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/init.h>
  23 #include <linux/err.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/input.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/slab.h>
  29 #include <linux/pm.h>
  30 #include <linux/of.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/of_device.h>
  33 #include <linux/gpio.h>
  34 #include <linux/spi/spi.h>
  35 #include <linux/spi/ads7846.h>
  36 #include <linux/regulator/consumer.h>
  37 #include <linux/module.h>
  38 #include <asm/irq.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 defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 105         struct attribute_group  *attr_group;
 106         struct device           *hwmon;
 107 #endif
 108
 109         u16                     model;
 110         u16                     vref_mv;
 111         u16                     vref_delay_usecs;
 112         u16                     x_plate_ohms;
 113         u16                     pressure_max;
 114
 115         bool                    swap_xy;
 116         bool                    use_internal;
 117
 118         struct ads7846_packet   *packet;
 119
 120         struct spi_transfer     xfer[18];
 121         struct spi_message      msg[5];
 122         int                     msg_count;
 123         wait_queue_head_t       wait;
 124
 125         bool                    pendown;
 126
 127         int                     read_cnt;
 128         int                     read_rep;
 129         int                     last_read;
 130
 131         u16                     debounce_max;
 132         u16                     debounce_tol;
 133         u16                     debounce_rep;
 134
 135         u16                     penirq_recheck_delay_usecs;
 136
 137         struct mutex            lock;
 138         bool                    stopped;        /* P: lock */
 139         bool                    disabled;       /* P: lock */
 140         bool                    suspended;      /* P: lock */
 141
 142         int                     (*filter)(void *data, int data_idx, int *val);
 143         void                    *filter_data;
 144         void                    (*filter_cleanup)(void *data);
 145         int                     (*get_pendown_state)(void);
 146         int                     gpio_pendown;
 147
 148         void                    (*wait_for_sync)(void);
 149 };
 150
 151 /* leave chip selected when we're done, for quicker re-select? */
 152 #if     0
 153 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 154 #else
 155 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 156 #endif
 157
 158 /*--------------------------------------------------------------------------*/
 159
 160 /* The ADS7846 has touchscreen and other sensors.
 161  * Earlier ads784x chips are somewhat compatible.
 162  */
 163 #define ADS_START               (1 << 7)
 164 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 165 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 166 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 167 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 168 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 169 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 170 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 171 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 172 #define ADS_8_BIT               (1 << 3)
 173 #define ADS_12_BIT              (0 << 3)
 174 #define ADS_SER                 (1 << 2)        /* non-differential */
 175 #define ADS_DFR                 (0 << 2)        /* differential */
 176 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 177 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 178 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 179 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 180
 181 #define MAX_12BIT       ((1<<12)-1)
 182
 183 /* leave ADC powered up (disables penirq) between differential samples */
 184 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 185         | ADS_12_BIT | ADS_DFR | \
 186         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 187
 188 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 189 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 190 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 191
 192 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 193 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 194
 195 /* single-ended samples need to first power up reference voltage;
 196  * we leave both ADC and VREF powered
 197  */
 198 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 199         | ADS_12_BIT | ADS_SER)
 200
 201 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 202 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 203
 204 /* Must be called with ts->lock held */
 205 static void ads7846_stop(struct ads7846 *ts)
 206 {
 207         if (!ts->disabled && !ts->suspended) {
 208                 /* Signal IRQ thread to stop polling and disable the handler. */
 209                 ts->stopped = true;
 210                 mb();
 211                 wake_up(&ts->wait);
 212                 disable_irq(ts->spi->irq);
 213         }
 214 }
 215
 216 /* Must be called with ts->lock held */
 217 static void ads7846_restart(struct ads7846 *ts)
 218 {
 219         if (!ts->disabled && !ts->suspended) {
 220                 /* Tell IRQ thread that it may poll the device. */
 221                 ts->stopped = false;
 222                 mb();
 223                 enable_irq(ts->spi->irq);
 224         }
 225 }
 226
 227 /* Must be called with ts->lock held */
 228 static void __ads7846_disable(struct ads7846 *ts)
 229 {
 230         ads7846_stop(ts);
 231         regulator_disable(ts->reg);
 232
 233         /*
 234          * We know the chip's in low power mode since we always
 235          * leave it that way after every request
 236          */
 237 }
 238
 239 /* Must be called with ts->lock held */
 240 static void __ads7846_enable(struct ads7846 *ts)
 241 {
 242         int error;
 243
 244         error = regulator_enable(ts->reg);
 245         if (error != 0)
 246                 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
 247
 248         ads7846_restart(ts);
 249 }
 250
 251 static void ads7846_disable(struct ads7846 *ts)
 252 {
 253         mutex_lock(&ts->lock);
 254
 255         if (!ts->disabled) {
 256
 257                 if  (!ts->suspended)
 258                         __ads7846_disable(ts);
 259
 260                 ts->disabled = true;
 261         }
 262
 263         mutex_unlock(&ts->lock);
 264 }
 265
 266 static void ads7846_enable(struct ads7846 *ts)
 267 {
 268         mutex_lock(&ts->lock);
 269
 270         if (ts->disabled) {
 271
 272                 ts->disabled = false;
 273
 274                 if (!ts->suspended)
 275                         __ads7846_enable(ts);
 276         }
 277
 278         mutex_unlock(&ts->lock);
 279 }
 280
 281 /*--------------------------------------------------------------------------*/
 282
 283 /*
 284  * Non-touchscreen sensors only use single-ended conversions.
 285  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 286  * ads7846 lets that pin be unconnected, to use internal vREF.
