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/hwmon.h>
  21 #include <linux/init.h>
  22 #include <linux/err.h>
  23 #include <linux/delay.h>
  24 #include <linux/input.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/slab.h>
  27 #include <linux/gpio.h>
  28 #include <linux/spi/spi.h>
  29 #include <linux/spi/ads7846.h>
  30 #include <linux/regulator/consumer.h>
  31 #include <asm/irq.h>
  32
  33 /*
  34  * This code has been heavily tested on a Nokia 770, and lightly
  35  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  36  * TSC2046 is just newer ads7846 silicon.
  37  * Support for ads7843 tested on Atmel at91sam926x-EK.
  38  * Support for ads7845 has only been stubbed in.
  39  * Support for Analog Devices AD7873 and AD7843 tested.
  40  *
  41  * IRQ handling needs a workaround because of a shortcoming in handling
  42  * edge triggered IRQs on some platforms like the OMAP1/2. These
  43  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  44  * have to maintain our own SW IRQ disabled status. This should be
  45  * removed as soon as the affected platform's IRQ handling is fixed.
  46  *
  47  * App note sbaa036 talks in more detail about accurate sampling...
  48  * that ought to help in situations like LCDs inducing noise (which
  49  * can also be helped by using synch signals) and more generally.
  50  * This driver tries to utilize the measures described in the app
  51  * note. The strength of filtering can be set in the board-* specific
  52  * files.
  53  */
  54
  55 #define TS_POLL_DELAY   (1 * 1000000)   /* ns delay before the first sample */
  56 #define TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
  57
  58 /* this driver doesn't aim at the peak continuous sample rate */
  59 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  60
  61 struct ts_event {
  62         /* For portability, we can't read 12 bit values using SPI (which
  63          * would make the controller deliver them as native byteorder u16
  64          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  65          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  66          */
  67         u16     x;
  68         u16     y;
  69         u16     z1, z2;
  70         int     ignore;
  71         u8      x_buf[3];
  72         u8      y_buf[3];
  73 };
  74
  75 /*
  76  * We allocate this separately to avoid cache line sharing issues when
  77  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  78  * systems where main memory is not DMA-coherent (most non-x86 boards).
  79  */
  80 struct ads7846_packet {
  81         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  82         u16                     dummy;          /* for the pwrdown read */
  83         struct ts_event         tc;
  84         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  85         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  86 };
  87
  88 struct ads7846 {
  89         struct input_dev        *input;
  90         char                    phys[32];
  91         char                    name[32];
  92
  93         struct spi_device       *spi;
  94         struct regulator        *reg;
  95
  96 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
  97         struct attribute_group  *attr_group;
  98         struct device           *hwmon;
  99 #endif
 100
 101         u16                     model;
 102         u16                     vref_mv;
 103         u16                     vref_delay_usecs;
 104         u16                     x_plate_ohms;
 105         u16                     pressure_max;
 106
 107         bool                    swap_xy;
 108
 109         struct ads7846_packet   *packet;
 110
 111         struct spi_transfer     xfer[18];
 112         struct spi_message      msg[5];
 113         struct spi_message      *last_msg;
 114         int                     msg_idx;
 115         int                     read_cnt;
 116         int                     read_rep;
 117         int                     last_read;
 118
 119         u16                     debounce_max;
 120         u16                     debounce_tol;
 121         u16                     debounce_rep;
 122
 123         u16                     penirq_recheck_delay_usecs;
 124
 125         spinlock_t              lock;
 126         struct hrtimer          timer;
 127         unsigned                pendown:1;      /* P: lock */
 128         unsigned                pending:1;      /* P: lock */
 129 // FIXME remove "irq_disabled"
 130         unsigned                irq_disabled:1; /* P: lock */
 131         unsigned                disabled:1;
 132         unsigned                is_suspended:1;
 133
 134         int                     (*filter)(void *data, int data_idx, int *val);
 135         void                    *filter_data;
 136         void                    (*filter_cleanup)(void *data);
 137         int                     (*get_pendown_state)(void);
 138         int                     gpio_pendown;
 139
 140         void                    (*wait_for_sync)(void);
 141 };
 142
 143 /* leave chip selected when we're done, for quicker re-select? */
 144 #if     0
 145 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 146 #else
 147 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 148 #endif
 149
 150 /*--------------------------------------------------------------------------*/
 151
 152 /* The ADS7846 has touchscreen and other sensors.
 153  * Earlier ads784x chips are somewhat compatible.
 154  */
 155 #define ADS_START               (1 << 7)
 156 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 157 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 158 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 159 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 160 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 161 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 162 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 163 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 164 #define ADS_8_BIT               (1 << 3)
 165 #define ADS_12_BIT              (0 << 3)
 166 #define ADS_SER                 (1 << 2)        /* non-differential */
 167 #define ADS_DFR                 (0 << 2)        /* differential */
 168 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 169 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 170 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 171 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 172
 173 #define MAX_12BIT       ((1<<12)-1)
 174
 175 /* leave ADC powered up (disables penirq) between differential samples */
 176 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 177         | ADS_12_BIT | ADS_DFR | \
 178         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 179
 180 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 181 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 182 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 183
 184 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 185 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 186
 187 /* single-ended samples need to first power up reference voltage;
 188  * we leave both ADC and VREF powered
 189  */
 190 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 191         | ADS_12_BIT | ADS_SER)
 192
 193 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 194 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 195
 196 /*--------------------------------------------------------------------------*/
 197
 198 /*
 199  * Non-touchscreen sensors only use single-ended conversions.
