linux/drivers/input/touchscreen/ads7846.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * ADS7846 based touchscreen and sensor driver
   4 *
   5 * Copyright (c) 2005 David Brownell
   6 * Copyright (c) 2006 Nokia Corporation
   7 * Various changes: Imre Deak <imre.deak@nokia.com>
   8 *
   9 * Using code from:
  10 *  - corgi_ts.c
  11 *      Copyright (C) 2004-2005 Richard Purdie
  12 *  - omap_ts.[hc], ads7846.h, ts_osk.c
  13 *      Copyright (C) 2002 MontaVista Software
  14 *      Copyright (C) 2004 Texas Instruments
  15 *      Copyright (C) 2005 Dirk Behme
  16 */
  17#include <linux/types.h>
  18#include <linux/hwmon.h>
  19#include <linux/err.h>
  20#include <linux/sched.h>
  21#include <linux/delay.h>
  22#include <linux/input.h>
  23#include <linux/input/touchscreen.h>
  24#include <linux/interrupt.h>
  25#include <linux/slab.h>
  26#include <linux/pm.h>
  27#include <linux/of.h>
  28#include <linux/of_gpio.h>
  29#include <linux/of_device.h>
  30#include <linux/gpio.h>
  31#include <linux/spi/spi.h>
  32#include <linux/spi/ads7846.h>
  33#include <linux/regulator/consumer.h>
  34#include <linux/module.h>
  35#include <asm/irq.h>
  36
  37/*
  38 * This code has been heavily tested on a Nokia 770, and lightly
  39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  40 * TSC2046 is just newer ads7846 silicon.
  41 * Support for ads7843 tested on Atmel at91sam926x-EK.
  42 * Support for ads7845 has only been stubbed in.
  43 * Support for Analog Devices AD7873 and AD7843 tested.
  44 *
  45 * IRQ handling needs a workaround because of a shortcoming in handling
  46 * edge triggered IRQs on some platforms like the OMAP1/2. These
  47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  48 * have to maintain our own SW IRQ disabled status. This should be
  49 * removed as soon as the affected platform's IRQ handling is fixed.
  50 *
  51 * App note sbaa036 talks in more detail about accurate sampling...
  52 * that ought to help in situations like LCDs inducing noise (which
  53 * can also be helped by using synch signals) and more generally.
  54 * This driver tries to utilize the measures described in the app
  55 * note. The strength of filtering can be set in the board-* specific
  56 * files.
  57 */
  58
  59#define TS_POLL_DELAY   1       /* ms delay before the first sample */
  60#define TS_POLL_PERIOD  5       /* ms delay between samples */
  61
  62/* this driver doesn't aim at the peak continuous sample rate */
  63#define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  64
  65struct ts_event {
  66        /*
  67         * For portability, we can't read 12 bit values using SPI (which
  68         * would make the controller deliver them as native byte order u16
  69         * with msbs zeroed).  Instead, we read them as two 8-bit values,
  70         * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  71         */
  72        u16     x;
  73        u16     y;
  74        u16     z1, z2;
  75        bool    ignore;
  76        u8      x_buf[3];
  77        u8      y_buf[3];
  78};
  79
  80/*
  81 * We allocate this separately to avoid cache line sharing issues when
  82 * driver is used with DMA-based SPI controllers (like atmel_spi) on
  83 * systems where main memory is not DMA-coherent (most non-x86 boards).
