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/gpio.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/spi/ads7846.h>
  32 #include <linux/regulator/consumer.h>
  33 #include <asm/irq.h>
  34
  35 /*
  36  * This code has been heavily tested on a Nokia 770, and lightly
  37  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  38  * TSC2046 is just newer ads7846 silicon.
  39  * Support for ads7843 tested on Atmel at91sam926x-EK.
  40  * Support for ads7845 has only been stubbed in.
  41  * Support for Analog Devices AD7873 and AD7843 tested.
  42  *
  43  * IRQ handling needs a workaround because of a shortcoming in handling
  44  * edge triggered IRQs on some platforms like the OMAP1/2. These
  45  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  46  * have to maintain our own SW IRQ disabled status. This should be
  47  * removed as soon as the affected platform's IRQ handling is fixed.
  48  *
  49  * App note sbaa036 talks in more detail about accurate sampling...
  50  * that ought to help in situations like LCDs inducing noise (which
  51  * can also be helped by using synch signals) and more generally.
  52  * This driver tries to utilize the measures described in the app
  53  * note. The strength of filtering can be set in the board-* specific
  54  * files.
  55  */
  56
  57 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
  58 #define TS_POLL_PERIOD  5       /* ms delay between samples */
  59
  60 /* this driver doesn't aim at the peak continuous sample rate */
  61 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  62
  63 struct ts_event {
  64         /*
  65          * For portability, we can't read 12 bit values using SPI (which
  66          * would make the controller deliver them as native byte order u16
  67          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  68          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  69          */
  70         u16     x;
  71         u16     y;
  72         u16     z1, z2;
  73         bool    ignore;
  74         u8      x_buf[3];
  75         u8      y_buf[3];
  76 };
  77
  78 /*
  79  * We allocate this separately to avoid cache line sharing issues when
  80  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  81  * systems where main memory is not DMA-coherent (most non-x86 boards).
  82  */
  83 struct ads7846_packet {
  84         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  85         u16                     dummy;          /* for the pwrdown read */
  86         struct ts_event         tc;
  87         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  88         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  89 };
  90
  91 struct ads7846 {
  92         struct input_dev        *input;
  93         char                    phys[32];
  94         char                    name[32];
  95
  96         struct spi_device       *spi;
  97         struct regulator        *reg;
  98
  99 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 100         struct attribute_group  *attr_group;
 101         struct device           *hwmon;
 102 #endif
 103
 104         u16                     model;
 105         u16                     vref_mv;
 106         u16                     vref_delay_usecs;
 107         u16                     x_plate_ohms;
 108         u16                     pressure_max;
 109
 110         bool                    swap_xy;
 111
 112         struct ads7846_packet   *packet;
 113
 114         struct spi_transfer     xfer[18];
 115         struct spi_message      msg[5];
 116         int                     msg_count;
 117         wait_queue_head_t       wait;
 118
 119         bool                    pendown;
 120
 121         int                     read_cnt;
 122         int                     read_rep;
 123         int                     last_read;
 124
 125         u16                     debounce_max;
 126         u16                     debounce_tol;
 127         u16                     debounce_rep;
 128
 129         u16                     penirq_recheck_delay_usecs;
 130
 131         struct mutex            lock;
 132         bool                    stopped;        /* P: lock */
 133         bool                    disabled;       /* P: lock */
 134         bool                    suspended;      /* P: lock */
 135
 136         int                     (*filter)(void *data, int data_idx, int *val);
 137         void                    *filter_data;
 138         void                    (*filter_cleanup)(void *data);
 139         int                     (*get_pendown_state)(void);
 140         int                     gpio_pendown;
 141
 142         void                    (*wait_for_sync)(void);
 143 };
 144
 145 /* leave chip selected when we're done, for quicker re-select? */
 146 #if     0
 147 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 148 #else
 149 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 150 #endif
 151
 152 /*--------------------------------------------------------------------------*/
 153
 154 /* The ADS7846 has touchscreen and other sensors.
 155  * Earlier ads784x chips are somewhat compatible.