 287  */
 288
 289 struct ser_req {
 290         u8                      ref_on;
 291         u8                      command;
 292         u8                      ref_off;
 293         u16                     scratch;
 294         struct spi_message      msg;
 295         struct spi_transfer     xfer[6];
 296         /*
 297          * DMA (thus cache coherency maintenance) requires the
 298          * transfer buffers to live in their own cache lines.
 299          */
 300         __be16 sample ____cacheline_aligned;
 301 };
 302
 303 struct ads7845_ser_req {
 304         u8                      command[3];
 305         struct spi_message      msg;
 306         struct spi_transfer     xfer[2];
 307         /*
 308          * DMA (thus cache coherency maintenance) requires the
 309          * transfer buffers to live in their own cache lines.
 310          */
 311         u8 sample[3] ____cacheline_aligned;
 312 };
 313
 314 static int ads7846_read12_ser(struct device *dev, unsigned command)
 315 {
 316         struct spi_device *spi = to_spi_device(dev);
 317         struct ads7846 *ts = dev_get_drvdata(dev);
 318         struct ser_req *req;
 319         int status;
 320
 321         req = kzalloc(sizeof *req, GFP_KERNEL);
 322         if (!req)
 323                 return -ENOMEM;
 324
 325         spi_message_init(&req->msg);
 326
 327         /* maybe turn on internal vREF, and let it settle */
 328         if (ts->use_internal) {
 329                 req->ref_on = REF_ON;
 330                 req->xfer[0].tx_buf = &req->ref_on;
 331                 req->xfer[0].len = 1;
 332                 spi_message_add_tail(&req->xfer[0], &req->msg);
 333
 334                 req->xfer[1].rx_buf = &req->scratch;
 335                 req->xfer[1].len = 2;
 336
 337                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 338                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 339                 spi_message_add_tail(&req->xfer[1], &req->msg);
 340
 341                 /* Enable reference voltage */
 342                 command |= ADS_PD10_REF_ON;
 343         }
 344
 345         /* Enable ADC in every case */
 346         command |= ADS_PD10_ADC_ON;
 347
 348         /* take sample */
 349         req->command = (u8) command;
 350         req->xfer[2].tx_buf = &req->command;
 351         req->xfer[2].len = 1;
 352         spi_message_add_tail(&req->xfer[2], &req->msg);
 353
 354         req->xfer[3].rx_buf = &req->sample;
 355         req->xfer[3].len = 2;
 356         spi_message_add_tail(&req->xfer[3], &req->msg);
 357
 358         /* REVISIT:  take a few more samples, and compare ... */
 359
 360         /* converter in low power mode & enable PENIRQ */
 361         req->ref_off = PWRDOWN;
 362         req->xfer[4].tx_buf = &req->ref_off;
 363         req->xfer[4].len = 1;
 364         spi_message_add_tail(&req->xfer[4], &req->msg);
 365
 366         req->xfer[5].rx_buf = &req->scratch;
 367         req->xfer[5].len = 2;
 368         CS_CHANGE(req->xfer[5]);
 369         spi_message_add_tail(&req->xfer[5], &req->msg);
 370
 371         mutex_lock(&ts->lock);
 372         ads7846_stop(ts);
 373         status = spi_sync(spi, &req->msg);
 374         ads7846_restart(ts);
 375         mutex_unlock(&ts->lock);
 376
 377         if (status == 0) {
 378                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 379                 status = be16_to_cpu(req->sample);
 380                 status = status >> 3;
 381                 status &= 0x0fff;
 382         }
 383
 384         kfree(req);
 385         return status;
 386 }
 387
 388 static int ads7845_read12_ser(struct device *dev, unsigned command)
 389 {
 390         struct spi_device *spi = to_spi_device(dev);
 391         struct ads7846 *ts = dev_get_drvdata(dev);
 392         struct ads7845_ser_req *req;
 393         int status;
 394
 395         req = kzalloc(sizeof *req, GFP_KERNEL);
 396         if (!req)
 397                 return -ENOMEM;
 398
 399         spi_message_init(&req->msg);
 400
 401         req->command[0] = (u8) command;
 402         req->xfer[0].tx_buf = req->command;
 403         req->xfer[0].rx_buf = req->sample;
 404         req->xfer[0].len = 3;
 405         spi_message_add_tail(&req->xfer[0], &req->msg);
 406
 407         mutex_lock(&ts->lock);
 408         ads7846_stop(ts);
 409         status = spi_sync(spi, &req->msg);
 410         ads7846_restart(ts);
 411         mutex_unlock(&ts->lock);
 412
 413         if (status == 0) {
 414                 /* BE12 value, then padding */
 415                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 416                 status = status >> 3;
 417                 status &= 0x0fff;
 418         }
 419
 420         kfree(req);
 421         return status;
 422 }
 423
 424 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 425
 426 #define SHOW(name, var, adjust) static ssize_t \
 427 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 428 { \
 429         struct ads7846 *ts = dev_get_drvdata(dev); \
 430         ssize_t v = ads7846_read12_ser(dev, \
 431                         READ_12BIT_SER(var)); \
 432         if (v < 0) \
 433                 return v; \
 434         return sprintf(buf, "%u\n", adjust(ts, v)); \
 435 } \
 436 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 437
 438
 439 /* Sysfs conventions report temperatures in millidegrees Celsius.
 440  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 441  * accuracy scheme without calibration data.  For now we won't try either;
 442  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 443  */
 444 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 445 {
 446         return v;
 447 }
 448
 449 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 450 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 451
 452
 453 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 454  * if we know vREF.  userspace may need to scale vAUX to match the board's
 455  * external resistors; we assume that vBATT only uses the internal ones.
