drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  * Copyright (c) 2006 Nokia Corporation
   6  * Various changes: Imre Deak <imre.deak@nokia.com>
   7  *
   8  * Using code from:
   9  *  - corgi_ts.c
  10  *      Copyright (C) 2004-2005 Richard Purdie
  11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  12  *      Copyright (C) 2002 MontaVista Software
  13  *      Copyright (C) 2004 Texas Instruments
  14  *      Copyright (C) 2005 Dirk Behme
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2 as
  18  *  published by the Free Software Foundation.
  19  */
  20 #include <linux/types.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/err.h>
  23 #include <linux/sched.h>
  24 #include <linux/delay.h>
  25 #include <linux/input.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/slab.h>
  28 #include <linux/pm.h>
  29 #include <linux/of.h>
  30 #include <linux/of_gpio.h>
  31 #include <linux/of_device.h>
  32 #include <linux/gpio.h>
  33 #include <linux/spi/spi.h>
  34 #include <linux/spi/ads7846.h>
  35 #include <linux/regulator/consumer.h>
  36 #include <linux/module.h>
  37 #include <asm/irq.h>
  38 #include <asm/unaligned.h>
  39
  40 /*
  41  * This code has been heavily tested on a Nokia 770, and lightly
  42  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  43  * TSC2046 is just newer ads7846 silicon.
  44  * Support for ads7843 tested on Atmel at91sam926x-EK.
  45  * Support for ads7845 has only been stubbed in.
  46  * Support for Analog Devices AD7873 and AD7843 tested.
  47  *
  48  * IRQ handling needs a workaround because of a shortcoming in handling
  49  * edge triggered IRQs on some platforms like the OMAP1/2. These
  50  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  51  * have to maintain our own SW IRQ disabled status. This should be
  52  * removed as soon as the affected platform's IRQ handling is fixed.
  53  *
  54  * App note sbaa036 talks in more detail about accurate sampling...
  55  * that ought to help in situations like LCDs inducing noise (which
  56  * can also be helped by using synch signals) and more generally.
  57  * This driver tries to utilize the measures described in the app
  58  * note. The strength of filtering can be set in the board-* specific
  59  * files.
  60  */
  61
  62 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
  63 #define TS_POLL_PERIOD  5       /* ms delay between samples */
  64
  65 /* this driver doesn't aim at the peak continuous sample rate */
  66 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  67
  68 struct ts_event {
  69         /*
  70          * For portability, we can't read 12 bit values using SPI (which
  71          * would make the controller deliver them as native byte order u16
  72          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  73          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  74          */
  75         u16     x;
  76         u16     y;
  77         u16     z1, z2;
  78         bool    ignore;
  79         u8      x_buf[3];
  80         u8      y_buf[3];
  81 };
  82
  83 /*
  84  * We allocate this separately to avoid cache line sharing issues when
  85  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  86  * systems where main memory is not DMA-coherent (most non-x86 boards).
  87  */
  88 struct ads7846_packet {
  89         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  90         u16                     dummy;          /* for the pwrdown read */
  91         struct ts_event         tc;
  92         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  93         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  94 };
  95
  96 struct ads7846 {
  97         struct input_dev        *input;
  98         char                    phys[32];
  99         char                    name[32];
 100
 101         struct spi_device       *spi;
 102         struct regulator        *reg;
 103
 104 #if IS_ENABLED(CONFIG_HWMON)
 105         struct device           *hwmon;
 106 #endif
 107
 108         u16                     model;
 109         u16                     vref_mv;
 110         u16                     vref_delay_usecs;
 111         u16                     x_plate_ohms;
 112         u16                     pressure_max;
 113
 114         bool                    swap_xy;
 115         bool                    use_internal;
 116
 117         struct ads7846_packet   *packet;
 118
 119         struct spi_transfer     xfer[18];
 120         struct spi_message      msg[5];
 121         int                     msg_count;
 122         wait_queue_head_t       wait;
 123
 124         bool                    pendown;
 125
 126         int                     read_cnt;
 127         int                     read_rep;
 128         int                     last_read;
 129
 130         u16                     debounce_max;
 131         u16                     debounce_tol;
 132         u16                     debounce_rep;
 133
 134         u16                     penirq_recheck_delay_usecs;
 135
 136         struct mutex            lock;
 137         bool                    stopped;        /* P: lock */
 138         bool                    disabled;       /* P: lock */
 139         bool                    suspended;      /* P: lock */
 140
 141         int                     (*filter)(void *data, int data_idx, int *val);
 142         void                    *filter_data;
 143         void                    (*filter_cleanup)(void *data);
 144         int                     (*get_pendown_state)(void);
 145         int                     gpio_pendown;
 146
 147         void                    (*wait_for_sync)(void);
 148 };
 149
 150 /* leave chip selected when we're done, for quicker re-select? */
 151 #if     0
 152 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 153 #else
 154 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 155 #endif
 156
 157 /*--------------------------------------------------------------------------*/
 158
 159 /* The ADS7846 has touchscreen and other sensors.
 160  * Earlier ads784x chips are somewhat compatible.