  84 */
  85struct ads7846_packet {
  86        u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  87        u16                     dummy;          /* for the pwrdown read */
  88        struct ts_event         tc;
  89        /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  90        u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  91};
  92
  93struct ads7846 {
  94        struct input_dev        *input;
  95        char                    phys[32];
  96        char                    name[32];
  97
  98        struct spi_device       *spi;
  99        struct regulator        *reg;
 100
 101#if IS_ENABLED(CONFIG_HWMON)
 102        struct device           *hwmon;
 103#endif
 104
 105        u16                     model;
 106        u16                     vref_mv;
 107        u16                     vref_delay_usecs;
 108        u16                     x_plate_ohms;
 109        u16                     pressure_max;
 110
 111        bool                    swap_xy;
 112        bool                    use_internal;
 113
 114        struct ads7846_packet   *packet;
 115
 116        struct spi_transfer     xfer[18];
 117        struct spi_message      msg[5];
 118        int                     msg_count;
 119        wait_queue_head_t       wait;
 120
 121        bool                    pendown;
 122
 123        int                     read_cnt;
 124        int                     read_rep;
 125        int                     last_read;
 126
 127        u16                     debounce_max;
 128        u16                     debounce_tol;
 129        u16                     debounce_rep;
 130
 131        u16                     penirq_recheck_delay_usecs;
 132
 133        struct touchscreen_properties core_prop;
 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 const 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 const 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->pendown) {
 830                        input_report_key(input, BTN_TOUCH, 1);
 831                        ts->pendown = true;
 832                        dev_vdbg(&ts->spi->dev, "DOWN\n");
 833                }
 834
 835                touchscreen_report_pos(input, &ts->core_prop, x, y, false);
 836                input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 837
 838                input_sync(input);
 839                dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 840        }
 841}
 842
 843static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 844{
 845        struct ads7846 *ts = handle;
 846
 847        return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 848}
 849
 850
 851static irqreturn_t ads7846_irq(int irq, void *handle)
 852{
 853        struct ads7846 *ts = handle;
 854
 855        /* Start with a small delay before checking pendown state */
 856        msleep(TS_POLL_DELAY);
 857
 858        while (!ts->stopped && get_pendown_state(ts)) {
 859
 860                /* pen is down, continue with the measurement */
 861                ads7846_read_state(ts);
 862
 863                if (!ts->stopped)
 864                        ads7846_report_state(ts);
 865
 866                wait_event_timeout(ts->wait, ts->stopped,
 867                                   msecs_to_jiffies(TS_POLL_PERIOD));
 868        }
 869
 870        if (ts->pendown && !ts->stopped) {
 871                struct input_dev *input = ts->input;
 872
 873                input_report_key(input, BTN_TOUCH, 0);
 874                input_report_abs(input, ABS_PRESSURE, 0);
 875                input_sync(input);
 876
 877                ts->pendown = false;
 878                dev_vdbg(&ts->spi->dev, "UP\n");
 879        }
 880
 881        return IRQ_HANDLED;
 882}
 883
 884static int __maybe_unused ads7846_suspend(struct device *dev)
 885{
 886        struct ads7846 *ts = dev_get_drvdata(dev);
 887
 888        mutex_lock(&ts->lock);
 889
 890        if (!ts->suspended) {
 891
 892                if (!ts->disabled)
 893                        __ads7846_disable(ts);
 894
 895                if (device_may_wakeup(&ts->spi->dev))
 896                        enable_irq_wake(ts->spi->irq);
 897
 898                ts->suspended = true;
 899        }
 900
 901        mutex_unlock(&ts->lock);
 902
 903        return 0;
 904}
 905
 906static int __maybe_unused ads7846_resume(struct device *dev)
 907{
 908        struct ads7846 *ts = dev_get_drvdata(dev);
 909
 910        mutex_lock(&ts->lock);
 911
 912        if (ts->suspended) {
 913
 914                ts->suspended = false;
 915
 916                if (device_may_wakeup(&ts->spi->dev))
 917                        disable_irq_wake(ts->spi->irq);
 918
 919                if (!ts->disabled)
 920                        __ads7846_enable(ts);
 921        }
 922
 923        mutex_unlock(&ts->lock);
 924
 925        return 0;
 926}
 927
 928static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 929
 930static int ads7846_setup_pendown(struct spi_device *spi,
 931                                 struct ads7846 *ts,
 932                                 const struct ads7846_platform_data *pdata)
 933{
 934        int err;
 935
 936        /*
 937         * REVISIT when the irq can be triggered active-low, or if for some
 938         * reason the touchscreen isn't hooked up, we don't need to access
 939         * the pendown state.
 940         */
 941
 942        if (pdata->get_pendown_state) {
 943                ts->get_pendown_state = pdata->get_pendown_state;
 944        } else if (gpio_is_valid(pdata->gpio_pendown)) {
 945
 946                err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 947                                       "ads7846_pendown");
 948                if (err) {
 949                        dev_err(&spi->dev,
 950                                "failed to request/setup pendown GPIO%d: %d\n",
 951                                pdata->gpio_pendown, err);
 952                        return err;
 953                }
 954
 955                ts->gpio_pendown = pdata->gpio_pendown;
 956
 957                if (pdata->gpio_pendown_debounce)
 958                        gpio_set_debounce(pdata->gpio_pendown,
 959                                          pdata->gpio_pendown_debounce);
 960        } else {
 961                dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 962                return -EINVAL;
 963        }
 964
 965        return 0;
 966}
 967
 968/*
 969 * Set up the transfers to read touchscreen state; this assumes we
 970 * use formula #2 for pressure, not #3.
