drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  * Copyright (c) 2006 Nokia Corporation
   6  * Various changes: Imre Deak <imre.deak@nokia.com>
   7  *
   8  * Using code from:
   9  *  - corgi_ts.c
  10  *      Copyright (C) 2004-2005 Richard Purdie
  11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  12  *      Copyright (C) 2002 MontaVista Software
  13  *      Copyright (C) 2004 Texas Instruments
  14  *      Copyright (C) 2005 Dirk Behme
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2 as
  18  *  published by the Free Software Foundation.
  19  */
  20 #include <linux/types.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/init.h>
  23 #include <linux/err.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/input.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/slab.h>
  29 #include <linux/pm.h>
  30 #include <linux/gpio.h>
  31 #include <linux/spi/spi.h>
  32 #include <linux/spi/ads7846.h>
  33 #include <linux/regulator/consumer.h>
  34 #include <asm/irq.h>
  35
  36 /*
  37  * This code has been heavily tested on a Nokia 770, and lightly
  38  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  39  * TSC2046 is just newer ads7846 silicon.
  40  * Support for ads7843 tested on Atmel at91sam926x-EK.
  41  * Support for ads7845 has only been stubbed in.
  42  * Support for Analog Devices AD7873 and AD7843 tested.
  43  *
  44  * IRQ handling needs a workaround because of a shortcoming in handling
  45  * edge triggered IRQs on some platforms like the OMAP1/2. These
  46  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  47  * have to maintain our own SW IRQ disabled status. This should be
  48  * removed as soon as the affected platform's IRQ handling is fixed.
  49  *
  50  * App note sbaa036 talks in more detail about accurate sampling...
  51  * that ought to help in situations like LCDs inducing noise (which
  52  * can also be helped by using synch signals) and more generally.
  53  * This driver tries to utilize the measures described in the app
  54  * note. The strength of filtering can be set in the board-* specific
  55  * files.
  56  */
  57
  58 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
  59 #define TS_POLL_PERIOD  5       /* ms delay between samples */
  60
  61 /* this driver doesn't aim at the peak continuous sample rate */
  62 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  63
  64 struct ts_event {
  65         /*
  66          * For portability, we can't read 12 bit values using SPI (which
  67          * would make the controller deliver them as native byte order u16
  68          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  69          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  70          */
  71         u16     x;
  72         u16     y;
  73         u16     z1, z2;
  74         bool    ignore;
  75         u8      x_buf[3];
  76         u8      y_buf[3];
  77 };
  78
  79 /*
  80  * We allocate this separately to avoid cache line sharing issues when
  81  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  82  * systems where main memory is not DMA-coherent (most non-x86 boards).
  83  */
  84 struct ads7846_packet {
  85         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  86         u16                     dummy;          /* for the pwrdown read */
  87         struct ts_event         tc;
  88         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  89         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  90 };
  91
  92 struct ads7846 {
  93         struct input_dev        *input;
  94         char                    phys[32];
  95         char                    name[32];
  96
  97         struct spi_device       *spi;
  98         struct regulator        *reg;
  99
 100 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 101         struct attribute_group  *attr_group;
 102         struct device           *hwmon;
 103 #endif
 104
 105         u16                     model;
 106         u16                     vref_mv;
 107         u16                     vref_delay_usecs;
 108         u16                     x_plate_ohms;
 109         u16                     pressure_max;
 110
 111         bool                    swap_xy;
 112
 113         struct ads7846_packet   *packet;
 114
 115         struct spi_transfer     xfer[18];
 116         struct spi_message      msg[5];
 117         int                     msg_count;
 118         wait_queue_head_t       wait;
 119
 120         bool                    pendown;
 121
 122         int                     read_cnt;
 123         int                     read_rep;
 124         int                     last_read;
 125
 126         u16                     debounce_max;
 127         u16                     debounce_tol;
 128         u16                     debounce_rep;
 129
 130         u16                     penirq_recheck_delay_usecs;
 131
 132         struct mutex            lock;
 133         bool                    stopped;        /* P: lock */
 134         bool                    disabled;       /* P: lock */
 135         bool                    suspended;      /* P: lock */
 136
 137         int                     (*filter)(void *data, int data_idx, int *val);
 138         void                    *filter_data;
 139         void                    (*filter_cleanup)(void *data);
 140         int                     (*get_pendown_state)(void);
 141         int                     gpio_pendown;
 142
 143         void                    (*wait_for_sync)(void);
 144 };
 145
 146 /* leave chip selected when we're done, for quicker re-select? */
 147 #if     0
 148 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 149 #else
 150 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 151 #endif
 152
 153 /*--------------------------------------------------------------------------*/
 154
 155 /* The ADS7846 has touchscreen and other sensors.
