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 const 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 
533 	return PTR_ERR_OR_ZERO(ts->hwmon);
534 }
535 
536 static void ads784x_hwmon_unregister(struct spi_device *spi,
537 				     struct ads7846 *ts)
538 {
539 	if (ts->hwmon)
540 		hwmon_device_unregister(ts->hwmon);
541 }
542 
543 #else
544 static inline int ads784x_hwmon_register(struct spi_device *spi,
545 					 struct ads7846 *ts)
546 {
547 	return 0;
548 }
549 
550 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
551 					    struct ads7846 *ts)
552 {
553 }
554 #endif
555 
556 static ssize_t ads7846_pen_down_show(struct device *dev,
557 				     struct device_attribute *attr, char *buf)
558 {
559 	struct ads7846 *ts = dev_get_drvdata(dev);
560 
561 	return sprintf(buf, "%u\n", ts->pendown);
562 }
563 
564 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
565 
566 static ssize_t ads7846_disable_show(struct device *dev,
567 				     struct device_attribute *attr, char *buf)
568 {
569 	struct ads7846 *ts = dev_get_drvdata(dev);
570 
571 	return sprintf(buf, "%u\n", ts->disabled);
572 }
573 
574 static ssize_t ads7846_disable_store(struct device *dev,
575 				     struct device_attribute *attr,
576 				     const char *buf, size_t count)
577 {
578 	struct ads7846 *ts = dev_get_drvdata(dev);
579 	unsigned int i;
580 	int err;
581 
582 	err = kstrtouint(buf, 10, &i);
583 	if (err)
584 		return err;
585 
586 	if (i)
587 		ads7846_disable(ts);
588 	else
589 		ads7846_enable(ts);
590 
591 	return count;
592 }
593 
594 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
595 
596 static struct attribute *ads784x_attributes[] = {
597 	&dev_attr_pen_down.attr,
598 	&dev_attr_disable.attr,
599 	NULL,
600 };
601 
602 static const struct attribute_group ads784x_attr_group = {
603 	.attrs = ads784x_attributes,
604 };
605 
606 /*--------------------------------------------------------------------------*/
607 
608 static int get_pendown_state(struct ads7846 *ts)
609 {
610 	if (ts->get_pendown_state)
611 		return ts->get_pendown_state();
612 
613 	return !gpio_get_value(ts->gpio_pendown);
614 }
615 
616 static void null_wait_for_sync(void)
617 {
618 }
619 
620 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
621 {
622 	struct ads7846 *ts = ads;
623 
624 	if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
625 		/* Start over collecting consistent readings. */
626 		ts->read_rep = 0;
627 		/*
628 		 * Repeat it, if this was the first read or the read
629 		 * wasn't consistent enough.
630 		 */
631 		if (ts->read_cnt < ts->debounce_max) {
632 			ts->last_read = *val;
633 			ts->read_cnt++;
634 			return ADS7846_FILTER_REPEAT;
635 		} else {
636 			/*
637 			 * Maximum number of debouncing reached and still
638 			 * not enough number of consistent readings. Abort
639 			 * the whole sample, repeat it in the next sampling
640 			 * period.
641 			 */
642 			ts->read_cnt = 0;
643 			return ADS7846_FILTER_IGNORE;
644 		}
645 	} else {
646 		if (++ts->read_rep > ts->debounce_rep) {
647 			/*
648 			 * Got a good reading for this coordinate,
649 			 * go for the next one.
650 			 */
651 			ts->read_cnt = 0;
652 			ts->read_rep = 0;
653 			return ADS7846_FILTER_OK;
654 		} else {
655 			/* Read more values that are consistent. */
656 			ts->read_cnt++;
657 			return ADS7846_FILTER_REPEAT;
658 		}
659 	}
660 }
661 
662 static int ads7846_no_filter(void *ads, int data_idx, int *val)
663 {
664 	return ADS7846_FILTER_OK;
665 }
666 
667 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
668 {
669 	int value;
670 	struct spi_transfer *t =
671 		list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
672 
673 	if (ts->model == 7845) {
674 		value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
675 	} else {
676 		/*
677 		 * adjust:  on-wire is a must-ignore bit, a BE12 value, then
678 		 * padding; built from two 8 bit values written msb-first.
