xref: /linux/drivers/input/touchscreen/ads7846.c (revision 0e8655b4e852ef97655648b91ce780384a073ff4)
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/property.h>
28 #include <linux/gpio/consumer.h>
29 #include <linux/spi/spi.h>
30 #include <linux/spi/ads7846.h>
31 #include <linux/regulator/consumer.h>
32 #include <linux/module.h>
33 #include <asm/unaligned.h>
34 
35 /*
36  * This code has been heavily tested on a Nokia 770, and lightly
37  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
38  * TSC2046 is just newer ads7846 silicon.
39  * Support for ads7843 tested on Atmel at91sam926x-EK.
40  * Support for ads7845 has only been stubbed in.
41  * Support for Analog Devices AD7873 and AD7843 tested.
42  *
43  * IRQ handling needs a workaround because of a shortcoming in handling
44  * edge triggered IRQs on some platforms like the OMAP1/2. These
45  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
46  * have to maintain our own SW IRQ disabled status. This should be
47  * removed as soon as the affected platform's IRQ handling is fixed.
48  *
49  * App note sbaa036 talks in more detail about accurate sampling...
50  * that ought to help in situations like LCDs inducing noise (which
51  * can also be helped by using synch signals) and more generally.
52  * This driver tries to utilize the measures described in the app
53  * note. The strength of filtering can be set in the board-* specific
54  * files.
55  */
56 
57 #define TS_POLL_DELAY	1	/* ms delay before the first sample */
58 #define TS_POLL_PERIOD	5	/* ms delay between samples */
59 
60 /* this driver doesn't aim at the peak continuous sample rate */
61 #define	SAMPLE_BITS	(8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
62 
63 struct ads7846_buf {
64 	u8 cmd;
65 	__be16 data;
66 } __packed;
67 
68 struct ads7846_buf_layout {
69 	unsigned int offset;
70 	unsigned int count;
71 	unsigned int skip;
72 };
73 
74 /*
75  * We allocate this separately to avoid cache line sharing issues when
76  * driver is used with DMA-based SPI controllers (like atmel_spi) on
77  * systems where main memory is not DMA-coherent (most non-x86 boards).
78  */
79 struct ads7846_packet {
80 	unsigned int count;
81 	unsigned int count_skip;
82 	unsigned int cmds;
83 	unsigned int last_cmd_idx;
84 	struct ads7846_buf_layout l[5];
85 	struct ads7846_buf *rx;
86 	struct ads7846_buf *tx;
87 
88 	struct ads7846_buf pwrdown_cmd;
89 
90 	bool ignore;
91 	u16 x, y, z1, z2;
92 };
93 
94 struct ads7846 {
95 	struct input_dev	*input;
96 	char			phys[32];
97 	char			name[32];
98 
99 	struct spi_device	*spi;
100 	struct regulator	*reg;
101 
102 	u16			model;
103 	u16			vref_mv;
104 	u16			vref_delay_usecs;
105 	u16			x_plate_ohms;
106 	u16			pressure_max;
107 
108 	bool			swap_xy;
109 	bool			use_internal;
110 
111 	struct ads7846_packet	*packet;
112 
113 	struct spi_transfer	xfer[18];
114 	struct spi_message	msg[5];
115 	int			msg_count;
116 	wait_queue_head_t	wait;
117 
118 	bool			pendown;
119 
120 	int			read_cnt;
121 	int			read_rep;
122 	int			last_read;
123 
124 	u16			debounce_max;
125 	u16			debounce_tol;
126 	u16			debounce_rep;
127 
128 	u16			penirq_recheck_delay_usecs;
129 
130 	struct touchscreen_properties core_prop;
131 
132 	struct mutex		lock;
133 	bool			stopped;	/* P: lock */
134 	bool			disabled;	/* P: lock */
135 	bool			suspended;	/* P: lock */
136 
137 	int			(*filter)(void *data, int data_idx, int *val);
138 	void			*filter_data;
139 	int			(*get_pendown_state)(void);
140 	struct gpio_desc	*gpio_pendown;
141 
142 	void			(*wait_for_sync)(void);
143 };
144 
145 enum ads7846_filter {
146 	ADS7846_FILTER_OK,
147 	ADS7846_FILTER_REPEAT,
148 	ADS7846_FILTER_IGNORE,
149 };
150 
151 /* leave chip selected when we're done, for quicker re-select? */
152 #if	0
153 #define	CS_CHANGE(xfer)	((xfer).cs_change = 1)
154 #else
155 #define	CS_CHANGE(xfer)	((xfer).cs_change = 0)
156 #endif
157 
158 /*--------------------------------------------------------------------------*/
159 
160 /* The ADS7846 has touchscreen and other sensors.
161  * Earlier ads784x chips are somewhat compatible.
