (void *) 7873 },
1180 	{ }
1181 };
1182 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1183 
1184 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1185 {
1186 	struct ads7846_platform_data *pdata;
1187 	struct device_node *node = dev->of_node;
1188 	const struct of_device_id *match;
1189 
1190 	if (!node) {
1191 		dev_err(dev, "Device does not have associated DT data\n");
1192 		return ERR_PTR(-EINVAL);
1193 	}
1194 
1195 	match = of_match_device(ads7846_dt_ids, dev);
1196 	if (!match) {
1197 		dev_err(dev, "Unknown device model\n");
1198 		return ERR_PTR(-EINVAL);
1199 	}
1200 
1201 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1202 	if (!pdata)
1203 		return ERR_PTR(-ENOMEM);
1204 
1205 	pdata->model = (unsigned long)match->data;
1206 
1207 	of_property_read_u16(node, "ti,vref-delay-usecs",
1208 			     &pdata->vref_delay_usecs);
1209 	of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1210 	pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1211 
1212 	pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1213 
1214 	of_property_read_u16(node, "ti,settle-delay-usec",
1215 			     &pdata->settle_delay_usecs);
1216 	of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1217 			     &pdata->penirq_recheck_delay_usecs);
1218 
1219 	of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1220 	of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1221 
1222 	of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1223 	of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1224 	of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1225 	of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1226 
1227 	of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1228 	of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1229 
1230 	of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1231 	of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1232 	of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1233 
1234 	of_property_read_u32(node, "ti,pendown-gpio-debounce",
1235 			     &pdata->gpio_pendown_debounce);
1236 
1237 	pdata->wakeup = of_property_read_bool(node, "linux,wakeup");
1238 
1239 	pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1240 
1241 	return pdata;
1242 }
1243 #else
1244 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1245 {
1246 	dev_err(dev, "no platform data defined\n");
1247 	return ERR_PTR(-EINVAL);
1248 }
1249 #endif
1250 
1251 static int ads7846_probe(struct spi_device *spi)
1252 {
1253 	const struct ads7846_platform_data *pdata;
1254 	struct ads7846 *ts;
1255 	struct ads7846_packet *packet;
1256 	struct input_dev *input_dev;
1257 	unsigned long irq_flags;
1258 	int err;
1259 
1260 	if (!spi->irq) {
1261 		dev_dbg(&spi->dev, "no IRQ?\n");
1262 		return -EINVAL;
1263 	}
1264 
1265 	/* don't exceed max specified sample rate */
1266 	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1267 		dev_err(&spi->dev, "f(sample) %d KHz?\n",
1268 				(spi->max_speed_hz/SAMPLE_BITS)/1000);
1269 		return -EINVAL;
1270 	}
1271 
1272 	/*
1273 	 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1274 	 * that even if the hardware can do that, the SPI controller driver
1275 	 * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1276 	 */
1277 	spi->bits_per_word = 8;
1278 	spi->mode = SPI_MODE_0;
1279 	err = spi_setup(spi);
1280 	if (err < 0)
1281 		return err;
1282 
1283 	ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1284 	packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1285 	input_dev = input_allocate_device();
1286 	if (!ts || !packet || !input_dev) {
1287 		err = -ENOMEM;
1288 		goto err_free_mem;
1289 	}
1290 
1291 	spi_set_drvdata(spi, ts);
1292 
1293 	ts->packet = packet;
1294 	ts->spi = spi;
1295 	ts->input = input_dev;
1296 
1297 	mutex_init(&ts->lock);
1298 	init_waitqueue_head(&ts->wait);
1299 
1300 	pdata = dev_get_platdata(&spi->dev);
1301 	if (!pdata) {
1302 		pdata = ads7846_probe_dt(&spi->dev);
1303 		if (IS_ERR(pdata)) {
1304 			err = PTR_ERR(pdata);
1305 			goto err_free_mem;
1306 		}
1307 	}
1308 
1309 	ts->model = pdata->model ? : 7846;
1310 	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1311 	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1312 	ts->pressure_max = pdata->pressure_max ? : ~0;
1313 
1314 	ts->vref_mv = pdata->vref_mv;
1315 	ts->swap_xy = pdata->swap_xy;
1316 
1317 	if (pdata->filter != NULL) {
1318 		if (pdata->filter_init != NULL) {
1319 			err = pdata->filter_init(pdata, &ts->filter_data);
1320 			if (err < 0)
1321 				goto err_free_mem;
1322 		}
1323 		ts->filter = pdata->filter;
1324 		ts->filter_cleanup = pdata->filter_cleanup;
1325 	} else if (pdata->debounce_max) {
1326 		ts->debounce_max = pdata->debounce_max;
1327 		if (ts->debounce_max < 2)
1328 			ts->debounce_max = 2;
1329 		ts->debounce_tol = pdata->debounce_tol;
1330 		ts->debounce_rep = pdata->debounce_rep;
1331 		ts->filter = ads7846_debounce_filter;
1332 		ts->filter_data = ts;
1333 	} else {
1334 		ts->filter = ads7846_no_filter;
1335 	}
1336 
1337 	err = ads7846_setup_pendown(spi, ts, pdata);