679 		 */
680 		value = be16_to_cpup((__be16 *)t->rx_buf);
681 	}
682 
683 	/* enforce ADC output is 12 bits width */
684 	return (value >> 3) & 0xfff;
685 }
686 
687 static void ads7846_update_value(struct spi_message *m, int val)
688 {
689 	struct spi_transfer *t =
690 		list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
691 
692 	*(u16 *)t->rx_buf = val;
693 }
694 
695 static void ads7846_read_state(struct ads7846 *ts)
696 {
697 	struct ads7846_packet *packet = ts->packet;
698 	struct spi_message *m;
699 	int msg_idx = 0;
700 	int val;
701 	int action;
702 	int error;
703 
704 	while (msg_idx < ts->msg_count) {
705 
706 		ts->wait_for_sync();
707 
708 		m = &ts->msg[msg_idx];
709 		error = spi_sync(ts->spi, m);
710 		if (error) {
711 			dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
712 			packet->tc.ignore = true;
713 			return;
714 		}
715 
716 		/*
717 		 * Last message is power down request, no need to convert
718 		 * or filter the value.
719 		 */
720 		if (msg_idx < ts->msg_count - 1) {
721 
722 			val = ads7846_get_value(ts, m);
723 
724 			action = ts->filter(ts->filter_data, msg_idx, &val);
725 			switch (action) {
726 			case ADS7846_FILTER_REPEAT:
727 				continue;
728 
729 			case ADS7846_FILTER_IGNORE:
730 				packet->tc.ignore = true;
731 				msg_idx = ts->msg_count - 1;
732 				continue;
733 
734 			case ADS7846_FILTER_OK:
735 				ads7846_update_value(m, val);
736 				packet->tc.ignore = false;
737 				msg_idx++;
738 				break;
739 
740 			default:
741 				BUG();
742 			}
743 		} else {
744 			msg_idx++;
745 		}
746 	}
747 }
748 
749 static void ads7846_report_state(struct ads7846 *ts)
750 {
751 	struct ads7846_packet *packet = ts->packet;
752 	unsigned int Rt;
753 	u16 x, y, z1, z2;
754 
755 	/*
756 	 * ads7846_get_value() does in-place conversion (including byte swap)
757 	 * from on-the-wire format as part of debouncing to get stable
758 	 * readings.
759 	 */
760 	if (ts->model == 7845) {
761 		x = *(u16 *)packet->tc.x_buf;
762 		y = *(u16 *)packet->tc.y_buf;
763 		z1 = 0;
764 		z2 = 0;
765 	} else {
766 		x = packet->tc.x;
767 		y = packet->tc.y;
768 		z1 = packet->tc.z1;
769 		z2 = packet->tc.z2;
770 	}
771 
772 	/* range filtering */
773 	if (x == MAX_12BIT)
774 		x = 0;
775 
776 	if (ts->model == 7843) {
777 		Rt = ts->pressure_max / 2;
778 	} else if (ts->model == 7845) {
779 		if (get_pendown_state(ts))
780 			Rt = ts->pressure_max / 2;
781 		else
782 			Rt = 0;
783 		dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
784 	} else if (likely(x && z1)) {
785 		/* compute touch pressure resistance using equation #2 */
786 		Rt = z2;
787 		Rt -= z1;
788 		Rt *= x;
789 		Rt *= ts->x_plate_ohms;
790 		Rt /= z1;
791 		Rt = (Rt + 2047) >> 12;
792 	} else {
793 		Rt = 0;
794 	}
795 
796 	/*
797 	 * Sample found inconsistent by debouncing or pressure is beyond
798 	 * the maximum. Don't report it to user space, repeat at least
799 	 * once more the measurement
800 	 */
801 	if (packet->tc.ignore || Rt > ts->pressure_max) {
802 		dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
803 			 packet->tc.ignore, Rt);
804 		return;
805 	}
806 
807 	/*
808 	 * Maybe check the pendown state before reporting. This discards
809 	 * false readings when the pen is lifted.