162  */
163 #define	ADS_START		(1 << 7)
164 #define	ADS_A2A1A0_d_y		(1 << 4)	/* differential */
165 #define	ADS_A2A1A0_d_z1		(3 << 4)	/* differential */
166 #define	ADS_A2A1A0_d_z2		(4 << 4)	/* differential */
167 #define	ADS_A2A1A0_d_x		(5 << 4)	/* differential */
168 #define	ADS_A2A1A0_temp0	(0 << 4)	/* non-differential */
169 #define	ADS_A2A1A0_vbatt	(2 << 4)	/* non-differential */
170 #define	ADS_A2A1A0_vaux		(6 << 4)	/* non-differential */
171 #define	ADS_A2A1A0_temp1	(7 << 4)	/* non-differential */
172 #define	ADS_8_BIT		(1 << 3)
173 #define	ADS_12_BIT		(0 << 3)
174 #define	ADS_SER			(1 << 2)	/* non-differential */
175 #define	ADS_DFR			(0 << 2)	/* differential */
176 #define	ADS_PD10_PDOWN		(0 << 0)	/* low power mode + penirq */
177 #define	ADS_PD10_ADC_ON		(1 << 0)	/* ADC on */
178 #define	ADS_PD10_REF_ON		(2 << 0)	/* vREF on + penirq */
179 #define	ADS_PD10_ALL_ON		(3 << 0)	/* ADC + vREF on */
180 
181 #define	MAX_12BIT	((1<<12)-1)
182 
183 /* leave ADC powered up (disables penirq) between differential samples */
184 #define	READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
185 	| ADS_12_BIT | ADS_DFR | \
186 	(adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
187 
188 #define	READ_Y(vref)	(READ_12BIT_DFR(y,  1, vref))
189 #define	READ_Z1(vref)	(READ_12BIT_DFR(z1, 1, vref))
190 #define	READ_Z2(vref)	(READ_12BIT_DFR(z2, 1, vref))
191 #define	READ_X(vref)	(READ_12BIT_DFR(x,  1, vref))
192 #define	PWRDOWN		(READ_12BIT_DFR(y,  0, 0))	/* LAST */
193 
194 /* single-ended samples need to first power up reference voltage;
195  * we leave both ADC and VREF powered
196  */
197 #define	READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
198 	| ADS_12_BIT | ADS_SER)
199 
200 #define	REF_ON	(READ_12BIT_DFR(x, 1, 1))
201 #define	REF_OFF	(READ_12BIT_DFR(y, 0, 0))
202 
203 /* Order commands in the most optimal way to reduce Vref switching and
204  * settling time:
205  * Measure:  X; Vref: X+, X-; IN: Y+
206  * Measure:  Y; Vref: Y+, Y-; IN: X+
207  * Measure: Z1; Vref: Y+, X-; IN: X+
208  * Measure: Z2; Vref: Y+, X-; IN: Y-
209  */
210 enum ads7846_cmds {
211 	ADS7846_X,
212 	ADS7846_Y,
213 	ADS7846_Z1,
214 	ADS7846_Z2,
215 	ADS7846_PWDOWN,
216 };
217 
218 static int get_pendown_state(struct ads7846 *ts)
219 {
220 	if (ts->get_pendown_state)
221 		return ts->get_pendown_state();
222 
223 	return gpiod_get_value(ts->gpio_pendown);
224 }
225 
226 static void ads7846_report_pen_up(struct ads7846 *ts)
227 {
228 	struct input_dev *input = ts->input;
229 
230 	input_report_key(input, BTN_TOUCH, 0);
231 	input_report_abs(input, ABS_PRESSURE, 0);
232 	input_sync(input);
233 
234 	ts->pendown = false;
235 	dev_vdbg(&ts->spi->dev, "UP\n");
236 }
237 
238 /* Must be called with ts->lock held */
239 static void ads7846_stop(struct ads7846 *ts)
240 {
241 	if (!ts->disabled && !ts->suspended) {
242 		/* Signal IRQ thread to stop polling and disable the handler. */
243 		ts->stopped = true;
244 		mb();
245 		wake_up(&ts->wait);
246 		disable_irq(ts->spi->irq);
247 	}
248 }
249 
250 /* Must be called with ts->lock held */
251 static void ads7846_restart(struct ads7846 *ts)
252 {
253 	if (!ts->disabled && !ts->suspended) {
254 		/* Check if pen was released since last stop */
255 		if (ts->pendown && !get_pendown_state(ts))
256 			ads7846_report_pen_up(ts);
257 
258 		/* Tell IRQ thread that it may poll the device. */
259 		ts->stopped = false;
260 		mb();
261 		enable_irq(ts->spi->irq);
262 	}
263 }
264 
265 /* Must be called with ts->lock held */
266 static void __ads7846_disable(struct ads7846 *ts)
267 {
268 	ads7846_stop(ts);
269 	regulator_disable(ts->reg);
270 
271 	/*
272 	 * We know the chip's in low power mode since we always
273 	 * leave it that way after every request
274 	 */
275 }
276 
277 /* Must be called with ts->lock held */
278 static void __ads7846_enable(struct ads7846 *ts)
279 {
280 	int error;
281 
282 	error = regulator_enable(ts->reg);
283 	if (error != 0)
284 		dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
285 
286 	ads7846_restart(ts);
287 }
288 
289 static void ads7846_disable(struct ads7846 *ts)
290 {
291 	mutex_lock(&ts->lock);
292 
293 	if (!ts->disabled) {
294 
295 		if  (!ts->suspended)
296 			__ads7846_disable(ts);
297 
298 		ts->disabled = true;
299 	}
300 
301 	mutex_unlock(&ts->lock);
302 }
303 
304 static void ads7846_enable(struct ads7846 *ts)
305 {
306 	mutex_lock(&ts->lock);
307 
308 	if (ts->disabled) {
309 
310 		ts->disabled = false;
311 
312 		if (!ts->suspended)
313 			__ads7846_enable(ts);
314 	}
315 
316 	mutex_unlock(&ts->lock);
317 }
318 
319 /*--------------------------------------------------------------------------*/
320 
321 /*
322  * Non-touchscreen sensors only use single-ended conversions.
323  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
324  * ads7846 lets that pin be unconnected, to use internal vREF.
325  */
326 
327 struct ser_req {
328 	u8			ref_on;
329 	u8			command;
330 	u8			ref_off;
331 	u16			scratch;
332 	struct spi_message	msg;
333 	struct spi_transfer	xfer[6];
334 	/*
335 	 * DMA (thus cache coherency maintenance) requires the
336 	 * transfer buffers to live in their own cache lines.