 971 */
 972static void ads7846_setup_spi_msg(struct ads7846 *ts,
 973                                  const struct ads7846_platform_data *pdata)
 974{
 975        struct spi_message *m = &ts->msg[0];
 976        struct spi_transfer *x = ts->xfer;
 977        struct ads7846_packet *packet = ts->packet;
 978        int vref = pdata->keep_vref_on;
 979
 980        if (ts->model == 7873) {
 981                /*
 982                 * The AD7873 is almost identical to the ADS7846
 983                 * keep VREF off during differential/ratiometric
 984                 * conversion modes.
 985                 */
 986                ts->model = 7846;
 987                vref = 0;
 988        }
 989
 990        ts->msg_count = 1;
 991        spi_message_init(m);
 992        m->context = ts;
 993
 994        if (ts->model == 7845) {
 995                packet->read_y_cmd[0] = READ_Y(vref);
 996                packet->read_y_cmd[1] = 0;
 997                packet->read_y_cmd[2] = 0;
 998                x->tx_buf = &packet->read_y_cmd[0];
 999                x->rx_buf = &packet->tc.y_buf[0];
1000                x->len = 3;
1001                spi_message_add_tail(x, m);
1002        } else {
1003                /* y- still on; turn on only y+ (and ADC) */
1004                packet->read_y = READ_Y(vref);
1005                x->tx_buf = &packet->read_y;
1006                x->len = 1;
1007                spi_message_add_tail(x, m);
1008
1009                x++;
1010                x->rx_buf = &packet->tc.y;
1011                x->len = 2;
1012                spi_message_add_tail(x, m);
1013        }
1014
1015        /*
1016         * The first sample after switching drivers can be low quality;
1017         * optionally discard it, using a second one after the signals
1018         * have had enough time to stabilize.
1019         */
1020        if (pdata->settle_delay_usecs) {
1021                x->delay_usecs = pdata->settle_delay_usecs;
1022
1023                x++;
1024                x->tx_buf = &packet->read_y;
1025                x->len = 1;
1026                spi_message_add_tail(x, m);
1027
1028                x++;
1029                x->rx_buf = &packet->tc.y;
1030                x->len = 2;
1031                spi_message_add_tail(x, m);
1032        }
1033
1034        ts->msg_count++;
1035        m++;
1036        spi_message_init(m);
1037        m->context = ts;
1038
1039        if (ts->model == 7845) {
1040                x++;
1041                packet->read_x_cmd[0] = READ_X(vref);
1042                packet->read_x_cmd[1] = 0;
1043                packet->read_x_cmd[2] = 0;
1044                x->tx_buf = &packet->read_x_cmd[0];
1045                x->rx_buf = &packet->tc.x_buf[0];
1046                x->len = 3;
1047                spi_message_add_tail(x, m);
1048        } else {
1049                /* turn y- off, x+ on, then leave in lowpower */
1050                x++;
1051                packet->read_x = READ_X(vref);
1052                x->tx_buf = &packet->read_x;
1053                x->len = 1;
1054                spi_message_add_tail(x, m);
1055
1056                x++;
1057                x->rx_buf = &packet->tc.x;
1058                x->len = 2;
1059                spi_message_add_tail(x, m);
1060        }
1061
1062        /* ... maybe discard first sample ... */
1063        if (pdata->settle_delay_usecs) {
1064                x->delay_usecs = pdata->settle_delay_usecs;
1065
1066                x++;
1067                x->tx_buf = &packet->read_x;
1068                x->len = 1;
1069                spi_message_add_tail(x, m);
1070
1071                x++;
1072                x->rx_buf = &packet->tc.x;
1073                x->len = 2;
1074                spi_message_add_tail(x, m);
1075        }
1076
1077        /* turn y+ off, x- on; we'll use formula #2 */
1078        if (ts->model == 7846) {
1079                ts->msg_count++;
1080                m++;
1081                spi_message_init(m);
1082                m->context = ts;
1083
1084                x++;
1085                packet->read_z1 = READ_Z1(vref);
1086                x->tx_buf = &packet->read_z1;
1087                x->len = 1;
1088                spi_message_add_tail(x, m);
1089
1090                x++;
1091                x->rx_buf = &packet->tc.z1;
1092                x->len = 2;
1093                spi_message_add_tail(x, m);
1094
1095                /* ... maybe discard first sample ... */
1096                if (pdata->settle_delay_usecs) {
1097                        x->delay_usecs = pdata->settle_delay_usecs;
1098
1099                        x++;
1100                        x->tx_buf = &packet->read_z1;
1101                        x->len = 1;
1102                        spi_message_add_tail(x, m);
1103
1104                        x++;
1105                        x->rx_buf = &packet->tc.z1;
1106                        x->len = 2;
1107                        spi_message_add_tail(x, m);
1108                }
1109
1110                ts->msg_count++;
1111                m++;
1112                spi_message_init(m);
1113                m->context = ts;
