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
  67struct 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 */
  87struct 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
  95struct 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 */
 203static 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 */
 215static 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 */
 226static 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 */
 238static 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
 249static 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
 264static 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
 287struct 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
 301struct 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
 312static 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
 386static 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 \
 425name ## _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} \
 434static 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 */
 442static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 443{
 444	return v;
 445}
 446
 447SHOW(temp0, temp0, null_adjust)		/* temp1_input */
 448SHOW(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 */
 455static 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
 466static 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
 477SHOW(in0_input, vaux, vaux_adjust)
 478SHOW(in1_input, vbatt, vbatt_adjust)
 479
 480static 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
 494static 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
 502static struct attribute_group ads7846_attr_group = {
 503	.attrs = ads7846_attributes,
 504	.is_visible = ads7846_is_visible,
 505};
 506__ATTRIBUTE_GROUPS(ads7846_attr);
 507
 508static 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
 536static 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
 544static inline int ads784x_hwmon_register(struct spi_device *spi,
 545					 struct ads7846 *ts)
 546{
 547	return 0;
 548}
 549
 550static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 551					    struct ads7846 *ts)
 552{
 553}
 554#endif
 555
 556static 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
 564static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 565
 566static 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
 574static 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
 594static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 595
 596static struct attribute *ads784x_attributes[] = {
 597	&dev_attr_pen_down.attr,
 598	&dev_attr_disable.attr,
 599	NULL,
 600};
 601
 602static struct attribute_group ads784x_attr_group = {
 603	.attrs = ads784x_attributes,
 604};
 605
 606/*--------------------------------------------------------------------------*/
 607
 608static 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
 616static void null_wait_for_sync(void)
 617{
 618}
 619
 620static 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
 662static int ads7846_no_filter(void *ads, int data_idx, int *val)
 663{
 664	return ADS7846_FILTER_OK;
 665}
 666
 667static 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
 687static 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
 695static 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
 749static 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
 847static 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
 855static 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) {
 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
 888static 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
 910static 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
 932static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 933
 934static 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 */
 976static 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
1176static 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};
1184MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1185
1186static 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
1247static 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
1254static 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
1461static int ads7846_remove(struct spi_device *spi)
1462{
1463	struct ads7846 *ts = spi_get_drvdata(spi);
1464
1465	device_init_wakeup(&spi->dev, false);
1466
1467	sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1468
1469	ads7846_disable(ts);
1470	free_irq(ts->spi->irq, ts);
1471
1472	input_unregister_device(ts->input);
1473
1474	ads784x_hwmon_unregister(spi, ts);
1475
1476	regulator_disable(ts->reg);
1477	regulator_put(ts->reg);
1478
1479	if (!ts->get_pendown_state) {
1480		/*
1481		 * If we are not using specialized pendown method we must
1482		 * have been relying on gpio we set up ourselves.
1483		 */
1484		gpio_free(ts->gpio_pendown);
1485	}
1486
1487	if (ts->filter_cleanup)
1488		ts->filter_cleanup(ts->filter_data);
1489
1490	kfree(ts->packet);
1491	kfree(ts);
1492
1493	dev_dbg(&spi->dev, "unregistered touchscreen\n");
1494
1495	return 0;
1496}
1497
1498static struct spi_driver ads7846_driver = {
1499	.driver = {
1500		.name	= "ads7846",
1501		.pm	= &ads7846_pm,
1502		.of_match_table = of_match_ptr(ads7846_dt_ids),
1503	},
1504	.probe		= ads7846_probe,
1505	.remove		= ads7846_remove,
1506};
1507
1508module_spi_driver(ads7846_driver);
1509
1510MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1511MODULE_LICENSE("GPL");
1512MODULE_ALIAS("spi:ads7846");