1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ADS7846 based touchscreen and sensor driver
4  *
5  * Copyright (c) 2005 David Brownell
6  * Copyright (c) 2006 Nokia Corporation
7  * Various changes: Imre Deak <imre.deak@nokia.com>
8  *
9  * Using code from:
10  *  - corgi_ts.c
11  *	Copyright (C) 2004-2005 Richard Purdie
12  *  - omap_ts.[hc], ads7846.h, ts_osk.c
13  *	Copyright (C) 2002 MontaVista Software
14  *	Copyright (C) 2004 Texas Instruments
15  *	Copyright (C) 2005 Dirk Behme
16  */
17 #include <linux/types.h>
18 #include <linux/hwmon.h>
19 #include <linux/err.h>
20 #include <linux/sched.h>
21 #include <linux/delay.h>
22 #include <linux/input.h>
23 #include <linux/input/touchscreen.h>
24 #include <linux/interrupt.h>
25 #include <linux/slab.h>
26 #include <linux/pm.h>
27 #include <linux/of.h>
28 #include <linux/of_gpio.h>
29 #include <linux/of_device.h>
30 #include <linux/gpio.h>
31 #include <linux/spi/spi.h>
32 #include <linux/spi/ads7846.h>
33 #include <linux/regulator/consumer.h>
34 #include <linux/module.h>
35 #include <asm/unaligned.h>
36 
37 /*
38  * This code has been heavily tested on a Nokia 770, and lightly
39  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
40  * TSC2046 is just newer ads7846 silicon.
41  * Support for ads7843 tested on Atmel at91sam926x-EK.
42  * Support for ads7845 has only been stubbed in.
43  * Support for Analog Devices AD7873 and AD7843 tested.
44  *
45  * IRQ handling needs a workaround because of a shortcoming in handling
46  * edge triggered IRQs on some platforms like the OMAP1/2. These
47  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48  * have to maintain our own SW IRQ disabled status. This should be
49  * removed as soon as the affected platform's IRQ handling is fixed.
50  *
51  * App note sbaa036 talks in more detail about accurate sampling...
52  * that ought to help in situations like LCDs inducing noise (which
53  * can also be helped by using synch signals) and more generally.
54  * This driver tries to utilize the measures described in the app
55  * note. The strength of filtering can be set in the board-* specific
56  * files.
57  */
58 
59 #define TS_POLL_DELAY	1	/* ms delay before the first sample */
60 #define TS_POLL_PERIOD	5	/* ms delay between samples */
61 
62 /* this driver doesn't aim at the peak continuous sample rate */
63 #define	SAMPLE_BITS	(8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
64 
65 struct ads7846_buf {
66 	u8 cmd;
67 	__be16 data;
68 } __packed;
69 
70 struct ads7846_buf_layout {
71 	unsigned int offset;
72 	unsigned int count;
73 	unsigned int skip;
74 };
75 
76 /*
77  * We allocate this separately to avoid cache line sharing issues when
78  * driver is used with DMA-based SPI controllers (like atmel_spi) on
79  * systems where main memory is not DMA-coherent (most non-x86 boards).
80  */
81 struct ads7846_packet {
82 	unsigned int count;
83 	unsigned int count_skip;
84 	unsigned int cmds;
85 	unsigned int last_cmd_idx;
86 	struct ads7846_buf_layout l[5];
87 	struct ads7846_buf *rx;
88 	struct ads7846_buf *tx;
89 
90 	struct ads7846_buf pwrdown_cmd;
91 
92 	bool ignore;
93 	u16 x, y, z1, z2;
94 };
95 
96 struct ads7846 {
97 	struct input_dev	*input;
98 	char			phys[32];
99 	char			name[32];
100 
101 	struct spi_device	*spi;
102 	struct regulator	*reg;
103 
104 #if IS_ENABLED(CONFIG_HWMON)
105 	struct device		*hwmon;
106 #endif
107 
108 	u16			model;
109 	u16			vref_mv;
110 	u16			vref_delay_usecs;
111 	u16			x_plate_ohms;
112 	u16			pressure_max;
113 
114 	bool			swap_xy;
115 	bool			use_internal;
116 
117 	struct ads7846_packet	*packet;
118 
119 	struct spi_transfer	xfer[18];
120 	struct spi_message	msg[5];
121 	int			msg_count;
122 	wait_queue_head_t	wait;
123 
124 	bool			pendown;
125 
126 	int			read_cnt;
127 	int			read_rep;
128 	int			last_read;
129 
130 	u16			debounce_max;
131 	u16			debounce_tol;
132 	u16			debounce_rep;
133 
134 	u16			penirq_recheck_delay_usecs;
135 
136 	struct touchscreen_properties core_prop;
137 
138 	struct mutex		lock;
139 	bool			stopped;	/* P: lock */
140 	bool			disabled;	/* P: lock */
141 	bool			suspended;	/* P: lock */
142 
143 	int			(*filter)(void *data, int data_idx, int *val);
144 	void			*filter_data;
145 	void			(*filter_cleanup)(void *data);
146 	int			(*get_pendown_state)(void);
147 	int			gpio_pendown;
148 
149 	void			(*wait_for_sync)(void);
150 };
151 
152 /* leave chip selected when we're done, for quicker re-select? */
153 #if	0
154 #define	CS_CHANGE(xfer)	((xfer).cs_change = 1)
155 #else
156 #define	CS_CHANGE(xfer)	((xfer).cs_change = 0)
157 #endif
158 
159 /*--------------------------------------------------------------------------*/
160 
161 /* The ADS7846 has touchscreen and other sensors.
162  * Earlier ads784x chips are somewhat compatible.