 156  * Earlier ads784x chips are somewhat compatible.
 157  */
 158 #define ADS_START               (1 << 7)
 159 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 160 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 161 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 162 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 163 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 164 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 165 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 166 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 167 #define ADS_8_BIT               (1 << 3)
 168 #define ADS_12_BIT              (0 << 3)
 169 #define ADS_SER                 (1 << 2)        /* non-differential */
 170 #define ADS_DFR                 (0 << 2)        /* differential */
 171 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 172 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 173 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 174 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 175
 176 #define MAX_12BIT       ((1<<12)-1)
 177
 178 /* leave ADC powered up (disables penirq) between differential samples */
 179 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 180         | ADS_12_BIT | ADS_DFR | \
 181         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 182
 183 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 184 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 185 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 186
 187 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 188 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 189
 190 /* single-ended samples need to first power up reference voltage;
 191  * we leave both ADC and VREF powered
 192  */
 193 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 194         | ADS_12_BIT | ADS_SER)
 195
 196 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 197 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 198
 199 /* Must be called with ts->lock held */
 200 static void ads7846_stop(struct ads7846 *ts)
 201 {
 202         if (!ts->disabled && !ts->suspended) {
 203                 /* Signal IRQ thread to stop polling and disable the handler. */
 204                 ts->stopped = true;
 205                 mb();
 206                 wake_up(&ts->wait);
 207                 disable_irq(ts->spi->irq);
 208         }
 209 }
 210
 211 /* Must be called with ts->lock held */
 212 static void ads7846_restart(struct ads7846 *ts)
 213 {
 214         if (!ts->disabled && !ts->suspended) {
 215                 /* Tell IRQ thread that it may poll the device. */
 216                 ts->stopped = false;
 217                 mb();
 218                 enable_irq(ts->spi->irq);
 219         }
 220 }
 221
 222 /* Must be called with ts->lock held */
 223 static void __ads7846_disable(struct ads7846 *ts)
 224 {
 225         ads7846_stop(ts);
 226         regulator_disable(ts->reg);
 227
 228         /*
 229          * We know the chip's in low power mode since we always
 230          * leave it that way after every request
 231          */
 232 }
 233
 234 /* Must be called with ts->lock held */
 235 static void __ads7846_enable(struct ads7846 *ts)
 236 {
 237         regulator_enable(ts->reg);
 238         ads7846_restart(ts);
 239 }
 240
 241 static void ads7846_disable(struct ads7846 *ts)
 242 {
 243         mutex_lock(&ts->lock);
 244
 245         if (!ts->disabled) {
 246
 247                 if  (!ts->suspended)
 248                         __ads7846_disable(ts);
 249
 250                 ts->disabled = true;
 251         }
 252
 253         mutex_unlock(&ts->lock);
 254 }
 255
 256 static void ads7846_enable(struct ads7846 *ts)
 257 {
 258         mutex_lock(&ts->lock);
 259
 260         if (ts->disabled) {
 261
 262                 ts->disabled = false;
 263
 264                 if (!ts->suspended)
 265                         __ads7846_enable(ts);
 266         }
 267
 268         mutex_unlock(&ts->lock);
 269 }
 270
 271 /*--------------------------------------------------------------------------*/
 272
 273 /*
 274  * Non-touchscreen sensors only use single-ended conversions.
 275  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 276  * ads7846 lets that pin be unconnected, to use internal vREF.