 200  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 201  * ads7846 lets that pin be unconnected, to use internal vREF.
 202  */
 203
 204 struct ser_req {
 205         u8                      ref_on;
 206         u8                      command;
 207         u8                      ref_off;
 208         u16                     scratch;
 209         __be16                  sample;
 210         struct spi_message      msg;
 211         struct spi_transfer     xfer[6];
 212 };
 213
 214 struct ads7845_ser_req {
 215         u8                      command[3];
 216         u8                      pwrdown[3];
 217         u8                      sample[3];
 218         struct spi_message      msg;
 219         struct spi_transfer     xfer[2];
 220 };
 221
 222 static void ads7846_enable(struct ads7846 *ts);
 223 static void ads7846_disable(struct ads7846 *ts);
 224
 225 static int device_suspended(struct device *dev)
 226 {
 227         struct ads7846 *ts = dev_get_drvdata(dev);
 228         return ts->is_suspended || ts->disabled;
 229 }
 230
 231 static int ads7846_read12_ser(struct device *dev, unsigned command)
 232 {
 233         struct spi_device       *spi = to_spi_device(dev);
 234         struct ads7846          *ts = dev_get_drvdata(dev);
 235         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
 236         int                     status;
 237         int                     use_internal;
 238
 239         if (!req)
 240                 return -ENOMEM;
 241
 242         spi_message_init(&req->msg);
 243
 244         /* FIXME boards with ads7846 might use external vref instead ... */
 245         use_internal = (ts->model == 7846);
 246
 247         /* maybe turn on internal vREF, and let it settle */
 248         if (use_internal) {
 249                 req->ref_on = REF_ON;
 250                 req->xfer[0].tx_buf = &req->ref_on;
 251                 req->xfer[0].len = 1;
 252                 spi_message_add_tail(&req->xfer[0], &req->msg);
 253
 254                 req->xfer[1].rx_buf = &req->scratch;
 255                 req->xfer[1].len = 2;
 256
 257                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 258                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 259                 spi_message_add_tail(&req->xfer[1], &req->msg);
 260         }
 261
 262         /* take sample */
 263         req->command = (u8) command;
 264         req->xfer[2].tx_buf = &req->command;
 265         req->xfer[2].len = 1;
 266         spi_message_add_tail(&req->xfer[2], &req->msg);
 267
 268         req->xfer[3].rx_buf = &req->sample;
 269         req->xfer[3].len = 2;
 270         spi_message_add_tail(&req->xfer[3], &req->msg);
 271
 272         /* REVISIT:  take a few more samples, and compare ... */
 273
 274         /* converter in low power mode & enable PENIRQ */
 275         req->ref_off = PWRDOWN;
 276         req->xfer[4].tx_buf = &req->ref_off;
 277         req->xfer[4].len = 1;
 278         spi_message_add_tail(&req->xfer[4], &req->msg);
 279
 280         req->xfer[5].rx_buf = &req->scratch;
 281         req->xfer[5].len = 2;
 282         CS_CHANGE(req->xfer[5]);
 283         spi_message_add_tail(&req->xfer[5], &req->msg);
 284
 285         ts->irq_disabled = 1;
 286         disable_irq(spi->irq);
 287         status = spi_sync(spi, &req->msg);
 288         ts->irq_disabled = 0;
 289         enable_irq(spi->irq);
 290
 291         if (status == 0) {
 292                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 293                 status = be16_to_cpu(req->sample);
 294                 status = status >> 3;
 295                 status &= 0x0fff;
 296         }
 297
 298         kfree(req);
 299         return status;
 300 }
 301
 302 static int ads7845_read12_ser(struct device *dev, unsigned command)
 303 {
 304         struct spi_device       *spi = to_spi_device(dev);
 305         struct ads7846          *ts = dev_get_drvdata(dev);
 306         struct ads7845_ser_req  *req = kzalloc(sizeof *req, GFP_KERNEL);
 307         int                     status;
 308
 309         if (!req)
 310                 return -ENOMEM;
 311
 312         spi_message_init(&req->msg);
 313
 314         req->command[0] = (u8) command;
 315         req->xfer[0].tx_buf = req->command;
 316         req->xfer[0].rx_buf = req->sample;
 317         req->xfer[0].len = 3;
 318         spi_message_add_tail(&req->xfer[0], &req->msg);
 319
 320         ts->irq_disabled = 1;
 321         disable_irq(spi->irq);
 322         status = spi_sync(spi, &req->msg);
 323         ts->irq_disabled = 0;
 324         enable_irq(spi->irq);
 325
 326         if (status == 0) {
 327                 /* BE12 value, then padding */
 328                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 329                 status = status >> 3;
 330                 status &= 0x0fff;
 331         }
 332
 333         kfree(req);
 334         return status;
 335 }
 336
 337 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 338
 339 #define SHOW(name, var, adjust) static ssize_t \
 340 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 341 { \
 342         struct ads7846 *ts = dev_get_drvdata(dev); \
 343         ssize_t v = ads7846_read12_ser(dev, \
 344                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
 345         if (v < 0) \
 346                 return v; \
 347         return sprintf(buf, "%u\n", adjust(ts, v)); \
 348 } \
 349 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 350
 351
 352 /* Sysfs conventions report temperatures in millidegrees Celsius.