163  */
164 #define	ADS_START		(1 << 7)
165 #define	ADS_A2A1A0_d_y		(1 << 4)	/* differential */
166 #define	ADS_A2A1A0_d_z1		(3 << 4)	/* differential */
167 #define	ADS_A2A1A0_d_z2		(4 << 4)	/* differential */
168 #define	ADS_A2A1A0_d_x		(5 << 4)	/* differential */
169 #define	ADS_A2A1A0_temp0	(0 << 4)	/* non-differential */
170 #define	ADS_A2A1A0_vbatt	(2 << 4)	/* non-differential */
171 #define	ADS_A2A1A0_vaux		(6 << 4)	/* non-differential */
172 #define	ADS_A2A1A0_temp1	(7 << 4)	/* non-differential */
173 #define	ADS_8_BIT		(1 << 3)
174 #define	ADS_12_BIT		(0 << 3)
175 #define	ADS_SER			(1 << 2)	/* non-differential */
176 #define	ADS_DFR			(0 << 2)	/* differential */
177 #define	ADS_PD10_PDOWN		(0 << 0)	/* low power mode + penirq */
178 #define	ADS_PD10_ADC_ON		(1 << 0)	/* ADC on */
179 #define	ADS_PD10_REF_ON		(2 << 0)	/* vREF on + penirq */
180 #define	ADS_PD10_ALL_ON		(3 << 0)	/* ADC + vREF on */
181 
182 #define	MAX_12BIT	((1<<12)-1)
183 
184 /* leave ADC powered up (disables penirq) between differential samples */
185 #define	READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
186 	| ADS_12_BIT | ADS_DFR | \
187 	(adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
188 
189 #define	READ_Y(vref)	(READ_12BIT_DFR(y,  1, vref))
190 #define	READ_Z1(vref)	(READ_12BIT_DFR(z1, 1, vref))
191 #define	READ_Z2(vref)	(READ_12BIT_DFR(z2, 1, vref))
192 #define	READ_X(vref)	(READ_12BIT_DFR(x,  1, vref))
193 #define	PWRDOWN		(READ_12BIT_DFR(y,  0, 0))	/* LAST */
194 
195 /* single-ended samples need to first power up reference voltage;
196  * we leave both ADC and VREF powered
197  */
198 #define	READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
199 	| ADS_12_BIT | ADS_SER)
200 
201 #define	REF_ON	(READ_12BIT_DFR(x, 1, 1))
202 #define	REF_OFF	(READ_12BIT_DFR(y, 0, 0))
203 
204 /* Order commands in the most optimal way to reduce Vref switching and
205  * settling time:
206  * Measure:  X; Vref: X+, X-; IN: Y+
207  * Measure:  Y; Vref: Y+, Y-; IN: X+
208  * Measure: Z1; Vref: Y+, X-; IN: X+
209  * Measure: Z2; Vref: Y+, X-; IN: Y-
210  */
211 enum ads7846_cmds {
212 	ADS7846_X,
213 	ADS7846_Y,
214 	ADS7846_Z1,
215 	ADS7846_Z2,
216 	ADS7846_PWDOWN,
217 };
218 
219 static int get_pendown_state(struct ads7846 *ts)
220 {
221 	if (ts->get_pendown_state)
222 		return ts->get_pendown_state();
223 
224 	return !gpio_get_value(ts->gpio_pendown);
225 }
226 
227 static void ads7846_report_pen_up(struct ads7846 *ts)
228 {
229 	struct input_dev *input = ts->input;
230 
231 	input_report_key(input, BTN_TOUCH, 0);
232 	input_report_abs(input, ABS_PRESSURE, 0);
233 	input_sync(input);
234 
235 	ts->pendown = false;
236 	dev_vdbg(&ts->spi->dev, "UP\n");
237 }
238 
239 /* Must be called with ts->lock held */
240 static void ads7846_stop(struct ads7846 *ts)
241 {
242 	if (!ts->disabled && !ts->suspended) {
243 		/* Signal IRQ thread to stop polling and disable the handler. */
244 		ts->stopped = true;
245 		mb();
246 		wake_up(&ts->wait);
247 		disable_irq(ts->spi->irq);
248 	}
249 }
250 
251 /* Must be called with ts->lock held */
252 static void ads7846_restart(struct ads7846 *ts)
253 {
254 	if (!ts->disabled && !ts->suspended) {
255 		/* Check if pen was released since last stop */
256 		if (ts->pendown && !get_pendown_state(ts))
257 			ads7846_report_pen_up(ts);
258 
259 		/* Tell IRQ thread that it may poll the device. */
260 		ts->stopped = false;
261 		mb();
262 		enable_irq(ts->spi->irq);
263 	}
264 }
265 
266 /* Must be called with ts->lock held */
267 static void __ads7846_disable(struct ads7846 *ts)
268 {
269 	ads7846_stop(ts);
270 	regulator_disable(ts->reg);
271 
272 	/*
273 	 * We know the chip's in low power mode since we always
274 	 * leave it that way after every request
275 	 */
276 }
277 
278 /* Must be called with ts->lock held */
279 static void __ads7846_enable(struct ads7846 *ts)
280 {
281 	int error;
282 
283 	error = regulator_enable(ts->reg);
284 	if (error != 0)
285 		dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
286 
287 	ads7846_restart(ts);
288 }
289 
290 static void ads7846_disable(struct ads7846 *ts)
291 {
292 	mutex_lock(&ts->lock);
293 
294 	if (!ts->disabled) {
295 
296 		if  (!ts->suspended)
297 			__ads7846_disable(ts);
298 
299 		ts->disabled = true;
300 	}
301 
302 	mutex_unlock(&ts->lock);
303 }
304 
305 static void ads7846_enable(struct ads7846 *ts)
306 {
307 	mutex_lock(&ts->lock);
308 
309 	if (ts->disabled) {
310 
311 		ts->disabled = false;
312 
313 		if (!ts->suspended)
314 			__ads7846_enable(ts);
315 	}
316 
317 	mutex_unlock(&ts->lock);
318 }
319 
320 /*--------------------------------------------------------------------------*/
321 
322 /*
323  * Non-touchscreen sensors only use single-ended conversions.
324  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
325  * ads7846 lets that pin be unconnected, to use internal vREF.
326  */
327 
328 struct ser_req {
329 	u8			ref_on;
330 	u8			command;
331 	u8			ref_off;
332 	u16			scratch;
333 	struct spi_message	msg;
334 	struct spi_transfer	xfer[6];
335 	/*
336 	 * DMA (thus cache coherency maintenance) requires the
337 	 * transfer buffers to live in their own cache lines.