 456  */
 457 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 458 {
 459         unsigned retval = v;
 460
 461         /* external resistors may scale vAUX into 0..vREF */
 462         retval *= ts->vref_mv;
 463         retval = retval >> 12;
 464
 465         return retval;
 466 }
 467
 468 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 469 {
 470         unsigned retval = vaux_adjust(ts, v);
 471
 472         /* ads7846 has a resistor ladder to scale this signal down */
 473         if (ts->model == 7846)
 474                 retval *= 4;
 475
 476         return retval;
 477 }
 478
 479 SHOW(in0_input, vaux, vaux_adjust)
 480 SHOW(in1_input, vbatt, vbatt_adjust)
 481
 482 static struct attribute *ads7846_attributes[] = {
 483         &dev_attr_temp0.attr,
 484         &dev_attr_temp1.attr,
 485         &dev_attr_in0_input.attr,
 486         &dev_attr_in1_input.attr,
 487         NULL,
 488 };
 489
 490 static struct attribute_group ads7846_attr_group = {
 491         .attrs = ads7846_attributes,
 492 };
 493
 494 static struct attribute *ads7843_attributes[] = {
 495         &dev_attr_in0_input.attr,
 496         &dev_attr_in1_input.attr,
 497         NULL,
 498 };
 499
 500 static struct attribute_group ads7843_attr_group = {
 501         .attrs = ads7843_attributes,
 502 };
 503
 504 static struct attribute *ads7845_attributes[] = {
 505         &dev_attr_in0_input.attr,
 506         NULL,
 507 };
 508
 509 static struct attribute_group ads7845_attr_group = {
 510         .attrs = ads7845_attributes,
 511 };
 512
 513 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 514 {
 515         struct device *hwmon;
 516         int err;
 517
 518         /* hwmon sensors need a reference voltage */
 519         switch (ts->model) {
 520         case 7846:
 521                 if (!ts->vref_mv) {
 522                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 523                         ts->vref_mv = 2500;
 524                         ts->use_internal = true;
 525                 }
 526                 break;
 527         case 7845:
 528         case 7843:
 529                 if (!ts->vref_mv) {
 530                         dev_warn(&spi->dev,
 531                                 "external vREF for ADS%d not specified\n",
 532                                 ts->model);
 533                         return 0;
 534                 }
 535                 break;
 536         }
 537
 538         /* different chips have different sensor groups */
 539         switch (ts->model) {
 540         case 7846:
 541                 ts->attr_group = &ads7846_attr_group;
 542                 break;
 543         case 7845:
 544                 ts->attr_group = &ads7845_attr_group;
 545                 break;
 546         case 7843:
 547                 ts->attr_group = &ads7843_attr_group;
 548                 break;
 549         default:
 550                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 551                 return 0;
 552         }
 553
 554         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 555         if (err)
 556                 return err;
 557
 558         hwmon = hwmon_device_register(&spi->dev);
 559         if (IS_ERR(hwmon)) {
 560                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 561                 return PTR_ERR(hwmon);
 562         }
 563
 564         ts->hwmon = hwmon;
 565         return 0;
 566 }
 567
 568 static void ads784x_hwmon_unregister(struct spi_device *spi,
 569                                      struct ads7846 *ts)
 570 {
 571         if (ts->hwmon) {
 572                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 573                 hwmon_device_unregister(ts->hwmon);
 574         }
 575 }
 576
 577 #else
 578 static inline int ads784x_hwmon_register(struct spi_device *spi,
 579                                          struct ads7846 *ts)
 580 {
 581         return 0;
 582 }
 583
 584 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 585                                             struct ads7846 *ts)
 586 {
 587 }
 588 #endif
 589
 590 static ssize_t ads7846_pen_down_show(struct device *dev,
 591                                      struct device_attribute *attr, char *buf)
 592 {
 593         struct ads7846 *ts = dev_get_drvdata(dev);
 594
 595         return sprintf(buf, "%u\n", ts->pendown);
 596 }
 597
 598 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 599
 600 static ssize_t ads7846_disable_show(struct device *dev,
 601                                      struct device_attribute *attr, char *buf)
 602 {
 603         struct ads7846 *ts = dev_get_drvdata(dev);
 604
 605         return sprintf(buf, "%u\n", ts->disabled);
 606 }
 607
 608 static ssize_t ads7846_disable_store(struct device *dev,
 609                                      struct device_attribute *attr,
 610                                      const char *buf, size_t count)
 611 {
 612         struct ads7846 *ts = dev_get_drvdata(dev);
 613         unsigned int i;
 614         int err;
 615
 616         err = kstrtouint(buf, 10, &i);
 617         if (err)
 618                 return err;
 619
 620         if (i)
 621                 ads7846_disable(ts);
 622         else
 623                 ads7846_enable(ts);
 624
 625         return count;
 626 }
 627
 628 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 629
 630 static struct attribute *ads784x_attributes[] = {
 631         &dev_attr_pen_down.attr,
 632         &dev_attr_disable.attr,
 633         NULL,
 634 };
 635
 636 static struct attribute_group ads784x_attr_group = {
 637         .attrs = ads784x_attributes,
 638 };
 639
 640 /*--------------------------------------------------------------------------*/
 641
 642 static int get_pendown_state(struct ads7846 *ts)
 643 {
 644         if (ts->get_pendown_state)
 645                 return ts->get_pendown_state();
 646
 647         return !gpio_get_value(ts->gpio_pendown);
 648 }
 649
 650 static void null_wait_for_sync(void)
 651 {
 652 }
 653
 654 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 655 {
 656         struct ads7846 *ts = ads;
 657
 658         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 659                 /* Start over collecting consistent readings. */
 660                 ts->read_rep = 0;
 661                 /*
 662                  * Repeat it, if this was the first read or the read
 663                  * wasn't consistent enough.