 353  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 354  * accuracy scheme without calibration data.  For now we won't try either;
 355  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 356  */
 357 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 358 {
 359         return v;
 360 }
 361
 362 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 363 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 364
 365
 366 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 367  * if we know vREF.  userspace may need to scale vAUX to match the board's
 368  * external resistors; we assume that vBATT only uses the internal ones.
 369  */
 370 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 371 {
 372         unsigned retval = v;
 373
 374         /* external resistors may scale vAUX into 0..vREF */
 375         retval *= ts->vref_mv;
 376         retval = retval >> 12;
 377         return retval;
 378 }
 379
 380 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 381 {
 382         unsigned retval = vaux_adjust(ts, v);
 383
 384         /* ads7846 has a resistor ladder to scale this signal down */
 385         if (ts->model == 7846)
 386                 retval *= 4;
 387         return retval;
 388 }
 389
 390 SHOW(in0_input, vaux, vaux_adjust)
 391 SHOW(in1_input, vbatt, vbatt_adjust)
 392
 393
 394 static struct attribute *ads7846_attributes[] = {
 395         &dev_attr_temp0.attr,
 396         &dev_attr_temp1.attr,
 397         &dev_attr_in0_input.attr,
 398         &dev_attr_in1_input.attr,
 399         NULL,
 400 };
 401
 402 static struct attribute_group ads7846_attr_group = {
 403         .attrs = ads7846_attributes,
 404 };
 405
 406 static struct attribute *ads7843_attributes[] = {
 407         &dev_attr_in0_input.attr,
 408         &dev_attr_in1_input.attr,
 409         NULL,
 410 };
 411
 412 static struct attribute_group ads7843_attr_group = {
 413         .attrs = ads7843_attributes,
 414 };
 415
 416 static struct attribute *ads7845_attributes[] = {
 417         &dev_attr_in0_input.attr,
 418         NULL,
 419 };
 420
 421 static struct attribute_group ads7845_attr_group = {
 422         .attrs = ads7845_attributes,
 423 };
 424
 425 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 426 {
 427         struct device *hwmon;
 428         int err;
 429
 430         /* hwmon sensors need a reference voltage */
 431         switch (ts->model) {
 432         case 7846:
 433                 if (!ts->vref_mv) {
 434                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 435                         ts->vref_mv = 2500;
 436                 }
 437                 break;
 438         case 7845:
 439         case 7843:
 440                 if (!ts->vref_mv) {
 441                         dev_warn(&spi->dev,
 442                                 "external vREF for ADS%d not specified\n",
 443                                 ts->model);
 444                         return 0;
 445                 }
 446                 break;
 447         }
 448
 449         /* different chips have different sensor groups */
 450         switch (ts->model) {
 451         case 7846:
 452                 ts->attr_group = &ads7846_attr_group;
 453                 break;
 454         case 7845:
 455                 ts->attr_group = &ads7845_attr_group;
 456                 break;
 457         case 7843:
 458                 ts->attr_group = &ads7843_attr_group;
 459                 break;
 460         default:
 461                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 462                 return 0;
 463         }
 464
 465         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 466         if (err)
 467                 return err;
 468
 469         hwmon = hwmon_device_register(&spi->dev);
 470         if (IS_ERR(hwmon)) {
 471                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 472                 return PTR_ERR(hwmon);
 473         }
 474
 475         ts->hwmon = hwmon;
 476         return 0;
 477 }
 478
 479 static void ads784x_hwmon_unregister(struct spi_device *spi,
 480                                      struct ads7846 *ts)
 481 {
 482         if (ts->hwmon) {
 483                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 484                 hwmon_device_unregister(ts->hwmon);
 485         }
 486 }
 487
 488 #else
 489 static inline int ads784x_hwmon_register(struct spi_device *spi,
 490                                          struct ads7846 *ts)
 491 {
 492         return 0;
 493 }
 494
 495 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 496                                             struct ads7846 *ts)
 497 {
 498 }
 499 #endif
 500
 501 static int is_pen_down(struct device *dev)
 502 {
 503         struct ads7846  *ts = dev_get_drvdata(dev);
 504
 505         return ts->pendown;
 506 }
 507
 508 static ssize_t ads7846_pen_down_show(struct device *dev,
 509                                      struct device_attribute *attr, char *buf)
 510 {
 511         return sprintf(buf, "%u\n", is_pen_down(dev));
 512 }
 513
 514 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 515
 516 static ssize_t ads7846_disable_show(struct device *dev,
 517                                      struct device_attribute *attr, char *buf)
 518 {
 519         struct ads7846  *ts = dev_get_drvdata(dev);
 520
 521         return sprintf(buf, "%u\n", ts->disabled);
 522 }
 523
 524 static ssize_t ads7846_disable_store(struct device *dev,
 525                                      struct device_attribute *attr,
 526                                      const char *buf, size_t count)
 527 {
 528         struct ads7846 *ts = dev_get_drvdata(dev);
 529         unsigned long i;
 530
 531         if (strict_strtoul(buf, 10, &i))
 532                 return -EINVAL;
 533
 534         spin_lock_irq(&ts->lock);
 535
 536         if (i)
 537                 ads7846_disable(ts);
 538         else
 539                 ads7846_enable(ts);
 540
 541         spin_unlock_irq(&ts->lock);
 542
 543         return count;
 544 }
 545
 546 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 547
 548 static struct attribute *ads784x_attributes[] = {
 549         &dev_attr_pen_down.attr,
 550         &dev_attr_disable.attr,
 551         NULL,
 552 };
 553
 554 static struct attribute_group ads784x_attr_group = {
 555         .attrs = ads784x_attributes,
 556 };
 557
 558 /*--------------------------------------------------------------------------*/
 559
 560 static int get_pendown_state(struct ads7846 *ts)
 561 {
 562         if (ts->get_pendown_state)
 563                 return ts->get_pendown_state();
 564
 565         return !gpio_get_value(ts->gpio_pendown);
 566 }
 567
 568 static void null_wait_for_sync(void)
 569 {
 570 }
 571
 572 /*
 573  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 574  * to retrieve touchscreen status.
