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
  63struct ads7846_buf {
  64	u8 cmd;
  65	__be16 data;
  66} __packed;
  67
  68struct 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 */
  79struct 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
  94struct 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
 145enum 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 */
 210enum ads7846_cmds {
 211	ADS7846_X,
 212	ADS7846_Y,
 213	ADS7846_Z1,
 214	ADS7846_Z2,
 215	ADS7846_PWDOWN,
 216};
 217
 218static 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
 226static 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 */
 239static 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 */
 251static 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 */
 266static 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 */
 278static 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
 289static 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
 304static 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
 327struct 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
 341struct 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
 352static 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
 427static 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 \
 466name ## _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} \
 475static 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 */
 483static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 484{
 485	return v;
 486}
 487
 488SHOW(temp0, temp0, null_adjust)		/* temp1_input */
 489SHOW(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 */
 496static 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
 507static 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
 518SHOW(in0_input, vaux, vaux_adjust)
 519SHOW(in1_input, vbatt, vbatt_adjust)
 520
 521static 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
 535static 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
 543static const struct attribute_group ads7846_attr_group = {
 544	.attrs = ads7846_attributes,
 545	.is_visible = ads7846_is_visible,
 546};
 547__ATTRIBUTE_GROUPS(ads7846_attr);
 548
 549static 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
 581static inline int ads784x_hwmon_register(struct spi_device *spi,
 582					 struct ads7846 *ts)
 583{
 584	return 0;
 585}
 586#endif
 587
 588static 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
 596static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 597
 598static 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
 606static 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
 626static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 627
 628static struct attribute *ads784x_attrs[] = {
 629	&dev_attr_pen_down.attr,
 630	&dev_attr_disable.attr,
 631	NULL,
 632};
 633ATTRIBUTE_GROUPS(ads784x);
 634
 635/*--------------------------------------------------------------------------*/
 636
 637static void null_wait_for_sync(void)
 638{
 639}
 640
 641static 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
 683static int ads7846_no_filter(void *ads, int data_idx, int *val)
 684{
 685	return ADS7846_FILTER_OK;
 686}
 687
 688static 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
 698static 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
 721static 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
 743static 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
 760static 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
 793static 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
 821static 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
 903static 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
 911static 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
 936static 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
 958static 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
 980static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 981
 982static 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 */
1012static 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
1104static 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};
1112MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1113
1114static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1115{
1116	struct ads7846_platform_data *pdata;
1117	u32 value;
1118
1119	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1120	if (!pdata)
1121		return ERR_PTR(-ENOMEM);
1122
1123	pdata->model = (uintptr_t)device_get_match_data(dev);
1124
1125	device_property_read_u16(dev, "ti,vref-delay-usecs",
1126				 &pdata->vref_delay_usecs);
1127	device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1128	pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1129
1130	pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1131
1132	device_property_read_u16(dev, "ti,settle-delay-usec",
1133				 &pdata->settle_delay_usecs);
1134	device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1135				 &pdata->penirq_recheck_delay_usecs);
1136
1137	device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1138	device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1139
1140	device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1141	device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1142	device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1143	device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1144
1145	/*
1146	 * touchscreen-max-pressure gets parsed during
1147	 * touchscreen_parse_properties()
1148	 */
1149	device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1150	if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1151		pdata->pressure_min = (u16) value;
1152	device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1153
1154	device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1155	if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1156		pdata->debounce_max = (u16) value;
1157	device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1158	device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1159
1160	device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1161			     &pdata->gpio_pendown_debounce);
1162
1163	pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1164			device_property_read_bool(dev, "linux,wakeup");
1165
1166	return pdata;
1167}
1168
1169static void ads7846_regulator_disable(void *regulator)