338 	 */
339 	__be16 sample ____cacheline_aligned;
340 };
341 
342 struct ads7845_ser_req {
343 	u8			command[3];
344 	struct spi_message	msg;
345 	struct spi_transfer	xfer[2];
346 	/*
347 	 * DMA (thus cache coherency maintenance) requires the
348 	 * transfer buffers to live in their own cache lines.
349 	 */
350 	u8 sample[3] ____cacheline_aligned;
351 };
352 
353 static int ads7846_read12_ser(struct device *dev, unsigned command)
354 {
355 	struct spi_device *spi = to_spi_device(dev);
356 	struct ads7846 *ts = dev_get_drvdata(dev);
357 	struct ser_req *req;
358 	int status;
359 
360 	req = kzalloc(sizeof *req, GFP_KERNEL);
361 	if (!req)
362 		return -ENOMEM;
363 
364 	spi_message_init(&req->msg);
365 
366 	/* maybe turn on internal vREF, and let it settle */
367 	if (ts->use_internal) {
368 		req->ref_on = REF_ON;
369 		req->xfer[0].tx_buf = &req->ref_on;
370 		req->xfer[0].len = 1;
371 		spi_message_add_tail(&req->xfer[0], &req->msg);
372 
373 		req->xfer[1].rx_buf = &req->scratch;
374 		req->xfer[1].len = 2;
375 
376 		/* for 1uF, settle for 800 usec; no cap, 100 usec.  */
377 		req->xfer[1].delay.value = ts->vref_delay_usecs;
378 		req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
379 		spi_message_add_tail(&req->xfer[1], &req->msg);
380 
381 		/* Enable reference voltage */
382 		command |= ADS_PD10_REF_ON;
383 	}
384 
385 	/* Enable ADC in every case */
386 	command |= ADS_PD10_ADC_ON;
387 
388 	/* take sample */
389 	req->command = (u8) command;
390 	req->xfer[2].tx_buf = &req->command;
391 	req->xfer[2].len = 1;
392 	spi_message_add_tail(&req->xfer[2], &req->msg);
393 
394 	req->xfer[3].rx_buf = &req->sample;
395 	req->xfer[3].len = 2;
396 	spi_message_add_tail(&req->xfer[3], &req->msg);
397 
398 	/* REVISIT:  take a few more samples, and compare ... */
399 
400 	/* converter in low power mode & enable PENIRQ */
401 	req->ref_off = PWRDOWN;
402 	req->xfer[4].tx_buf = &req->ref_off;
403 	req->xfer[4].len = 1;
404 	spi_message_add_tail(&req->xfer[4], &req->msg);
405 
406 	req->xfer[5].rx_buf = &req->scratch;
407 	req->xfer[5].len = 2;
408 	CS_CHANGE(req->xfer[5]);
409 	spi_message_add_tail(&req->xfer[5], &req->msg);
410 
411 	mutex_lock(&ts->lock);
412 	ads7846_stop(ts);
413 	status = spi_sync(spi, &req->msg);
414 	ads7846_restart(ts);
415 	mutex_unlock(&ts->lock);
416 
417 	if (status == 0) {
418 		/* on-wire is a must-ignore bit, a BE12 value, then padding */
419 		status = be16_to_cpu(req->sample);
420 		status = status >> 3;
421 		status &= 0x0fff;
422 	}
423 
424 	kfree(req);
425 	return status;
426 }
427 
428 static int ads7845_read12_ser(struct device *dev, unsigned command)
429 {
430 	struct spi_device *spi = to_spi_device(dev);
431 	struct ads7846 *ts = dev_get_drvdata(dev);
432 	struct ads7845_ser_req *req;
433 	int status;
434 
435 	req = kzalloc(sizeof *req, GFP_KERNEL);
436 	if (!req)
437 		return -ENOMEM;
438 
439 	spi_message_init(&req->msg);
440 
441 	req->command[0] = (u8) command;
442 	req->xfer[0].tx_buf = req->command;
443 	req->xfer[0].rx_buf = req->sample;
444 	req->xfer[0].len = 3;
445 	spi_message_add_tail(&req->xfer[0], &req->msg);
446 
447 	mutex_lock(&ts->lock);
448 	ads7846_stop(ts);
449 	status = spi_sync(spi, &req->msg);
450 	ads7846_restart(ts);
451 	mutex_unlock(&ts->lock);
452 
453 	if (status == 0) {
454 		/* BE12 value, then padding */
455 		status = get_unaligned_be16(&req->sample[1]);
456 		status = status >> 3;
457 		status &= 0x0fff;
458 	}
459 
460 	kfree(req);
461 	return status;
462 }
463 
464 #if IS_ENABLED(CONFIG_HWMON)
465 
466 #define SHOW(name, var, adjust) static ssize_t \
467 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
468 { \
469 	struct ads7846 *ts = dev_get_drvdata(dev); \
470 	ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
471 			READ_12BIT_SER(var)); \
472 	if (v < 0) \
473 		return v; \
474 	return sprintf(buf, "%u\n", adjust(ts, v)); \
475 } \
476 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
477 
478 
479 /* Sysfs conventions report temperatures in millidegrees Celsius.
480  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
481  * accuracy scheme without calibration data.  For now we won't try either;
482  * userspace sees raw sensor values, and must scale/calibrate appropriately.
483  */
484 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
485 {
486 	return v;
487 }
488 
489 SHOW(temp0, temp0, null_adjust)		/* temp1_input */
490 SHOW(temp1, temp1, null_adjust)		/* temp2_input */
491 
492 
493 /* sysfs conventions report voltages in millivolts.  We can convert voltages
494  * if we know vREF.  userspace may need to scale vAUX to match the board's
495  * external resistors; we assume that vBATT only uses the internal ones.