 575  *
 576  * The SPI transfer completion callback does the real work.  It reports
 577  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 578  */
 579
 580 static void ads7846_rx(void *ads)
 581 {
 582         struct ads7846          *ts = ads;
 583         struct ads7846_packet   *packet = ts->packet;
 584         unsigned                Rt;
 585         u16                     x, y, z1, z2;
 586
 587         /* ads7846_rx_val() did in-place conversion (including byteswap) from
 588          * on-the-wire format as part of debouncing to get stable readings.
 589          */
 590         if (ts->model == 7845) {
 591                 x = *(u16 *)packet->tc.x_buf;
 592                 y = *(u16 *)packet->tc.y_buf;
 593                 z1 = 0;
 594                 z2 = 0;
 595         } else {
 596                 x = packet->tc.x;
 597                 y = packet->tc.y;
 598                 z1 = packet->tc.z1;
 599                 z2 = packet->tc.z2;
 600         }
 601
 602         /* range filtering */
 603         if (x == MAX_12BIT)
 604                 x = 0;
 605
 606         if (ts->model == 7843) {
 607                 Rt = ts->pressure_max / 2;
 608         } else if (ts->model == 7845) {
 609                 if (get_pendown_state(ts))
 610                         Rt = ts->pressure_max / 2;
 611                 else
 612                         Rt = 0;
 613                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 614         } else if (likely(x && z1)) {
 615                 /* compute touch pressure resistance using equation #2 */
 616                 Rt = z2;
 617                 Rt -= z1;
 618                 Rt *= x;
 619                 Rt *= ts->x_plate_ohms;
 620                 Rt /= z1;
 621                 Rt = (Rt + 2047) >> 12;
 622         } else {
 623                 Rt = 0;
 624         }
 625
 626         /* Sample found inconsistent by debouncing or pressure is beyond
 627          * the maximum. Don't report it to user space, repeat at least
 628          * once more the measurement
 629          */
 630         if (packet->tc.ignore || Rt > ts->pressure_max) {
 631                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 632                          packet->tc.ignore, Rt);
 633                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
 634                               HRTIMER_MODE_REL);
 635                 return;
 636         }
 637
 638         /* Maybe check the pendown state before reporting. This discards
 639          * false readings when the pen is lifted.
 640          */
 641         if (ts->penirq_recheck_delay_usecs) {
 642                 udelay(ts->penirq_recheck_delay_usecs);
 643                 if (!get_pendown_state(ts))
 644                         Rt = 0;
 645         }
 646
 647         /* NOTE: We can't rely on the pressure to determine the pen down
 648          * state, even this controller has a pressure sensor.  The pressure
 649          * value can fluctuate for quite a while after lifting the pen and
 650          * in some cases may not even settle at the expected value.
 651          *
 652          * The only safe way to check for the pen up condition is in the
 653          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 654          */
 655         if (Rt) {
 656                 struct input_dev *input = ts->input;
 657
 658                 if (!ts->pendown) {
 659                         input_report_key(input, BTN_TOUCH, 1);
 660                         ts->pendown = 1;
 661                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 662                 }
 663
 664                 if (ts->swap_xy)
 665                         swap(x, y);
 666
 667                 input_report_abs(input, ABS_X, x);
 668                 input_report_abs(input, ABS_Y, y);
 669                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 670
 671                 input_sync(input);
 672                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 673         }
 674
 675         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
 676                         HRTIMER_MODE_REL);
 677 }
 678
 679 static int ads7846_debounce(void *ads, int data_idx, int *val)
 680 {
 681         struct ads7846          *ts = ads;
 682
 683         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 684                 /* Start over collecting consistent readings. */
 685                 ts->read_rep = 0;
 686                 /* Repeat it, if this was the first read or the read
 687                  * wasn't consistent enough. */
 688                 if (ts->read_cnt < ts->debounce_max) {
 689                         ts->last_read = *val;
 690                         ts->read_cnt++;
 691                         return ADS7846_FILTER_REPEAT;
 692                 } else {
 693                         /* Maximum number of debouncing reached and still
 694                          * not enough number of consistent readings. Abort
 695                          * the whole sample, repeat it in the next sampling
 696                          * period.
 697                          */
 698                         ts->read_cnt = 0;
 699                         return ADS7846_FILTER_IGNORE;
 700                 }
 701         } else {
 702                 if (++ts->read_rep > ts->debounce_rep) {
 703                         /* Got a good reading for this coordinate,
 704                          * go for the next one. */
 705                         ts->read_cnt = 0;
 706                         ts->read_rep = 0;
 707                         return ADS7846_FILTER_OK;
 708                 } else {
 709                         /* Read more values that are consistent. */
 710                         ts->read_cnt++;
 711                         return ADS7846_FILTER_REPEAT;
 712                 }
 713         }
 714 }
 715
 716 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 717 {
 718         return ADS7846_FILTER_OK;
 719 }
 720
 721 static void ads7846_rx_val(void *ads)
 722 {
 723         struct ads7846 *ts = ads;
 724         struct ads7846_packet *packet = ts->packet;
 725         struct spi_message *m;
 726         struct spi_transfer *t;
 727         int val;
 728         int action;
 729         int status;
 730
 731         m = &ts->msg[ts->msg_idx];
 732         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 733
 734         if (ts->model == 7845) {
 735                 val = be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 736         } else {
 737                 /* adjust:  on-wire is a must-ignore bit, a BE12 value, then
 738                  * padding; built from two 8 bit values written msb-first.