810 	 */
811 	if (ts->penirq_recheck_delay_usecs) {
812 		udelay(ts->penirq_recheck_delay_usecs);
813 		if (!get_pendown_state(ts))
814 			Rt = 0;
815 	}
816 
817 	/*
818 	 * NOTE: We can't rely on the pressure to determine the pen down
819 	 * state, even this controller has a pressure sensor. The pressure
820 	 * value can fluctuate for quite a while after lifting the pen and
821 	 * in some cases may not even settle at the expected value.
822 	 *
823 	 * The only safe way to check for the pen up condition is in the
824 	 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
825 	 */
826 	if (Rt) {
827 		struct input_dev *input = ts->input;
828 
829 		if (ts->swap_xy)
830 			swap(x, y);
831 
832 		if (!ts->pendown) {
833 			input_report_key(input, BTN_TOUCH, 1);
834 			ts->pendown = true;
835 			dev_vdbg(&ts->spi->dev, "DOWN\n");
836 		}
837 
838 		input_report_abs(input, ABS_X, x);
839 		input_report_abs(input, ABS_Y, y);
840 		input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
841 
842 		input_sync(input);
843 		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
844 	}
845 }
846 
847 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
848 {
849 	struct ads7846 *ts = handle;
850 
851 	return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
852 }
853 
854 
855 static irqreturn_t ads7846_irq(int irq, void *handle)
856 {
857 	struct ads7846 *ts = handle;
858 
859 	/* Start with a small delay before checking pendown state */
860 	msleep(TS_POLL_DELAY);
861 
862 	while (!ts->stopped && get_pendown_state(ts)) {
863 
864 		/* pen is down, continue with the measurement */
865 		ads7846_read_state(ts);
866 
867 		if (!ts->stopped)
868 			ads7846_report_state(ts);
869 
870 		wait_event_timeout(ts->wait, ts->stopped,
871 				   msecs_to_jiffies(TS_POLL_PERIOD));
872 	}
873 
874 	if (ts->pendown && !ts->stopped) {
875 		struct input_dev *input = ts->input;
876 
877 		input_report_key(input, BTN_TOUCH, 0);
878 		input_report_abs(input, ABS_PRESSURE, 0);
879 		input_sync(input);
880 
881 		ts->pendown = false;
882 		dev_vdbg(&ts->spi->dev, "UP\n");
883 	}
884 
885 	return IRQ_HANDLED;
886 }
887 
888 static int __maybe_unused ads7846_suspend(struct device *dev)
889 {
890 	struct ads7846 *ts = dev_get_drvdata(dev);
891 
892 	mutex_lock(&ts->lock);
893 
894 	if (!ts->suspended) {
895 
896 		if (!ts->disabled)
897 			__ads7846_disable(ts);
898 
899 		if (device_may_wakeup(&ts->spi->dev))
900 			enable_irq_wake(ts->spi->irq);
901 
902 		ts->suspended = true;
903 	}
904 
905 	mutex_unlock(&ts->lock);
906 
907 	return 0;
908 }
909 
910 static int __maybe_unused ads7846_resume(struct device *dev)
911 {
912 	struct ads7846 *ts = dev_get_drvdata(dev);
913 
914 	mutex_lock(&ts->lock);
915 
916 	if (ts->suspended) {
917 
918 		ts->suspended = false;
919 
920 		if (device_may_wakeup(&ts->spi->dev))
921 			disable_irq_wake(ts->spi->irq);
922 
923 		if (!ts->disabled)
924 			__ads7846_enable(ts);
925 	}
926 
927 	mutex_unlock(&ts->lock);
928 
929 	return 0;
930 }
931 
932 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
933 
934 static int ads7846_setup_pendown(struct spi_device *spi,
935 				 struct ads7846 *ts,
936 				 const struct ads7846_platform_data *pdata)
937 {
938 	int err;
939 
940 	/*
941 	 * REVISIT when the irq can be triggered active-low, or if for some
942 	 * reason the touchscreen isn't hooked up, we don't need to access
943 	 * the pendown state.