496  */
497 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
498 {
499 	unsigned retval = v;
500 
501 	/* external resistors may scale vAUX into 0..vREF */
502 	retval *= ts->vref_mv;
503 	retval = retval >> 12;
504 
505 	return retval;
506 }
507 
508 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
509 {
510 	unsigned retval = vaux_adjust(ts, v);
511 
512 	/* ads7846 has a resistor ladder to scale this signal down */
513 	if (ts->model == 7846)
514 		retval *= 4;
515 
516 	return retval;
517 }
518 
519 SHOW(in0_input, vaux, vaux_adjust)
520 SHOW(in1_input, vbatt, vbatt_adjust)
521 
522 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
523 				  int index)
524 {
525 	struct device *dev = kobj_to_dev(kobj);
526 	struct ads7846 *ts = dev_get_drvdata(dev);
527 
528 	if (ts->model == 7843 && index < 2)	/* in0, in1 */
529 		return 0;
530 	if (ts->model == 7845 && index != 2)	/* in0 */
531 		return 0;
532 
533 	return attr->mode;
534 }
535 
536 static struct attribute *ads7846_attributes[] = {
537 	&dev_attr_temp0.attr,		/* 0 */
538 	&dev_attr_temp1.attr,		/* 1 */
539 	&dev_attr_in0_input.attr,	/* 2 */
540 	&dev_attr_in1_input.attr,	/* 3 */
541 	NULL,
542 };
543 
544 static const struct attribute_group ads7846_attr_group = {
545 	.attrs = ads7846_attributes,
546 	.is_visible = ads7846_is_visible,
547 };
548 __ATTRIBUTE_GROUPS(ads7846_attr);
549 
550 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
551 {
552 	/* hwmon sensors need a reference voltage */
553 	switch (ts->model) {
554 	case 7846:
555 		if (!ts->vref_mv) {
556 			dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
557 			ts->vref_mv = 2500;
558 			ts->use_internal = true;
559 		}
560 		break;
561 	case 7845:
562 	case 7843:
563 		if (!ts->vref_mv) {
564 			dev_warn(&spi->dev,
565 				"external vREF for ADS%d not specified\n",
566 				ts->model);
567 			return 0;
568 		}
569 		break;
570 	}
571 
572 	ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
573 						      ts, ads7846_attr_groups);
574 
575 	return PTR_ERR_OR_ZERO(ts->hwmon);
576 }
577 
578 static void ads784x_hwmon_unregister(struct spi_device *spi,
579 				     struct ads7846 *ts)
580 {
581 	if (ts->hwmon)
582 		hwmon_device_unregister(ts->hwmon);
583 }
584 
585 #else
586 static inline int ads784x_hwmon_register(struct spi_device *spi,
587 					 struct ads7846 *ts)
588 {
589 	return 0;
590 }
591 
592 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
593 					    struct ads7846 *ts)
594 {
595 }
596 #endif
597 
598 static ssize_t ads7846_pen_down_show(struct device *dev,
599 				     struct device_attribute *attr, char *buf)
600 {
601 	struct ads7846 *ts = dev_get_drvdata(dev);
602 
603 	return sprintf(buf, "%u\n", ts->pendown);
604 }
605 
606 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
607 
608 static ssize_t ads7846_disable_show(struct device *dev,
609 				     struct device_attribute *attr, char *buf)
610 {
611 	struct ads7846 *ts = dev_get_drvdata(dev);
612 
613 	return sprintf(buf, "%u\n", ts->disabled);
614 }
615 
616 static ssize_t ads7846_disable_store(struct device *dev,
617 				     struct device_attribute *attr,
618 				     const char *buf, size_t count)
619 {
620 	struct ads7846 *ts = dev_get_drvdata(dev);
621 	unsigned int i;
622 	int err;
623 
624 	err = kstrtouint(buf, 10, &i);
625 	if (err)
626 		return err;
627 
628 	if (i)
629 		ads7846_disable(ts);
630 	else
631 		ads7846_enable(ts);
632 
633 	return count;
634 }
635 
636 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
637 
638 static struct attribute *ads784x_attributes[] = {
639 	&dev_attr_pen_down.attr,
640 	&dev_attr_disable.attr,
641 	NULL,
642 };
643 
644 static const struct attribute_group ads784x_attr_group = {
645 	.attrs = ads784x_attributes,
646 };
647 
648 /*--------------------------------------------------------------------------*/
649 
650 static void null_wait_for_sync(void)
651 {
652 }
653 
654 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
655 {
656 	struct ads7846 *ts = ads;
657 
658 	if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
659 		/* Start over collecting consistent readings. */
660 		ts->read_rep = 0;
661 		/*
662 		 * Repeat it, if this was the first read or the read
663 		 * wasn't consistent enough.
664 		 */
665 		if (ts->read_cnt < ts->debounce_max) {
666 			ts->last_read = *val;
667 			ts->read_cnt++;
668 			return ADS7846_FILTER_REPEAT;
669 		} else {
670 			/*
671 			 * Maximum number of debouncing reached and still
672 			 * not enough number of consistent readings. Abort
673 			 * the whole sample, repeat it in the next sampling
674 			 * period.
675 			 */
676 			ts->read_cnt = 0;
677 			return ADS7846_FILTER_IGNORE;
678 		}
679 	} else {
680 		if (++ts->read_rep > ts->debounce_rep) {
681 			/*
682 			 * Got a good reading for this coordinate,
683 			 * go for the next one.