 664                  */
 665                 if (ts->read_cnt < ts->debounce_max) {
 666                         ts->last_read = *val;
 667                         ts->read_cnt++;
 668                         return ADS7846_FILTER_REPEAT;
 669                 } else {
 670                         /*
 671                          * Maximum number of debouncing reached and still
 672                          * not enough number of consistent readings. Abort
 673                          * the whole sample, repeat it in the next sampling
 674                          * period.
 675                          */
 676                         ts->read_cnt = 0;
 677                         return ADS7846_FILTER_IGNORE;
 678                 }
 679         } else {
 680                 if (++ts->read_rep > ts->debounce_rep) {
 681                         /*
 682                          * Got a good reading for this coordinate,
 683                          * go for the next one.
 684                          */
 685                         ts->read_cnt = 0;
 686                         ts->read_rep = 0;
 687                         return ADS7846_FILTER_OK;
 688                 } else {
 689                         /* Read more values that are consistent. */
 690                         ts->read_cnt++;
 691                         return ADS7846_FILTER_REPEAT;
 692                 }
 693         }
 694 }
 695
 696 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 697 {
 698         return ADS7846_FILTER_OK;
 699 }
 700
 701 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 702 {
 703         struct spi_transfer *t =
 704                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 705
 706         if (ts->model == 7845) {
 707                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 708         } else {
 709                 /*
 710                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 711                  * padding; built from two 8 bit values written msb-first.
 712                  */
 713                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 714         }
 715 }
 716
 717 static void ads7846_update_value(struct spi_message *m, int val)
 718 {
 719         struct spi_transfer *t =
 720                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 721
 722         *(u16 *)t->rx_buf = val;
 723 }
 724
 725 static void ads7846_read_state(struct ads7846 *ts)
 726 {
 727         struct ads7846_packet *packet = ts->packet;
 728         struct spi_message *m;
 729         int msg_idx = 0;
 730         int val;
 731         int action;
 732         int error;
 733
 734         while (msg_idx < ts->msg_count) {
 735
 736                 ts->wait_for_sync();
 737
 738                 m = &ts->msg[msg_idx];
 739                 error = spi_sync(ts->spi, m);
 740                 if (error) {
 741                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
 742                         packet->tc.ignore = true;
 743                         return;
 744                 }
 745
 746                 /*
 747                  * Last message is power down request, no need to convert
 748                  * or filter the value.
 749                  */
 750                 if (msg_idx < ts->msg_count - 1) {
 751
 752                         val = ads7846_get_value(ts, m);
 753
 754                         action = ts->filter(ts->filter_data, msg_idx, &val);
 755                         switch (action) {
 756                         case ADS7846_FILTER_REPEAT:
 757                                 continue;
 758
 759                         case ADS7846_FILTER_IGNORE:
 760                                 packet->tc.ignore = true;
 761                                 msg_idx = ts->msg_count - 1;
 762                                 continue;
 763
 764                         case ADS7846_FILTER_OK:
 765                                 ads7846_update_value(m, val);
 766                                 packet->tc.ignore = false;
 767                                 msg_idx++;
 768                                 break;
 769
 770                         default:
 771                                 BUG();
 772                         }
 773                 } else {
 774                         msg_idx++;
 775                 }
 776         }
 777 }
 778
 779 static void ads7846_report_state(struct ads7846 *ts)
 780 {
 781         struct ads7846_packet *packet = ts->packet;
 782         unsigned int Rt;
 783         u16 x, y, z1, z2;
 784
 785         /*
 786          * ads7846_get_value() does in-place conversion (including byte swap)
 787          * from on-the-wire format as part of debouncing to get stable
 788          * readings.
 789          */
 790         if (ts->model == 7845) {
 791                 x = *(u16 *)packet->tc.x_buf;
 792                 y = *(u16 *)packet->tc.y_buf;
 793                 z1 = 0;
 794                 z2 = 0;
 795         } else {
 796                 x = packet->tc.x;
 797                 y = packet->tc.y;
 798                 z1 = packet->tc.z1;
 799                 z2 = packet->tc.z2;
 800         }
 801
 802         /* range filtering */
 803         if (x == MAX_12BIT)
 804                 x = 0;
 805
 806         if (ts->model == 7843) {
 807                 Rt = ts->pressure_max / 2;
 808         } else if (ts->model == 7845) {
 809                 if (get_pendown_state(ts))
 810                         Rt = ts->pressure_max / 2;
 811                 else
 812                         Rt = 0;
 813                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 814         } else if (likely(x && z1)) {
 815                 /* compute touch pressure resistance using equation #2 */
 816                 Rt = z2;
 817                 Rt -= z1;
 818                 Rt *= x;
 819                 Rt *= ts->x_plate_ohms;
 820                 Rt /= z1;
 821                 Rt = (Rt + 2047) >> 12;
 822         } else {
 823                 Rt = 0;
 824         }
 825
 826         /*
 827          * Sample found inconsistent by debouncing or pressure is beyond
 828          * the maximum. Don't report it to user space, repeat at least
 829          * once more the measurement
 830          */
 831         if (packet->tc.ignore || Rt > ts->pressure_max) {
 832                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 833                          packet->tc.ignore, Rt);
 834                 return;
 835         }
 836
 837         /*
 838          * Maybe check the pendown state before reporting. This discards
 839          * false readings when the pen is lifted.