1114
1115                x++;
1116                packet->read_z2 = READ_Z2(vref);
1117                x->tx_buf = &packet->read_z2;
1118                x->len = 1;
1119                spi_message_add_tail(x, m);
1120
1121                x++;
1122                x->rx_buf = &packet->tc.z2;
1123                x->len = 2;
1124                spi_message_add_tail(x, m);
1125
1126                /* ... maybe discard first sample ... */
1127                if (pdata->settle_delay_usecs) {
1128                        x->delay_usecs = pdata->settle_delay_usecs;
1129
1130                        x++;
1131                        x->tx_buf = &packet->read_z2;
1132                        x->len = 1;
1133                        spi_message_add_tail(x, m);
1134
1135                        x++;
1136                        x->rx_buf = &packet->tc.z2;
1137                        x->len = 2;
1138                        spi_message_add_tail(x, m);
1139                }
1140        }
1141
1142        /* power down */
1143        ts->msg_count++;
1144        m++;
1145        spi_message_init(m);
1146        m->context = ts;
1147
1148        if (ts->model == 7845) {
1149                x++;
1150                packet->pwrdown_cmd[0] = PWRDOWN;
1151                packet->pwrdown_cmd[1] = 0;
1152                packet->pwrdown_cmd[2] = 0;
1153                x->tx_buf = &packet->pwrdown_cmd[0];
1154                x->len = 3;
1155        } else {
1156                x++;
1157                packet->pwrdown = PWRDOWN;
1158                x->tx_buf = &packet->pwrdown;
1159                x->len = 1;
1160                spi_message_add_tail(x, m);
1161
1162                x++;
1163                x->rx_buf = &packet->dummy;
1164                x->len = 2;
1165        }
1166
1167        CS_CHANGE(*x);
1168        spi_message_add_tail(x, m);
1169}
1170
1171#ifdef CONFIG_OF
1172static const struct of_device_id ads7846_dt_ids[] = {
1173        { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
1174        { .compatible = "ti,ads7843",   .data = (void *) 7843 },
1175        { .compatible = "ti,ads7845",   .data = (void *) 7845 },
1176        { .compatible = "ti,ads7846",   .data = (void *) 7846 },
1177        { .compatible = "ti,ads7873",   .data = (void *) 7873 },
1178        { }
1179};
1180MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1181
1182static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1183{
1184        struct ads7846_platform_data *pdata;
1185        struct device_node *node = dev->of_node;
1186        const struct of_device_id *match;
1187        u32 value;
1188
1189        if (!node) {
1190                dev_err(dev, "Device does not have associated DT data\n");
1191                return ERR_PTR(-EINVAL);
1192        }
1193
1194        match = of_match_device(ads7846_dt_ids, dev);
1195        if (!match) {
1196                dev_err(dev, "Unknown device model\n");
1197                return ERR_PTR(-EINVAL);
1198        }
1199
1200        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1201        if (!pdata)
1202                return ERR_PTR(-ENOMEM);
1203
1204        pdata->model = (unsigned long)match->data;
1205
1206        of_property_read_u16(node, "ti,vref-delay-usecs",
1207                             &pdata->vref_delay_usecs);
1208        of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1209        pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1210
1211        pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1212
1213        of_property_read_u16(node, "ti,settle-delay-usec",
1214                             &pdata->settle_delay_usecs);
1215        of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1216                             &pdata->penirq_recheck_delay_usecs);
1217
1218        of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1219        of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1220
1221        of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1222        of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1223        of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1224        of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1225
1226        /*
1227         * touchscreen-max-pressure gets parsed during
1228         * touchscreen_parse_properties()
1229         */
1230        of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1231        if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1232                pdata->pressure_min = (u16) value;
1233        of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1234
1235        of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1236        if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1237                pdata->debounce_max = (u16) value;
1238        of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1239        of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1240
1241        of_property_read_u32(node, "ti,pendown-gpio-debounce",
1242                             &pdata->gpio_pendown_debounce);
1243