337 	 */
338 	__be16 sample ____cacheline_aligned;
339 };
340 
341 struct ads7845_ser_req {
342 	u8			command[3];
343 	struct spi_message	msg;
344 	struct spi_transfer	xfer[2];
345 	/*
346 	 * DMA (thus cache coherency maintenance) requires the
347 	 * transfer buffers to live in their own cache lines.
348 	 */
349 	u8 sample[3] ____cacheline_aligned;
350 };
351 
352 static int ads7846_read12_ser(struct device *dev, unsigned command)
353 {
354 	struct spi_device *spi = to_spi_device(dev);
355 	struct ads7846 *ts = dev_get_drvdata(dev);
356 	struct ser_req *req;
357 	int status;
358 
359 	req = kzalloc(sizeof *req, GFP_KERNEL);
360 	if (!req)
361 		return -ENOMEM;
362 
363 	spi_message_init(&req->msg);
364 
365 	/* maybe turn on internal vREF, and let it settle */
366 	if (ts->use_internal) {
367 		req->ref_on = REF_ON;
368 		req->xfer[0].tx_buf = &req->ref_on;
369 		req->xfer[0].len = 1;
370 		spi_message_add_tail(&req->xfer[0], &req->msg);
371 
372 		req->xfer[1].rx_buf = &req->scratch;
373 		req->xfer[1].len = 2;
374 
375 		/* for 1uF, settle for 800 usec; no cap, 100 usec.  */
376 		req->xfer[1].delay.value = ts->vref_delay_usecs;
377 		req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
378 		spi_message_add_tail(&req->xfer[1], &req->msg);
379 
380 		/* Enable reference voltage */
381 		command |= ADS_PD10_REF_ON;
382 	}
383 
384 	/* Enable ADC in every case */
385 	command |= ADS_PD10_ADC_ON;
386 
387 	/* take sample */
388 	req->command = (u8) command;
389 	req->xfer[2].tx_buf = &req->command;
390 	req->xfer[2].len = 1;
391 	spi_message_add_tail(&req->xfer[2], &req->msg);
392 
393 	req->xfer[3].rx_buf = &req->sample;
394 	req->xfer[3].len = 2;
395 	spi_message_add_tail(&req->xfer[3], &req->msg);
396 
397 	/* REVISIT:  take a few more samples, and compare ... */
398 
399 	/* converter in low power mode & enable PENIRQ */
400 	req->ref_off = PWRDOWN;
401 	req->xfer[4].tx_buf = &req->ref_off;
402 	req->xfer[4].len = 1;
403 	spi_message_add_tail(&req->xfer[4], &req->msg);
404 
405 	req->xfer[5].rx_buf = &req->scratch;
406 	req->xfer[5].len = 2;
407 	CS_CHANGE(req->xfer[5]);
408 	spi_message_add_tail(&req->xfer[5], &req->msg);
409 
410 	mutex_lock(&ts->lock);
411 	ads7846_stop(ts);
412 	status = spi_sync(spi, &req->msg);
413 	ads7846_restart(ts);
414 	mutex_unlock(&ts->lock);
415 
416 	if (status == 0) {
417 		/* on-wire is a must-ignore bit, a BE12 value, then padding */
418 		status = be16_to_cpu(req->sample);
419 		status = status >> 3;
420 		status &= 0x0fff;
421 	}
422 
423 	kfree(req);
424 	return status;
425 }
426 
427 static int ads7845_read12_ser(struct device *dev, unsigned command)
428 {
429 	struct spi_device *spi = to_spi_device(dev);
430 	struct ads7846 *ts = dev_get_drvdata(dev);
431 	struct ads7845_ser_req *req;
432 	int status;
433 
434 	req = kzalloc(sizeof *req, GFP_KERNEL);
435 	if (!req)
436 		return -ENOMEM;
437 
438 	spi_message_init(&req->msg);
439 
440 	req->command[0] = (u8) command;
441 	req->xfer[0].tx_buf = req->command;
442 	req->xfer[0].rx_buf = req->sample;
443 	req->xfer[0].len = 3;
444 	spi_message_add_tail(&req->xfer[0], &req->msg);
445 
446 	mutex_lock(&ts->lock);
447 	ads7846_stop(ts);
448 	status = spi_sync(spi, &req->msg);
449 	ads7846_restart(ts);
450 	mutex_unlock(&ts->lock);
451 
452 	if (status == 0) {
453 		/* BE12 value, then padding */
454 		status = get_unaligned_be16(&req->sample[1]);
455 		status = status >> 3;
456 		status &= 0x0fff;
457 	}
458 
459 	kfree(req);
460 	return status;
461 }
462 
463 #if IS_ENABLED(CONFIG_HWMON)
464 
465 #define SHOW(name, var, adjust) static ssize_t \
466 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
467 { \
468 	struct ads7846 *ts = dev_get_drvdata(dev); \
469 	ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
470 			READ_12BIT_SER(var)); \
471 	if (v < 0) \
472 		return v; \
473 	return sprintf(buf, "%u\n", adjust(ts, v)); \
474 } \
475 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
476 
477 
478 /* Sysfs conventions report temperatures in millidegrees Celsius.
479  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
480  * accuracy scheme without calibration data.  For now we won't try either;
481  * userspace sees raw sensor values, and must scale/calibrate appropriately.
482  */
483 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
484 {
485 	return v;
486 }
487 
488 SHOW(temp0, temp0, null_adjust)		/* temp1_input */
489 SHOW(temp1, temp1, null_adjust)		/* temp2_input */
490 
491 
492 /* sysfs conventions report voltages in millivolts.  We can convert voltages
493  * if we know vREF.  userspace may need to scale vAUX to match the board's
494  * external resistors; we assume that vBATT only uses the internal ones.