 840          */
 841         if (ts->penirq_recheck_delay_usecs) {
 842                 udelay(ts->penirq_recheck_delay_usecs);
 843                 if (!get_pendown_state(ts))
 844                         Rt = 0;
 845         }
 846
 847         /*
 848          * NOTE: We can't rely on the pressure to determine the pen down
 849          * state, even this controller has a pressure sensor. The pressure
 850          * value can fluctuate for quite a while after lifting the pen and
 851          * in some cases may not even settle at the expected value.
 852          *
 853          * The only safe way to check for the pen up condition is in the
 854          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 855          */
 856         if (Rt) {
 857                 struct input_dev *input = ts->input;
 858
 859                 if (ts->swap_xy)
 860                         swap(x, y);
 861
 862                 if (!ts->pendown) {
 863                         input_report_key(input, BTN_TOUCH, 1);
 864                         ts->pendown = true;
 865                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 866                 }
 867
 868                 input_report_abs(input, ABS_X, x);
 869                 input_report_abs(input, ABS_Y, y);
 870                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 871
 872                 input_sync(input);
 873                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 874         }
 875 }
 876
 877 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 878 {
 879         struct ads7846 *ts = handle;
 880
 881         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 882 }
 883
 884
 885 static irqreturn_t ads7846_irq(int irq, void *handle)
 886 {
 887         struct ads7846 *ts = handle;
 888
 889         /* Start with a small delay before checking pendown state */
 890         msleep(TS_POLL_DELAY);
 891
 892         while (!ts->stopped && get_pendown_state(ts)) {
 893
 894                 /* pen is down, continue with the measurement */
 895                 ads7846_read_state(ts);
 896
 897                 if (!ts->stopped)
 898                         ads7846_report_state(ts);
 899
 900                 wait_event_timeout(ts->wait, ts->stopped,
 901                                    msecs_to_jiffies(TS_POLL_PERIOD));
 902         }
 903
 904         if (ts->pendown) {
 905                 struct input_dev *input = ts->input;
 906
 907                 input_report_key(input, BTN_TOUCH, 0);
 908                 input_report_abs(input, ABS_PRESSURE, 0);
 909                 input_sync(input);
 910
 911                 ts->pendown = false;
 912                 dev_vdbg(&ts->spi->dev, "UP\n");
 913         }
 914
 915         return IRQ_HANDLED;
 916 }
 917
 918 #ifdef CONFIG_PM_SLEEP
 919 static int ads7846_suspend(struct device *dev)
 920 {
 921         struct ads7846 *ts = dev_get_drvdata(dev);
 922
 923         mutex_lock(&ts->lock);
 924
 925         if (!ts->suspended) {
 926
 927                 if (!ts->disabled)
 928                         __ads7846_disable(ts);
 929
 930                 if (device_may_wakeup(&ts->spi->dev))
 931                         enable_irq_wake(ts->spi->irq);
 932
 933                 ts->suspended = true;
 934         }
 935
 936         mutex_unlock(&ts->lock);
 937
 938         return 0;
 939 }
 940
 941 static int ads7846_resume(struct device *dev)
 942 {
 943         struct ads7846 *ts = dev_get_drvdata(dev);
 944
 945         mutex_lock(&ts->lock);
 946
 947         if (ts->suspended) {
 948
 949                 ts->suspended = false;
 950
 951                 if (device_may_wakeup(&ts->spi->dev))
 952                         disable_irq_wake(ts->spi->irq);
 953
 954                 if (!ts->disabled)
 955                         __ads7846_enable(ts);
 956         }
 957
 958         mutex_unlock(&ts->lock);
 959
 960         return 0;
 961 }
 962 #endif
 963
 964 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 965
 966 static int ads7846_setup_pendown(struct spi_device *spi,
 967                                  struct ads7846 *ts,
 968                                  const struct ads7846_platform_data *pdata)
 969 {
 970         int err;
 971
 972         /*
 973          * REVISIT when the irq can be triggered active-low, or if for some
 974          * reason the touchscreen isn't hooked up, we don't need to access
 975          * the pendown state.
 976          */
 977
 978         if (pdata->get_pendown_state) {
 979                 ts->get_pendown_state = pdata->get_pendown_state;
 980         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 981
 982                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 983                                        "ads7846_pendown");
 984                 if (err) {
 985                         dev_err(&spi->dev,
 986                                 "failed to request/setup pendown GPIO%d: %d\n",
 987                                 pdata->gpio_pendown, err);
 988                         return err;
 989                 }
 990
 991                 ts->gpio_pendown = pdata->gpio_pendown;
 992
 993                 if (pdata->gpio_pendown_debounce)
 994                         gpio_set_debounce(pdata->gpio_pendown,
 995                                           pdata->gpio_pendown_debounce);
 996         } else {
 997                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 998                 return -EINVAL;
 999         }
1000
1001         return 0;
1002 }
1003
1004 /*
1005  * Set up the transfers to read touchscreen state; this assumes we
1006  * use formula #2 for pressure, not #3.
1007  */
1008 static void ads7846_setup_spi_msg(struct ads7846 *ts,
1009                                   const struct ads7846_platform_data *pdata)
1010 {
1011         struct spi_message *m = &ts->msg[0];
1012         struct spi_transfer *x = ts->xfer;
1013         struct ads7846_packet *packet = ts->packet;
1014         int vref = pdata->keep_vref_on;
1015
1016         if (ts->model == 7873) {
1017                 /*
1018                  * The AD7873 is almost identical to the ADS7846
1019                  * keep VREF off during differential/ratiometric
1020                  * conversion modes.