1170{
1171	regulator_disable(regulator);
1172}
1173
1174static int ads7846_probe(struct spi_device *spi)
1175{
1176	const struct ads7846_platform_data *pdata;
1177	struct ads7846 *ts;
1178	struct device *dev = &spi->dev;
1179	struct ads7846_packet *packet;
1180	struct input_dev *input_dev;
1181	unsigned long irq_flags;
1182	int err;
1183
1184	if (!spi->irq) {
1185		dev_dbg(dev, "no IRQ?\n");
1186		return -EINVAL;
1187	}
1188
1189	/* don't exceed max specified sample rate */
1190	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1191		dev_err(dev, "f(sample) %d KHz?\n",
1192			(spi->max_speed_hz/SAMPLE_BITS)/1000);
1193		return -EINVAL;
1194	}
1195
1196	/*
1197	 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1198	 * that even if the hardware can do that, the SPI controller driver
1199	 * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1200	 */
1201	spi->bits_per_word = 8;
1202	spi->mode &= ~SPI_MODE_X_MASK;
1203	spi->mode |= SPI_MODE_0;
1204	err = spi_setup(spi);
1205	if (err < 0)
1206		return err;
1207
1208	ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1209	if (!ts)
1210		return -ENOMEM;
1211
1212	packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1213	if (!packet)
1214		return -ENOMEM;
1215
1216	input_dev = devm_input_allocate_device(dev);
1217	if (!input_dev)
1218		return -ENOMEM;
1219
1220	spi_set_drvdata(spi, ts);
1221
1222	ts->packet = packet;
1223	ts->spi = spi;
1224	ts->input = input_dev;
1225
1226	mutex_init(&ts->lock);
1227	init_waitqueue_head(&ts->wait);
1228
1229	pdata = dev_get_platdata(dev);
1230	if (!pdata) {
1231		pdata = ads7846_get_props(dev);
1232		if (IS_ERR(pdata))
1233			return PTR_ERR(pdata);
1234	}
1235
1236	ts->model = pdata->model ? : 7846;
1237	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1238	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1239	ts->vref_mv = pdata->vref_mv;
1240
1241	if (pdata->debounce_max) {
1242		ts->debounce_max = pdata->debounce_max;
1243		if (ts->debounce_max < 2)
1244			ts->debounce_max = 2;
1245		ts->debounce_tol = pdata->debounce_tol;
1246		ts->debounce_rep = pdata->debounce_rep;
1247		ts->filter = ads7846_debounce_filter;
1248		ts->filter_data = ts;
1249	} else {
1250		ts->filter = ads7846_no_filter;
1251	}
1252
1253	err = ads7846_setup_pendown(spi, ts, pdata);
1254	if (err)
1255		return err;
1256
1257	if (pdata->penirq_recheck_delay_usecs)
1258		ts->penirq_recheck_delay_usecs =
1259				pdata->penirq_recheck_delay_usecs;
1260
1261	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1262
1263	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1264	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1265
1266	input_dev->name = ts->name;
1267	input_dev->phys = ts->phys;
1268
1269	input_dev->id.bustype = BUS_SPI;
1270	input_dev->id.product = pdata->model;
1271
1272	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1273	input_set_abs_params(input_dev, ABS_X,
1274			pdata->x_min ? : 0,
1275			pdata->x_max ? : MAX_12BIT,
1276			0, 0);
1277	input_set_abs_params(input_dev, ABS_Y,
1278			pdata->y_min ? : 0,
1279			pdata->y_max ? : MAX_12BIT,
1280			0, 0);
1281	if (ts->model != 7845)
1282		input_set_abs_params(input_dev, ABS_PRESSURE,
1283				pdata->pressure_min, pdata->pressure_max, 0, 0);
1284
1285	/*
1286	 * Parse common framework properties. Must be done here to ensure the
1287	 * correct behaviour in case of using the legacy vendor bindings. The
1288	 * general binding value overrides the vendor specific one.
1289	 */
1290	touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1291	ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1292
1293	/*
1294	 * Check if legacy ti,swap-xy binding is used instead of
1295	 * touchscreen-swapped-x-y
1296	 */
1297	if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1298		swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1299		ts->core_prop.swap_x_y = true;
1300	}
1301
1302	ads7846_setup_spi_msg(ts, pdata);
1303
1304	ts->reg = devm_regulator_get(dev, "vcc");
1305	if (IS_ERR(ts->reg)) {
1306		err = PTR_ERR(ts->reg);
1307		dev_err(dev, "unable to get regulator: %d\n", err);
1308		return err;
1309	}
1310
1311	err = regulator_enable(ts->reg);
1312	if (err) {
1313		dev_err(dev, "unable to enable regulator: %d\n", err);
1314		return err;
1315	}
1316
1317	err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1318	if (err)
1319		return err;
1320
1321	irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1322	irq_flags |= IRQF_ONESHOT;
1323
1324	err = devm_request_threaded_irq(dev, spi->irq,
1325					ads7846_hard_irq, ads7846_irq,
1326					irq_flags, dev->driver->name, ts);
1327	if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1328		dev_info(dev,
1329			"trying pin change workaround on irq %d\n", spi->irq);
1330		irq_flags |= IRQF_TRIGGER_RISING;
1331		err = devm_request_threaded_irq(dev, spi->irq,
1332						ads7846_hard_irq, ads7846_irq,
1333						irq_flags, dev->driver->name,
1334						ts);
1335	}
1336
1337	if (err) {
1338		dev_dbg(dev, "irq %d busy?\n", spi->irq);
1339		return err;
1340	}
1341
1342	err = ads784x_hwmon_register(spi, ts);
1343	if (err)
1344		return err;
1345
1346	dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1347
1348	/*
1349	 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1350	 * the touchscreen, in case it's not connected.
1351	 */
1352	if (ts->model == 7845)
1353		ads7845_read12_ser(dev, PWRDOWN);
1354	else
1355		(void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1356
1357	err = input_register_device(input_dev);
1358	if (err)
1359		return err;
1360
1361	device_init_wakeup(dev, pdata->wakeup);
1362
1363	/*
1364	 * If device does not carry platform data we must have allocated it
1365	 * when parsing DT data.
1366	 */
1367	if (!dev_get_platdata(dev))
1368		devm_kfree(dev, (void *)pdata);
1369
1370	return 0;
1371}
1372
1373static void ads7846_remove(struct spi_device *spi)
1374{
1375	struct ads7846 *ts = spi_get_drvdata(spi);
1376
1377	ads7846_stop(ts);
1378}
1379
1380static struct spi_driver ads7846_driver = {
1381	.driver = {
1382		.name		= "ads7846",
1383		.dev_groups	= ads784x_groups,
1384		.pm		= pm_sleep_ptr(&ads7846_pm),
1385		.of_match_table	= ads7846_dt_ids,
1386	},
1387	.probe		= ads7846_probe,
1388	.remove		= ads7846_remove,
1389};
1390
1391module_spi_driver(ads7846_driver);
1392
1393MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1394MODULE_LICENSE("GPL");
1395MODULE_ALIAS("spi:ads7846");