 161  */
 162 #define ADS_START               (1 << 7)
 163 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 164 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 165 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 166 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 167 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 168 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 169 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 170 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 171 #define ADS_8_BIT               (1 << 3)
 172 #define ADS_12_BIT              (0 << 3)
 173 #define ADS_SER                 (1 << 2)        /* non-differential */
 174 #define ADS_DFR                 (0 << 2)        /* differential */
 175 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 176 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 177 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 178 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 179
 180 #define MAX_12BIT       ((1<<12)-1)
 181
 182 /* leave ADC powered up (disables penirq) between differential samples */
 183 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 184         | ADS_12_BIT | ADS_DFR | \
 185         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 186
 187 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 188 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 189 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 190
 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 static int get_pendown_state(struct ads7846 *ts)
 204 {
 205         if (ts->get_pendown_state)
 206                 return ts->get_pendown_state();
 207
 208         return !gpio_get_value(ts->gpio_pendown);
 209 }
 210
 211 static void ads7846_report_pen_up(struct ads7846 *ts)
 212 {
 213         struct input_dev *input = ts->input;
 214
 215         input_report_key(input, BTN_TOUCH, 0);
 216         input_report_abs(input, ABS_PRESSURE, 0);
 217         input_sync(input);
 218
 219         ts->pendown = false;
 220         dev_vdbg(&ts->spi->dev, "UP\n");
 221 }
 222
 223 /* Must be called with ts->lock held */
 224 static void ads7846_stop(struct ads7846 *ts)
 225 {
 226         if (!ts->disabled && !ts->suspended) {
 227                 /* Signal IRQ thread to stop polling and disable the handler. */
 228                 ts->stopped = true;
 229                 mb();
 230                 wake_up(&ts->wait);
 231                 disable_irq(ts->spi->irq);
 232         }
 233 }
 234
 235 /* Must be called with ts->lock held */
 236 static void ads7846_restart(struct ads7846 *ts)
 237 {
 238         if (!ts->disabled && !ts->suspended) {
 239                 /* Check if pen was released since last stop */
 240                 if (ts->pendown && !get_pendown_state(ts))
 241                         ads7846_report_pen_up(ts);
 242
 243                 /* Tell IRQ thread that it may poll the device. */
 244                 ts->stopped = false;
 245                 mb();
 246                 enable_irq(ts->spi->irq);
 247         }
 248 }
 249
 250 /* Must be called with ts->lock held */
 251 static void __ads7846_disable(struct ads7846 *ts)
 252 {
 253         ads7846_stop(ts);
 254         regulator_disable(ts->reg);
 255
 256         /*
 257          * We know the chip's in low power mode since we always
 258          * leave it that way after every request
 259          */
 260 }
 261
 262 /* Must be called with ts->lock held */
 263 static void __ads7846_enable(struct ads7846 *ts)
 264 {
 265         int error;
 266
 267         error = regulator_enable(ts->reg);
 268         if (error != 0)
 269                 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
 270
 271         ads7846_restart(ts);
 272 }
 273
 274 static void ads7846_disable(struct ads7846 *ts)
 275 {
 276         mutex_lock(&ts->lock);
 277
 278         if (!ts->disabled) {
 279
 280                 if  (!ts->suspended)
 281                         __ads7846_disable(ts);
 282
 283                 ts->disabled = true;
 284         }
 285
 286         mutex_unlock(&ts->lock);
 287 }
 288
 289 static void ads7846_enable(struct ads7846 *ts)
 290 {
 291         mutex_lock(&ts->lock);
 292
 293         if (ts->disabled) {
 294
 295                 ts->disabled = false;
 296
 297                 if (!ts->suspended)
 298                         __ads7846_enable(ts);
 299         }
 300
 301         mutex_unlock(&ts->lock);
 302 }
 303
 304 /*--------------------------------------------------------------------------*/
 305
 306 /*
 307  * Non-touchscreen sensors only use single-ended conversions.
 308  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 309  * ads7846 lets that pin be unconnected, to use internal vREF.
 310  */
 311
 312 struct ser_req {
 313         u8                      ref_on;
 314         u8                      command;
 315         u8                      ref_off;
 316         u16                     scratch;
 317         struct spi_message      msg;
 318         struct spi_transfer     xfer[6];
 319         /*
 320          * DMA (thus cache coherency maintenance) requires the
 321          * transfer buffers to live in their own cache lines.
 322          */
 323         __be16 sample ____cacheline_aligned;
 324 };
 325
 326 struct ads7845_ser_req {
 327         u8                      command[3];
 328         struct spi_message      msg;
 329         struct spi_transfer     xfer[2];
 330         /*
 331          * DMA (thus cache coherency maintenance) requires the
 332          * transfer buffers to live in their own cache lines.
 333          */
 334         u8 sample[3] ____cacheline_aligned;
 335 };
 336
 337 static int ads7846_read12_ser(struct device *dev, unsigned command)
 338 {
 339         struct spi_device *spi = to_spi_device(dev);
 340         struct ads7846 *ts = dev_get_drvdata(dev);
 341         struct ser_req *req;
 342         int status;
 343
 344         req = kzalloc(sizeof *req, GFP_KERNEL);
 345         if (!req)
 346                 return -ENOMEM;
 347
 348         spi_message_init(&req->msg);
 349
 350         /* maybe turn on internal vREF, and let it settle */
 351         if (ts->use_internal) {
 352                 req->ref_on = REF_ON;
 353                 req->xfer[0].tx_buf = &req->ref_on;
 354                 req->xfer[0].len = 1;
 355                 spi_message_add_tail(&req->xfer[0], &req->msg);
 356
 357                 req->xfer[1].rx_buf = &req->scratch;
 358                 req->xfer[1].len = 2;
 359
 360                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 361                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 362                 spi_message_add_tail(&req->xfer[1], &req->msg);
 363
 364                 /* Enable reference voltage */
 365                 command |= ADS_PD10_REF_ON;
 366         }
 367
 368         /* Enable ADC in every case */
 369         command |= ADS_PD10_ADC_ON;
 370
 371         /* take sample */
 372         req->command = (u8) command;