1244        pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1245                        of_property_read_bool(node, "linux,wakeup");
1246
1247        pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1248
1249        return pdata;
1250}
1251#else
1252static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1253{
1254        dev_err(dev, "no platform data defined\n");
1255        return ERR_PTR(-EINVAL);
1256}
1257#endif
1258
1259static int ads7846_probe(struct spi_device *spi)
1260{
1261        const struct ads7846_platform_data *pdata;
1262        struct ads7846 *ts;
1263        struct ads7846_packet *packet;
1264        struct input_dev *input_dev;
1265        unsigned long irq_flags;
1266        int err;
1267
1268        if (!spi->irq) {
1269                dev_dbg(&spi->dev, "no IRQ?\n");
1270                return -EINVAL;
1271        }
1272
1273        /* don't exceed max specified sample rate */
1274        if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1275                dev_err(&spi->dev, "f(sample) %d KHz?\n",
1276                                (spi->max_speed_hz/SAMPLE_BITS)/1000);
1277                return -EINVAL;
1278        }
1279
1280        /*
1281         * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1282         * that even if the hardware can do that, the SPI controller driver
1283         * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1284         */
1285        spi->bits_per_word = 8;
1286        spi->mode = SPI_MODE_0;
1287        err = spi_setup(spi);
1288        if (err < 0)
1289                return err;
1290
1291        ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1292        packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1293        input_dev = input_allocate_device();
1294        if (!ts || !packet || !input_dev) {
1295                err = -ENOMEM;
1296                goto err_free_mem;
1297        }
1298
1299        spi_set_drvdata(spi, ts);
1300
1301        ts->packet = packet;
1302        ts->spi = spi;
1303        ts->input = input_dev;
1304
1305        mutex_init(&ts->lock);
1306        init_waitqueue_head(&ts->wait);
1307
1308        pdata = dev_get_platdata(&spi->dev);
1309        if (!pdata) {
1310                pdata = ads7846_probe_dt(&spi->dev);
1311                if (IS_ERR(pdata)) {
1312                        err = PTR_ERR(pdata);
1313                        goto err_free_mem;
1314                }
1315        }
1316
1317        ts->model = pdata->model ? : 7846;
1318        ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1319        ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1320        ts->vref_mv = pdata->vref_mv;
1321
1322        if (pdata->filter != NULL) {
1323                if (pdata->filter_init != NULL) {
1324                        err = pdata->filter_init(pdata, &ts->filter_data);
1325                        if (err < 0)
1326                                goto err_free_mem;
1327                }
1328                ts->filter = pdata->filter;
1329                ts->filter_cleanup = pdata->filter_cleanup;
1330        } else if (pdata->debounce_max) {
1331                ts->debounce_max = pdata->debounce_max;
1332                if (ts->debounce_max < 2)
1333                        ts->debounce_max = 2;
1334                ts->debounce_tol = pdata->debounce_tol;
1335                ts->debounce_rep = pdata->debounce_rep;
1336                ts->filter = ads7846_debounce_filter;
1337                ts->filter_data = ts;
1338        } else {
1339                ts->filter = ads7846_no_filter;
1340        }
1341
1342        err = ads7846_setup_pendown(spi, ts, pdata);
1343        if (err)
1344                goto err_cleanup_filter;
1345
1346        if (pdata->penirq_recheck_delay_usecs)
1347                ts->penirq_recheck_delay_usecs =
1348                                pdata->penirq_recheck_delay_usecs;
1349
1350        ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1351
1352        snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1353        snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1354
1355        input_dev->name = ts->name;
1356        input_dev->phys = ts->phys;
1357        input_dev->dev.parent = &spi->dev;
1358
1359        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1360        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1361        input_set_abs_params(input_dev, ABS_X,
1362                        pdata->x_min ? : 0,
1363                        pdata->x_max ? : MAX_12BIT,
1364                        0, 0);
1365        input_set_abs_params(input_dev, ABS_Y,
1366                        pdata->y_min ? : 0,
1367                        pdata->y_max ? : MAX_12BIT,
1368                        0, 0);
1369        input_set_abs_params(input_dev, ABS_PRESSURE,
1370                        pdata->pressure_min, pdata->pressure_max, 0, 0);
1371
1372        /*
1373         * Parse common framework properties. Must be done here to ensure the
1374         * correct behaviour in case of using the legacy vendor bindings. The
1375         * general binding value overrides the vendor specific one.