 739                  */
 740                 val = be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 741         }
 742
 743         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
 744         switch (action) {
 745         case ADS7846_FILTER_REPEAT:
 746                 break;
 747         case ADS7846_FILTER_IGNORE:
 748                 packet->tc.ignore = 1;
 749                 /* Last message will contain ads7846_rx() as the
 750                  * completion function.
 751                  */
 752                 m = ts->last_msg;
 753                 break;
 754         case ADS7846_FILTER_OK:
 755                 *(u16 *)t->rx_buf = val;
 756                 packet->tc.ignore = 0;
 757                 m = &ts->msg[++ts->msg_idx];
 758                 break;
 759         default:
 760                 BUG();
 761         }
 762         ts->wait_for_sync();
 763         status = spi_async(ts->spi, m);
 764         if (status)
 765                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 766                                 status);
 767 }
 768
 769 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
 770 {
 771         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
 772         int             status = 0;
 773
 774         spin_lock(&ts->lock);
 775
 776         if (unlikely(!get_pendown_state(ts) ||
 777                      device_suspended(&ts->spi->dev))) {
 778                 if (ts->pendown) {
 779                         struct input_dev *input = ts->input;
 780
 781                         input_report_key(input, BTN_TOUCH, 0);
 782                         input_report_abs(input, ABS_PRESSURE, 0);
 783                         input_sync(input);
 784
 785                         ts->pendown = 0;
 786                         dev_vdbg(&ts->spi->dev, "UP\n");
 787                 }
 788
 789                 /* measurement cycle ended */
 790                 if (!device_suspended(&ts->spi->dev)) {
 791                         ts->irq_disabled = 0;
 792                         enable_irq(ts->spi->irq);
 793                 }
 794                 ts->pending = 0;
 795         } else {
 796                 /* pen is still down, continue with the measurement */
 797                 ts->msg_idx = 0;
 798                 ts->wait_for_sync();
 799                 status = spi_async(ts->spi, &ts->msg[0]);
 800                 if (status)
 801                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 802         }
 803
 804         spin_unlock(&ts->lock);
 805         return HRTIMER_NORESTART;
 806 }
 807
 808 static irqreturn_t ads7846_irq(int irq, void *handle)
 809 {
 810         struct ads7846 *ts = handle;
 811         unsigned long flags;
 812
 813         spin_lock_irqsave(&ts->lock, flags);
 814         if (likely(get_pendown_state(ts))) {
 815                 if (!ts->irq_disabled) {
 816                         /* The ARM do_simple_IRQ() dispatcher doesn't act
 817                          * like the other dispatchers:  it will report IRQs
 818                          * even after they've been disabled.  We work around
 819                          * that here.  (The "generic irq" framework may help...)
 820                          */
 821                         ts->irq_disabled = 1;
 822                         disable_irq_nosync(ts->spi->irq);
 823                         ts->pending = 1;
 824                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
 825                                         HRTIMER_MODE_REL);
 826                 }
 827         }
 828         spin_unlock_irqrestore(&ts->lock, flags);
 829
 830         return IRQ_HANDLED;
 831 }
 832
 833 /*--------------------------------------------------------------------------*/
 834
 835 /* Must be called with ts->lock held */
 836 static void ads7846_disable(struct ads7846 *ts)
 837 {
 838         if (ts->disabled)
 839                 return;
 840
 841         ts->disabled = 1;
 842
 843         /* are we waiting for IRQ, or polling? */
 844         if (!ts->pending) {
 845                 ts->irq_disabled = 1;
 846                 disable_irq(ts->spi->irq);
 847         } else {
 848                 /* the timer will run at least once more, and
 849                  * leave everything in a clean state, IRQ disabled
 850                  */
 851                 while (ts->pending) {
 852                         spin_unlock_irq(&ts->lock);
 853                         msleep(1);
 854                         spin_lock_irq(&ts->lock);
 855                 }
 856         }
 857
 858         regulator_disable(ts->reg);
 859
 860         /* we know the chip's in lowpower mode since we always
 861          * leave it that way after every request
 862          */
 863 }
 864
 865 /* Must be called with ts->lock held */
 866 static void ads7846_enable(struct ads7846 *ts)
 867 {
 868         if (!ts->disabled)
 869                 return;
 870
 871         regulator_enable(ts->reg);
 872
 873         ts->disabled = 0;
 874         ts->irq_disabled = 0;
 875         enable_irq(ts->spi->irq);
 876 }
 877
 878 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 879 {
 880         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 881
 882         spin_lock_irq(&ts->lock);
 883
 884         ts->is_suspended = 1;
 885         ads7846_disable(ts);
 886
 887         spin_unlock_irq(&ts->lock);
 888
 889         if (device_may_wakeup(&ts->spi->dev))
 890                 enable_irq_wake(ts->spi->irq);
 891
 892         return 0;
 893
 894 }
 895
 896 static int ads7846_resume(struct spi_device *spi)
 897 {
 898         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 899
 900         if (device_may_wakeup(&ts->spi->dev))
 901                 disable_irq_wake(ts->spi->irq);
 902
 903         spin_lock_irq(&ts->lock);
 904
 905         ts->is_suspended = 0;
 906         ads7846_enable(ts);
 907
 908         spin_unlock_irq(&ts->lock);
 909
 910         return 0;
 911 }
 912
 913 static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts)
 914 {
 915         struct ads7846_platform_data *pdata = spi->dev.platform_data;
 916         int err;
 917
 918         /* REVISIT when the irq can be triggered active-low, or if for some
 919          * reason the touchscreen isn't hooked up, we don't need to access
 920          * the pendown state.