 156  */
 157 #define ADS_START               (1 << 7)
 158 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 159 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 160 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 161 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 162 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 163 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 164 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 165 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 166 #define ADS_8_BIT               (1 << 3)
 167 #define ADS_12_BIT              (0 << 3)
 168 #define ADS_SER                 (1 << 2)        /* non-differential */
 169 #define ADS_DFR                 (0 << 2)        /* differential */
 170 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 171 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 172 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 173 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 174
 175 #define MAX_12BIT       ((1<<12)-1)
 176
 177 /* leave ADC powered up (disables penirq) between differential samples */
 178 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 179         | ADS_12_BIT | ADS_DFR | \
 180         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 181
 182 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 183 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 184 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 185
 186 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 187 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 188
 189 /* single-ended samples need to first power up reference voltage;
 190  * we leave both ADC and VREF powered
 191  */
 192 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 193         | ADS_12_BIT | ADS_SER)
 194
 195 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 196 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 197
 198 /* Must be called with ts->lock held */
 199 static void ads7846_stop(struct ads7846 *ts)
 200 {
 201         if (!ts->disabled && !ts->suspended) {
 202                 /* Signal IRQ thread to stop polling and disable the handler. */
 203                 ts->stopped = true;
 204                 mb();
 205                 wake_up(&ts->wait);
 206                 disable_irq(ts->spi->irq);
 207         }
 208 }
 209
 210 /* Must be called with ts->lock held */
 211 static void ads7846_restart(struct ads7846 *ts)
 212 {
 213         if (!ts->disabled && !ts->suspended) {
 214                 /* Tell IRQ thread that it may poll the device. */
 215                 ts->stopped = false;
 216                 mb();
 217                 enable_irq(ts->spi->irq);
 218         }
 219 }
 220
 221 /* Must be called with ts->lock held */
 222 static void __ads7846_disable(struct ads7846 *ts)
 223 {
 224         ads7846_stop(ts);
 225         regulator_disable(ts->reg);
 226
 227         /*
 228          * We know the chip's in low power mode since we always
 229          * leave it that way after every request
 230          */
 231 }
 232
 233 /* Must be called with ts->lock held */
 234 static void __ads7846_enable(struct ads7846 *ts)
 235 {
 236         regulator_enable(ts->reg);
 237         ads7846_restart(ts);
 238 }
 239
 240 static void ads7846_disable(struct ads7846 *ts)
 241 {
 242         mutex_lock(&ts->lock);
 243
 244         if (!ts->disabled) {
 245
 246                 if  (!ts->suspended)
 247                         __ads7846_disable(ts);
 248
 249                 ts->disabled = true;
 250         }
 251
 252         mutex_unlock(&ts->lock);
 253 }
 254
 255 static void ads7846_enable(struct ads7846 *ts)
 256 {
 257         mutex_lock(&ts->lock);
 258
 259         if (ts->disabled) {
 260
 261                 ts->disabled = false;
 262
 263                 if (!ts->suspended)
 264                         __ads7846_enable(ts);
 265         }
 266
 267         mutex_unlock(&ts->lock);
 268 }
 269
 270 /*--------------------------------------------------------------------------*/
 271
 272 /*
 273  * Non-touchscreen sensors only use single-ended conversions.
 274  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 275  * ads7846 lets that pin be unconnected, to use internal vREF.
 276  */
 277
 278 struct ser_req {
 279         u8                      ref_on;
 280         u8                      command;
 281         u8                      ref_off;
 282         u16                     scratch;
 283         __be16                  sample;
 284         struct spi_message      msg;
 285         struct spi_transfer     xfer[6];
 286 };
 287
 288 struct ads7845_ser_req {
 289         u8                      command[3];
 290         u8                      pwrdown[3];
 291         u8                      sample[3];
 292         struct spi_message      msg;
 293         struct spi_transfer     xfer[2];
 294 };
 295
 296 static int ads7846_read12_ser(struct device *dev, unsigned command)
 297 {
 298         struct spi_device *spi = to_spi_device(dev);
 299         struct ads7846 *ts = dev_get_drvdata(dev);
 300         struct ser_req *req;
 301         int status;
 302         int use_internal;
 303
 304         req = kzalloc(sizeof *req, GFP_KERNEL);
 305         if (!req)
 306                 return -ENOMEM;
 307
 308         spi_message_init(&req->msg);
 309
 310         /* FIXME boards with ads7846 might use external vref instead ... */
 311         use_internal = (ts->model == 7846);
 312
 313         /* maybe turn on internal vREF, and let it settle */
 314         if (use_internal) {
 315                 req->ref_on = REF_ON;
 316                 req->xfer[0].tx_buf = &req->ref_on;
 317                 req->xfer[0].len = 1;
 318                 spi_message_add_tail(&req->xfer[0], &req->msg);
 319
 320                 req->xfer[1].rx_buf = &req->scratch;
 321                 req->xfer[1].len = 2;
 322
 323                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 324                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 325                 spi_message_add_tail(&req->xfer[1], &req->msg);
 326         }
 327
 328         /* take sample */
 329         req->command = (u8) command;
 330         req->xfer[2].tx_buf = &req->command;
 331         req->xfer[2].len = 1;
 332         spi_message_add_tail(&req->xfer[2], &req->msg);
 333
 334         req->xfer[3].rx_buf = &req->sample;
 335         req->xfer[3].len = 2;
 336         spi_message_add_tail(&req->xfer[3], &req->msg);
 337
 338         /* REVISIT:  take a few more samples, and compare ... */
 339
 340         /* converter in low power mode & enable PENIRQ */
 341         req->ref_off = PWRDOWN;
 342         req->xfer[4].tx_buf = &req->ref_off;
 343         req->xfer[4].len = 1;
 344         spi_message_add_tail(&req->xfer[4], &req->msg);
 345
 346         req->xfer[5].rx_buf = &req->scratch;
 347         req->xfer[5].len = 2;
 348         CS_CHANGE(req->xfer[5]);
 349         spi_message_add_tail(&req->xfer[5], &req->msg);
 350
 351         mutex_lock(&ts->lock);
 352         ads7846_stop(ts);
 353         status = spi_sync(spi, &req->msg);
 354         ads7846_restart(ts);
 355         mutex_unlock(&ts->lock);
 356
 357         if (status == 0) {
 358                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 359                 status = be16_to_cpu(req->sample);
 360                 status = status >> 3;
 361                 status &= 0x0fff;
 362         }
 363
 364         kfree(req);
 365         return status;
 366 }
 367
 368 static int ads7845_read12_ser(struct device *dev, unsigned command)
 369 {
 370         struct spi_device *spi = to_spi_device(dev);
 371         struct ads7846 *ts = dev_get_drvdata(dev);
 372         struct ads7845_ser_req *req;
 373         int status;
 374
 375         req = kzalloc(sizeof *req, GFP_KERNEL);
 376         if (!req)
 377                 return -ENOMEM;
 378
 379         spi_message_init(&req->msg);
 380
 381         req->command[0] = (u8) command;
 382         req->xfer[0].tx_buf = req->command;
 383         req->xfer[0].rx_buf = req->sample;
 384         req->xfer[0].len = 3;
 385         spi_message_add_tail(&req->xfer[0], &req->msg);
 386
 387         mutex_lock(&ts->lock);
 388         ads7846_stop(ts);
 389         status = spi_sync(spi, &req->msg);
 390         ads7846_restart(ts);
 391         mutex_unlock(&ts->lock);
 392
 393         if (status == 0) {
 394                 /* BE12 value, then padding */
 395                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 396                 status = status >> 3;
 397                 status &= 0x0fff;
 398         }
 399
 400         kfree(req);
 401         return status;
 402 }
 403
 404 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 405
 406 #define SHOW(name, var, adjust) static ssize_t \
 407 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 408 { \
 409         struct ads7846 *ts = dev_get_drvdata(dev); \
 410         ssize_t v = ads7846_read12_ser(dev, \
 411                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
 412         if (v < 0) \
 413                 return v; \
 414         return sprintf(buf, "%u\n", adjust(ts, v)); \
 415 } \
 416 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 417
 418
 419 /* Sysfs conventions report temperatures in millidegrees Celsius.