1021                  */
1022                 ts->model = 7846;
1023                 vref = 0;
1024         }
1025
1026         ts->msg_count = 1;
1027         spi_message_init(m);
1028         m->context = ts;
1029
1030         if (ts->model == 7845) {
1031                 packet->read_y_cmd[0] = READ_Y(vref);
1032                 packet->read_y_cmd[1] = 0;
1033                 packet->read_y_cmd[2] = 0;
1034                 x->tx_buf = &packet->read_y_cmd[0];
1035                 x->rx_buf = &packet->tc.y_buf[0];
1036                 x->len = 3;
1037                 spi_message_add_tail(x, m);
1038         } else {
1039                 /* y- still on; turn on only y+ (and ADC) */
1040                 packet->read_y = READ_Y(vref);
1041                 x->tx_buf = &packet->read_y;
1042                 x->len = 1;
1043                 spi_message_add_tail(x, m);
1044
1045                 x++;
1046                 x->rx_buf = &packet->tc.y;
1047                 x->len = 2;
1048                 spi_message_add_tail(x, m);
1049         }
1050
1051         /*
1052          * The first sample after switching drivers can be low quality;
1053          * optionally discard it, using a second one after the signals
1054          * have had enough time to stabilize.
1055          */
1056         if (pdata->settle_delay_usecs) {
1057                 x->delay_usecs = pdata->settle_delay_usecs;
1058
1059                 x++;
1060                 x->tx_buf = &packet->read_y;
1061                 x->len = 1;
1062                 spi_message_add_tail(x, m);
1063
1064                 x++;
1065                 x->rx_buf = &packet->tc.y;
1066                 x->len = 2;
1067                 spi_message_add_tail(x, m);
1068         }
1069
1070         ts->msg_count++;
1071         m++;
1072         spi_message_init(m);
1073         m->context = ts;
1074
1075         if (ts->model == 7845) {
1076                 x++;
1077                 packet->read_x_cmd[0] = READ_X(vref);
1078                 packet->read_x_cmd[1] = 0;
1079                 packet->read_x_cmd[2] = 0;
1080                 x->tx_buf = &packet->read_x_cmd[0];
1081                 x->rx_buf = &packet->tc.x_buf[0];
1082                 x->len = 3;
1083                 spi_message_add_tail(x, m);
1084         } else {
1085                 /* turn y- off, x+ on, then leave in lowpower */
1086                 x++;
1087                 packet->read_x = READ_X(vref);
1088                 x->tx_buf = &packet->read_x;
1089                 x->len = 1;
1090                 spi_message_add_tail(x, m);
1091
1092                 x++;
1093                 x->rx_buf = &packet->tc.x;
1094                 x->len = 2;
1095                 spi_message_add_tail(x, m);
1096         }
1097
1098         /* ... maybe discard first sample ... */
1099         if (pdata->settle_delay_usecs) {
1100                 x->delay_usecs = pdata->settle_delay_usecs;
1101
1102                 x++;
1103                 x->tx_buf = &packet->read_x;
1104                 x->len = 1;
1105                 spi_message_add_tail(x, m);
1106
1107                 x++;
1108                 x->rx_buf = &packet->tc.x;
1109                 x->len = 2;
1110                 spi_message_add_tail(x, m);
1111         }
1112
1113         /* turn y+ off, x- on; we'll use formula #2 */
1114         if (ts->model == 7846) {
1115                 ts->msg_count++;
1116                 m++;
1117                 spi_message_init(m);
1118                 m->context = ts;
1119
1120                 x++;
1121                 packet->read_z1 = READ_Z1(vref);
1122                 x->tx_buf = &packet->read_z1;
1123                 x->len = 1;
1124                 spi_message_add_tail(x, m);
1125
1126                 x++;
1127                 x->rx_buf = &packet->tc.z1;
1128                 x->len = 2;
1129                 spi_message_add_tail(x, m);
1130
1131                 /* ... maybe discard first sample ... */
1132                 if (pdata->settle_delay_usecs) {
1133                         x->delay_usecs = pdata->settle_delay_usecs;
1134
1135                         x++;
1136                         x->tx_buf = &packet->read_z1;
1137                         x->len = 1;
1138                         spi_message_add_tail(x, m);
1139
1140                         x++;
1141                         x->rx_buf = &packet->tc.z1;
1142                         x->len = 2;
1143                         spi_message_add_tail(x, m);
1144                 }
1145
1146                 ts->msg_count++;
1147                 m++;
1148                 spi_message_init(m);
1149                 m->context = ts;
1150
1151                 x++;
1152                 packet->read_z2 = READ_Z2(vref);
1153                 x->tx_buf = &packet->read_z2;
1154                 x->len = 1;
1155                 spi_message_add_tail(x, m);
1156
1157                 x++;
1158                 x->rx_buf = &packet->tc.z2;
1159                 x->len = 2;
1160                 spi_message_add_tail(x, m);
1161
1162                 /* ... maybe discard first sample ... */
1163                 if (pdata->settle_delay_usecs) {
1164                         x->delay_usecs = pdata->settle_delay_usecs;
1165
1166                         x++;
1167                         x->tx_buf = &packet->read_z2;
1168                         x->len = 1;
1169                         spi_message_add_tail(x, m);
1170
1171                         x++;
1172                         x->rx_buf = &packet->tc.z2;
1173                         x->len = 2;
1174                         spi_message_add_tail(x, m);
1175                 }
1176         }
1177
1178         /* power down */
1179         ts->msg_count++;
1180         m++;
1181         spi_message_init(m);
1182         m->context = ts;
1183
1184         if (ts->model == 7845) {
1185                 x++;
1186                 packet->pwrdown_cmd[0] = PWRDOWN;
1187                 packet->pwrdown_cmd[1] = 0;
1188                 packet->pwrdown_cmd[2] = 0;
1189                 x->tx_buf = &packet->pwrdown_cmd[0];
1190                 x->len = 3;
1191         } else {
1192                 x++;
1193                 packet->pwrdown = PWRDOWN;
1194                 x->tx_buf = &packet->pwrdown;
1195                 x->len = 1;
1196                 spi_message_add_tail(x, m);
1197
1198                 x++;
1199                 x->rx_buf = &packet->dummy;
1200                 x->len = 2;