 921          */
 922         if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) {
 923                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 924                 return -EINVAL;
 925         }
 926
 927         if (pdata->get_pendown_state) {
 928                 ts->get_pendown_state = pdata->get_pendown_state;
 929                 return 0;
 930         }
 931
 932         err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
 933         if (err) {
 934                 dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
 935                                 pdata->gpio_pendown);
 936                 return err;
 937         }
 938
 939         ts->gpio_pendown = pdata->gpio_pendown;
 940         return 0;
 941 }
 942
 943 static int __devinit ads7846_probe(struct spi_device *spi)
 944 {
 945         struct ads7846 *ts;
 946         struct ads7846_packet *packet;
 947         struct input_dev *input_dev;
 948         const struct ads7846_platform_data *pdata = spi->dev.platform_data;
 949         struct spi_message *m;
 950         struct spi_transfer *x;
 951         unsigned long irq_flags;
 952         int vref;
 953         int err;
 954
 955         if (!spi->irq) {
 956                 dev_dbg(&spi->dev, "no IRQ?\n");
 957                 return -ENODEV;
 958         }
 959
 960         if (!pdata) {
 961                 dev_dbg(&spi->dev, "no platform data?\n");
 962                 return -ENODEV;
 963         }
 964
 965         /* don't exceed max specified sample rate */
 966         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 967                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 968                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 969                 return -EINVAL;
 970         }
 971
 972         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
 973          * that even if the hardware can do that, the SPI controller driver
 974          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
 975          */
 976         spi->bits_per_word = 8;
 977         spi->mode = SPI_MODE_0;
 978         err = spi_setup(spi);
 979         if (err < 0)
 980                 return err;
 981
 982         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 983         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
 984         input_dev = input_allocate_device();
 985         if (!ts || !packet || !input_dev) {
 986                 err = -ENOMEM;
 987                 goto err_free_mem;
 988         }
 989
 990         dev_set_drvdata(&spi->dev, ts);
 991
 992         ts->packet = packet;
 993         ts->spi = spi;
 994         ts->input = input_dev;
 995         ts->vref_mv = pdata->vref_mv;
 996         ts->swap_xy = pdata->swap_xy;
 997
 998         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 999         ts->timer.function = ads7846_timer;
1000
1001         spin_lock_init(&ts->lock);
1002
1003         ts->model = pdata->model ? : 7846;
1004         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1005         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1006         ts->pressure_max = pdata->pressure_max ? : ~0;
1007
1008         if (pdata->filter != NULL) {
1009                 if (pdata->filter_init != NULL) {
1010                         err = pdata->filter_init(pdata, &ts->filter_data);
1011                         if (err < 0)
1012                                 goto err_free_mem;
1013                 }
1014                 ts->filter = pdata->filter;
1015                 ts->filter_cleanup = pdata->filter_cleanup;
1016         } else if (pdata->debounce_max) {
1017                 ts->debounce_max = pdata->debounce_max;
1018                 if (ts->debounce_max < 2)
1019                         ts->debounce_max = 2;
1020                 ts->debounce_tol = pdata->debounce_tol;
1021                 ts->debounce_rep = pdata->debounce_rep;
1022                 ts->filter = ads7846_debounce;
1023                 ts->filter_data = ts;
1024         } else
1025                 ts->filter = ads7846_no_filter;
1026
1027         err = setup_pendown(spi, ts);
1028         if (err)
1029                 goto err_cleanup_filter;
1030
1031         if (pdata->penirq_recheck_delay_usecs)
1032                 ts->penirq_recheck_delay_usecs =
1033                                 pdata->penirq_recheck_delay_usecs;
1034
1035         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1036
1037         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1038         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1039
1040         input_dev->name = ts->name;
1041         input_dev->phys = ts->phys;
1042         input_dev->dev.parent = &spi->dev;
1043
1044         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1045         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1046         input_set_abs_params(input_dev, ABS_X,
1047                         pdata->x_min ? : 0,
1048                         pdata->x_max ? : MAX_12BIT,
1049                         0, 0);
1050         input_set_abs_params(input_dev, ABS_Y,
1051                         pdata->y_min ? : 0,
1052                         pdata->y_max ? : MAX_12BIT,
1053                         0, 0);
1054         input_set_abs_params(input_dev, ABS_PRESSURE,
1055                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1056
1057         vref = pdata->keep_vref_on;
1058
1059         if (ts->model == 7873) {
1060                 /* The AD7873 is almost identical to the ADS7846
1061                  * keep VREF off during differential/ratiometric
1062                  * conversion modes
1063                  */
1064                 ts->model = 7846;
1065                 vref = 0;
1066         }
1067
1068         /* set up the transfers to read touchscreen state; this assumes we
1069          * use formula #2 for pressure, not #3.