 373         req->xfer[2].tx_buf = &req->command;
 374         req->xfer[2].len = 1;
 375         spi_message_add_tail(&req->xfer[2], &req->msg);
 376
 377         req->xfer[3].rx_buf = &req->sample;
 378         req->xfer[3].len = 2;
 379         spi_message_add_tail(&req->xfer[3], &req->msg);
 380
 381         /* REVISIT:  take a few more samples, and compare ... */
 382
 383         /* converter in low power mode & enable PENIRQ */
 384         req->ref_off = PWRDOWN;
 385         req->xfer[4].tx_buf = &req->ref_off;
 386         req->xfer[4].len = 1;
 387         spi_message_add_tail(&req->xfer[4], &req->msg);
 388
 389         req->xfer[5].rx_buf = &req->scratch;
 390         req->xfer[5].len = 2;
 391         CS_CHANGE(req->xfer[5]);
 392         spi_message_add_tail(&req->xfer[5], &req->msg);
 393
 394         mutex_lock(&ts->lock);
 395         ads7846_stop(ts);
 396         status = spi_sync(spi, &req->msg);
 397         ads7846_restart(ts);
 398         mutex_unlock(&ts->lock);
 399
 400         if (status == 0) {
 401                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 402                 status = be16_to_cpu(req->sample);
 403                 status = status >> 3;
 404                 status &= 0x0fff;
 405         }
 406
 407         kfree(req);
 408         return status;
 409 }
 410
 411 static int ads7845_read12_ser(struct device *dev, unsigned command)
 412 {
 413         struct spi_device *spi = to_spi_device(dev);
 414         struct ads7846 *ts = dev_get_drvdata(dev);
 415         struct ads7845_ser_req *req;
 416         int status;
 417
 418         req = kzalloc(sizeof *req, GFP_KERNEL);
 419         if (!req)
 420                 return -ENOMEM;
 421
 422         spi_message_init(&req->msg);
 423
 424         req->command[0] = (u8) command;
 425         req->xfer[0].tx_buf = req->command;
 426         req->xfer[0].rx_buf = req->sample;
 427         req->xfer[0].len = 3;
 428         spi_message_add_tail(&req->xfer[0], &req->msg);
 429
 430         mutex_lock(&ts->lock);
 431         ads7846_stop(ts);
 432         status = spi_sync(spi, &req->msg);
 433         ads7846_restart(ts);
 434         mutex_unlock(&ts->lock);
 435
 436         if (status == 0) {
 437                 /* BE12 value, then padding */
 438                 status = get_unaligned_be16(&req->sample[1]);
 439                 status = status >> 3;
 440                 status &= 0x0fff;
 441         }
 442
 443         kfree(req);
 444         return status;
 445 }
 446
 447 #if IS_ENABLED(CONFIG_HWMON)
 448
 449 #define SHOW(name, var, adjust) static ssize_t \
 450 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 451 { \
 452         struct ads7846 *ts = dev_get_drvdata(dev); \
 453         ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
 454                         READ_12BIT_SER(var)); \
 455         if (v < 0) \
 456                 return v; \
 457         return sprintf(buf, "%u\n", adjust(ts, v)); \
 458 } \
 459 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 460
 461
 462 /* Sysfs conventions report temperatures in millidegrees Celsius.
 463  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 464  * accuracy scheme without calibration data.  For now we won't try either;
 465  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 466  */
 467 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 468 {
 469         return v;
 470 }
 471
 472 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 473 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 474
 475
 476 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 477  * if we know vREF.  userspace may need to scale vAUX to match the board's
 478  * external resistors; we assume that vBATT only uses the internal ones.
 479  */
 480 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 481 {
 482         unsigned retval = v;
 483
 484         /* external resistors may scale vAUX into 0..vREF */
 485         retval *= ts->vref_mv;
 486         retval = retval >> 12;
 487
 488         return retval;
 489 }
 490
 491 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 492 {
 493         unsigned retval = vaux_adjust(ts, v);
 494
 495         /* ads7846 has a resistor ladder to scale this signal down */
 496         if (ts->model == 7846)
 497                 retval *= 4;
 498
 499         return retval;
 500 }
 501
 502 SHOW(in0_input, vaux, vaux_adjust)
 503 SHOW(in1_input, vbatt, vbatt_adjust)
 504
 505 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
 506                                   int index)
 507 {
 508         struct device *dev = container_of(kobj, struct device, kobj);
 509         struct ads7846 *ts = dev_get_drvdata(dev);
 510
 511         if (ts->model == 7843 && index < 2)     /* in0, in1 */
 512                 return 0;
 513         if (ts->model == 7845 && index != 2)    /* in0 */
 514                 return 0;
 515
 516         return attr->mode;
 517 }
 518
 519 static struct attribute *ads7846_attributes[] = {
 520         &dev_attr_temp0.attr,           /* 0 */
 521         &dev_attr_temp1.attr,           /* 1 */
 522         &dev_attr_in0_input.attr,       /* 2 */
 523         &dev_attr_in1_input.attr,       /* 3 */
 524         NULL,
 525 };
 526
 527 static const struct attribute_group ads7846_attr_group = {
 528         .attrs = ads7846_attributes,
 529         .is_visible = ads7846_is_visible,
 530 };
 531 __ATTRIBUTE_GROUPS(ads7846_attr);
 532
 533 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 534 {
 535         /* hwmon sensors need a reference voltage */
 536         switch (ts->model) {
 537         case 7846:
 538                 if (!ts->vref_mv) {
 539                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 540                         ts->vref_mv = 2500;
 541                         ts->use_internal = true;
 542                 }
 543                 break;
 544         case 7845:
 545         case 7843:
 546                 if (!ts->vref_mv) {
 547                         dev_warn(&spi->dev,
 548                                 "external vREF for ADS%d not specified\n",
 549                                 ts->model);
 550                         return 0;
 551                 }
 552                 break;
 553         }
 554
 555         ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
 556                                                       ts, ads7846_attr_groups);
 557
 558         return PTR_ERR_OR_ZERO(ts->hwmon);
 559 }
 560
 561 static void ads784x_hwmon_unregister(struct spi_device *spi,
 562                                      struct ads7846 *ts)
 563 {
 564         if (ts->hwmon)
 565                 hwmon_device_unregister(ts->hwmon);
 566 }
 567
 568 #else
 569 static inline int ads784x_hwmon_register(struct spi_device *spi,
 570                                          struct ads7846 *ts)
 571 {
 572         return 0;
 573 }
 574
 575 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 576                                             struct ads7846 *ts)
 577 {
 578 }