 277  */
 278
 279 struct ser_req {
 280         u8                      ref_on;
 281         u8                      command;
 282         u8                      ref_off;
 283         u16                     scratch;
 284         __be16                  sample;
 285         struct spi_message      msg;
 286         struct spi_transfer     xfer[6];
 287 };
 288
 289 struct ads7845_ser_req {
 290         u8                      command[3];
 291         u8                      pwrdown[3];
 292         u8                      sample[3];
 293         struct spi_message      msg;
 294         struct spi_transfer     xfer[2];
 295 };
 296
 297 static int ads7846_read12_ser(struct device *dev, unsigned command)
 298 {
 299         struct spi_device *spi = to_spi_device(dev);
 300         struct ads7846 *ts = dev_get_drvdata(dev);
 301         struct ser_req *req;
 302         int status;
 303         int use_internal;
 304
 305         req = kzalloc(sizeof *req, GFP_KERNEL);
 306         if (!req)
 307                 return -ENOMEM;
 308
 309         spi_message_init(&req->msg);
 310
 311         /* FIXME boards with ads7846 might use external vref instead ... */
 312         use_internal = (ts->model == 7846);
 313
 314         /* maybe turn on internal vREF, and let it settle */
 315         if (use_internal) {
 316                 req->ref_on = REF_ON;
 317                 req->xfer[0].tx_buf = &req->ref_on;
 318                 req->xfer[0].len = 1;
 319                 spi_message_add_tail(&req->xfer[0], &req->msg);
 320
 321                 req->xfer[1].rx_buf = &req->scratch;
 322                 req->xfer[1].len = 2;
 323
 324                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 325                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 326                 spi_message_add_tail(&req->xfer[1], &req->msg);
 327         }
 328
 329         /* take sample */
 330         req->command = (u8) command;
 331         req->xfer[2].tx_buf = &req->command;
 332         req->xfer[2].len = 1;
 333         spi_message_add_tail(&req->xfer[2], &req->msg);
 334
 335         req->xfer[3].rx_buf = &req->sample;
 336         req->xfer[3].len = 2;
 337         spi_message_add_tail(&req->xfer[3], &req->msg);
 338
 339         /* REVISIT:  take a few more samples, and compare ... */
 340
 341         /* converter in low power mode & enable PENIRQ */
 342         req->ref_off = PWRDOWN;
 343         req->xfer[4].tx_buf = &req->ref_off;
 344         req->xfer[4].len = 1;
 345         spi_message_add_tail(&req->xfer[4], &req->msg);
 346
 347         req->xfer[5].rx_buf = &req->scratch;
 348         req->xfer[5].len = 2;
 349         CS_CHANGE(req->xfer[5]);
 350         spi_message_add_tail(&req->xfer[5], &req->msg);
 351
 352         mutex_lock(&ts->lock);
 353         ads7846_stop(ts);
 354         status = spi_sync(spi, &req->msg);
 355         ads7846_restart(ts);
 356         mutex_unlock(&ts->lock);
 357
 358         if (status == 0) {
 359                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 360                 status = be16_to_cpu(req->sample);
 361                 status = status >> 3;
 362                 status &= 0x0fff;
 363         }
 364
 365         kfree(req);
 366         return status;
 367 }
 368
 369 static int ads7845_read12_ser(struct device *dev, unsigned command)
 370 {
 371         struct spi_device *spi = to_spi_device(dev);
 372         struct ads7846 *ts = dev_get_drvdata(dev);
 373         struct ads7845_ser_req *req;
 374         int status;
 375
 376         req = kzalloc(sizeof *req, GFP_KERNEL);
 377         if (!req)
 378                 return -ENOMEM;
 379
 380         spi_message_init(&req->msg);
 381
 382         req->command[0] = (u8) command;
 383         req->xfer[0].tx_buf = req->command;
 384         req->xfer[0].rx_buf = req->sample;
 385         req->xfer[0].len = 3;
 386         spi_message_add_tail(&req->xfer[0], &req->msg);
 387
 388         mutex_lock(&ts->lock);
 389         ads7846_stop(ts);
 390         status = spi_sync(spi, &req->msg);
 391         ads7846_restart(ts);
 392         mutex_unlock(&ts->lock);
 393
 394         if (status == 0) {
 395                 /* BE12 value, then padding */
 396                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 397                 status = status >> 3;
 398                 status &= 0x0fff;
 399         }
 400
 401         kfree(req);
 402         return status;
 403 }
 404
 405 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 406
 407 #define SHOW(name, var, adjust) static ssize_t \
 408 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 409 { \
 410         struct ads7846 *ts = dev_get_drvdata(dev); \
 411         ssize_t v = ads7846_read12_ser(dev, \
 412                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
 413         if (v < 0) \
 414                 return v; \
 415         return sprintf(buf, "%u\n", adjust(ts, v)); \
 416 } \
 417 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 418
 419
 420 /* Sysfs conventions report temperatures in millidegrees Celsius.