684 			 */
685 			ts->read_cnt = 0;
686 			ts->read_rep = 0;
687 			return ADS7846_FILTER_OK;
688 		} else {
689 			/* Read more values that are consistent. */
690 			ts->read_cnt++;
691 			return ADS7846_FILTER_REPEAT;
692 		}
693 	}
694 }
695 
696 static int ads7846_no_filter(void *ads, int data_idx, int *val)
697 {
698 	return ADS7846_FILTER_OK;
699 }
700 
701 static int ads7846_get_value(struct ads7846_buf *buf)
702 {
703 	int value;
704 
705 	value = be16_to_cpup(&buf->data);
706 
707 	/* enforce ADC output is 12 bits width */
708 	return (value >> 3) & 0xfff;
709 }
710 
711 static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
712 				u16 val)
713 {
714 	struct ads7846_packet *packet = ts->packet;
715 
716 	switch (cmd_idx) {
717 	case ADS7846_Y:
718 		packet->y = val;
719 		break;
720 	case ADS7846_X:
721 		packet->x = val;
722 		break;
723 	case ADS7846_Z1:
724 		packet->z1 = val;
725 		break;
726 	case ADS7846_Z2:
727 		packet->z2 = val;
728 		break;
729 	default:
730 		WARN_ON_ONCE(1);
731 	}
732 }
733 
734 static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
735 {
736 	switch (cmd_idx) {
737 	case ADS7846_Y:
738 		return READ_Y(vref);
739 	case ADS7846_X:
740 		return READ_X(vref);
741 
742 	/* 7846 specific commands  */
743 	case ADS7846_Z1:
744 		return READ_Z1(vref);
745 	case ADS7846_Z2:
746 		return READ_Z2(vref);
747 	case ADS7846_PWDOWN:
748 		return PWRDOWN;
749 	default:
750 		WARN_ON_ONCE(1);
751 	}
752 
753 	return 0;
754 }
755 
756 static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
757 {
758 	switch (cmd_idx) {
759 	case ADS7846_X:
760 	case ADS7846_Y:
761 	case ADS7846_Z1:
762 	case ADS7846_Z2:
763 		return true;
764 	case ADS7846_PWDOWN:
765 		return false;
766 	default:
767 		WARN_ON_ONCE(1);
768 	}
769 
770 	return false;
771 }
772 
773 static int ads7846_filter(struct ads7846 *ts)
774 {
775 	struct ads7846_packet *packet = ts->packet;
776 	int action;
777 	int val;
778 	unsigned int cmd_idx, b;
779 
780 	packet->ignore = false;
781 	for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
782 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
783 
784 		packet->last_cmd_idx = cmd_idx;
785 
786 		for (b = l->skip; b < l->count; b++) {
787 			val = ads7846_get_value(&packet->rx[l->offset + b]);
788 
789 			action = ts->filter(ts->filter_data, cmd_idx, &val);
790 			if (action == ADS7846_FILTER_REPEAT) {
791 				if (b == l->count - 1)
792 					return -EAGAIN;
793 			} else if (action == ADS7846_FILTER_OK) {
794 				ads7846_set_cmd_val(ts, cmd_idx, val);
795 				break;
796 			} else {
797 				packet->ignore = true;
798 				return 0;
799 			}
800 		}
801 	}
802 
803 	return 0;
804 }
805 
806 static void ads7846_read_state(struct ads7846 *ts)
807 {
808 	struct ads7846_packet *packet = ts->packet;
809 	struct spi_message *m;
810 	int msg_idx = 0;
811 	int error;
812 
813 	packet->last_cmd_idx = 0;
814 
815 	while (true) {
816 		ts->wait_for_sync();
817 
818 		m = &ts->msg[msg_idx];
819 		error = spi_sync(ts->spi, m);
820 		if (error) {
821 			dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
822 			packet->ignore = true;
823 			return;
824 		}
825 
826 		error = ads7846_filter(ts);
827 		if (error)
828 			continue;
829 
830 		return;
831 	}
832 }
833 
834 static void ads7846_report_state(struct ads7846 *ts)
835 {
836 	struct ads7846_packet *packet = ts->packet;
837 	unsigned int Rt;
838 	u16 x, y, z1, z2;
839 
840 	x = packet->x;
841 	y = packet->y;
842 	if (ts->model == 7845) {
843 		z1 = 0;
844 		z2 = 0;
845 	} else {
846 		z1 = packet->z1;
847 		z2 = packet->z2;
848 	}
849 
850 	/* range filtering */
851 	if (x == MAX_12BIT)
852 		x = 0;
853 
854 	if (ts->model == 7843) {
855 		Rt = ts->pressure_max / 2;
856 	} else if (ts->model == 7845) {
857 		if (get_pendown_state(ts))
858 			Rt = ts->pressure_max / 2;
859 		else
860 			Rt = 0;
861 		dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
862 	} else if (likely(x && z1)) {
863 		/* compute touch pressure resistance using equation #2 */
864 		Rt = z2;
865 		Rt -= z1;
866 		Rt *= ts->x_plate_ohms;
867 		Rt = DIV_ROUND_CLOSEST(Rt, 16);
868 		Rt *= x;
869 		Rt /= z1;
870 		Rt = DIV_ROUND_CLOSEST(Rt, 256);
871 	} else {
872 		Rt = 0;
873 	}
874 
875 	/*
876 	 * Sample found inconsistent by debouncing or pressure is beyond
877 	 * the maximum. Don't report it to user space, repeat at least
878 	 * once more the measurement
879 	 */
880 	if (packet->ignore || Rt > ts->pressure_max) {
881 		dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
882 			 packet->ignore, Rt);
883 		return;
884 	}
885 
886 	/*
887 	 * Maybe check the pendown state before reporting. This discards
888 	 * false readings when the pen is lifted.
889 	 */
890 	if (ts->penirq_recheck_delay_usecs) {
891 		udelay(ts->penirq_recheck_delay_usecs);
892 		if (!get_pendown_state(ts))
893 			Rt = 0;
894 	}
895 
896 	/*
897 	 * NOTE: We can't rely on the pressure to determine the pen down
898 	 * state, even this controller has a pressure sensor. The pressure
899 	 * value can fluctuate for quite a while after lifting the pen and
900 	 * in some cases may not even settle at the expected value.