 579 #endif
 580
 581 static ssize_t ads7846_pen_down_show(struct device *dev,
 582                                      struct device_attribute *attr, char *buf)
 583 {
 584         struct ads7846 *ts = dev_get_drvdata(dev);
 585
 586         return sprintf(buf, "%u\n", ts->pendown);
 587 }
 588
 589 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 590
 591 static ssize_t ads7846_disable_show(struct device *dev,
 592                                      struct device_attribute *attr, char *buf)
 593 {
 594         struct ads7846 *ts = dev_get_drvdata(dev);
 595
 596         return sprintf(buf, "%u\n", ts->disabled);
 597 }
 598
 599 static ssize_t ads7846_disable_store(struct device *dev,
 600                                      struct device_attribute *attr,
 601                                      const char *buf, size_t count)
 602 {
 603         struct ads7846 *ts = dev_get_drvdata(dev);
 604         unsigned int i;
 605         int err;
 606
 607         err = kstrtouint(buf, 10, &i);
 608         if (err)
 609                 return err;
 610
 611         if (i)
 612                 ads7846_disable(ts);
 613         else
 614                 ads7846_enable(ts);
 615
 616         return count;
 617 }
 618
 619 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 620
 621 static struct attribute *ads784x_attributes[] = {
 622         &dev_attr_pen_down.attr,
 623         &dev_attr_disable.attr,
 624         NULL,
 625 };
 626
 627 static const struct attribute_group ads784x_attr_group = {
 628         .attrs = ads784x_attributes,
 629 };
 630
 631 /*--------------------------------------------------------------------------*/
 632
 633 static void null_wait_for_sync(void)
 634 {
 635 }
 636
 637 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 638 {
 639         struct ads7846 *ts = ads;
 640
 641         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 642                 /* Start over collecting consistent readings. */
 643                 ts->read_rep = 0;
 644                 /*
 645                  * Repeat it, if this was the first read or the read
 646                  * wasn't consistent enough.
 647                  */
 648                 if (ts->read_cnt < ts->debounce_max) {
 649                         ts->last_read = *val;
 650                         ts->read_cnt++;
 651                         return ADS7846_FILTER_REPEAT;
 652                 } else {
 653                         /*
 654                          * Maximum number of debouncing reached and still
 655                          * not enough number of consistent readings. Abort
 656                          * the whole sample, repeat it in the next sampling
 657                          * period.
 658                          */
 659                         ts->read_cnt = 0;
 660                         return ADS7846_FILTER_IGNORE;
 661                 }
 662         } else {
 663                 if (++ts->read_rep > ts->debounce_rep) {
 664                         /*
 665                          * Got a good reading for this coordinate,
 666                          * go for the next one.
 667                          */
 668                         ts->read_cnt = 0;
 669                         ts->read_rep = 0;
 670                         return ADS7846_FILTER_OK;
 671                 } else {
 672                         /* Read more values that are consistent. */
 673                         ts->read_cnt++;
 674                         return ADS7846_FILTER_REPEAT;
 675                 }
 676         }
 677 }
 678
 679 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 680 {
 681         return ADS7846_FILTER_OK;
 682 }
 683
 684 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 685 {
 686         int value;
 687         struct spi_transfer *t =
 688                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 689
 690         if (ts->model == 7845) {
 691                 value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
 692         } else {
 693                 /*
 694                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 695                  * padding; built from two 8 bit values written msb-first.
 696                  */
 697                 value = be16_to_cpup((__be16 *)t->rx_buf);
 698         }
 699
 700         /* enforce ADC output is 12 bits width */
 701         return (value >> 3) & 0xfff;
 702 }
 703
 704 static void ads7846_update_value(struct spi_message *m, int val)
 705 {
 706         struct spi_transfer *t =
 707                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 708
 709         *(u16 *)t->rx_buf = val;
 710 }
 711
 712 static void ads7846_read_state(struct ads7846 *ts)
 713 {
 714         struct ads7846_packet *packet = ts->packet;
 715         struct spi_message *m;
 716         int msg_idx = 0;
 717         int val;
 718         int action;
 719         int error;
 720
 721         while (msg_idx < ts->msg_count) {
 722
 723                 ts->wait_for_sync();
 724
 725                 m = &ts->msg[msg_idx];
 726                 error = spi_sync(ts->spi, m);
 727                 if (error) {
 728                         dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
 729                         packet->tc.ignore = true;
 730                         return;
 731                 }
 732
 733                 /*
 734                  * Last message is power down request, no need to convert
 735                  * or filter the value.
 736                  */
 737                 if (msg_idx < ts->msg_count - 1) {
 738
 739                         val = ads7846_get_value(ts, m);
 740
 741                         action = ts->filter(ts->filter_data, msg_idx, &val);
 742                         switch (action) {
 743                         case ADS7846_FILTER_REPEAT:
 744                                 continue;
 745
 746                         case ADS7846_FILTER_IGNORE:
 747                                 packet->tc.ignore = true;
 748                                 msg_idx = ts->msg_count - 1;
 749                                 continue;
 750
 751                         case ADS7846_FILTER_OK:
 752                                 ads7846_update_value(m, val);
 753                                 packet->tc.ignore = false;
 754                                 msg_idx++;
 755                                 break;
 756
 757                         default:
 758                                 BUG();
 759                         }
 760                 } else {
 761                         msg_idx++;
 762                 }
 763         }
 764 }
 765
 766 static void ads7846_report_state(struct ads7846 *ts)
 767 {
 768         struct ads7846_packet *packet = ts->packet;
 769         unsigned int Rt;
 770         u16 x, y, z1, z2;
 771
 772         /*
 773          * ads7846_get_value() does in-place conversion (including byte swap)
 774          * from on-the-wire format as part of debouncing to get stable
 775          * readings.