495  */
496 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
497 {
498 	unsigned retval = v;
499 
500 	/* external resistors may scale vAUX into 0..vREF */
501 	retval *= ts->vref_mv;
502 	retval = retval >> 12;
503 
504 	return retval;
505 }
506 
507 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
508 {
509 	unsigned retval = vaux_adjust(ts, v);
510 
511 	/* ads7846 has a resistor ladder to scale this signal down */
512 	if (ts->model == 7846)
513 		retval *= 4;
514 
515 	return retval;
516 }
517 
518 SHOW(in0_input, vaux, vaux_adjust)
519 SHOW(in1_input, vbatt, vbatt_adjust)
520 
521 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
522 				  int index)
523 {
524 	struct device *dev = kobj_to_dev(kobj);
525 	struct ads7846 *ts = dev_get_drvdata(dev);
526 
527 	if (ts->model == 7843 && index < 2)	/* in0, in1 */
528 		return 0;
529 	if (ts->model == 7845 && index != 2)	/* in0 */
530 		return 0;
531 
532 	return attr->mode;
533 }
534 
535 static struct attribute *ads7846_attributes[] = {
536 	&dev_attr_temp0.attr,		/* 0 */
537 	&dev_attr_temp1.attr,		/* 1 */
538 	&dev_attr_in0_input.attr,	/* 2 */
539 	&dev_attr_in1_input.attr,	/* 3 */
540 	NULL,
541 };
542 
543 static const struct attribute_group ads7846_attr_group = {
544 	.attrs = ads7846_attributes,
545 	.is_visible = ads7846_is_visible,
546 };
547 __ATTRIBUTE_GROUPS(ads7846_attr);
548 
549 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
550 {
551 	struct device *hwmon;
552 
553 	/* hwmon sensors need a reference voltage */
554 	switch (ts->model) {
555 	case 7846:
556 		if (!ts->vref_mv) {
557 			dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
558 			ts->vref_mv = 2500;
559 			ts->use_internal = true;
560 		}
561 		break;
562 	case 7845:
563 	case 7843:
564 		if (!ts->vref_mv) {
565 			dev_warn(&spi->dev,
566 				"external vREF for ADS%d not specified\n",
567 				ts->model);
568 			return 0;
569 		}
570 		break;
571 	}
572 
573 	hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
574 						       spi->modalias, ts,
575 						       ads7846_attr_groups);
576 
577 	return PTR_ERR_OR_ZERO(hwmon);
578 }
579 
580 #else
581 static inline int ads784x_hwmon_register(struct spi_device *spi,
582 					 struct ads7846 *ts)
583 {
584 	return 0;
585 }
586 #endif
587 
588 static ssize_t ads7846_pen_down_show(struct device *dev,
589 				     struct device_attribute *attr, char *buf)
590 {
591 	struct ads7846 *ts = dev_get_drvdata(dev);
592 
593 	return sprintf(buf, "%u\n", ts->pendown);
594 }
595 
596 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
597 
598 static ssize_t ads7846_disable_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->disabled);
604 }
605 
606 static ssize_t ads7846_disable_store(struct device *dev,
607 				     struct device_attribute *attr,
608 				     const char *buf, size_t count)
609 {
610 	struct ads7846 *ts = dev_get_drvdata(dev);
611 	unsigned int i;
612 	int err;
613 
614 	err = kstrtouint(buf, 10, &i);
615 	if (err)
616 		return err;
617 
618 	if (i)
619 		ads7846_disable(ts);
620 	else
621 		ads7846_enable(ts);
622 
623 	return count;
624 }
625 
626 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
627 
628 static struct attribute *ads784x_attrs[] = {
629 	&dev_attr_pen_down.attr,
630 	&dev_attr_disable.attr,
631 	NULL,
632 };
633 ATTRIBUTE_GROUPS(ads784x);
634 
635 /*--------------------------------------------------------------------------*/
636 
637 static void null_wait_for_sync(void)
638 {
639 }
640 
641 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
642 {
643 	struct ads7846 *ts = ads;
644 
645 	if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
646 		/* Start over collecting consistent readings. */
647 		ts->read_rep = 0;
648 		/*
649 		 * Repeat it, if this was the first read or the read
650 		 * wasn't consistent enough.
651 		 */
652 		if (ts->read_cnt < ts->debounce_max) {
653 			ts->last_read = *val;
654 			ts->read_cnt++;
655 			return ADS7846_FILTER_REPEAT;
656 		} else {
657 			/*
658 			 * Maximum number of debouncing reached and still
659 			 * not enough number of consistent readings. Abort
660 			 * the whole sample, repeat it in the next sampling
661 			 * period.
662 			 */
663 			ts->read_cnt = 0;
664 			return ADS7846_FILTER_IGNORE;
665 		}
666 	} else {
667 		if (++ts->read_rep > ts->debounce_rep) {
668 			/*
669 			 * Got a good reading for this coordinate,
670 			 * go for the next one.