1376         */
1377        touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1378        ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1379
1380        /*
1381         * Check if legacy ti,swap-xy binding is used instead of
1382         * touchscreen-swapped-x-y
1383         */
1384        if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1385                swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1386                ts->core_prop.swap_x_y = true;
1387        }
1388
1389        ads7846_setup_spi_msg(ts, pdata);
1390
1391        ts->reg = regulator_get(&spi->dev, "vcc");
1392        if (IS_ERR(ts->reg)) {
1393                err = PTR_ERR(ts->reg);
1394                dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1395                goto err_free_gpio;
1396        }
1397
1398        err = regulator_enable(ts->reg);
1399        if (err) {
1400                dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1401                goto err_put_regulator;
1402        }
1403
1404        irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1405        irq_flags |= IRQF_ONESHOT;
1406
1407        err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1408                                   irq_flags, spi->dev.driver->name, ts);
1409        if (err && !pdata->irq_flags) {
1410                dev_info(&spi->dev,
1411                        "trying pin change workaround on irq %d\n", spi->irq);
1412                irq_flags |= IRQF_TRIGGER_RISING;
1413                err = request_threaded_irq(spi->irq,
1414                                  ads7846_hard_irq, ads7846_irq,
1415                                  irq_flags, spi->dev.driver->name, ts);
1416        }
1417
1418        if (err) {
1419                dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1420                goto err_disable_regulator;
1421        }
1422
1423        err = ads784x_hwmon_register(spi, ts);
1424        if (err)
1425                goto err_free_irq;
1426
1427        dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1428
1429        /*
1430         * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1431         * the touchscreen, in case it's not connected.
1432         */
1433        if (ts->model == 7845)
1434                ads7845_read12_ser(&spi->dev, PWRDOWN);
1435        else
1436                (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1437
1438        err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1439        if (err)
1440                goto err_remove_hwmon;
1441
1442        err = input_register_device(input_dev);
1443        if (err)
1444                goto err_remove_attr_group;
1445
1446        device_init_wakeup(&spi->dev, pdata->wakeup);
1447
1448        /*
1449         * If device does not carry platform data we must have allocated it
1450         * when parsing DT data.
1451         */
1452        if (!dev_get_platdata(&spi->dev))
1453                devm_kfree(&spi->dev, (void *)pdata);
1454
1455        return 0;
1456
1457 err_remove_attr_group:
1458        sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1459 err_remove_hwmon:
1460        ads784x_hwmon_unregister(spi, ts);
1461 err_free_irq:
1462        free_irq(spi->irq, ts);
1463 err_disable_regulator:
1464        regulator_disable(ts->reg);
1465 err_put_regulator:
1466        regulator_put(ts->reg);
1467 err_free_gpio:
1468        if (!ts->get_pendown_state)
1469                gpio_free(ts->gpio_pendown);
1470 err_cleanup_filter:
1471        if (ts->filter_cleanup)
1472                ts->filter_cleanup(ts->filter_data);
1473 err_free_mem:
1474        input_free_device(input_dev);
1475        kfree(packet);
1476        kfree(ts);
1477        return err;
1478}
1479
1480static int ads7846_remove(struct spi_device *spi)
1481{
1482        struct ads7846 *ts = spi_get_drvdata(spi);
1483
1484        sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1485
1486        ads7846_disable(ts);
1487        free_irq(ts->spi->irq, ts);
1488
1489        input_unregister_device(ts->input);
1490
1491        ads784x_hwmon_unregister(spi, ts);
1492
1493        regulator_put(ts->reg);
1494
1495        if (!ts->get_pendown_state) {
1496                /*
1497                 * If we are not using specialized pendown method we must
1498                 * have been relying on gpio we set up ourselves.
1499                 */
1500                gpio_free(ts->gpio_pendown);
1501        }
1502
1503        if (ts->filter_cleanup)
1504                ts->filter_cleanup(ts->filter_data);
1505
1506        kfree(ts->packet);
1507        kfree(ts);
1508
1509        dev_dbg(&spi->dev, "unregistered touchscreen\n");
1510
1511        return 0;
1512}
1513
1514static struct spi_driver ads7846_driver = {
1515        .driver = {
1516                .name   = "ads7846",
1517                .pm     = &ads7846_pm,
1518                .of_match_table = of_match_ptr(ads7846_dt_ids),
1519        },
1520        .probe          = ads7846_probe,
1521        .remove         = ads7846_remove,
1522};
1523
1524module_spi_driver(ads7846_driver);
1525
1526MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1527MODULE_LICENSE("GPL");
1528MODULE_ALIAS("spi:ads7846");
1529