 776          */
 777         if (ts->model == 7845) {
 778                 x = *(u16 *)packet->tc.x_buf;
 779                 y = *(u16 *)packet->tc.y_buf;
 780                 z1 = 0;
 781                 z2 = 0;
 782         } else {
 783                 x = packet->tc.x;
 784                 y = packet->tc.y;
 785                 z1 = packet->tc.z1;
 786                 z2 = packet->tc.z2;
 787         }
 788
 789         /* range filtering */
 790         if (x == MAX_12BIT)
 791                 x = 0;
 792
 793         if (ts->model == 7843) {
 794                 Rt = ts->pressure_max / 2;
 795         } else if (ts->model == 7845) {
 796                 if (get_pendown_state(ts))
 797                         Rt = ts->pressure_max / 2;
 798                 else
 799                         Rt = 0;
 800                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 801         } else if (likely(x && z1)) {
 802                 /* compute touch pressure resistance using equation #2 */
 803                 Rt = z2;
 804                 Rt -= z1;
 805                 Rt *= ts->x_plate_ohms;
 806                 Rt = DIV_ROUND_CLOSEST(Rt, 16);
 807                 Rt *= x;
 808                 Rt /= z1;
 809                 Rt = DIV_ROUND_CLOSEST(Rt, 256);
 810         } else {
 811                 Rt = 0;
 812         }
 813
 814         /*
 815          * Sample found inconsistent by debouncing or pressure is beyond
 816          * the maximum. Don't report it to user space, repeat at least
 817          * once more the measurement
 818          */
 819         if (packet->tc.ignore || Rt > ts->pressure_max) {
 820                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 821                          packet->tc.ignore, Rt);
 822                 return;
 823         }
 824
 825         /*
 826          * Maybe check the pendown state before reporting. This discards
 827          * false readings when the pen is lifted.
 828          */
 829         if (ts->penirq_recheck_delay_usecs) {
 830                 udelay(ts->penirq_recheck_delay_usecs);
 831                 if (!get_pendown_state(ts))
 832                         Rt = 0;
 833         }
 834
 835         /*
 836          * NOTE: We can't rely on the pressure to determine the pen down
 837          * state, even this controller has a pressure sensor. The pressure
 838          * value can fluctuate for quite a while after lifting the pen and
 839          * in some cases may not even settle at the expected value.
 840          *
 841          * The only safe way to check for the pen up condition is in the
 842          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 843          */
 844         if (Rt) {
 845                 struct input_dev *input = ts->input;
 846
 847                 if (ts->swap_xy)
 848                         swap(x, y);
 849
 850                 if (!ts->pendown) {
 851                         input_report_key(input, BTN_TOUCH, 1);
 852                         ts->pendown = true;
 853                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 854                 }
 855
 856                 input_report_abs(input, ABS_X, x);
 857                 input_report_abs(input, ABS_Y, y);
 858                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 859
 860                 input_sync(input);
 861                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 862         }
 863 }
 864
 865 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 866 {
 867         struct ads7846 *ts = handle;
 868
 869         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 870 }
 871
 872
 873 static irqreturn_t ads7846_irq(int irq, void *handle)
 874 {
 875         struct ads7846 *ts = handle;
 876
 877         /* Start with a small delay before checking pendown state */
 878         msleep(TS_POLL_DELAY);
 879
 880         while (!ts->stopped && get_pendown_state(ts)) {
 881
 882                 /* pen is down, continue with the measurement */
 883                 ads7846_read_state(ts);
 884
 885                 if (!ts->stopped)
 886                         ads7846_report_state(ts);
 887
 888                 wait_event_timeout(ts->wait, ts->stopped,
 889                                    msecs_to_jiffies(TS_POLL_PERIOD));
 890         }
 891
 892         if (ts->pendown && !ts->stopped)
 893                 ads7846_report_pen_up(ts);
 894
 895         return IRQ_HANDLED;
 896 }
 897
 898 static int __maybe_unused ads7846_suspend(struct device *dev)
 899 {
 900         struct ads7846 *ts = dev_get_drvdata(dev);
 901
 902         mutex_lock(&ts->lock);
 903
 904         if (!ts->suspended) {
 905
 906                 if (!ts->disabled)
 907                         __ads7846_disable(ts);
 908
 909                 if (device_may_wakeup(&ts->spi->dev))
 910                         enable_irq_wake(ts->spi->irq);
 911
 912                 ts->suspended = true;
 913         }
 914
 915         mutex_unlock(&ts->lock);
 916
 917         return 0;
 918 }
 919
 920 static int __maybe_unused ads7846_resume(struct device *dev)
 921 {
 922         struct ads7846 *ts = dev_get_drvdata(dev);
 923
 924         mutex_lock(&ts->lock);
 925
 926         if (ts->suspended) {
 927
 928                 ts->suspended = false;
 929
 930                 if (device_may_wakeup(&ts->spi->dev))
 931                         disable_irq_wake(ts->spi->irq);
 932
 933                 if (!ts->disabled)
 934                         __ads7846_enable(ts);
 935         }
 936
 937         mutex_unlock(&ts->lock);
 938
 939         return 0;
 940 }
 941
 942 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 943
 944 static int ads7846_setup_pendown(struct spi_device *spi,
 945                                  struct ads7846 *ts,
 946                                  const struct ads7846_platform_data *pdata)
 947 {
 948         int err;
 949
 950         /*
 951          * REVISIT when the irq can be triggered active-low, or if for some
 952          * reason the touchscreen isn't hooked up, we don't need to access
 953          * the pendown state.