944 	 */
945 
946 	if (pdata->get_pendown_state) {
947 		ts->get_pendown_state = pdata->get_pendown_state;
948 	} else if (gpio_is_valid(pdata->gpio_pendown)) {
949 
950 		err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
951 				       "ads7846_pendown");
952 		if (err) {
953 			dev_err(&spi->dev,
954 				"failed to request/setup pendown GPIO%d: %d\n",
955 				pdata->gpio_pendown, err);
956 			return err;
957 		}
958 
959 		ts->gpio_pendown = pdata->gpio_pendown;
960 
961 		if (pdata->gpio_pendown_debounce)
962 			gpio_set_debounce(pdata->gpio_pendown,
963 					  pdata->gpio_pendown_debounce);
964 	} else {
965 		dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
966 		return -EINVAL;
967 	}
968 
969 	return 0;
970 }
971 
972 /*
973  * Set up the transfers to read touchscreen state; this assumes we
974  * use formula #2 for pressure, not #3.
975  */
976 static void ads7846_setup_spi_msg(struct ads7846 *ts,
977 				  const struct ads7846_platform_data *pdata)
978 {
979 	struct spi_message *m = &ts->msg[0];
980 	struct spi_transfer *x = ts->xfer;
981 	struct ads7846_packet *packet = ts->packet;
982 	int vref = pdata->keep_vref_on;
983 
984 	if (ts->model == 7873) {
985 		/*
986 		 * The AD7873 is almost identical to the ADS7846
987 		 * keep VREF off during differential/ratiometric
988 		 * conversion modes.
989 		 */
990 		ts->model = 7846;
991 		vref = 0;
992 	}
993 
994 	ts->msg_count = 1;
995 	spi_message_init(m);
996 	m->context = ts;
997 
998 	if (ts->model == 7845) {
999 		packet->read_y_cmd[0] = READ_Y(vref);
1000 		packet->read_y_cmd[1] = 0;
1001 		packet->read_y_cmd[2] = 0;
1002 		x->tx_buf = &packet->read_y_cmd[0];
1003 		x->rx_buf = &packet->tc.y_buf[0];
1004 		x->len = 3;
1005 		spi_message_add_tail(x, m);
1006 	} else {
1007 		/* y- still on; turn on only y+ (and ADC) */
1008 		packet->read_y = READ_Y(vref);
1009 		x->tx_buf = &packet->read_y;
1010 		x->len = 1;
1011 		spi_message_add_tail(x, m);
1012 
1013 		x++;
1014 		x->rx_buf = &packet->tc.y;
1015 		x->len = 2;
1016 		spi_message_add_tail(x, m);
1017 	}
1018 
1019 	/*
1020 	 * The first sample after switching drivers can be low quality;
1021 	 * optionally discard it, using a second one after the signals
1022 	 * have had enough time to stabilize.