 420  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 421  * accuracy scheme without calibration data.  For now we won't try either;
 422  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 423  */
 424 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 425 {
 426         return v;
 427 }
 428
 429 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 430 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 431
 432
 433 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 434  * if we know vREF.  userspace may need to scale vAUX to match the board's
 435  * external resistors; we assume that vBATT only uses the internal ones.
 436  */
 437 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 438 {
 439         unsigned retval = v;
 440
 441         /* external resistors may scale vAUX into 0..vREF */
 442         retval *= ts->vref_mv;
 443         retval = retval >> 12;
 444
 445         return retval;
 446 }
 447
 448 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 449 {
 450         unsigned retval = vaux_adjust(ts, v);
 451
 452         /* ads7846 has a resistor ladder to scale this signal down */
 453         if (ts->model == 7846)
 454                 retval *= 4;
 455
 456         return retval;
 457 }
 458
 459 SHOW(in0_input, vaux, vaux_adjust)
 460 SHOW(in1_input, vbatt, vbatt_adjust)
 461
 462 static struct attribute *ads7846_attributes[] = {
 463         &dev_attr_temp0.attr,
 464         &dev_attr_temp1.attr,
 465         &dev_attr_in0_input.attr,
 466         &dev_attr_in1_input.attr,
 467         NULL,
 468 };
 469
 470 static struct attribute_group ads7846_attr_group = {
 471         .attrs = ads7846_attributes,
 472 };
 473
 474 static struct attribute *ads7843_attributes[] = {
 475         &dev_attr_in0_input.attr,
 476         &dev_attr_in1_input.attr,
 477         NULL,
 478 };
 479
 480 static struct attribute_group ads7843_attr_group = {
 481         .attrs = ads7843_attributes,
 482 };
 483
 484 static struct attribute *ads7845_attributes[] = {
 485         &dev_attr_in0_input.attr,
 486         NULL,
 487 };
 488
 489 static struct attribute_group ads7845_attr_group = {
 490         .attrs = ads7845_attributes,
 491 };
 492
 493 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 494 {
 495         struct device *hwmon;
 496         int err;
 497
 498         /* hwmon sensors need a reference voltage */
 499         switch (ts->model) {
 500         case 7846:
 501                 if (!ts->vref_mv) {
 502                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 503                         ts->vref_mv = 2500;
 504                 }
 505                 break;
 506         case 7845:
 507         case 7843:
 508                 if (!ts->vref_mv) {
 509                         dev_warn(&spi->dev,
 510                                 "external vREF for ADS%d not specified\n",
 511                                 ts->model);
 512                         return 0;
 513                 }
 514                 break;
 515         }
 516
 517         /* different chips have different sensor groups */
 518         switch (ts->model) {
 519         case 7846:
 520                 ts->attr_group = &ads7846_attr_group;
 521                 break;
 522         case 7845:
 523                 ts->attr_group = &ads7845_attr_group;
 524                 break;
 525         case 7843:
 526                 ts->attr_group = &ads7843_attr_group;
 527                 break;
 528         default:
 529                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 530                 return 0;
 531         }
 532
 533         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 534         if (err)
 535                 return err;
 536
 537         hwmon = hwmon_device_register(&spi->dev);
 538         if (IS_ERR(hwmon)) {
 539                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 540                 return PTR_ERR(hwmon);
 541         }
 542
 543         ts->hwmon = hwmon;
 544         return 0;
 545 }
 546
 547 static void ads784x_hwmon_unregister(struct spi_device *spi,
 548                                      struct ads7846 *ts)
 549 {
 550         if (ts->hwmon) {
 551                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 552                 hwmon_device_unregister(ts->hwmon);
 553         }
 554 }
 555
 556 #else
 557 static inline int ads784x_hwmon_register(struct spi_device *spi,
 558                                          struct ads7846 *ts)
 559 {
 560         return 0;
 561 }
 562
 563 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 564                                             struct ads7846 *ts)
 565 {
 566 }
 567 #endif
 568
 569 static ssize_t ads7846_pen_down_show(struct device *dev,
 570                                      struct device_attribute *attr, char *buf)
 571 {
 572         struct ads7846 *ts = dev_get_drvdata(dev);
 573
 574         return sprintf(buf, "%u\n", ts->pendown);
 575 }
 576
 577 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 578
 579 static ssize_t ads7846_disable_show(struct device *dev,
 580                                      struct device_attribute *attr, char *buf)
 581 {
 582         struct ads7846 *ts = dev_get_drvdata(dev);
 583
 584         return sprintf(buf, "%u\n", ts->disabled);
 585 }
 586
 587 static ssize_t ads7846_disable_store(struct device *dev,
 588                                      struct device_attribute *attr,
 589                                      const char *buf, size_t count)
 590 {
 591         struct ads7846 *ts = dev_get_drvdata(dev);
 592         unsigned long i;
 593
 594         if (strict_strtoul(buf, 10, &i))
 595                 return -EINVAL;
 596
 597         if (i)
 598                 ads7846_disable(ts);
 599         else
 600                 ads7846_enable(ts);
 601
 602         return count;
 603 }
 604