 421  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 422  * accuracy scheme without calibration data.  For now we won't try either;
 423  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 424  */
 425 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 426 {
 427         return v;
 428 }
 429
 430 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 431 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 432
 433
 434 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 435  * if we know vREF.  userspace may need to scale vAUX to match the board's
 436  * external resistors; we assume that vBATT only uses the internal ones.
 437  */
 438 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 439 {
 440         unsigned retval = v;
 441
 442         /* external resistors may scale vAUX into 0..vREF */
 443         retval *= ts->vref_mv;
 444         retval = retval >> 12;
 445
 446         return retval;
 447 }
 448
 449 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 450 {
 451         unsigned retval = vaux_adjust(ts, v);
 452
 453         /* ads7846 has a resistor ladder to scale this signal down */
 454         if (ts->model == 7846)
 455                 retval *= 4;
 456
 457         return retval;
 458 }
 459
 460 SHOW(in0_input, vaux, vaux_adjust)
 461 SHOW(in1_input, vbatt, vbatt_adjust)
 462
 463 static struct attribute *ads7846_attributes[] = {
 464         &dev_attr_temp0.attr,
 465         &dev_attr_temp1.attr,
 466         &dev_attr_in0_input.attr,
 467         &dev_attr_in1_input.attr,
 468         NULL,
 469 };
 470
 471 static struct attribute_group ads7846_attr_group = {
 472         .attrs = ads7846_attributes,
 473 };
 474
 475 static struct attribute *ads7843_attributes[] = {
 476         &dev_attr_in0_input.attr,
 477         &dev_attr_in1_input.attr,
 478         NULL,
 479 };
 480
 481 static struct attribute_group ads7843_attr_group = {
 482         .attrs = ads7843_attributes,
 483 };
 484
 485 static struct attribute *ads7845_attributes[] = {
 486         &dev_attr_in0_input.attr,
 487         NULL,
 488 };
 489
 490 static struct attribute_group ads7845_attr_group = {
 491         .attrs = ads7845_attributes,
 492 };
 493
 494 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 495 {
 496         struct device *hwmon;
 497         int err;
 498
 499         /* hwmon sensors need a reference voltage */
 500         switch (ts->model) {
 501         case 7846:
 502                 if (!ts->vref_mv) {
 503                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 504                         ts->vref_mv = 2500;
 505                 }
 506                 break;
 507         case 7845:
 508         case 7843:
 509                 if (!ts->vref_mv) {
 510                         dev_warn(&spi->dev,
 511                                 "external vREF for ADS%d not specified\n",
 512                                 ts->model);
 513                         return 0;
 514                 }
 515                 break;
 516         }
 517
 518         /* different chips have different sensor groups */
 519         switch (ts->model) {
 520         case 7846:
 521                 ts->attr_group = &ads7846_attr_group;
 522                 break;
 523         case 7845:
 524                 ts->attr_group = &ads7845_attr_group;
 525                 break;
 526         case 7843:
 527                 ts->attr_group = &ads7843_attr_group;
 528                 break;
 529         default:
 530                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 531                 return 0;
 532         }
 533
 534         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 535         if (err)
 536                 return err;
 537
 538         hwmon = hwmon_device_register(&spi->dev);
 539         if (IS_ERR(hwmon)) {
 540                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 541                 return PTR_ERR(hwmon);
 542         }
 543
 544         ts->hwmon = hwmon;
 545         return 0;
 546 }
 547
 548 static void ads784x_hwmon_unregister(struct spi_device *spi,
 549                                      struct ads7846 *ts)
 550 {
 551         if (ts->hwmon) {
 552                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 553                 hwmon_device_unregister(ts->hwmon);
 554         }
 555 }
 556
 557 #else
 558 static inline int ads784x_hwmon_register(struct spi_device *spi,
 559                                          struct ads7846 *ts)
 560 {
 561         return 0;