901 	 *
902 	 * The only safe way to check for the pen up condition is in the
903 	 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
904 	 */
905 	if (Rt) {
906 		struct input_dev *input = ts->input;
907 
908 		if (!ts->pendown) {
909 			input_report_key(input, BTN_TOUCH, 1);
910 			ts->pendown = true;
911 			dev_vdbg(&ts->spi->dev, "DOWN\n");
912 		}
913 
914 		touchscreen_report_pos(input, &ts->core_prop, x, y, false);
915 		input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
916 
917 		input_sync(input);
918 		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
919 	}
920 }
921 
922 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
923 {
924 	struct ads7846 *ts = handle;
925 
926 	return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
927 }
928 
929 
930 static irqreturn_t ads7846_irq(int irq, void *handle)
931 {
932 	struct ads7846 *ts = handle;
933 
934 	/* Start with a small delay before checking pendown state */
935 	msleep(TS_POLL_DELAY);
936 
937 	while (!ts->stopped && get_pendown_state(ts)) {
938 
939 		/* pen is down, continue with the measurement */
940 		ads7846_read_state(ts);
941 
942 		if (!ts->stopped)
943 			ads7846_report_state(ts);
944 
945 		wait_event_timeout(ts->wait, ts->stopped,
946 				   msecs_to_jiffies(TS_POLL_PERIOD));
947 	}
948 
949 	if (ts->pendown && !ts->stopped)
950 		ads7846_report_pen_up(ts);
951 
952 	return IRQ_HANDLED;
953 }
954 
955 static int __maybe_unused ads7846_suspend(struct device *dev)
956 {
957 	struct ads7846 *ts = dev_get_drvdata(dev);
958 
959 	mutex_lock(&ts->lock);
960 
961 	if (!ts->suspended) {
962 
963 		if (!ts->disabled)
964 			__ads7846_disable(ts);
965 
966 		if (device_may_wakeup(&ts->spi->dev))
967 			enable_irq_wake(ts->spi->irq);
968 
969 		ts->suspended = true;
970 	}
971 
972 	mutex_unlock(&ts->lock);
973 
974 	return 0;
975 }
976 
977 static int __maybe_unused ads7846_resume(struct device *dev)
978 {
979 	struct ads7846 *ts = dev_get_drvdata(dev);
980 
981 	mutex_lock(&ts->lock);
982 
983 	if (ts->suspended) {
984 
985 		ts->suspended = false;
986 
987 		if (device_may_wakeup(&ts->spi->dev))
988 			disable_irq_wake(ts->spi->irq);
989 
990 		if (!ts->disabled)
991 			__ads7846_enable(ts);
992 	}
993 
994 	mutex_unlock(&ts->lock);
995 
996 	return 0;
997 }
998 
999 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
1000 
1001 static int ads7846_setup_pendown(struct spi_device *spi,
1002 				 struct ads7846 *ts,
1003 				 const struct ads7846_platform_data *pdata)
1004 {
1005 	int err;
1006 
1007 	/*
1008 	 * REVISIT when the irq can be triggered active-low, or if for some
1009 	 * reason the touchscreen isn't hooked up, we don't need to access
1010 	 * the pendown state.
1011 	 */
1012 
1013 	if (pdata->get_pendown_state) {
1014 		ts->get_pendown_state = pdata->get_pendown_state;
1015 	} else if (gpio_is_valid(pdata->gpio_pendown)) {
1016 
1017 		err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
1018 				       "ads7846_pendown");
1019 		if (err) {
1020 			dev_err(&spi->dev,
1021 				"failed to request/setup pendown GPIO%d: %d\n",
1022 				pdata->gpio_pendown, err);
1023 			return err;
1024 		}
1025 
1026 		ts->gpio_pendown = pdata->gpio_pendown;
1027 
1028 		if (pdata->gpio_pendown_debounce)
1029 			gpio_set_debounce(pdata->gpio_pendown,
1030 					  pdata->gpio_pendown_debounce);
1031 	} else {
1032 		dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
1033 		return -EINVAL;
1034 	}
1035 
1036 	return 0;
1037 }
1038 
1039 /*
1040  * Set up the transfers to read touchscreen state; this assumes we
1041  * use formula #2 for pressure, not #3.
1042  */
1043 static int ads7846_setup_spi_msg(struct ads7846 *ts,
1044 				  const struct ads7846_platform_data *pdata)
1045 {
1046 	struct spi_message *m = &ts->msg[0];
1047 	struct spi_transfer *x = ts->xfer;
1048 	struct ads7846_packet *packet = ts->packet;
1049 	int vref = pdata->keep_vref_on;
1050 	unsigned int count, offset = 0;
1051 	unsigned int cmd_idx, b;
1052 	unsigned long time;
1053 	size_t size = 0;
1054 
1055 	/* time per bit */
1056 	time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1057 
1058 	count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1059 	packet->count_skip = DIV_ROUND_UP(count, 24);
1060 
1061 	if (ts->debounce_max && ts->debounce_rep)
1062 		/* ads7846_debounce_filter() is making ts->debounce_rep + 2
1063 		 * reads. So we need to get all samples for normal case. */
1064 		packet->count = ts->debounce_rep + 2;
1065 	else
1066 		packet->count = 1;
1067 
1068 	if (ts->model == 7846)
1069 		packet->cmds = 5; /* x, y, z1, z2, pwdown */
1070 	else
1071 		packet->cmds = 3; /* x, y, pwdown */
1072 
1073 	for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1074 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1075 		unsigned int max_count;
1076 
1077 		if (ads7846_cmd_need_settle(cmd_idx))
1078 			max_count = packet->count + packet->count_skip;
1079 		else
1080 			max_count = packet->count;
1081 
1082 		l->offset = offset;
1083 		offset += max_count;
1084 		l->count = max_count;
1085 		l->skip = packet->count_skip;
1086 		size += sizeof(*packet->tx) * max_count;
1087 	}
1088 
1089 	packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1090 	if (!packet->tx)
1091 		return -ENOMEM;
1092 
1093 	packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1094 	if (!packet->rx)
1095 		return -ENOMEM;
1096 
1097 	if (ts->model == 7873) {
1098 		/*
1099 		 * The AD7873 is almost identical to the ADS7846
1100 		 * keep VREF off during differential/ratiometric
1101 		 * conversion modes.