 954          */
 955
 956         if (pdata->get_pendown_state) {
 957                 ts->get_pendown_state = pdata->get_pendown_state;
 958         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 959
 960                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 961                                        "ads7846_pendown");
 962                 if (err) {
 963                         dev_err(&spi->dev,
 964                                 "failed to request/setup pendown GPIO%d: %d\n",
 965                                 pdata->gpio_pendown, err);
 966                         return err;
 967                 }
 968
 969                 ts->gpio_pendown = pdata->gpio_pendown;
 970
 971                 if (pdata->gpio_pendown_debounce)
 972                         gpio_set_debounce(pdata->gpio_pendown,
 973                                           pdata->gpio_pendown_debounce);
 974         } else {
 975                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 976                 return -EINVAL;
 977         }
 978
 979         return 0;
 980 }
 981
 982 /*
 983  * Set up the transfers to read touchscreen state; this assumes we
 984  * use formula #2 for pressure, not #3.
 985  */
 986 static void ads7846_setup_spi_msg(struct ads7846 *ts,
 987                                   const struct ads7846_platform_data *pdata)
 988 {
 989         struct spi_message *m = &ts->msg[0];
 990         struct spi_transfer *x = ts->xfer;
 991         struct ads7846_packet *packet = ts->packet;
 992         int vref = pdata->keep_vref_on;
 993
 994         if (ts->model == 7873) {
 995                 /*
 996                  * The AD7873 is almost identical to the ADS7846
 997                  * keep VREF off during differential/ratiometric
 998                  * conversion modes.
 999                  */
1000                 ts->model = 7846;
1001                 vref = 0;
1002         }
1003
1004         ts->msg_count = 1;
1005         spi_message_init(m);
1006         m->context = ts;
1007
1008         if (ts->model == 7845) {
1009                 packet->read_y_cmd[0] = READ_Y(vref);
1010                 packet->read_y_cmd[1] = 0;
1011                 packet->read_y_cmd[2] = 0;
1012                 x->tx_buf = &packet->read_y_cmd[0];
1013                 x->rx_buf = &packet->tc.y_buf[0];
1014                 x->len = 3;
1015                 spi_message_add_tail(x, m);
1016         } else {
1017                 /* y- still on; turn on only y+ (and ADC) */
1018                 packet->read_y = READ_Y(vref);
1019                 x->tx_buf = &packet->read_y;
1020                 x->len = 1;
1021                 spi_message_add_tail(x, m);
1022
1023                 x++;
1024                 x->rx_buf = &packet->tc.y;
1025                 x->len = 2;
1026                 spi_message_add_tail(x, m);
1027         }
1028
1029         /*
1030          * The first sample after switching drivers can be low quality;
1031          * optionally discard it, using a second one after the signals
1032          * have had enough time to stabilize.
1033          */
1034         if (pdata->settle_delay_usecs) {
1035                 x->delay_usecs = pdata->settle_delay_usecs;
1036
1037                 x++;
1038                 x->tx_buf = &packet->read_y;
1039                 x->len = 1;
1040                 spi_message_add_tail(x, m);
1041
1042                 x++;
1043                 x->rx_buf = &packet->tc.y;
1044                 x->len = 2;
1045                 spi_message_add_tail(x, m);
1046         }
1047
1048         ts->msg_count++;
1049         m++;
1050         spi_message_init(m);
1051         m->context = ts;
1052
1053         if (ts->model == 7845) {
1054                 x++;
1055                 packet->read_x_cmd[0] = READ_X(vref);
1056                 packet->read_x_cmd[1] = 0;
1057                 packet->read_x_cmd[2] = 0;
1058                 x->tx_buf = &packet->read_x_cmd[0];
1059                 x->rx_buf = &packet->tc.x_buf[0];
1060                 x->len = 3;
1061                 spi_message_add_tail(x, m);
1062         } else {
1063                 /* turn y- off, x+ on, then leave in lowpower */
1064                 x++;
1065                 packet->read_x = READ_X(vref);
1066                 x->tx_buf = &packet->read_x;
1067                 x->len = 1;
1068                 spi_message_add_tail(x, m);
1069
1070                 x++;
1071                 x->rx_buf = &packet->tc.x;
1072                 x->len = 2;
1073                 spi_message_add_tail(x, m);
1074         }
1075
1076         /* ... maybe discard first sample ... */
1077         if (pdata->settle_delay_usecs) {
1078                 x->delay_usecs = pdata->settle_delay_usecs;
1079
1080                 x++;
1081                 x->tx_buf = &packet->read_x;
1082                 x->len = 1;
1083                 spi_message_add_tail(x, m);
1084
1085                 x++;
1086                 x->rx_buf = &packet->tc.x;
1087                 x->len = 2;
1088                 spi_message_add_tail(x, m);
1089         }
1090
1091         /* turn y+ off, x- on; we'll use formula #2 */
1092         if (ts->model == 7846) {
1093                 ts->msg_count++;
1094                 m++;
1095                 spi_message_init(m);
1096                 m->context = ts;
1097
1098                 x++;
1099                 packet->read_z1 = READ_Z1(vref);
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                 /* ... maybe discard first sample ... */
1110                 if (pdata->settle_delay_usecs) {
1111                         x->delay_usecs = pdata->settle_delay_usecs;
1112
1113                         x++;
1114                         x->tx_buf = &packet->read_z1;
1115                         x->len = 1;
1116                         spi_message_add_tail(x, m);
1117
1118                         x++;
1119                         x->rx_buf = &packet->tc.z1;
1120                         x->len = 2;
1121                         spi_message_add_tail(x, m);
1122                 }
1123
1124                 ts->msg_count++;
1125                 m++;
1126                 spi_message_init(m);
1127                 m->context = ts;
1128
1129                 x++;
1130                 packet->read_z2 = READ_Z2(vref);
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                 /* ... maybe discard first sample ... */
1141                 if (pdata->settle_delay_usecs) {
1142                         x->delay_usecs = pdata->settle_delay_usecs;
1143
1144                         x++;
1145                         x->tx_buf = &packet->read_z2;
1146                         x->len = 1;
1147                         spi_message_add_tail(x, m);
1148
1149                         x++;
1150                         x->rx_buf = &packet->tc.z2;
1151                         x->len = 2;