 562 }
 563
 564 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 565                                             struct ads7846 *ts)
 566 {
 567 }
 568 #endif
 569
 570 static ssize_t ads7846_pen_down_show(struct device *dev,
 571                                      struct device_attribute *attr, char *buf)
 572 {
 573         struct ads7846 *ts = dev_get_drvdata(dev);
 574
 575         return sprintf(buf, "%u\n", ts->pendown);
 576 }
 577
 578 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 579
 580 static ssize_t ads7846_disable_show(struct device *dev,
 581                                      struct device_attribute *attr, char *buf)
 582 {
 583         struct ads7846 *ts = dev_get_drvdata(dev);
 584
 585         return sprintf(buf, "%u\n", ts->disabled);
 586 }
 587
 588 static ssize_t ads7846_disable_store(struct device *dev,
 589                                      struct device_attribute *attr,
 590                                      const char *buf, size_t count)
 591 {
 592         struct ads7846 *ts = dev_get_drvdata(dev);
 593         unsigned long i;
 594
 595         if (strict_strtoul(buf, 10, &i))
 596                 return -EINVAL;
 597
 598         if (i)
 599                 ads7846_disable(ts);
 600         else
 601                 ads7846_enable(ts);
 602
 603         return count;
 604 }
 605
 606 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 607
 608 static struct attribute *ads784x_attributes[] = {
 609         &dev_attr_pen_down.attr,
 610         &dev_attr_disable.attr,
 611         NULL,
 612 };
 613
 614 static struct attribute_group ads784x_attr_group = {
 615         .attrs = ads784x_attributes,
 616 };
 617
 618 /*--------------------------------------------------------------------------*/
 619
 620 static int get_pendown_state(struct ads7846 *ts)
 621 {
 622         if (ts->get_pendown_state)
 623                 return ts->get_pendown_state();
 624
 625         return !gpio_get_value(ts->gpio_pendown);
 626 }
 627
 628 static void null_wait_for_sync(void)
 629 {
 630 }
 631
 632 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 633 {
 634         struct ads7846 *ts = ads;
 635
 636         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 637                 /* Start over collecting consistent readings. */
 638                 ts->read_rep = 0;
 639                 /*
 640                  * Repeat it, if this was the first read or the read
 641                  * wasn't consistent enough.
 642                  */
 643                 if (ts->read_cnt < ts->debounce_max) {
 644                         ts->last_read = *val;
 645                         ts->read_cnt++;
 646                         return ADS7846_FILTER_REPEAT;
 647                 } else {
 648                         /*
 649                          * Maximum number of debouncing reached and still
 650                          * not enough number of consistent readings. Abort
 651                          * the whole sample, repeat it in the next sampling
 652                          * period.
 653                          */
 654                         ts->read_cnt = 0;
 655                         return ADS7846_FILTER_IGNORE;
 656                 }
 657         } else {
 658                 if (++ts->read_rep > ts->debounce_rep) {
 659                         /*
 660                          * Got a good reading for this coordinate,
 661                          * go for the next one.
 662                          */
 663                         ts->read_cnt = 0;
 664                         ts->read_rep = 0;
 665                         return ADS7846_FILTER_OK;
 666                 } else {
 667                         /* Read more values that are consistent. */
 668                         ts->read_cnt++;
 669                         return ADS7846_FILTER_REPEAT;
 670                 }
 671         }
 672 }
 673
 674 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 675 {
 676         return ADS7846_FILTER_OK;
 677 }
 678
 679 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 680 {
 681         struct spi_transfer *t =
 682                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 683
 684         if (ts->model == 7845) {
 685                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 686         } else {
 687                 /*
 688                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 689                  * padding; built from two 8 bit values written msb-first.