1070          */
1071         m = &ts->msg[0];
1072         x = ts->xfer;
1073
1074         spi_message_init(m);
1075
1076         if (ts->model == 7845) {
1077                 packet->read_y_cmd[0] = READ_Y(vref);
1078                 packet->read_y_cmd[1] = 0;
1079                 packet->read_y_cmd[2] = 0;
1080                 x->tx_buf = &packet->read_y_cmd[0];
1081                 x->rx_buf = &packet->tc.y_buf[0];
1082                 x->len = 3;
1083                 spi_message_add_tail(x, m);
1084         } else {
1085                 /* y- still on; turn on only y+ (and ADC) */
1086                 packet->read_y = READ_Y(vref);
1087                 x->tx_buf = &packet->read_y;
1088                 x->len = 1;
1089                 spi_message_add_tail(x, m);
1090
1091                 x++;
1092                 x->rx_buf = &packet->tc.y;
1093                 x->len = 2;
1094                 spi_message_add_tail(x, m);
1095         }
1096
1097         /* the first sample after switching drivers can be low quality;
1098          * optionally discard it, using a second one after the signals
1099          * have had enough time to stabilize.
1100          */
1101         if (pdata->settle_delay_usecs) {
1102                 x->delay_usecs = pdata->settle_delay_usecs;
1103
1104                 x++;
1105                 x->tx_buf = &packet->read_y;
1106                 x->len = 1;
1107                 spi_message_add_tail(x, m);
1108
1109                 x++;
1110                 x->rx_buf = &packet->tc.y;
1111                 x->len = 2;
1112                 spi_message_add_tail(x, m);
1113         }
1114
1115         m->complete = ads7846_rx_val;
1116         m->context = ts;
1117
1118         m++;
1119         spi_message_init(m);
1120
1121         if (ts->model == 7845) {
1122                 x++;
1123                 packet->read_x_cmd[0] = READ_X(vref);
1124                 packet->read_x_cmd[1] = 0;
1125                 packet->read_x_cmd[2] = 0;
1126                 x->tx_buf = &packet->read_x_cmd[0];
1127                 x->rx_buf = &packet->tc.x_buf[0];
1128                 x->len = 3;
1129                 spi_message_add_tail(x, m);
1130         } else {
1131                 /* turn y- off, x+ on, then leave in lowpower */
1132                 x++;
1133                 packet->read_x = READ_X(vref);
1134                 x->tx_buf = &packet->read_x;
1135                 x->len = 1;
1136                 spi_message_add_tail(x, m);
1137
1138                 x++;
1139                 x->rx_buf = &packet->tc.x;
1140                 x->len = 2;
1141                 spi_message_add_tail(x, m);
1142         }
1143
1144         /* ... maybe discard first sample ... */
1145         if (pdata->settle_delay_usecs) {
1146                 x->delay_usecs = pdata->settle_delay_usecs;
1147
1148                 x++;
1149                 x->tx_buf = &packet->read_x;
1150                 x->len = 1;
1151                 spi_message_add_tail(x, m);
1152
1153                 x++;
1154                 x->rx_buf = &packet->tc.x;
1155                 x->len = 2;
1156                 spi_message_add_tail(x, m);
1157         }
1158
1159         m->complete = ads7846_rx_val;
1160         m->context = ts;
1161
1162         /* turn y+ off, x- on; we'll use formula #2 */
1163         if (ts->model == 7846) {
1164                 m++;
1165                 spi_message_init(m);
1166
1167                 x++;
1168                 packet->read_z1 = READ_Z1(vref);
1169                 x->tx_buf = &packet->read_z1;
1170                 x->len = 1;
1171                 spi_message_add_tail(x, m);
1172
1173                 x++;
1174                 x->rx_buf = &packet->tc.z1;
1175                 x->len = 2;
1176                 spi_message_add_tail(x, m);
1177
1178                 /* ... maybe discard first sample ... */
1179                 if (pdata->settle_delay_usecs) {
1180                         x->delay_usecs = pdata->settle_delay_usecs;
1181
1182                         x++;
1183                         x->tx_buf = &packet->read_z1;
1184                         x->len = 1;
1185                         spi_message_add_tail(x, m);
1186
1187                         x++;
1188                         x->rx_buf = &packet->tc.z1;
1189                         x->len = 2;
1190                         spi_message_add_tail(x, m);
1191                 }
1192
1193                 m->complete = ads7846_rx_val;
1194                 m->context = ts;
1195
1196                 m++;
1197                 spi_message_init(m);
1198
1199                 x++;
1200                 packet->read_z2 = READ_Z2(vref);
1201                 x->tx_buf = &packet->read_z2;
1202                 x->len = 1;
1203                 spi_message_add_tail(x, m);
1204
1205                 x++;
1206                 x->rx_buf = &packet->tc.z2;
1207                 x->len = 2;
1208                 spi_message_add_tail(x, m);
1209
1210                 /* ... maybe discard first sample ... */
1211                 if (pdata->settle_delay_usecs) {
1212                         x->delay_usecs = pdata->settle_delay_usecs;
1213
1214                         x++;
1215                         x->tx_buf = &packet->read_z2;
1216                         x->len = 1;
1217                         spi_message_add_tail(x, m);
1218
1219                         x++;
1220                         x->rx_buf = &packet->tc.z2;
1221                         x->len = 2;
1222                         spi_message_add_tail(x, m);
1223                 }
1224
1225                 m->complete = ads7846_rx_val;
1226                 m->context = ts;
1227         }
1228
1229         /* power down */
1230         m++;