1023 	 */
1024 	if (pdata->settle_delay_usecs) {
1025 		x->delay_usecs = pdata->settle_delay_usecs;
1026 
1027 		x++;
1028 		x->tx_buf = &packet->read_y;
1029 		x->len = 1;
1030 		spi_message_add_tail(x, m);
1031 
1032 		x++;
1033 		x->rx_buf = &packet->tc.y;
1034 		x->len = 2;
1035 		spi_message_add_tail(x, m);
1036 	}
1037 
1038 	ts->msg_count++;
1039 	m++;
1040 	spi_message_init(m);
1041 	m->context = ts;
1042 
1043 	if (ts->model == 7845) {
1044 		x++;
1045 		packet->read_x_cmd[0] = READ_X(vref);
1046 		packet->read_x_cmd[1] = 0;
1047 		packet->read_x_cmd[2] = 0;
1048 		x->tx_buf = &packet->read_x_cmd[0];
1049 		x->rx_buf = &packet->tc.x_buf[0];
1050 		x->len = 3;
1051 		spi_message_add_tail(x, m);
1052 	} else {
1053 		/* turn y- off, x+ on, then leave in lowpower */
1054 		x++;
1055 		packet->read_x = READ_X(vref);
1056 		x->tx_buf = &packet->read_x;
1057 		x->len = 1;
1058 		spi_message_add_tail(x, m);
1059 
1060 		x++;
1061 		x->rx_buf = &packet->tc.x;
1062 		x->len = 2;
1063 		spi_message_add_tail(x, m);
1064 	}
1065 
1066 	/* ... maybe discard first sample ... */
1067 	if (pdata->settle_delay_usecs) {
1068 		x->delay_usecs = pdata->settle_delay_usecs;
1069 
1070 		x++;
1071 		x->tx_buf = &packet->read_x;
1072 		x->len = 1;
1073 		spi_message_add_tail(x, m);
1074 
1075 		x++;
1076 		x->rx_buf = &packet->tc.x;
1077 		x->len = 2;
1078 		spi_message_add_tail(x, m);
1079 	}
1080 
1081 	/* turn y+ off, x- on; we'll use formula #2 */
1082 	if (ts->model == 7846) {
1083 		ts->msg_count++;
1084 		m++;
1085 		spi_message_init(m);
1086 		m->context = ts;
1087 
1088 		x++;
1089 		packet->read_z1 = READ_Z1(vref);
1090 		x->tx_buf = &packet->read_z1;
1091 		x->len = 1;
1092 		spi_message_add_tail(x, m);
1093 
1094 		x++;
1095 		x->rx_buf = &packet->tc.z1;
1096 		x->len = 2;
1097 		spi_message_add_tail(x, m);
1098 
1099 		/* ... maybe discard first sample ... */
1100 		if (pdata->settle_delay_usecs) {
1101 			x->delay_usecs = pdata->settle_delay_usecs;
1102 
1103 			x++;
1104 			x->tx_buf = &packet->read_z1;
1105 			x->len = 1;
1106 			spi_message_add_tail(x, m);
1107 
1108 			x++;
1109 			x->rx_buf = &packet->tc.z1;
1110 			x->len = 2;
1111 			spi_message_add_tail(x, m);
1112 		}
1113 
1114 		ts->msg_count++;
1115 		m++;
1116 		spi_message_init(m);
1117 		m->context = ts;
1118 
1119 		x++;
1120 		packet->read_z2 = READ_Z2(vref);
1121 		x->tx_buf = &packet->read_z2;
1122 		x->len = 1;
1123 		spi_message_add_tail(x, m);
1124 
1125 		x++;
1126 		x->rx_buf = &packet->tc.z2;
1127 		x->len = 2;
1128 		spi_message_add_tail(x, m);
1129 
1130 		/* ... maybe discard first sample ... */
1131 		if (pdata->settle_delay_usecs) {
1132 			x->delay_usecs = pdata->settle_delay_usecs;
1133 
1134 			x++;
1135 			x->tx_buf = &packet->read_z2;
1136 			x->len = 1;
1137 			spi_message_add_tail(x, m);
1138 
1139 			x++;
1140 			x->rx_buf = &packet->tc.z2;
1141 			x->len = 2;
1142 			spi_message_add_tail(x, m);
1143 		}
1144 	}
1145 
1146 	/* power down */
1147 	ts->msg_count++;
1148 	m++;
1149 	spi_message_init(m);
1150 	m->context = ts;
1151 
1152 	if (ts->model == 7845) {
1153 		x++;
1154 		packet->pwrdown_cmd[0] = PWRDOWN;
1155 		packet->pwrdown_cmd[1] = 0;
1156 		packet->pwrdown_cmd[2] = 0;
1157 		x->tx_buf = &packet->pwrdown_cmd[0];
1158 		x->len = 3;
1159 	} else {
1160 		x++;
1161 		packet->pwrdown = PWRDOWN;