 690                  */
 691                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 692         }
 693 }
 694
 695 static void ads7846_update_value(struct spi_message *m, int val)
 696 {
 697         struct spi_transfer *t =
 698                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 699
 700         *(u16 *)t->rx_buf = val;
 701 }
 702
 703 static void ads7846_read_state(struct ads7846 *ts)
 704 {
 705         struct ads7846_packet *packet = ts->packet;
 706         struct spi_message *m;
 707         int msg_idx = 0;
 708         int val;
 709         int action;
 710         int error;
 711
 712         while (msg_idx < ts->msg_count) {
 713
 714                 ts->wait_for_sync();
 715
 716                 m = &ts->msg[msg_idx];
 717                 error = spi_sync(ts->spi, m);
 718                 if (error) {
 719                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
 720                         packet->tc.ignore = true;
 721                         return;
 722                 }
 723
 724                 /*
 725                  * Last message is power down request, no need to convert
 726                  * or filter the value.
 727                  */
 728                 if (msg_idx < ts->msg_count - 1) {
 729
 730                         val = ads7846_get_value(ts, m);
 731
 732                         action = ts->filter(ts->filter_data, msg_idx, &val);
 733                         switch (action) {
 734                         case ADS7846_FILTER_REPEAT:
 735                                 continue;
 736
 737                         case ADS7846_FILTER_IGNORE:
 738                                 packet->tc.ignore = true;
 739                                 msg_idx = ts->msg_count - 1;
 740                                 continue;
 741
 742                         case ADS7846_FILTER_OK:
 743                                 ads7846_update_value(m, val);
 744                                 packet->tc.ignore = false;
 745                                 msg_idx++;
 746                                 break;
 747
 748                         default:
 749                                 BUG();
 750                         }
 751                 } else {
 752                         msg_idx++;
 753                 }
 754         }
 755 }
 756
 757 static void ads7846_report_state(struct ads7846 *ts)
 758 {
 759         struct ads7846_packet *packet = ts->packet;
 760         unsigned int Rt;
 761         u16 x, y, z1, z2;
 762
 763         /*
 764          * ads7846_get_value() does in-place conversion (including byte swap)
 765          * from on-the-wire format as part of debouncing to get stable
 766          * readings.
 767          */
 768         if (ts->model == 7845) {
 769                 x = *(u16 *)packet->tc.x_buf;
 770                 y = *(u16 *)packet->tc.y_buf;
 771                 z1 = 0;
 772                 z2 = 0;
 773         } else {
 774                 x = packet->tc.x;
 775                 y = packet->tc.y;
 776                 z1 = packet->tc.z1;
 777                 z2 = packet->tc.z2;
 778         }
 779
 780         /* range filtering */
 781         if (x == MAX_12BIT)
 782                 x = 0;
 783
 784         if (ts->model == 7843) {
 785                 Rt = ts->pressure_max / 2;
 786         } else if (ts->model == 7845) {
 787                 if (get_pendown_state(ts))
 788                         Rt = ts->pressure_max / 2;
 789                 else
 790                         Rt = 0;
 791                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 792         } else if (likely(x && z1)) {
 793                 /* compute touch pressure resistance using equation #2 */
 794                 Rt = z2;
 795                 Rt -= z1;
 796                 Rt *= x;
 797                 Rt *= ts->x_plate_ohms;
 798                 Rt /= z1;
 799                 Rt = (Rt + 2047) >> 12;
 800         } else {
 801                 Rt = 0;
 802         }
 803
 804         /*
 805          * Sample found inconsistent by debouncing or pressure is beyond
 806          * the maximum. Don't report it to user space, repeat at least
 807          * once more the measurement
 808          */
 809         if (packet->tc.ignore || Rt > ts->pressure_max) {
 810                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 811                          packet->tc.ignore, Rt);
 812                 return;
 813         }
 814
 815         /*
 816          * Maybe check the pendown state before reporting. This discards
 817          * false readings when the pen is lifted.