1231         spi_message_init(m);
1232
1233         if (ts->model == 7845) {
1234                 x++;
1235                 packet->pwrdown_cmd[0] = PWRDOWN;
1236                 packet->pwrdown_cmd[1] = 0;
1237                 packet->pwrdown_cmd[2] = 0;
1238                 x->tx_buf = &packet->pwrdown_cmd[0];
1239                 x->len = 3;
1240         } else {
1241                 x++;
1242                 packet->pwrdown = PWRDOWN;
1243                 x->tx_buf = &packet->pwrdown;
1244                 x->len = 1;
1245                 spi_message_add_tail(x, m);
1246
1247                 x++;
1248                 x->rx_buf = &packet->dummy;
1249                 x->len = 2;
1250         }
1251
1252         CS_CHANGE(*x);
1253         spi_message_add_tail(x, m);
1254
1255         m->complete = ads7846_rx;
1256         m->context = ts;
1257
1258         ts->last_msg = m;
1259
1260         ts->reg = regulator_get(&spi->dev, "vcc");
1261         if (IS_ERR(ts->reg)) {
1262                 err = PTR_ERR(ts->reg);
1263                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1264                 goto err_free_gpio;
1265         }
1266
1267         err = regulator_enable(ts->reg);
1268         if (err) {
1269                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1270                 goto err_put_regulator;
1271         }
1272
1273         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1274
1275         err = request_irq(spi->irq, ads7846_irq, irq_flags,
1276                           spi->dev.driver->name, ts);
1277
1278         if (err && !pdata->irq_flags) {
1279                 dev_info(&spi->dev,
1280                         "trying pin change workaround on irq %d\n", spi->irq);
1281                 err = request_irq(spi->irq, ads7846_irq,
1282                                   IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
1283                                   spi->dev.driver->name, ts);
1284         }
1285
1286         if (err) {
1287                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1288                 goto err_disable_regulator;
1289         }
1290
1291         err = ads784x_hwmon_register(spi, ts);
1292         if (err)
1293                 goto err_free_irq;
1294
1295         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1296
1297         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1298          * the touchscreen, in case it's not connected.
1299          */
1300         if (ts->model == 7845)
1301                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1302         else
1303                 (void) ads7846_read12_ser(&spi->dev,
1304                                 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1305
1306         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1307         if (err)
1308                 goto err_remove_hwmon;
1309
1310         err = input_register_device(input_dev);
1311         if (err)
1312                 goto err_remove_attr_group;
1313
1314         device_init_wakeup(&spi->dev, pdata->wakeup);
1315
1316         return 0;
1317
1318  err_remove_attr_group:
1319         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1320  err_remove_hwmon:
1321         ads784x_hwmon_unregister(spi, ts);
1322  err_free_irq:
1323         free_irq(spi->irq, ts);
1324  err_disable_regulator:
1325         regulator_disable(ts->reg);
1326  err_put_regulator:
1327         regulator_put(ts->reg);
1328  err_free_gpio:
1329         if (ts->gpio_pendown != -1)
1330                 gpio_free(ts->gpio_pendown);
1331  err_cleanup_filter:
1332         if (ts->filter_cleanup)
1333                 ts->filter_cleanup(ts->filter_data);
1334  err_free_mem:
1335         input_free_device(input_dev);
1336         kfree(packet);
1337         kfree(ts);
1338         return err;
1339 }
1340
1341 static int __devexit ads7846_remove(struct spi_device *spi)
1342 {
1343         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1344
1345         device_init_wakeup(&spi->dev, false);
1346
1347         ads784x_hwmon_unregister(spi, ts);
1348         input_unregister_device(ts->input);
1349
1350         ads7846_suspend(spi, PMSG_SUSPEND);
1351
1352         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1353
1354         free_irq(ts->spi->irq, ts);
1355         /* suspend left the IRQ disabled */
1356         enable_irq(ts->spi->irq);
1357
1358         regulator_disable(ts->reg);
1359         regulator_put(ts->reg);
1360
1361         if (ts->gpio_pendown != -1)
1362                 gpio_free(ts->gpio_pendown);
1363
1364         if (ts->filter_cleanup)
1365                 ts->filter_cleanup(ts->filter_data);
1366
1367         kfree(ts->packet);
1368         kfree(ts);
1369
1370         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1371         return 0;
1372 }
1373
1374 static struct spi_driver ads7846_driver = {
1375         .driver = {
1376                 .name   = "ads7846",
1377                 .bus    = &spi_bus_type,
1378                 .owner  = THIS_MODULE,
1379         },
1380         .probe          = ads7846_probe,
1381         .remove         = __devexit_p(ads7846_remove),
1382         .suspend        = ads7846_suspend,
1383         .resume         = ads7846_resume,
1384 };
1385
1386 static int __init ads7846_init(void)
1387 {
1388         return spi_register_driver(&ads7846_driver);
1389 }
1390 module_init(ads7846_init);
1391
1392 static void __exit ads7846_exit(void)
1393 {
1394         spi_unregister_driver(&ads7846_driver);
1395 }
1396 module_exit(ads7846_exit);
1397
1398 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1399 MODULE_LICENSE("GPL");
1400 MODULE_ALIAS("spi:ads7846");