1201         }
1202
1203         CS_CHANGE(*x);
1204         spi_message_add_tail(x, m);
1205 }
1206
1207 #ifdef CONFIG_OF
1208 static const struct of_device_id ads7846_dt_ids[] = {
1209         { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
1210         { .compatible = "ti,ads7843",   .data = (void *) 7843 },
1211         { .compatible = "ti,ads7845",   .data = (void *) 7845 },
1212         { .compatible = "ti,ads7846",   .data = (void *) 7846 },
1213         { .compatible = "ti,ads7873",   .data = (void *) 7873 },
1214         { }
1215 };
1216 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1217
1218 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1219 {
1220         struct ads7846_platform_data *pdata;
1221         struct device_node *node = dev->of_node;
1222         const struct of_device_id *match;
1223
1224         if (!node) {
1225                 dev_err(dev, "Device does not have associated DT data\n");
1226                 return ERR_PTR(-EINVAL);
1227         }
1228
1229         match = of_match_device(ads7846_dt_ids, dev);
1230         if (!match) {
1231                 dev_err(dev, "Unknown device model\n");
1232                 return ERR_PTR(-EINVAL);
1233         }
1234
1235         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1236         if (!pdata)
1237                 return ERR_PTR(-ENOMEM);
1238
1239         pdata->model = (unsigned long)match->data;
1240
1241         of_property_read_u16(node, "ti,vref-delay-usecs",
1242                              &pdata->vref_delay_usecs);
1243         of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1244         pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1245
1246         pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1247
1248         of_property_read_u16(node, "ti,settle-delay-usec",
1249                              &pdata->settle_delay_usecs);
1250         of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1251                              &pdata->penirq_recheck_delay_usecs);
1252
1253         of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1254         of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1255
1256         of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1257         of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1258         of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1259         of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1260
1261         of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1262         of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1263
1264         of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1265         of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1266         of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1267
1268         of_property_read_u32(node, "ti,pendown-gpio-debounce",
1269                              &pdata->gpio_pendown_debounce);
1270
1271         pdata->wakeup = of_property_read_bool(node, "linux,wakeup");
1272
1273         pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1274
1275         return pdata;
1276 }
1277 #else
1278 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1279 {
1280         dev_err(dev, "no platform data defined\n");
1281         return ERR_PTR(-EINVAL);
1282 }
1283 #endif
1284
1285 static int ads7846_probe(struct spi_device *spi)
1286 {
1287         const struct ads7846_platform_data *pdata;
1288         struct ads7846 *ts;
1289         struct ads7846_packet *packet;
1290         struct input_dev *input_dev;
1291         unsigned long irq_flags;
1292         int err;
1293
1294         if (!spi->irq) {
1295                 dev_dbg(&spi->dev, "no IRQ?\n");
1296                 return -EINVAL;
1297         }
1298
1299         /* don't exceed max specified sample rate */
1300         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1301                 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1302                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1303                 return -EINVAL;
1304         }
1305
1306         /*
1307          * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1308          * that even if the hardware can do that, the SPI controller driver
1309          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1310          */
1311         spi->bits_per_word = 8;
1312         spi->mode = SPI_MODE_0;
1313         err = spi_setup(spi);
1314         if (err < 0)
1315                 return err;
1316
1317         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1318         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1319         input_dev = input_allocate_device();
1320         if (!ts || !packet || !input_dev) {
1321                 err = -ENOMEM;
1322                 goto err_free_mem;
1323         }
1324
1325         spi_set_drvdata(spi, ts);
1326
1327         ts->packet = packet;
1328         ts->spi = spi;
1329         ts->input = input_dev;
1330
1331         mutex_init(&ts->lock);
1332         init_waitqueue_head(&ts->wait);
1333
1334         pdata = dev_get_platdata(&spi->dev);
1335         if (!pdata) {
1336                 pdata = ads7846_probe_dt(&spi->dev);
1337                 if (IS_ERR(pdata))
1338                         return PTR_ERR(pdata);
1339         }
1340
1341         ts->model = pdata->model ? : 7846;
1342         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1343         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1344         ts->pressure_max = pdata->pressure_max ? : ~0;
1345
1346         ts->vref_mv = pdata->vref_mv;
1347         ts->swap_xy = pdata->swap_xy;
1348
1349         if (pdata->filter != NULL) {
1350                 if (pdata->filter_init != NULL) {
1351                         err = pdata->filter_init(pdata, &ts->filter_data);
1352                         if (err < 0)
1353                                 goto err_free_mem;
1354                 }
1355                 ts->filter = pdata->filter;
1356                 ts->filter_cleanup = pdata->filter_cleanup;
1357         } else if (pdata->debounce_max) {
1358                 ts->debounce_max = pdata->debounce_max;
1359                 if (ts->debounce_max < 2)
1360                         ts->debounce_max = 2;
1361                 ts->debounce_tol = pdata->debounce_tol;
1362                 ts->debounce_rep = pdata->debounce_rep;
1363                 ts->filter = ads7846_debounce_filter;