1102 		 */
1103 		ts->model = 7846;
1104 		vref = 0;
1105 	}
1106 
1107 	ts->msg_count = 1;
1108 	spi_message_init(m);
1109 	m->context = ts;
1110 
1111 	for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1112 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1113 		u8 cmd = ads7846_get_cmd(cmd_idx, vref);
1114 
1115 		for (b = 0; b < l->count; b++)
1116 			packet->tx[l->offset + b].cmd = cmd;
1117 	}
1118 
1119 	x->tx_buf = packet->tx;
1120 	x->rx_buf = packet->rx;
1121 	x->len = size;
1122 	spi_message_add_tail(x, m);
1123 
1124 	return 0;
1125 }
1126 
1127 #ifdef CONFIG_OF
1128 static const struct of_device_id ads7846_dt_ids[] = {
1129 	{ .compatible = "ti,tsc2046",	.data = (void *) 7846 },
1130 	{ .compatible = "ti,ads7843",	.data = (void *) 7843 },
1131 	{ .compatible = "ti,ads7845",	.data = (void *) 7845 },
1132 	{ .compatible = "ti,ads7846",	.data = (void *) 7846 },
1133 	{ .compatible = "ti,ads7873",	.data = (void *) 7873 },
1134 	{ }
1135 };
1136 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1137 
1138 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1139 {
1140 	struct ads7846_platform_data *pdata;
1141 	struct device_node *node = dev->of_node;
1142 	const struct of_device_id *match;
1143 	u32 value;
1144 
1145 	if (!node) {
1146 		dev_err(dev, "Device does not have associated DT data\n");
1147 		return ERR_PTR(-EINVAL);
1148 	}
1149 
1150 	match = of_match_device(ads7846_dt_ids, dev);
1151 	if (!match) {
1152 		dev_err(dev, "Unknown device model\n");
1153 		return ERR_PTR(-EINVAL);
1154 	}
1155 
1156 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1157 	if (!pdata)
1158 		return ERR_PTR(-ENOMEM);
1159 
1160 	pdata->model = (unsigned long)match->data;
1161 
1162 	of_property_read_u16(node, "ti,vref-delay-usecs",
1163 			     &pdata->vref_delay_usecs);
1164 	of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1165 	pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1166 
1167 	pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1168 
1169 	of_property_read_u16(node, "ti,settle-delay-usec",
1170 			     &pdata->settle_delay_usecs);
1171 	of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1172 			     &pdata->penirq_recheck_delay_usecs);
1173 
1174 	of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1175 	of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1176 
1177 	of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1178 	of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1179 	of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1180 	of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1181 
1182 	/*
1183 	 * touchscreen-max-pressure gets parsed during
1184 	 * touchscreen_parse_properties()
1185 	 */
1186 	of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1187 	if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1188 		pdata->pressure_min = (u16) value;
1189 	of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1190 
1191 	of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1192 	if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1193 		pdata->debounce_max = (u16) value;
1194 	of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1195 	of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1196 
1197 	of_property_read_u32(node, "ti,pendown-gpio-debounce",
1198 			     &pdata->gpio_pendown_debounce);
1199 
1200 	pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1201 			of_property_read_bool(node, "linux,wakeup");
1202 
1203 	pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1204 
1205 	return pdata;
1206 }
1207 #else
1208 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1209 {
1210 	dev_err(dev, "no platform data defined\n");
1211 	return ERR_PTR(-EINVAL);
1212 }
1213 #endif
1214 
1215 static int ads7846_probe(struct spi_device *spi)
1216 {
1217 	const struct ads7846_platform_data *pdata;
1218 	struct ads7846 *ts;
1219 	struct ads7846_packet *packet;
1220 	struct input_dev *input_dev;
1221 	unsigned long irq_flags;
1222 	int err;
1223 
1224 	if (!spi->irq) {
1225 		dev_dbg(&spi->dev, "no IRQ?\n");
1226 		return -EINVAL;
1227 	}
1228 
1229 	/* don't exceed max specified sample rate */
1230 	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1231 		dev_err(&spi->dev, "f(sample) %d KHz?\n",
1232 				(spi->max_speed_hz/SAMPLE_BITS)/1000);
1233 		return -EINVAL;
1234 	}
1235 
1236 	/*
1237 	 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1238 	 * that even if the hardware can do that, the SPI controller driver
1239 	 * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1240 	 */
1241 	spi->bits_per_word = 8;
1242 	spi->mode &= ~SPI_MODE_X_MASK;
1243 	spi->mode |= SPI_MODE_0;
1244 	err = spi_setup(spi);
1245 	if (err < 0)
1246 		return err;
1247 
1248 	ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1249 	packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1250 	input_dev = input_allocate_device();
1251 	if (!ts || !packet || !input_dev) {
1252 		err = -ENOMEM;
1253 		goto err_free_mem;
1254 	}
1255 
1256 	spi_set_drvdata(spi, ts);
1257 
1258 	ts->packet = packet;
1259 	ts->spi = spi;
1260 	ts->input = input_dev;
1261 
1262 	mutex_init(&ts->lock);
1263 	init_waitqueue_head(&ts->wait);
1264 
1265 	pdata = dev_get_platdata(&spi->dev);
1266 	if (!pdata) {
1267 		pdata = ads7846_probe_dt(&spi->dev);
1268 		if (IS_ERR(pdata)) {
1269 			err = PTR_ERR(pdata);
1270 			goto err_free_mem;
1271 		}
1272 	}
1273 
1274 	ts->model = pdata->model ? : 7846;
1275 	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1276 	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1277 	ts->vref_mv = pdata->vref_mv;
1278 
1279 	if (pdata->filter != NULL) {
1280 		if (pdata->filter_init != NULL) {
1281 			err = pdata->filter_init(pdata, &ts->filter_data);
1282 			if (err < 0)
1283 				goto err_free_mem;
1284 		}
1285 		ts->filter = pdata->filter;
1286 		ts->filter_cleanup = pdata->filter_cleanup;
1287 	} else if (pdata->debounce_max) {
1288 		ts->debounce_max = pdata->debounce_max;
1289 		if (ts->debounce_max < 2)
1290 			ts->debounce_max = 2;
1291 		ts->debounce_tol = pdata->debounce_tol;
1292 		ts->debounce_rep = pdata->debounce_rep;
1293 		ts->filter = ads7846_debounce_filter;
1294 		ts->filter_data = ts;
1295 	} else {
1296 		ts->filter = ads7846_no_filter;
1297 	}
1298 
1299 	err = ads7846_setup_pendown(spi, ts, pdata);
1300 	if (err)
1301 		goto err_cleanup_filter;
1302 
1303 	if (pdata->penirq_recheck_delay_usecs)
1304 		ts->penirq_recheck_delay_usecs =
1305 				pdata->penirq_recheck_delay_usecs;
1306 
1307 	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1308 
1309 	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1310 	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1311 
1312 	input_dev->name = ts->name;
1313 	input_dev->phys = ts->phys;
1314 	input_dev->dev.parent = &spi->dev;
1315 
1316 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1317 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1318 	input_set_abs_params(input_dev, ABS_X,
1319 			pdata->x_min ? : 0,
1320 			pdata->x_max ? : MAX_12BIT,
1321 			0, 0);
1322 	input_set_abs_params(input_dev, ABS_Y,
1323 			pdata->y_min ? : 0,
1324 			pdata->y_max ? : MAX_12BIT,
1325 			0, 0);
1326 	input_set_abs_params(input_dev, ABS_PRESSURE,
1327 			pdata->pressure_min, pdata->pressure_max, 0, 0);
1328 
1329 	/*
1330 	 * Parse common framework properties. Must be done here to ensure the
1331 	 * correct behaviour in case of using the legacy vendor bindings. The
1332 	 * general binding value overrides the vendor specific one.