 605 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 606
 607 static struct attribute *ads784x_attributes[] = {
 608         &dev_attr_pen_down.attr,
 609         &dev_attr_disable.attr,
 610         NULL,
 611 };
 612
 613 static struct attribute_group ads784x_attr_group = {
 614         .attrs = ads784x_attributes,
 615 };
 616
 617 /*--------------------------------------------------------------------------*/
 618
 619 static int get_pendown_state(struct ads7846 *ts)
 620 {
 621         if (ts->get_pendown_state)
 622                 return ts->get_pendown_state();
 623
 624         return !gpio_get_value(ts->gpio_pendown);
 625 }
 626
 627 static void null_wait_for_sync(void)
 628 {
 629 }
 630
 631 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 632 {
 633         struct ads7846 *ts = ads;
 634
 635         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 636                 /* Start over collecting consistent readings. */
 637                 ts->read_rep = 0;
 638                 /*
 639                  * Repeat it, if this was the first read or the read
 640                  * wasn't consistent enough.
 641                  */
 642                 if (ts->read_cnt < ts->debounce_max) {
 643                         ts->last_read = *val;
 644                         ts->read_cnt++;
 645                         return ADS7846_FILTER_REPEAT;
 646                 } else {
 647                         /*
 648                          * Maximum number of debouncing reached and still
 649                          * not enough number of consistent readings. Abort
 650                          * the whole sample, repeat it in the next sampling
 651                          * period.
 652                          */
 653                         ts->read_cnt = 0;
 654                         return ADS7846_FILTER_IGNORE;
 655                 }
 656         } else {
 657                 if (++ts->read_rep > ts->debounce_rep) {
 658                         /*
 659                          * Got a good reading for this coordinate,
 660                          * go for the next one.
 661                          */
 662                         ts->read_cnt = 0;
 663                         ts->read_rep = 0;
 664                         return ADS7846_FILTER_OK;
 665                 } else {
 666                         /* Read more values that are consistent. */
 667                         ts->read_cnt++;
 668                         return ADS7846_FILTER_REPEAT;
 669                 }
 670         }
 671 }
 672
 673 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 674 {
 675         return ADS7846_FILTER_OK;
 676 }
 677
 678 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 679 {
 680         struct spi_transfer *t =
 681                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 682
 683         if (ts->model == 7845) {
 684                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 685         } else {
 686                 /*
 687                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 688                  * padding; built from two 8 bit values written msb-first.
 689                  */
 690                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 691         }
 692 }
 693
 694 static void ads7846_update_value(struct spi_message *m, int val)
 695 {
 696         struct spi_transfer *t =
 697                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 698
 699         *(u16 *)t->rx_buf = val;
 700 }
 701
 702 static void ads7846_read_state(struct ads7846 *ts)
 703 {
 704         struct ads7846_packet *packet = ts->packet;
 705         struct spi_message *m;
 706         int msg_idx = 0;
 707         int val;
 708         int action;
 709         int error;
 710
 711         while (msg_idx < ts->msg_count) {
 712
 713                 ts->wait_for_sync();
 714
 715                 m = &ts->msg[msg_idx];
 716                 error = spi_sync(ts->spi, m);
 717                 if (error) {
 718                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
 719                         packet->tc.ignore = true;
 720                         return;
 721                 }
 722
 723                 /*
 724                  * Last message is power down request, no need to convert
 725                  * or filter the value.
 726                  */
 727                 if (msg_idx < ts->msg_count - 1) {
 728
 729                         val = ads7846_get_value(ts, m);
 730
 731                         action = ts->filter(ts->filter_data, msg_idx, &val);
 732                         switch (action) {
 733                         case ADS7846_FILTER_REPEAT:
 734                                 continue;
 735
 736                         case ADS7846_FILTER_IGNORE:
 737                                 packet->tc.ignore = true;
 738                                 msg_idx = ts->msg_count - 1;
 739                                 continue;
 740
 741                         case ADS7846_FILTER_OK:
 742                                 ads7846_update_value(m, val);
 743                                 packet->tc.ignore = false;
 744                                 msg_idx++;
 745                                 break;
 746
 747                         default:
 748                                 BUG();
 749                         }
 750                 } else {
 751                         msg_idx++;
 752                 }
 753         }
 754 }
 755
 756 static void ads7846_report_state(struct ads7846 *ts)
 757 {
 758         struct ads7846_packet *packet = ts->packet;
 759         unsigned int Rt;
 760         u16 x, y, z1, z2;
 761
 762         /*
 763          * ads7846_get_value() does in-place conversion (including byte swap)
 764          * from on-the-wire format as part of debouncing to get stable
 765          * readings.