671 			 */
672 			ts->read_cnt = 0;
673 			ts->read_rep = 0;
674 			return ADS7846_FILTER_OK;
675 		} else {
676 			/* Read more values that are consistent. */
677 			ts->read_cnt++;
678 			return ADS7846_FILTER_REPEAT;
679 		}
680 	}
681 }
682 
683 static int ads7846_no_filter(void *ads, int data_idx, int *val)
684 {
685 	return ADS7846_FILTER_OK;
686 }
687 
688 static int ads7846_get_value(struct ads7846_buf *buf)
689 {
690 	int value;
691 
692 	value = be16_to_cpup(&buf->data);
693 
694 	/* enforce ADC output is 12 bits width */
695 	return (value >> 3) & 0xfff;
696 }
697 
698 static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
699 				u16 val)
700 {
701 	struct ads7846_packet *packet = ts->packet;
702 
703 	switch (cmd_idx) {
704 	case ADS7846_Y:
705 		packet->y = val;
706 		break;
707 	case ADS7846_X:
708 		packet->x = val;
709 		break;
710 	case ADS7846_Z1:
711 		packet->z1 = val;
712 		break;
713 	case ADS7846_Z2:
714 		packet->z2 = val;
715 		break;
716 	default:
717 		WARN_ON_ONCE(1);
718 	}
719 }
720 
721 static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
722 {
723 	switch (cmd_idx) {
724 	case ADS7846_Y:
725 		return READ_Y(vref);
726 	case ADS7846_X:
727 		return READ_X(vref);
728 
729 	/* 7846 specific commands  */
730 	case ADS7846_Z1:
731 		return READ_Z1(vref);
732 	case ADS7846_Z2:
733 		return READ_Z2(vref);
734 	case ADS7846_PWDOWN:
735 		return PWRDOWN;
736 	default:
737 		WARN_ON_ONCE(1);
738 	}
739 
740 	return 0;
741 }
742 
743 static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
744 {
745 	switch (cmd_idx) {
746 	case ADS7846_X:
747 	case ADS7846_Y:
748 	case ADS7846_Z1:
749 	case ADS7846_Z2:
750 		return true;
751 	case ADS7846_PWDOWN:
752 		return false;
753 	default:
754 		WARN_ON_ONCE(1);
755 	}
756 
757 	return false;
758 }
759 
760 static int ads7846_filter(struct ads7846 *ts)
761 {
762 	struct ads7846_packet *packet = ts->packet;
763 	int action;
764 	int val;
765 	unsigned int cmd_idx, b;
766 
767 	packet->ignore = false;
768 	for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
769 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
770 
771 		packet->last_cmd_idx = cmd_idx;
772 
773 		for (b = l->skip; b < l->count; b++) {
774 			val = ads7846_get_value(&packet->rx[l->offset + b]);
775 
776 			action = ts->filter(ts->filter_data, cmd_idx, &val);
777 			if (action == ADS7846_FILTER_REPEAT) {
778 				if (b == l->count - 1)
779 					return -EAGAIN;
780 			} else if (action == ADS7846_FILTER_OK) {
781 				ads7846_set_cmd_val(ts, cmd_idx, val);
782 				break;
783 			} else {
784 				packet->ignore = true;
785 				return 0;
786 			}
787 		}
788 	}
789 
790 	return 0;
791 }
792 
793 static void ads7846_read_state(struct ads7846 *ts)
794 {
795 	struct ads7846_packet *packet = ts->packet;
796 	struct spi_message *m;
797 	int msg_idx = 0;
798 	int error;
799 
800 	packet->last_cmd_idx = 0;
801 
802 	while (true) {
803 		ts->wait_for_sync();
804 
805 		m = &ts->msg[msg_idx];
806 		error = spi_sync(ts->spi, m);
807 		if (error) {
808 			dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
809 			packet->ignore = true;
810 			return;
811 		}
812 
813 		error = ads7846_filter(ts);
814 		if (error)
815 			continue;
816 
817 		return;
818 	}
819 }
820 
821 static void ads7846_report_state(struct ads7846 *ts)
822 {
823 	struct ads7846_packet *packet = ts->packet;
824 	unsigned int Rt;
825 	u16 x, y, z1, z2;
826 
827 	x = packet->x;
828 	y = packet->y;
829 	if (ts->model == 7845) {
830 		z1 = 0;
831 		z2 = 0;
832 	} else {
833 		z1 = packet->z1;
834 		z2 = packet->z2;
835 	}
836 
837 	/* range filtering */
838 	if (x == MAX_12BIT)
839 		x = 0;
840 
841 	if (ts->model == 7843 || ts->model == 7845) {
842 		Rt = ts->pressure_max / 2;
843 	} else if (likely(x && z1)) {
844 		/* compute touch pressure resistance using equation #2 */
845 		Rt = z2;
846 		Rt -= z1;
847 		Rt *= ts->x_plate_ohms;
848 		Rt = DIV_ROUND_CLOSEST(Rt, 16);
849 		Rt *= x;
850 		Rt /= z1;
851 		Rt = DIV_ROUND_CLOSEST(Rt, 256);
852 	} else {
853 		Rt = 0;
854 	}
855 
856 	/*
857 	 * Sample found inconsistent by debouncing or pressure is beyond
858 	 * the maximum. Don't report it to user space, repeat at least
859 	 * once more the measurement
860 	 */
861 	if (packet->ignore || Rt > ts->pressure_max) {
862 		dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
863 			 packet->ignore, Rt);
864 		return;
865 	}
866 
867 	/*
868 	 * Maybe check the pendown state before reporting. This discards
869 	 * false readings when the pen is lifted.
870 	 */
871 	if (ts->penirq_recheck_delay_usecs) {
872 		udelay(ts->penirq_recheck_delay_usecs);
873 		if (!get_pendown_state(ts))
874 			Rt = 0;
875 	}
876 
877 	/*
878 	 * NOTE: We can't rely on the pressure to determine the pen down
879 	 * state, even this controller has a pressure sensor. The pressure
880 	 * value can fluctuate for quite a while after lifting the pen and
881 	 * in some cases may not even settle at the expected value.