1333 	 */
1334 	touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1335 	ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1336 
1337 	/*
1338 	 * Check if legacy ti,swap-xy binding is used instead of
1339 	 * touchscreen-swapped-x-y
1340 	 */
1341 	if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1342 		swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1343 		ts->core_prop.swap_x_y = true;
1344 	}
1345 
1346 	ads7846_setup_spi_msg(ts, pdata);
1347 
1348 	ts->reg = regulator_get(&spi->dev, "vcc");
1349 	if (IS_ERR(ts->reg)) {
1350 		err = PTR_ERR(ts->reg);
1351 		dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1352 		goto err_free_gpio;
1353 	}
1354 
1355 	err = regulator_enable(ts->reg);
1356 	if (err) {
1357 		dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1358 		goto err_put_regulator;
1359 	}
1360 
1361 	irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1362 	irq_flags |= IRQF_ONESHOT;
1363 
1364 	err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1365 				   irq_flags, spi->dev.driver->name, ts);
1366 	if (err && !pdata->irq_flags) {
1367 		dev_info(&spi->dev,
1368 			"trying pin change workaround on irq %d\n", spi->irq);
1369 		irq_flags |= IRQF_TRIGGER_RISING;
1370 		err = request_threaded_irq(spi->irq,
1371 				  ads7846_hard_irq, ads7846_irq,
1372 				  irq_flags, spi->dev.driver->name, ts);
1373 	}
1374 
1375 	if (err) {
1376 		dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1377 		goto err_disable_regulator;
1378 	}
1379 
1380 	err = ads784x_hwmon_register(spi, ts);
1381 	if (err)
1382 		goto err_free_irq;
1383 
1384 	dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1385 
1386 	/*
1387 	 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1388 	 * the touchscreen, in case it's not connected.
1389 	 */
1390 	if (ts->model == 7845)
1391 		ads7845_read12_ser(&spi->dev, PWRDOWN);
1392 	else
1393 		(void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1394 
1395 	err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1396 	if (err)
1397 		goto err_remove_hwmon;
1398 
1399 	err = input_register_device(input_dev);
1400 	if (err)
1401 		goto err_remove_attr_group;
1402 
1403 	device_init_wakeup(&spi->dev, pdata->wakeup);
1404 
1405 	/*
1406 	 * If device does not carry platform data we must have allocated it
1407 	 * when parsing DT data.
1408 	 */
1409 	if (!dev_get_platdata(&spi->dev))
1410 		devm_kfree(&spi->dev, (void *)pdata);
1411 
1412 	return 0;
1413 
1414  err_remove_attr_group:
1415 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1416  err_remove_hwmon:
1417 	ads784x_hwmon_unregister(spi, ts);
1418  err_free_irq:
1419 	free_irq(spi->irq, ts);
1420  err_disable_regulator:
1421 	regulator_disable(ts->reg);
1422  err_put_regulator:
1423 	regulator_put(ts->reg);
1424  err_free_gpio:
1425 	if (!ts->get_pendown_state)
1426 		gpio_free(ts->gpio_pendown);
1427  err_cleanup_filter:
1428 	if (ts->filter_cleanup)
1429 		ts->filter_cleanup(ts->filter_data);
1430  err_free_mem:
1431 	input_free_device(input_dev);
1432 	kfree(packet);
1433 	kfree(ts);
1434 	return err;
1435 }
1436 
1437 static int ads7846_remove(struct spi_device *spi)
1438 {
1439 	struct ads7846 *ts = spi_get_drvdata(spi);
1440 
1441 	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1442 
1443 	ads7846_disable(ts);
1444 	free_irq(ts->spi->irq, ts);
1445 
1446 	input_unregister_device(ts->input);
1447 
1448 	ads784x_hwmon_unregister(spi, ts);
1449 
1450 	regulator_put(ts->reg);
1451 
1452 	if (!ts->get_pendown_state) {
1453 		/*
1454 		 * If we are not using specialized pendown method we must
1455 		 * have been relying on gpio we set up ourselves.
1456 		 */
1457 		gpio_free(ts->gpio_pendown);
1458 	}
1459 
1460 	if (ts->filter_cleanup)
1461 		ts->filter_cleanup(ts->filter_data);
1462 
1463 	kfree(ts->packet);
1464 	kfree(ts);
1465 
1466 	dev_dbg(&spi->dev, "unregistered touchscreen\n");
1467 
1468 	return 0;
1469 }
1470 
1471 static struct spi_driver ads7846_driver = {
1472 	.driver = {
1473 		.name	= "ads7846",
1474 		.pm	= &ads7846_pm,
1475 		.of_match_table = of_match_ptr(ads7846_dt_ids),
1476 	},
1477 	.probe		= ads7846_probe,
1478 	.remove		= ads7846_remove,
1479 };
1480 
1481 module_spi_driver(ads7846_driver);
1482 
1483 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1484 MODULE_LICENSE("GPL");
1485 MODULE_ALIAS("spi:ads7846");
1486