1162 		x->tx_buf = &packet->pwrdown;
1163 		x->len = 1;
1164 		spi_message_add_tail(x, m);
1165 
1166 		x++;
1167 		x->rx_buf = &packet->dummy;
1168 		x->len = 2;
1169 	}
1170 
1171 	CS_CHANGE(*x);
1172 	spi_message_add_tail(x, m);
1173 }
1174 
1175 #ifdef CONFIG_OF
1176 static const struct of_device_id ads7846_dt_ids[] = {
1177 	{ .compatible = "ti,tsc2046",	.data = (void *) 7846 },
1178 	{ .compatible = "ti,ads7843",	.data = (void *) 7843 },
1179 	{ .compatible = "ti,ads7845",	.data = (void *) 7845 },
1180 	{ .compatible = "ti,ads7846",	.data = (void *) 7846 },
1181 	{ .compatible = "ti,ads7873",	.data = (void *) 7873 },
1182 	{ }
1183 };
1184 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1185 
1186 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1187 {
1188 	struct ads7846_platform_data *pdata;
1189 	struct device_node *node = dev->of_node;
1190 	const struct of_device_id *match;
1191 
1192 	if (!node) {
1193 		dev_err(dev, "Device does not have associated DT data\n");
1194 		return ERR_PTR(-EINVAL);
1195 	}
1196 
1197 	match = of_match_device(ads7846_dt_ids, dev);
1198 	if (!match) {
1199 		dev_err(dev, "Unknown device model\n");
1200 		return ERR_PTR(-EINVAL);
1201 	}
1202 
1203 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1204 	if (!pdata)
1205 		return ERR_PTR(-ENOMEM);
1206 
1207 	pdata->model = (unsigned long)match->data;
1208 
1209 	of_property_read_u16(node, "ti,vref-delay-usecs",
1210 			     &pdata->vref_delay_usecs);
1211 	of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1212 	pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1213 
1214 	pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1215 
1216 	of_property_read_u16(node, "ti,settle-delay-usec",
1217 			     &pdata->settle_delay_usecs);
1218 	of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1219 			     &pdata->penirq_recheck_delay_usecs);
1220 
1221 	of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1222 	of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1223 
1224 	of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1225 	of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1226 	of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1227 	of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1228 
1229 	of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1230 	of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1231 
1232 	of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1233 	of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1234 	of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1235 
1236 	of_property_read_u32(node, "ti,pendown-gpio-debounce",
1237 			     &pdata->gpio_pendown_debounce);
1238 
1239 	pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1240 			of_property_read_bool(node, "linux,wakeup");
1241 
1242 	pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1243 
1244 	return pdata;
1245 }
1246 #else
1247 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1248 {
1249 	dev_err(dev, "no platform data defined\n");
1250 	return ERR_PTR(-EINVAL);
1251 }
1252 #endif
1253 
1254 static int ads7846_probe(struct spi_device *spi)
1255 {
1256 	const struct ads7846_platform_data *pdata;
1257 	struct ads7846 *ts;
1258 	struct ads7846_packet *packet;
1259 	struct input_dev *input_dev;
1260 	unsigned long irq_flags;
1261 	int err;
1262 
1263 	if (!spi->irq) {