882 	 *
883 	 * The only safe way to check for the pen up condition is in the
884 	 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
885 	 */
886 	if (Rt) {
887 		struct input_dev *input = ts->input;
888 
889 		if (!ts->pendown) {
890 			input_report_key(input, BTN_TOUCH, 1);
891 			ts->pendown = true;
892 			dev_vdbg(&ts->spi->dev, "DOWN\n");
893 		}
894 
895 		touchscreen_report_pos(input, &ts->core_prop, x, y, false);
896 		input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
897 
898 		input_sync(input);
899 		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
900 	}
901 }
902 
903 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
904 {
905 	struct ads7846 *ts = handle;
906 
907 	return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
908 }
909 
910 
911 static irqreturn_t ads7846_irq(int irq, void *handle)
912 {
913 	struct ads7846 *ts = handle;
914 
915 	/* Start with a small delay before checking pendown state */
916 	msleep(TS_POLL_DELAY);
917 
918 	while (!ts->stopped && get_pendown_state(ts)) {
919 
920 		/* pen is down, continue with the measurement */
921 		ads7846_read_state(ts);
922 
923 		if (!ts->stopped)
924 			ads7846_report_state(ts);
925 
926 		wait_event_timeout(ts->wait, ts->stopped,
927 				   msecs_to_jiffies(TS_POLL_PERIOD));
928 	}
929 
930 	if (ts->pendown && !ts->stopped)
931 		ads7846_report_pen_up(ts);
932 
933 	return IRQ_HANDLED;
934 }
935 
936 static int ads7846_suspend(struct device *dev)
937 {
938 	struct ads7846 *ts = dev_get_drvdata(dev);
939 
940 	mutex_lock(&ts->lock);
941 
942 	if (!ts->suspended) {
943 
944 		if (!ts->disabled)
945 			__ads7846_disable(ts);
946 
947 		if (device_may_wakeup(&ts->spi->dev))
948 			enable_irq_wake(ts->spi->irq);
949 
950 		ts->suspended = true;
951 	}
952 
953 	mutex_unlock(&ts->lock);
954 
955 	return 0;
956 }
957 
958 static int ads7846_resume(struct device *dev)
959 {
960 	struct ads7846 *ts = dev_get_drvdata(dev);
961 
962 	mutex_lock(&ts->lock);
963 
964 	if (ts->suspended) {
965 
966 		ts->suspended = false;
967 
968 		if (device_may_wakeup(&ts->spi->dev))
969 			disable_irq_wake(ts->spi->irq);
970 
971 		if (!ts->disabled)
972 			__ads7846_enable(ts);
973 	}
974 
975 	mutex_unlock(&ts->lock);
976 
977 	return 0;
978 }
979 
980 static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
981 
982 static int ads7846_setup_pendown(struct spi_device *spi,
983 				 struct ads7846 *ts,
984 				 const struct ads7846_platform_data *pdata)
985 {
986 	/*
987 	 * REVISIT when the irq can be triggered active-low, or if for some
988 	 * reason the touchscreen isn't hooked up, we don't need to access
989 	 * the pendown state.
990 	 */
991 
992 	if (pdata->get_pendown_state) {
993 		ts->get_pendown_state = pdata->get_pendown_state;
994 	} else {
995 		ts->gpio_pendown = gpiod_get(&spi->dev, "pendown", GPIOD_IN);
996 		if (IS_ERR(ts->gpio_pendown)) {
997 			dev_err(&spi->dev, "failed to request pendown GPIO\n");
998 			return PTR_ERR(ts->gpio_pendown);
999 		}
1000 		if (pdata->gpio_pendown_debounce)
1001 			gpiod_set_debounce(ts->gpio_pendown,
1002 					   pdata->gpio_pendown_debounce);
1003 	}
1004 
1005 	return 0;
1006 }
1007 
1008 /*
1009  * Set up the transfers to read touchscreen state; this assumes we
1010  * use formula #2 for pressure, not #3.
1011  */
1012 static int ads7846_setup_spi_msg(struct ads7846 *ts,
1013 				  const struct ads7846_platform_data *pdata)
1014 {
1015 	struct spi_message *m = &ts->msg[0];
1016 	struct spi_transfer *x = ts->xfer;
1017 	struct ads7846_packet *packet = ts->packet;
1018 	int vref = pdata->keep_vref_on;
1019 	unsigned int count, offset = 0;
1020 	unsigned int cmd_idx, b;
1021 	unsigned long time;
1022 	size_t size = 0;
1023 
1024 	/* time per bit */
1025 	time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1026 
1027 	count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1028 	packet->count_skip = DIV_ROUND_UP(count, 24);
1029 
1030 	if (ts->debounce_max && ts->debounce_rep)
1031 		/* ads7846_debounce_filter() is making ts->debounce_rep + 2
1032 		 * reads. So we need to get all samples for normal case. */
1033 		packet->count = ts->debounce_rep + 2;
1034 	else
1035 		packet->count = 1;
1036 
1037 	if (ts->model == 7846)
1038 		packet->cmds = 5; /* x, y, z1, z2, pwdown */
1039 	else
1040 		packet->cmds = 3; /* x, y, pwdown */
1041 
1042 	for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1043 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1044 		unsigned int max_count;
1045 
1046 		if (cmd_idx == packet->cmds - 1)
1047 			cmd_idx = ADS7846_PWDOWN;
1048 
1049 		if (ads7846_cmd_need_settle(cmd_idx))
1050 			max_count = packet->count + packet->count_skip;
1051 		else
1052 			max_count = packet->count;
1053 
1054 		l->offset = offset;
1055 		offset += max_count;
1056 		l->count = max_count;
1057 		l->skip = packet->count_skip;
1058 		size += sizeof(*packet->tx) * max_count;
1059 	}
1060 
1061 	packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1062 	if (!packet->tx)
1063 		return -ENOMEM;
1064 
1065 	packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1066 	if (!packet->rx)
1067 		return -ENOMEM;
1068 
1069 	if (ts->model == 7873) {
1070 		/*
1071 		 * The AD7873 is almost identical to the ADS7846
1072 		 * keep VREF off during differential/ratiometric
1073 		 * conversion modes.