 766          */
 767         if (ts->model == 7845) {
 768                 x = *(u16 *)packet->tc.x_buf;
 769                 y = *(u16 *)packet->tc.y_buf;
 770                 z1 = 0;
 771                 z2 = 0;
 772         } else {
 773                 x = packet->tc.x;
 774                 y = packet->tc.y;
 775                 z1 = packet->tc.z1;
 776                 z2 = packet->tc.z2;
 777         }
 778
 779         /* range filtering */
 780         if (x == MAX_12BIT)
 781                 x = 0;
 782
 783         if (ts->model == 7843) {
 784                 Rt = ts->pressure_max / 2;
 785         } else if (ts->model == 7845) {
 786                 if (get_pendown_state(ts))
 787                         Rt = ts->pressure_max / 2;
 788                 else
 789                         Rt = 0;
 790                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 791         } else if (likely(x && z1)) {
 792                 /* compute touch pressure resistance using equation #2 */
 793                 Rt = z2;
 794                 Rt -= z1;
 795                 Rt *= x;
 796                 Rt *= ts->x_plate_ohms;
 797                 Rt /= z1;
 798                 Rt = (Rt + 2047) >> 12;
 799         } else {
 800                 Rt = 0;
 801         }
 802
 803         /*
 804          * Sample found inconsistent by debouncing or pressure is beyond
 805          * the maximum. Don't report it to user space, repeat at least
 806          * once more the measurement
 807          */
 808         if (packet->tc.ignore || Rt > ts->pressure_max) {
 809                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 810                          packet->tc.ignore, Rt);
 811                 return;
 812         }
 813
 814         /*
 815          * Maybe check the pendown state before reporting. This discards
 816          * false readings when the pen is lifted.
 817          */
 818         if (ts->penirq_recheck_delay_usecs) {
 819                 udelay(ts->penirq_recheck_delay_usecs);
 820                 if (!get_pendown_state(ts))
 821                         Rt = 0;
 822         }
 823
 824         /*
 825          * NOTE: We can't rely on the pressure to determine the pen down
 826          * state, even this controller has a pressure sensor. The pressure
 827          * value can fluctuate for quite a while after lifting the pen and
 828          * in some cases may not even settle at the expected value.
 829          *
 830          * The only safe way to check for the pen up condition is in the
 831          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 832          */
 833         if (Rt) {
 834                 struct input_dev *input = ts->input;
 835
 836                 if (ts->swap_xy)
 837                         swap(x, y);
 838
 839                 if (!ts->pendown) {
 840                         input_report_key(input, BTN_TOUCH, 1);
 841                         ts->pendown = true;
 842                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 843                 }
 844
 845                 input_report_abs(input, ABS_X, x);
 846                 input_report_abs(input, ABS_Y, y);
 847                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 848
 849                 input_sync(input);
 850                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 851         }
 852 }
 853
 854 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 855 {
 856         struct ads7846 *ts = handle;
 857
 858         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 859 }
 860
 861
 862 static irqreturn_t ads7846_irq(int irq, void *handle)
 863 {
 864         struct ads7846 *ts = handle;
 865
 866         /* Start with a small delay before checking pendown state */
 867         msleep(TS_POLL_DELAY);
 868
 869         while (!ts->stopped && get_pendown_state(ts)) {
 870
 871                 /* pen is down, continue with the measurement */
 872                 ads7846_read_state(ts);
 873
 874                 if (!ts->stopped)
 875                         ads7846_report_state(ts);
 876
 877                 wait_event_timeout(ts->wait, ts->stopped,
 878                                    msecs_to_jiffies(TS_POLL_PERIOD));
 879         }
 880
 881         if (ts->pendown) {
 882                 struct input_dev *input = ts->input;
 883
 884                 input_report_key(input, BTN_TOUCH, 0);
 885                 input_report_abs(input, ABS_PRESSURE, 0);
 886                 input_sync(input);
 887
 888                 ts->pendown = false;
 889                 dev_vdbg(&ts->spi->dev, "UP\n");
 890         }
 891
 892         return IRQ_HANDLED;
 893 }
 894
 895 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 896 {
 897         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 898
 899         mutex_lock(&ts->lock);
 900
 901         if (!ts->suspended) {
 902
 903                 if (!ts->disabled)
 904                         __ads7846_disable(ts);
 905
 906                 if (device_may_wakeup(&ts->spi->dev))
 907                         enable_irq_wake(ts->spi->irq);
 908
 909                 ts->suspended = true;
 910         }
 911
 912         mutex_unlock(&ts->lock);
 913
 914         return 0;
 915 }
 916
 917 static int ads7846_resume(struct spi_device *spi)
 918 {
 919         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 920
 921         mutex_lock(&ts->lock);
 922
 923         if (ts->suspended) {
 924
 925                 ts->suspended = false;
 926
 927                 if (device_may_wakeup(&ts->spi->dev))
 928                         disable_irq_wake(ts->spi->irq);
 929
 930                 if (!ts->disabled)
 931                         __ads7846_enable(ts);
 932         }
 933
 934         mutex_unlock(&ts->lock);
 935
 936         return 0;
 937 }
 938
 939 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
 940 {
 941         struct ads7846_platform_data *pdata = spi->dev.platform_data;
 942         int err;
 943
 944         /*
 945          * REVISIT when the irq can be triggered active-low, or if for some
 946          * reason the touchscreen isn't hooked up, we don't need to access
 947          * the pendown state.