1152                         spi_message_add_tail(x, m);
1153                 }
1154         }
1155
1156         /* power down */
1157         ts->msg_count++;
1158         m++;
1159         spi_message_init(m);
1160         m->context = ts;
1161
1162         if (ts->model == 7845) {
1163                 x++;
1164                 packet->pwrdown_cmd[0] = PWRDOWN;
1165                 packet->pwrdown_cmd[1] = 0;
1166                 packet->pwrdown_cmd[2] = 0;
1167                 x->tx_buf = &packet->pwrdown_cmd[0];
1168                 x->len = 3;
1169         } else {
1170                 x++;
1171                 packet->pwrdown = PWRDOWN;
1172                 x->tx_buf = &packet->pwrdown;
1173                 x->len = 1;
1174                 spi_message_add_tail(x, m);
1175
1176                 x++;
1177                 x->rx_buf = &packet->dummy;
1178                 x->len = 2;
1179         }
1180
1181         CS_CHANGE(*x);
1182         spi_message_add_tail(x, m);
1183 }
1184
1185 #ifdef CONFIG_OF
1186 static const struct of_device_id ads7846_dt_ids[] = {
1187         { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
1188         { .compatible = "ti,ads7843",   .data = (void *) 7843 },
1189         { .compatible = "ti,ads7845",   .data = (void *) 7845 },
1190         { .compatible = "ti,ads7846",   .data = (void *) 7846 },
1191         { .compatible = "ti,ads7873",   .data = (void *) 7873 },
1192         { }
1193 };
1194 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1195
1196 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1197 {
1198         struct ads7846_platform_data *pdata;
1199         struct device_node *node = dev->of_node;
1200         const struct of_device_id *match;
1201
1202         if (!node) {
1203                 dev_err(dev, "Device does not have associated DT data\n");
1204                 return ERR_PTR(-EINVAL);
1205         }
1206
1207         match = of_match_device(ads7846_dt_ids, dev);
1208         if (!match) {
1209                 dev_err(dev, "Unknown device model\n");
1210                 return ERR_PTR(-EINVAL);
1211         }
1212
1213         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1214         if (!pdata)
1215                 return ERR_PTR(-ENOMEM);
1216
1217         pdata->model = (unsigned long)match->data;
1218
1219         of_property_read_u16(node, "ti,vref-delay-usecs",
1220                              &pdata->vref_delay_usecs);
1221         of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1222         pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1223
1224         pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1225
1226         of_property_read_u16(node, "ti,settle-delay-usec",
1227                              &pdata->settle_delay_usecs);
1228         of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1229                              &pdata->penirq_recheck_delay_usecs);
1230
1231         of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1232         of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1233
1234         of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1235         of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1236         of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1237         of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1238
1239         of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1240         of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1241
1242         of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1243         of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1244         of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1245
1246         of_property_read_u32(node, "ti,pendown-gpio-debounce",
1247                              &pdata->gpio_pendown_debounce);
1248
1249         pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1250                         of_property_read_bool(node, "linux,wakeup");
1251
1252         pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1253
1254         return pdata;
1255 }
1256 #else
1257 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1258 {
1259         dev_err(dev, "no platform data defined\n");
1260         return ERR_PTR(-EINVAL);
1261 }
1262 #endif
1263
1264 static int ads7846_probe(struct spi_device *spi)
1265 {
1266         const struct ads7846_platform_data *pdata;
1267         struct ads7846 *ts;
1268         struct ads7846_packet *packet;
1269         struct input_dev *input_dev;
1270         unsigned long irq_flags;
1271         int err;
1272
1273         if (!spi->irq) {
1274                 dev_dbg(&spi->dev, "no IRQ?\n");
1275                 return -EINVAL;
1276         }
1277
1278         /* don't exceed max specified sample rate */
1279         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1280                 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1281                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1282                 return -EINVAL;
1283         }
1284
1285         /*
1286          * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1287          * that even if the hardware can do that, the SPI controller driver
1288          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1289          */
1290         spi->bits_per_word = 8;
1291         spi->mode = SPI_MODE_0;
1292         err = spi_setup(spi);
1293         if (err < 0)
1294                 return err;
1295
1296         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1297         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1298         input_dev = input_allocate_device();
1299         if (!ts || !packet || !input_dev) {
1300                 err = -ENOMEM;
1301                 goto err_free_mem;
1302         }
1303
1304         spi_set_drvdata(spi, ts);
1305
1306         ts->packet = packet;
1307         ts->spi = spi;
1308         ts->input = input_dev;
1309
1310         mutex_init(&ts->lock);
1311         init_waitqueue_head(&ts->wait);
1312
1313         pdata = dev_get_platdata(&spi->dev);
1314         if (!pdata) {
1315                 pdata = ads7846_probe_dt(&spi->dev);
1316                 if (IS_ERR(pdata)) {
1317                         err = PTR_ERR(pdata);
1318                         goto err_free_mem;
1319                 }
1320         }
1321
1322         ts->model = pdata->model ? : 7846;
1323         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1324         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1325         ts->pressure_max = pdata->pressure_max ? : ~0;
1326
1327         ts->vref_mv = pdata->vref_mv;
1328         ts->swap_xy = pdata->swap_xy;
1329
1330         if (pdata->filter != NULL) {
1331                 if (pdata->filter_init != NULL) {
1332                         err = pdata->filter_init(pdata, &ts->filter_data);
1333                         if (err < 0)