1364                 ts->filter_data = ts;
1365         } else {
1366                 ts->filter = ads7846_no_filter;
1367         }
1368
1369         err = ads7846_setup_pendown(spi, ts, pdata);
1370         if (err)
1371                 goto err_cleanup_filter;
1372
1373         if (pdata->penirq_recheck_delay_usecs)
1374                 ts->penirq_recheck_delay_usecs =
1375                                 pdata->penirq_recheck_delay_usecs;
1376
1377         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1378
1379         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1380         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1381
1382         input_dev->name = ts->name;
1383         input_dev->phys = ts->phys;
1384         input_dev->dev.parent = &spi->dev;
1385
1386         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1387         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1388         input_set_abs_params(input_dev, ABS_X,
1389                         pdata->x_min ? : 0,
1390                         pdata->x_max ? : MAX_12BIT,
1391                         0, 0);
1392         input_set_abs_params(input_dev, ABS_Y,
1393                         pdata->y_min ? : 0,
1394                         pdata->y_max ? : MAX_12BIT,
1395                         0, 0);
1396         input_set_abs_params(input_dev, ABS_PRESSURE,
1397                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1398
1399         ads7846_setup_spi_msg(ts, pdata);
1400
1401         ts->reg = regulator_get(&spi->dev, "vcc");
1402         if (IS_ERR(ts->reg)) {
1403                 err = PTR_ERR(ts->reg);
1404                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1405                 goto err_free_gpio;
1406         }
1407
1408         err = regulator_enable(ts->reg);
1409         if (err) {
1410                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1411                 goto err_put_regulator;
1412         }
1413
1414         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1415         irq_flags |= IRQF_ONESHOT;
1416
1417         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1418                                    irq_flags, spi->dev.driver->name, ts);
1419         if (err && !pdata->irq_flags) {
1420                 dev_info(&spi->dev,
1421                         "trying pin change workaround on irq %d\n", spi->irq);
1422                 irq_flags |= IRQF_TRIGGER_RISING;
1423                 err = request_threaded_irq(spi->irq,
1424                                   ads7846_hard_irq, ads7846_irq,
1425                                   irq_flags, spi->dev.driver->name, ts);
1426         }
1427
1428         if (err) {
1429                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1430                 goto err_disable_regulator;
1431         }
1432
1433         err = ads784x_hwmon_register(spi, ts);
1434         if (err)
1435                 goto err_free_irq;
1436
1437         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1438
1439         /*
1440          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1441          * the touchscreen, in case it's not connected.
1442          */
1443         if (ts->model == 7845)
1444                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1445         else
1446                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1447
1448         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1449         if (err)
1450                 goto err_remove_hwmon;
1451
1452         err = input_register_device(input_dev);
1453         if (err)
1454                 goto err_remove_attr_group;
1455
1456         device_init_wakeup(&spi->dev, pdata->wakeup);
1457
1458         /*
1459          * If device does not carry platform data we must have allocated it
1460          * when parsing DT data.
1461          */
1462         if (!dev_get_platdata(&spi->dev))
1463                 devm_kfree(&spi->dev, (void *)pdata);
1464
1465         return 0;
1466
1467  err_remove_attr_group:
1468         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1469  err_remove_hwmon:
1470         ads784x_hwmon_unregister(spi, ts);
1471  err_free_irq:
1472         free_irq(spi->irq, ts);
1473  err_disable_regulator:
1474         regulator_disable(ts->reg);
1475  err_put_regulator:
1476         regulator_put(ts->reg);
1477  err_free_gpio:
1478         if (!ts->get_pendown_state)
1479                 gpio_free(ts->gpio_pendown);
1480  err_cleanup_filter:
1481         if (ts->filter_cleanup)
1482                 ts->filter_cleanup(ts->filter_data);
1483  err_free_mem:
1484         input_free_device(input_dev);
1485         kfree(packet);
1486         kfree(ts);
1487         return err;
1488 }
1489
1490 static int ads7846_remove(struct spi_device *spi)
1491 {
1492         struct ads7846 *ts = spi_get_drvdata(spi);
1493
1494         device_init_wakeup(&spi->dev, false);
1495
1496         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1497
1498         ads7846_disable(ts);
1499         free_irq(ts->spi->irq, ts);
1500
1501         input_unregister_device(ts->input);
1502
1503         ads784x_hwmon_unregister(spi, ts);
1504
1505         regulator_disable(ts->reg);
1506         regulator_put(ts->reg);
1507
1508         if (!ts->get_pendown_state) {
1509                 /*
1510                  * If we are not using specialized pendown method we must
1511                  * have been relying on gpio we set up ourselves.
1512                  */
1513                 gpio_free(ts->gpio_pendown);
1514         }
1515
1516         if (ts->filter_cleanup)
1517                 ts->filter_cleanup(ts->filter_data);
1518
1519         kfree(ts->packet);
1520         kfree(ts);
1521
1522         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1523
1524         return 0;
1525 }
1526
1527 static struct spi_driver ads7846_driver = {
1528         .driver = {
1529                 .name   = "ads7846",
1530                 .owner  = THIS_MODULE,
1531                 .pm     = &ads7846_pm,
1532                 .of_match_table = of_match_ptr(ads7846_dt_ids),
1533         },
1534         .probe          = ads7846_probe,
1535         .remove         = ads7846_remove,
1536 };
1537
1538 module_spi_driver(ads7846_driver);
1539
1540 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1541 MODULE_LICENSE("GPL");
1542 MODULE_ALIAS("spi:ads7846");