1074 		 */
1075 		ts->model = 7846;
1076 		vref = 0;
1077 	}
1078 
1079 	ts->msg_count = 1;
1080 	spi_message_init(m);
1081 	m->context = ts;
1082 
1083 	for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1084 		struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1085 		u8 cmd;
1086 
1087 		if (cmd_idx == packet->cmds - 1)
1088 			cmd_idx = ADS7846_PWDOWN;
1089 
1090 		cmd = ads7846_get_cmd(cmd_idx, vref);
1091 
1092 		for (b = 0; b < l->count; b++)
1093 			packet->tx[l->offset + b].cmd = cmd;
1094 	}
1095 
1096 	x->tx_buf = packet->tx;
1097 	x->rx_buf = packet->rx;
1098 	x->len = size;
1099 	spi_message_add_tail(x, m);
1100 
1101 	return 0;
1102 }
1103 
1104 static const struct of_device_id ads7846_dt_ids[] = {
1105 	{ .compatible = "ti,tsc2046",	.data = (void *) 7846 },
1106 	{ .compatible = "ti,ads7843",	.data = (void *) 7843 },
1107 	{ .compatible = "ti,ads7845",	.data = (void *) 7845 },
1108 	{ .compatible = "ti,ads7846",	.data = (void *) 7846 },
1109 	{ .compatible = "ti,ads7873",	.data = (void *) 7873 },
1110 	{ }
1111 };
1112 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1113 
1114 static const struct spi_device_id ads7846_spi_ids[] = {
1115 	{ "tsc2046", 7846 },
1116 	{ "ads7843", 7843 },
1117 	{ "ads7845", 7845 },
1118 	{ "ads7846", 7846 },
1119 	{ "ads7873", 7873 },
1120 	{ },
1121 };
1122 MODULE_DEVICE_TABLE(spi, ads7846_spi_ids);
1123 
1124 static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1125 {
1126 	struct ads7846_platform_data *pdata;
1127 	u32 value;
1128 
1129 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1130 	if (!pdata)
1131 		return ERR_PTR(-ENOMEM);
1132 
1133 	pdata->model = (uintptr_t)device_get_match_data(dev);
1134 
1135 	device_property_read_u16(dev, "ti,vref-delay-usecs",
1136 				 &pdata->vref_delay_usecs);
1137 	device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1138 	pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1139 
1140 	pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1141 
1142 	device_property_read_u16(dev, "ti,settle-delay-usec",
1143 				 &pdata->settle_delay_usecs);
1144 	device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1145 				 &pdata->penirq_recheck_delay_usecs);
1146 
1147 	device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1148 	device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1149 
1150 	device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1151 	device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1152 	device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1153 	device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1154 
1155 	/*
1156 	 * touchscreen-max-pressure gets parsed during
1157 	 * touchscreen_parse_properties()
1158 	 */
1159 	device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1160 	if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1161 		pdata->pressure_min = (u16) value;
1162 	device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1163 
1164 	device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1165 	if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1166 		pdata->debounce_max = (u16) value;
1167 	device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1168 	device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1169 
1170 	device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1171 			     &pdata->gpio_pendown_debounce);
1172 
1173 	pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1174 			device_property_read_bool(dev, "linux,wakeup");
1175 
1176 	return pdata;
1177 }
1178 
1179 static void ads7846_regulator_disable(void *regulator)
1180 {
1181 	regulator_disable(regulator);
1182 }
1183 
1184 static int ads7846_probe(struct spi_device *spi)
1185 {
1186 	const struct ads7846_platform_data *pdata;
1187 	struct ads7846 *ts;
1188 	struct device *dev = &spi->dev;
1189 	struct ads7846_packet *packet;
1190 	struct input_dev *input_dev;
1191 	unsigned long irq_flags;
1192 	int err;
1193 
1194 	if (!spi->irq) {
1195 		dev_dbg(dev, "no IRQ?\n");
1196 		return -EINVAL;
1197 	}
1198 
1199 	/* don't exceed max specified sample rate */
1200 	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1201 		dev_err(dev, "f(sample) %d KHz?\n",
1202 			(spi->max_speed_hz/SAMPLE_BITS)/1000);
1203 		return -EINVAL;
1204 	}
1205 
1206 	/*
1207 	 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1208 	 * that even if the hardware can do that, the SPI controller driver
1209 	 * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1210 	 */
1211 	spi->bits_per_word = 8;
1212 	spi->mode &= ~SPI_MODE_X_MASK;
1213 	spi->mode |= SPI_MODE_0;
1214 	err = spi_setup(spi);
1215 	if (err < 0)
1216 		return err;
1217 
1218 	ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1219 	if (!ts)
1220 		return -ENOMEM;
1221 
1222 	packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1223 	if (!packet)
1224 		return -ENOMEM;
1225 
1226 	input_dev = devm_input_allocate_device(dev);
1227 	if (!input_dev)
1228 		return -ENOMEM;
1229 
1230 	spi_set_drvdata(spi, ts);
1231 
1232 	ts->packet = packet;
1233 	ts->spi = spi;
1234 	ts->input = input_dev;
1235 