1334                                 goto err_free_mem;
1335                 }
1336                 ts->filter = pdata->filter;
1337                 ts->filter_cleanup = pdata->filter_cleanup;
1338         } else if (pdata->debounce_max) {
1339                 ts->debounce_max = pdata->debounce_max;
1340                 if (ts->debounce_max < 2)
1341                         ts->debounce_max = 2;
1342                 ts->debounce_tol = pdata->debounce_tol;
1343                 ts->debounce_rep = pdata->debounce_rep;
1344                 ts->filter = ads7846_debounce_filter;
1345                 ts->filter_data = ts;
1346         } else {
1347                 ts->filter = ads7846_no_filter;
1348         }
1349
1350         err = ads7846_setup_pendown(spi, ts, pdata);
1351         if (err)
1352                 goto err_cleanup_filter;
1353
1354         if (pdata->penirq_recheck_delay_usecs)
1355                 ts->penirq_recheck_delay_usecs =
1356                                 pdata->penirq_recheck_delay_usecs;
1357
1358         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1359
1360         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1361         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1362
1363         input_dev->name = ts->name;
1364         input_dev->phys = ts->phys;
1365         input_dev->dev.parent = &spi->dev;
1366
1367         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1368         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1369         input_set_abs_params(input_dev, ABS_X,
1370                         pdata->x_min ? : 0,
1371                         pdata->x_max ? : MAX_12BIT,
1372                         0, 0);
1373         input_set_abs_params(input_dev, ABS_Y,
1374                         pdata->y_min ? : 0,
1375                         pdata->y_max ? : MAX_12BIT,
1376                         0, 0);
1377         input_set_abs_params(input_dev, ABS_PRESSURE,
1378                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1379
1380         ads7846_setup_spi_msg(ts, pdata);
1381
1382         ts->reg = regulator_get(&spi->dev, "vcc");
1383         if (IS_ERR(ts->reg)) {
1384                 err = PTR_ERR(ts->reg);
1385                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1386                 goto err_free_gpio;
1387         }
1388
1389         err = regulator_enable(ts->reg);
1390         if (err) {
1391                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1392                 goto err_put_regulator;
1393         }
1394
1395         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1396         irq_flags |= IRQF_ONESHOT;
1397
1398         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1399                                    irq_flags, spi->dev.driver->name, ts);
1400         if (err && !pdata->irq_flags) {
1401                 dev_info(&spi->dev,
1402                         "trying pin change workaround on irq %d\n", spi->irq);
1403                 irq_flags |= IRQF_TRIGGER_RISING;
1404                 err = request_threaded_irq(spi->irq,
1405                                   ads7846_hard_irq, ads7846_irq,
1406                                   irq_flags, spi->dev.driver->name, ts);
1407         }
1408
1409         if (err) {
1410                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1411                 goto err_disable_regulator;
1412         }
1413
1414         err = ads784x_hwmon_register(spi, ts);
1415         if (err)
1416                 goto err_free_irq;
1417
1418         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1419
1420         /*
1421          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1422          * the touchscreen, in case it's not connected.
1423          */
1424         if (ts->model == 7845)
1425                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1426         else
1427                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1428
1429         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1430         if (err)
1431                 goto err_remove_hwmon;
1432
1433         err = input_register_device(input_dev);
1434         if (err)
1435                 goto err_remove_attr_group;
1436
1437         device_init_wakeup(&spi->dev, pdata->wakeup);
1438
1439         /*
1440          * If device does not carry platform data we must have allocated it
1441          * when parsing DT data.
1442          */
1443         if (!dev_get_platdata(&spi->dev))
1444                 devm_kfree(&spi->dev, (void *)pdata);
1445
1446         return 0;
1447
1448  err_remove_attr_group:
1449         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1450  err_remove_hwmon:
1451         ads784x_hwmon_unregister(spi, ts);
1452  err_free_irq:
1453         free_irq(spi->irq, ts);
1454  err_disable_regulator:
1455         regulator_disable(ts->reg);
1456  err_put_regulator:
1457         regulator_put(ts->reg);
1458  err_free_gpio:
1459         if (!ts->get_pendown_state)
1460                 gpio_free(ts->gpio_pendown);
1461  err_cleanup_filter:
1462         if (ts->filter_cleanup)
1463                 ts->filter_cleanup(ts->filter_data);
1464  err_free_mem:
1465         input_free_device(input_dev);
1466         kfree(packet);
1467         kfree(ts);
1468         return err;
1469 }
1470
1471 static int ads7846_remove(struct spi_device *spi)
1472 {
1473         struct ads7846 *ts = spi_get_drvdata(spi);
1474
1475         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1476
1477         ads7846_disable(ts);
1478         free_irq(ts->spi->irq, ts);
1479
1480         input_unregister_device(ts->input);
1481
1482         ads784x_hwmon_unregister(spi, ts);
1483
1484         regulator_put(ts->reg);
1485
1486         if (!ts->get_pendown_state) {
1487                 /*
1488                  * If we are not using specialized pendown method we must
1489                  * have been relying on gpio we set up ourselves.
1490                  */
1491                 gpio_free(ts->gpio_pendown);
1492         }
1493
1494         if (ts->filter_cleanup)
1495                 ts->filter_cleanup(ts->filter_data);
1496
1497         kfree(ts->packet);
1498         kfree(ts);
1499
1500         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1501
1502         return 0;
1503 }
1504
1505 static struct spi_driver ads7846_driver = {
1506         .driver = {
1507                 .name   = "ads7846",
1508                 .pm     = &ads7846_pm,
1509                 .of_match_table = of_match_ptr(ads7846_dt_ids),
1510         },
1511         .probe          = ads7846_probe,
1512         .remove         = ads7846_remove,
1513 };
1514
1515 module_spi_driver(ads7846_driver);
1516
1517 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1518 MODULE_LICENSE("GPL");
1519 MODULE_ALIAS("spi:ads7846");