 948          */
 949
 950         if (pdata->get_pendown_state) {
 951                 ts->get_pendown_state = pdata->get_pendown_state;
 952         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 953
 954                 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
 955                 if (err) {
 956                         dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
 957                                 pdata->gpio_pendown);
 958                         return err;
 959                 }
 960
 961                 ts->gpio_pendown = pdata->gpio_pendown;
 962
 963         } else {
 964                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 965                 return -EINVAL;
 966         }
 967
 968         return 0;
 969 }
 970
 971 /*
 972  * Set up the transfers to read touchscreen state; this assumes we
 973  * use formula #2 for pressure, not #3.
 974  */
 975 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
 976                                 const struct ads7846_platform_data *pdata)
 977 {
 978         struct spi_message *m = &ts->msg[0];
 979         struct spi_transfer *x = ts->xfer;
 980         struct ads7846_packet *packet = ts->packet;
 981         int vref = pdata->keep_vref_on;
 982
 983         if (ts->model == 7873) {
 984                 /*
 985                  * The AD7873 is almost identical to the ADS7846
 986                  * keep VREF off during differential/ratiometric
 987                  * conversion modes.
 988                  */
 989                 ts->model = 7846;
 990                 vref = 0;
 991         }
 992
 993         ts->msg_count = 1;
 994         spi_message_init(m);
 995         m->context = ts;
 996
 997         if (ts->model == 7845) {
 998                 packet->read_y_cmd[0] = READ_Y(vref);
 999                 packet->read_y_cmd[1] = 0;
1000                 packet->read_y_cmd[2] = 0;
1001                 x->tx_buf = &packet->read_y_cmd[0];
1002                 x->rx_buf = &packet->tc.y_buf[0];
1003                 x->len = 3;
1004                 spi_message_add_tail(x, m);
1005         } else {
1006                 /* y- still on; turn on only y+ (and ADC) */
1007                 packet->read_y = READ_Y(vref);
1008                 x->tx_buf = &packet->read_y;
1009                 x->len = 1;
1010                 spi_message_add_tail(x, m);
1011
1012                 x++;
1013                 x->rx_buf = &packet->tc.y;
1014                 x->len = 2;
1015                 spi_message_add_tail(x, m);
1016         }
1017
1018         /*
1019          * The first sample after switching drivers can be low quality;
1020          * optionally discard it, using a second one after the signals
1021          * have had enough time to stabilize.
1022          */
1023         if (pdata->settle_delay_usecs) {
1024                 x->delay_usecs = pdata->settle_delay_usecs;
1025
1026                 x++;
1027                 x->tx_buf = &packet->read_y;
1028                 x->len = 1;
1029                 spi_message_add_tail(x, m);
1030
1031                 x++;
1032                 x->rx_buf = &packet->tc.y;
1033                 x->len = 2;
1034                 spi_message_add_tail(x, m);
1035         }
1036
1037         ts->msg_count++;
1038         m++;
1039         spi_message_init(m);
1040         m->context = ts;
1041
1042         if (ts->model == 7845) {
1043                 x++;
1044                 packet->read_x_cmd[0] = READ_X(vref);
1045                 packet->read_x_cmd[1] = 0;
1046                 packet->read_x_cmd[2] = 0;
1047                 x->tx_buf = &packet->read_x_cmd[0];
1048                 x->rx_buf = &packet->tc.x_buf[0];
1049                 x->len = 3;
1050                 spi_message_add_tail(x, m);
1051         } else {
1052                 /* turn y- off, x+ on, then leave in lowpower */
1053                 x++;
1054                 packet->read_x = READ_X(vref);
1055                 x->tx_buf = &packet->read_x;
1056                 x->len = 1;
1057                 spi_message_add_tail(x, m);
1058
1059                 x++;
1060                 x->rx_buf = &packet->tc.x;
1061                 x->len = 2;
1062                 spi_message_add_tail(x, m);
1063         }
1064
1065         /* ... maybe discard first sample ... */
1066         if (pdata->settle_delay_usecs) {
1067                 x->delay_usecs = pdata->settle_delay_usecs;
1068
1069                 x++;
1070                 x->tx_buf = &packet->read_x;
1071                 x->len = 1;
1072                 spi_message_add_tail(x, m);
1073
1074                 x++;
1075                 x->rx_buf = &packet->tc.x;
1076                 x->len = 2;
1077                 spi_message_add_tail(x, m);
1078         }
1079
1080         /* turn y+ off, x- on; we'll use formula #2 */
1081         if (ts->model == 7846) {
1082                 ts->msg_count++;
1083                 m++;
1084                 spi_message_init(m);
1085                 m->context = ts;
1086
1087                 x++;
1088                 packet->read_z1 = READ_Z1(vref);
1089                 x->tx_buf = &packet->read_z1;
1090                 x->len = 1;
1091                 spi_message_add_tail(x, m);
1092
1093                 x++;
1094                 x->rx_buf = &packet->tc.z1;
1095                 x->len = 2;
1096                 spi_message_add_tail(x, m);
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_z1;
1104                         x->len = 1;
1105                         spi_message_add_tail(x, m);
1106
1107                         x++;
1108                         x->rx_buf = &packet->tc.z1;
1109                         x->len = 2;
1110                         spi_message_add_tail(x, m);
1111                 }
1112
1113                 ts->msg_count++;