1338 	if (err)
1339 		goto err_cleanup_filter;
1340 
1341 	if (pdata->penirq_recheck_delay_usecs)
1342 		ts->penirq_recheck_delay_usecs =
1343 				pdata->penirq_recheck_delay_usecs;
1344 
1345 	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1346 
1347 	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1348 	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1349 
1350 	input_dev->name = ts->name;
1351 	input_dev->phys = ts->phys;
1352 	input_dev->dev.parent = &spi->dev;
1353 
1354 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1355 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1356 	input_set_abs_params(input_dev, ABS_X,
1357 			pdata->x_min ? : 0,
1358 			pdata->x_max ? : MAX_12BIT,
1359 			0, 0);
1360 	input_set_abs_params(input_dev, ABS_Y,
1361 			pdata->y_min ? : 0,
1362 			pdata->y_max ? : MAX_12BIT,
1363 			0, 0);
1364 	input_set_abs_params(input_dev, ABS_PRESSURE,
1365 			pdata->pressure_min, pdata->pressure_max, 0, 0);
1366 
1367 	ads7846_setup_spi_msg(ts, pdata);
1368 
1369 	ts->reg = regulator_get(&spi->dev, "vcc");
1370 	if (IS_ERR(ts->reg)) {
1371 		err = PTR_ERR(ts->reg);
1372 		dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1373 		goto err_free_gpio;
1374 	}
1375 
1376 	err = regulator_enable(ts->reg);
1377 	if (err) {
1378 		dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1379 		goto err_put_regulator;
1380 	}
1381 
1382 	irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1383 	irq_flags |= IRQF_ONESHOT;
1384 
1385 	err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1386 				   irq_flags, spi->dev.driver->name, ts);
1387 	if (err && !pdata->irq_flags) {
1388 		dev_info(&spi->dev,
1389 			"trying pin change workaround on irq %d\n", spi->irq);
1390 		irq_flags |= IRQF_TRIGGER_RISING;
1391 		err = request_threaded_irq(spi->irq,
1392 				  ads7846_hard_irq, ads7846_irq,
1393 				  irq_flags, spi->dev.driver->name, ts);
1394 	}
1395 
1396 	if (err) {
1397 		dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1398 		goto err_disable_regulator;
1399 	}
1400 
1401 	err = ads784x_hwmon_register(spi, ts);
1402 	if (err)
1403 		goto err_free_irq;
1404 
1405 	dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1406 
1407 	/*
1408 	 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1409 	 * the touchscreen, in case it's not connected.
1410 	 */
1411 	if (ts->model == 7845)
1412 		ads7845_read12_ser(&spi->dev, PWRDOWN);
1413 	else
1414 		(void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1415 
1416 	err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1417 	if (err)
1418 		goto err_remove_hwmon;
1419 
1420 	err = input_register_device(input_dev);
1421 	if (err)
1422 		goto err_remove_attr_group;
1423 
1424 	device_init_wakeup(&spi->dev, pdata->wakeup);
1425 
1426 	/*
1427 	 * If device does not carry platform data we must have allocated it
1428 	 * when parsing DT data.
1429 	 */
1430 	if (!dev_get_platdata(&spi->dev))
1431 		devm_kfree(&spi->dev, (void *)pdata);
1432 
1433 	return 0;
1434 
1435  err_remove_attr_group:
1436 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1437  err_remove_hwmon:
1438 	ads784x_hwmon_unregister(spi, ts);
1439  err_free_irq:
1440 	free_irq(spi->irq, ts);
1441  err_disable_regulator:
1442 	regulator_disable(ts->reg);
1443  err_put_regulator:
1444 	regulator_put(ts->reg);
1445  err_free_gpio:
1446 	if (!ts->get_pendown_state)
1447 		gpio_free(ts->gpio_pendown);
1448  err_cleanup_filter:
1449 	if (ts->filter_cleanup)
1450 		ts->filter_cleanup(ts->filter_data);
1451  err_free_mem:
1452 	input_free_device(input_dev);
1453 	kfree(packet);
1454 	kfree(ts);
1455 	return err;
1456 }
1457 
1458 static int ads7846_remove(struct spi_device *spi)
1459 {
1460 	struct ads7846 *ts = spi_get_drvdata(spi);
1461 
1462 	device_init_wakeup(&spi->dev, false);
1463 
1464 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1465 
1466 	ads7846_disable(ts);
1467 	free_irq(ts->spi->irq, ts);
1468 
1469 	input_unregister_device(ts->input);
1470 
1471 	ads784x_hwmon_unregister(spi, ts);
1472 
1473 	regulator_disable(ts->reg);
1474 	regulator_put(ts->reg);
1475 
1476 	if (!ts->get_pendown_state) {
1477 		/*
1478 		 * If we are not using specialized pendown method we must
1479 		 * have been relying on gpio we set up ourselves.
1480 		 */
1481 		gpio_free(ts->gpio_pendown);
1482 	}
1483 
1484 	if (ts->filter_cleanup)
1485 		ts->filter_cleanup(ts->filter_data);
1486 
1487 	kfree(ts->packet);
1488 	kfree(ts);
1489 
1490 	dev_dbg(&spi->dev, "unregistered touchscreen\n");
1491 
1492 	return 0;
1493 }
1494 
1495 static struct spi_driver ads7846_driver = {
1496 	.driver = {
1497 		.name	= "ads7846",
1498 		.owner	= THIS_MODULE,
1499 		.pm	= &ads7846_pm,
1500 		.of_match_table = of_match_ptr(ads7846_dt_ids),
1501 	},
1502 	.probe		= ads7846_probe,
1503 	.remove		= ads7846_remove,
1504 };
1505 
1506 module_spi_driver(ads7846_driver);
1507 
1508 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1509 MODULE_LICENSE("GPL");
1510 MODULE_ALIAS("spi:ads7846");
1511