1236 	mutex_init(&ts->lock);
1237 	init_waitqueue_head(&ts->wait);
1238 
1239 	pdata = dev_get_platdata(dev);
1240 	if (!pdata) {
1241 		pdata = ads7846_get_props(dev);
1242 		if (IS_ERR(pdata))
1243 			return PTR_ERR(pdata);
1244 	}
1245 
1246 	ts->model = pdata->model ? : 7846;
1247 	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1248 	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1249 	ts->vref_mv = pdata->vref_mv;
1250 
1251 	if (pdata->debounce_max) {
1252 		ts->debounce_max = pdata->debounce_max;
1253 		if (ts->debounce_max < 2)
1254 			ts->debounce_max = 2;
1255 		ts->debounce_tol = pdata->debounce_tol;
1256 		ts->debounce_rep = pdata->debounce_rep;
1257 		ts->filter = ads7846_debounce_filter;
1258 		ts->filter_data = ts;
1259 	} else {
1260 		ts->filter = ads7846_no_filter;
1261 	}
1262 
1263 	err = ads7846_setup_pendown(spi, ts, pdata);
1264 	if (err)
1265 		return err;
1266 
1267 	if (pdata->penirq_recheck_delay_usecs)
1268 		ts->penirq_recheck_delay_usecs =
1269 				pdata->penirq_recheck_delay_usecs;
1270 
1271 	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1272 
1273 	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1274 	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1275 
1276 	input_dev->name = ts->name;
1277 	input_dev->phys = ts->phys;
1278 
1279 	input_dev->id.bustype = BUS_SPI;
1280 	input_dev->id.product = pdata->model;
1281 
1282 	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1283 	input_set_abs_params(input_dev, ABS_X,
1284 			pdata->x_min ? : 0,
1285 			pdata->x_max ? : MAX_12BIT,
1286 			0, 0);
1287 	input_set_abs_params(input_dev, ABS_Y,
1288 			pdata->y_min ? : 0,
1289 			pdata->y_max ? : MAX_12BIT,
1290 			0, 0);
1291 	if (ts->model != 7845)
1292 		input_set_abs_params(input_dev, ABS_PRESSURE,
1293 				pdata->pressure_min, pdata->pressure_max, 0, 0);
1294 
1295 	/*
1296 	 * Parse common framework properties. Must be done here to ensure the
1297 	 * correct behaviour in case of using the legacy vendor bindings. The
1298 	 * general binding value overrides the vendor specific one.
1299 	 */
1300 	touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1301 	ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1302 
1303 	/*
1304 	 * Check if legacy ti,swap-xy binding is used instead of
1305 	 * touchscreen-swapped-x-y
1306 	 */
1307 	if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1308 		swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1309 		ts->core_prop.swap_x_y = true;
1310 	}
1311 
1312 	ads7846_setup_spi_msg(ts, pdata);
1313 
1314 	ts->reg = devm_regulator_get(dev, "vcc");
1315 	if (IS_ERR(ts->reg)) {
1316 		err = PTR_ERR(ts->reg);
1317 		dev_err(dev, "unable to get regulator: %d\n", err);
1318 		return err;
1319 	}
1320 
1321 	err = regulator_enable(ts->reg);
1322 	if (err) {
1323 		dev_err(dev, "unable to enable regulator: %d\n", err);
1324 		return err;
1325 	}
1326 
1327 	err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1328 	if (err)
1329 		return err;
1330 
1331 	irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1332 	irq_flags |= IRQF_ONESHOT;
1333 
1334 	err = devm_request_threaded_irq(dev, spi->irq,
1335 					ads7846_hard_irq, ads7846_irq,
1336 					irq_flags, dev->driver->name, ts);
1337 	if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1338 		dev_info(dev,
1339 			"trying pin change workaround on irq %d\n", spi->irq);
1340 		irq_flags |= IRQF_TRIGGER_RISING;
1341 		err = devm_request_threaded_irq(dev, spi->irq,
1342 						ads7846_hard_irq, ads7846_irq,
1343 						irq_flags, dev->driver->name,
1344 						ts);
1345 	}
1346 
1347 	if (err) {
1348 		dev_dbg(dev, "irq %d busy?\n", spi->irq);
1349 		return err;
1350 	}
1351 
1352 	err = ads784x_hwmon_register(spi, ts);
1353 	if (err)
1354 		return err;
1355 
1356 	dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1357 
1358 	/*
1359 	 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1360 	 * the touchscreen, in case it's not connected.
1361 	 */
1362 	if (ts->model == 7845)
1363 		ads7845_read12_ser(dev, PWRDOWN);
1364 	else
1365 		(void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1366 
1367 	err = input_register_device(input_dev);
1368 	if (err)
1369 		return err;
1370 
1371 	device_init_wakeup(dev, pdata->wakeup);
1372 
1373 	/*
1374 	 * If device does not carry platform data we must have allocated it
1375 	 * when parsing DT data.
1376 	 */
1377 	if (!dev_get_platdata(dev))
1378 		devm_kfree(dev, (void *)pdata);
1379 
1380 	return 0;
1381 }
1382 
1383 static void ads7846_remove(struct spi_device *spi)
1384 {
1385 	struct ads7846 *ts = spi_get_drvdata(spi);
1386 
1387 	ads7846_stop(ts);
1388 }
1389 
1390 static struct spi_driver ads7846_driver = {
1391 	.driver = {
1392 		.name		= "ads7846",
1393 		.dev_groups	= ads784x_groups,
1394 		.pm		= pm_sleep_ptr(&ads7846_pm),
1395 		.of_match_table	= ads7846_dt_ids,
1396 	},
1397 	.probe		= ads7846_probe,
1398 	.remove		= ads7846_remove,
1399 	.id_table	= ads7846_spi_ids,
1400 };
1401 
1402 module_spi_driver(ads7846_driver);
1403 
1404 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1405 MODULE_LICENSE("GPL");
1406