1114                 m++;
1115                 spi_message_init(m);
1116                 m->context = ts;
1117
1118                 x++;
1119                 packet->read_z2 = READ_Z2(vref);
1120                 x->tx_buf = &packet->read_z2;
1121                 x->len = 1;
1122                 spi_message_add_tail(x, m);
1123
1124                 x++;
1125                 x->rx_buf = &packet->tc.z2;
1126                 x->len = 2;
1127                 spi_message_add_tail(x, m);
1128
1129                 /* ... maybe discard first sample ... */
1130                 if (pdata->settle_delay_usecs) {
1131                         x->delay_usecs = pdata->settle_delay_usecs;
1132
1133                         x++;
1134                         x->tx_buf = &packet->read_z2;
1135                         x->len = 1;
1136                         spi_message_add_tail(x, m);
1137
1138                         x++;
1139                         x->rx_buf = &packet->tc.z2;
1140                         x->len = 2;
1141                         spi_message_add_tail(x, m);
1142                 }
1143         }
1144
1145         /* power down */
1146         ts->msg_count++;
1147         m++;
1148         spi_message_init(m);
1149         m->context = ts;
1150
1151         if (ts->model == 7845) {
1152                 x++;
1153                 packet->pwrdown_cmd[0] = PWRDOWN;
1154                 packet->pwrdown_cmd[1] = 0;
1155                 packet->pwrdown_cmd[2] = 0;
1156                 x->tx_buf = &packet->pwrdown_cmd[0];
1157                 x->len = 3;
1158         } else {
1159                 x++;
1160                 packet->pwrdown = PWRDOWN;
1161                 x->tx_buf = &packet->pwrdown;
1162                 x->len = 1;
1163                 spi_message_add_tail(x, m);
1164
1165                 x++;
1166                 x->rx_buf = &packet->dummy;
1167                 x->len = 2;
1168         }
1169
1170         CS_CHANGE(*x);
1171         spi_message_add_tail(x, m);
1172 }
1173
1174 static int __devinit ads7846_probe(struct spi_device *spi)
1175 {
1176         struct ads7846 *ts;
1177         struct ads7846_packet *packet;
1178         struct input_dev *input_dev;
1179         struct ads7846_platform_data *pdata = spi->dev.platform_data;
1180         unsigned long irq_flags;
1181         int err;
1182
1183         if (!spi->irq) {
1184                 dev_dbg(&spi->dev, "no IRQ?\n");
1185                 return -ENODEV;
1186         }
1187
1188         if (!pdata) {
1189                 dev_dbg(&spi->dev, "no platform data?\n");
1190                 return -ENODEV;
1191         }
1192
1193         /* don't exceed max specified sample rate */
1194         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1195                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1196                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1197                 return -EINVAL;
1198         }
1199
1200         /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1201          * that even if the hardware can do that, the SPI controller driver
1202          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1203          */
1204         spi->bits_per_word = 8;
1205         spi->mode = SPI_MODE_0;
1206         err = spi_setup(spi);
1207         if (err < 0)
1208                 return err;
1209
1210         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1211         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1212         input_dev = input_allocate_device();
1213         if (!ts || !packet || !input_dev) {
1214                 err = -ENOMEM;
1215                 goto err_free_mem;
1216         }
1217
1218         dev_set_drvdata(&spi->dev, ts);
1219
1220         ts->packet = packet;
1221         ts->spi = spi;
1222         ts->input = input_dev;
1223         ts->vref_mv = pdata->vref_mv;
1224         ts->swap_xy = pdata->swap_xy;
1225
1226         mutex_init(&ts->lock);
1227         init_waitqueue_head(&ts->wait);
1228
1229         ts->model = pdata->model ? : 7846;
1230         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1231         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1232         ts->pressure_max = pdata->pressure_max ? : ~0;
1233
1234         if (pdata->filter != NULL) {
1235                 if (pdata->filter_init != NULL) {
1236                         err = pdata->filter_init(pdata, &ts->filter_data);
1237                         if (err < 0)
1238                                 goto err_free_mem;
1239                 }
1240                 ts->filter = pdata->filter;
1241                 ts->filter_cleanup = pdata->filter_cleanup;
1242         } else if (pdata->debounce_max) {
1243                 ts->debounce_max = pdata->debounce_max;
1244                 if (ts->debounce_max < 2)
1245                         ts->debounce_max = 2;
1246                 ts->debounce_tol = pdata->debounce_tol;
1247                 ts->debounce_rep = pdata->debounce_rep;
1248                 ts->filter = ads7846_debounce_filter;
1249                 ts->filter_data = ts;
1250         } else {
1251                 ts->filter = ads7846_no_filter;
1252         }
1253
1254         err = ads7846_setup_pendown(spi, ts);
1255         if (err)
1256                 goto err_cleanup_filter;
1257
1258         if (pdata->penirq_recheck_delay_usecs)
1259                 ts->penirq_recheck_delay_usecs =
1260                                 pdata->penirq_recheck_delay_usecs;
1261
1262         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1263
1264         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1265         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1266
1267         input_dev->name = ts->name;
1268         input_dev->phys = ts->phys;