1264 		dev_dbg(&spi->dev, "no IRQ?\n");
1265 		return -EINVAL;
1266 	}
1267 
1268 	/* don't exceed max specified sample rate */
1269 	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1270 		dev_err(&spi->dev, "f(sample) %d KHz?\n",
1271 				(spi->max_speed_hz/SAMPLE_BITS)/1000);
1272 		return -EINVAL;
1273 	}
1274 
1275 	/*
1276 	 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1277 	 * that even if the hardware can do that, the SPI controller driver
1278 	 * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1279 	 */
1280 	spi->bits_per_word = 8;
1281 	spi->mode = SPI_MODE_0;
1282 	err = spi_setup(spi);
1283 	if (err < 0)
1284 		return err;
1285 
1286 	ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1287 	packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1288 	input_dev = input_allocate_device();
1289 	if (!ts || !packet || !input_dev) {
1290 		err = -ENOMEM;
1291 		goto err_free_mem;
1292 	}
1293 
1294 	spi_set_drvdata(spi, ts);
1295 
1296 	ts->packet = packet;
1297 	ts->spi = spi;
1298 	ts->input = input_dev;
1299 
1300 	mutex_init(&ts->lock);
1301 	init_waitqueue_head(&ts->wait);
1302 
1303 	pdata = dev_get_platdata(&spi->dev);
1304 	if (!pdata) {
1305 		pdata = ads7846_probe_dt(&spi->dev);
1306 		if (IS_ERR(pdata)) {
1307 			err = PTR_ERR(pdata);
1308 			goto err_free_mem;
1309 		}
1310 	}
1311 
1312 	ts->model = pdata->model ? : 7846;
1313 	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1314 	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1315 	ts->pressure_max = pdata->pressure_max ? : ~0;
1316 
1317 	ts->vref_mv = pdata->vref_mv;
1318 	ts->swap_xy = pdata->swap_xy;
1319 
1320 	if (pdata->filter != NULL) {
1321 		if (pdata->filter_init != NULL) {
1322 			err = pdata->filter_init(pdata, &ts->filter_data);
1323 			if (err < 0)
1324 				goto err_free_mem;
1325 		}
1326 		ts->filter = pdata->filter;
1327 		ts->filter_cleanup = pdata->filter_cleanup;
1328 	} else if (pdata->debounce_max) {
1329 		ts->debounce_max = pdata->debounce_max;
1330 		if (ts->debounce_max < 2)
1331 			ts->debounce_max = 2;
1332 		ts->debounce_tol = pdata->debounce_tol;
1333 		ts->debounce_rep = pdata->debounce_rep;
1334 		ts->filter = ads7846_debounce_filter;
1335 		ts->filter_data = ts;
1336 	} else {
1337 		ts->filter = ads7846_no_filter;
1338 	}
1339 
1340 	err = ads7846_setup_pendown(spi, ts, pdata);
1341 	if (err)
1342 		goto err_cleanup_filter;
1343 
1344 	if (pdata->penirq_recheck_delay_usecs)
1345 		ts->penirq_recheck_delay_usecs =
1346 				pdata->penirq_recheck_delay_usecs;
1347 
1348 	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1349 
1350 	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1351 	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1352 
1353 	input_dev->name = ts->name;
1354 	input_dev->phys = ts->phys;
1355 	input_dev->dev.parent = &spi->dev;
1356 
1357 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1358 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1359 	input_set_abs_params(input_dev, ABS_X,
1360 			pdata->x_min ? : 0,
1361 			pdata->x_max ? : MAX_12BIT,
1362 			0, 0);
1363 	input_set_abs_params(input_dev, ABS_Y,
1364 			pdata->y_min ? : 0,
1365 			pdata->y_max ? : MAX_12BIT,
1366 			0, 0);
1367 	input_set_abs_params(input_dev, ABS_PRESSURE,
1368 			pdata->pressure_min, pdata->pressure_max, 0, 0);
1369 
1370 	ads7846_setup_spi_msg(ts, pdata);