1269         input_dev->dev.parent = &spi->dev;
1270
1271         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1272         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1273         input_set_abs_params(input_dev, ABS_X,
1274                         pdata->x_min ? : 0,
1275                         pdata->x_max ? : MAX_12BIT,
1276                         0, 0);
1277         input_set_abs_params(input_dev, ABS_Y,
1278                         pdata->y_min ? : 0,
1279                         pdata->y_max ? : MAX_12BIT,
1280                         0, 0);
1281         input_set_abs_params(input_dev, ABS_PRESSURE,
1282                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1283
1284         ads7846_setup_spi_msg(ts, pdata);
1285
1286         ts->reg = regulator_get(&spi->dev, "vcc");
1287         if (IS_ERR(ts->reg)) {
1288                 err = PTR_ERR(ts->reg);
1289                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1290                 goto err_free_gpio;
1291         }
1292
1293         err = regulator_enable(ts->reg);
1294         if (err) {
1295                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1296                 goto err_put_regulator;
1297         }
1298
1299         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1300         irq_flags |= IRQF_ONESHOT;
1301
1302         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1303                                    irq_flags, spi->dev.driver->name, ts);
1304         if (err && !pdata->irq_flags) {
1305                 dev_info(&spi->dev,
1306                         "trying pin change workaround on irq %d\n", spi->irq);
1307                 irq_flags |= IRQF_TRIGGER_RISING;
1308                 err = request_threaded_irq(spi->irq,
1309                                   ads7846_hard_irq, ads7846_irq,
1310                                   irq_flags, spi->dev.driver->name, ts);
1311         }
1312
1313         if (err) {
1314                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1315                 goto err_disable_regulator;
1316         }
1317
1318         err = ads784x_hwmon_register(spi, ts);
1319         if (err)
1320                 goto err_free_irq;
1321
1322         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1323
1324         /*
1325          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1326          * the touchscreen, in case it's not connected.
1327          */
1328         if (ts->model == 7845)
1329                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1330         else
1331                 (void) ads7846_read12_ser(&spi->dev,
1332                                 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1333
1334         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1335         if (err)
1336                 goto err_remove_hwmon;
1337
1338         err = input_register_device(input_dev);
1339         if (err)
1340                 goto err_remove_attr_group;
1341
1342         device_init_wakeup(&spi->dev, pdata->wakeup);
1343
1344         return 0;
1345
1346  err_remove_attr_group:
1347         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1348  err_remove_hwmon:
1349         ads784x_hwmon_unregister(spi, ts);
1350  err_free_irq:
1351         free_irq(spi->irq, ts);
1352  err_disable_regulator:
1353         regulator_disable(ts->reg);
1354  err_put_regulator:
1355         regulator_put(ts->reg);
1356  err_free_gpio:
1357         if (!ts->get_pendown_state)
1358                 gpio_free(ts->gpio_pendown);
1359  err_cleanup_filter:
1360         if (ts->filter_cleanup)
1361                 ts->filter_cleanup(ts->filter_data);
1362  err_free_mem:
1363         input_free_device(input_dev);
1364         kfree(packet);
1365         kfree(ts);
1366         return err;
1367 }
1368
1369 static int __devexit ads7846_remove(struct spi_device *spi)
1370 {
1371         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1372
1373         device_init_wakeup(&spi->dev, false);
1374
1375         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1376
1377         ads7846_disable(ts);
1378         free_irq(ts->spi->irq, ts);
1379
1380         input_unregister_device(ts->input);
1381
1382         ads784x_hwmon_unregister(spi, ts);
1383
1384         regulator_disable(ts->reg);
1385         regulator_put(ts->reg);
1386
1387         if (!ts->get_pendown_state) {
1388                 /*
1389                  * If we are not using specialized pendown method we must
1390                  * have been relying on gpio we set up ourselves.
1391                  */
1392                 gpio_free(ts->gpio_pendown);
1393         }
1394
1395         if (ts->filter_cleanup)
1396                 ts->filter_cleanup(ts->filter_data);
1397
1398         kfree(ts->packet);
1399         kfree(ts);
1400
1401         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1402
1403         return 0;
1404 }
1405
1406 static struct spi_driver ads7846_driver = {
1407         .driver = {
1408                 .name   = "ads7846",
1409                 .bus    = &spi_bus_type,
1410                 .owner  = THIS_MODULE,
1411         },
1412         .probe          = ads7846_probe,
1413         .remove         = __devexit_p(ads7846_remove),
1414         .suspend        = ads7846_suspend,
1415         .resume         = ads7846_resume,
1416 };
1417
1418 static int __init ads7846_init(void)
1419 {
1420         return spi_register_driver(&ads7846_driver);
1421 }
1422 module_init(ads7846_init);
1423
1424 static void __exit ads7846_exit(void)
1425 {
1426         spi_unregister_driver(&ads7846_driver);
1427 }
1428 module_exit(ads7846_exit);
1429
1430 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1431 MODULE_LICENSE("GPL");
1432 MODULE_ALIAS("spi:ads7846");