1371 
1372 	ts->reg = regulator_get(&spi->dev, "vcc");
1373 	if (IS_ERR(ts->reg)) {
1374 		err = PTR_ERR(ts->reg);
1375 		dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1376 		goto err_free_gpio;
1377 	}
1378 
1379 	err = regulator_enable(ts->reg);
1380 	if (err) {
1381 		dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1382 		goto err_put_regulator;
1383 	}
1384 
1385 	irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1386 	irq_flags |= IRQF_ONESHOT;
1387 
1388 	err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1389 				   irq_flags, spi->dev.driver->name, ts);
1390 	if (err && !pdata->irq_flags) {
1391 		dev_info(&spi->dev,
1392 			"trying pin change workaround on irq %d\n", spi->irq);
1393 		irq_flags |= IRQF_TRIGGER_RISING;
1394 		err = request_threaded_irq(spi->irq,
1395 				  ads7846_hard_irq, ads7846_irq,
1396 				  irq_flags, spi->dev.driver->name, ts);
1397 	}
1398 
1399 	if (err) {
1400 		dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1401 		goto err_disable_regulator;
1402 	}
1403 
1404 	err = ads784x_hwmon_register(spi, ts);
1405 	if (err)
1406 		goto err_free_irq;
1407 
1408 	dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1409 
1410 	/*
1411 	 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1412 	 * the touchscreen, in case it's not connected.
1413 	 */
1414 	if (ts->model == 7845)
1415 		ads7845_read12_ser(&spi->dev, PWRDOWN);
1416 	else
1417 		(void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1418 
1419 	err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1420 	if (err)
1421 		goto err_remove_hwmon;
1422 
1423 	err = input_register_device(input_dev);
1424 	if (err)
1425 		goto err_remove_attr_group;
1426 
1427 	device_init_wakeup(&spi->dev, pdata->wakeup);
1428 
1429 	/*
1430 	 * If device does not carry platform data we must have allocated it
1431 	 * when parsing DT data.
1432 	 */
1433 	if (!dev_get_platdata(&spi->dev))
1434 		devm_kfree(&spi->dev, (void *)pdata);
1435 
1436 	return 0;
1437 
1438  err_remove_attr_group:
1439 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1440  err_remove_hwmon:
1441 	ads784x_hwmon_unregister(spi, ts);
1442  err_free_irq:
1443 	free_irq(spi->irq, ts);
1444  err_disable_regulator:
1445 	regulator_disable(ts->reg);
1446  err_put_regulator:
1447 	regulator_put(ts->reg);
1448  err_free_gpio:
1449 	if (!ts->get_pendown_state)
1450 		gpio_free(ts->gpio_pendown);
1451  err_cleanup_filter:
1452 	if (ts->filter_cleanup)
1453 		ts->filter_cleanup(ts->filter_data);
1454  err_free_mem:
1455 	input_free_device(input_dev);
1456 	kfree(packet);
1457 	kfree(ts);
1458 	return err;
1459 }
1460 
1461 static int ads7846_remove(struct spi_device *spi)
1462 {
1463 	struct ads7846 *ts = spi_get_drvdata(spi);
1464 
1465 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1466 
1467 	ads7846_disable(ts);
1468 	free_irq(ts->spi->irq, ts);
1469 
1470 	input_unregister_device(ts->input);
1471 
1472 	ads784x_hwmon_unregister(spi, ts);
1473 
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 		.pm	= &ads7846_pm,
1499 		.of_match_table = of_match_ptr(ads7846_dt_ids),
1500 	},
1501 	.probe		= ads7846_probe,
1502 	.remove		= ads7846_remove,
1503 };
1504 
1505 module_spi_driver(ads7846_driver);
1506 
1507 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1508 MODULE_LICENSE("GPL");
1509 MODULE_ALIAS("spi:ads7846");
1510