 818          */
 819         if (ts->penirq_recheck_delay_usecs) {
 820                 udelay(ts->penirq_recheck_delay_usecs);
 821                 if (!get_pendown_state(ts))
 822                         Rt = 0;
 823         }
 824
 825         /*
 826          * NOTE: We can't rely on the pressure to determine the pen down
 827          * state, even this controller has a pressure sensor. The pressure
 828          * value can fluctuate for quite a while after lifting the pen and
 829          * in some cases may not even settle at the expected value.
 830          *
 831          * The only safe way to check for the pen up condition is in the
 832          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 833          */
 834         if (Rt) {
 835                 struct input_dev *input = ts->input;
 836
 837                 if (ts->swap_xy)
 838                         swap(x, y);
 839
 840                 if (!ts->pendown) {
 841                         input_report_key(input, BTN_TOUCH, 1);
 842                         ts->pendown = true;
 843                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 844                 }
 845
 846                 input_report_abs(input, ABS_X, x);
 847                 input_report_abs(input, ABS_Y, y);
 848                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 849
 850                 input_sync(input);
 851                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 852         }
 853 }
 854
 855 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 856 {
 857         struct ads7846 *ts = handle;
 858
 859         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 860 }
 861
 862
 863 static irqreturn_t ads7846_irq(int irq, void *handle)
 864 {
 865         struct ads7846 *ts = handle;
 866
 867         /* Start with a small delay before checking pendown state */
 868         msleep(TS_POLL_DELAY);
 869
 870         while (!ts->stopped && get_pendown_state(ts)) {
 871
 872                 /* pen is down, continue with the measurement */
 873                 ads7846_read_state(ts);
 874
 875                 if (!ts->stopped)
 876                         ads7846_report_state(ts);
 877
 878                 wait_event_timeout(ts->wait, ts->stopped,
 879                                    msecs_to_jiffies(TS_POLL_PERIOD));
 880         }
 881
 882         if (ts->pendown) {
 883                 struct input_dev *input = ts->input;
 884
 885                 input_report_key(input, BTN_TOUCH, 0);
 886                 input_report_abs(input, ABS_PRESSURE, 0);
 887                 input_sync(input);
 888
 889                 ts->pendown = false;
 890                 dev_vdbg(&ts->spi->dev, "UP\n");
 891         }
 892
 893         return IRQ_HANDLED;
 894 }
 895
 896 #ifdef CONFIG_PM_SLEEP
 897 static int ads7846_suspend(struct device *dev)
 898 {
 899         struct ads7846 *ts = dev_get_drvdata(dev);
 900
 901         mutex_lock(&ts->lock);
 902
 903         if (!ts->suspended) {
 904
 905                 if (!ts->disabled)
 906                         __ads7846_disable(ts);
 907
 908                 if (device_may_wakeup(&ts->spi->dev))
 909                         enable_irq_wake(ts->spi->irq);
 910
 911                 ts->suspended = true;
 912         }
 913
 914         mutex_unlock(&ts->lock);
 915
 916         return 0;
 917 }
 918
 919 static int ads7846_resume(struct device *dev)
 920 {
 921         struct ads7846 *ts = dev_get_drvdata(dev);
 922
 923         mutex_lock(&ts->lock);
 924
 925         if (ts->suspended) {
 926
 927                 ts->suspended = false;
 928
 929                 if (device_may_wakeup(&ts->spi->dev))
 930                         disable_irq_wake(ts->spi->irq);
 931
 932                 if (!ts->disabled)
 933                         __ads7846_enable(ts);
 934         }
 935
 936         mutex_unlock(&ts->lock);
 937
 938         return 0;
 939 }
 940 #endif
 941
 942 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 943
 944 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
 945 {
 946         struct ads7846_platform_data *pdata = spi->dev.platform_data;
 947         int err;
 948
 949         /*
 950          * REVISIT when the irq can be triggered active-low, or if for some
 951          * reason the touchscreen isn't hooked up, we don't need to access
 952          * the pendown state.
 953          */
 954
 955         if (pdata->get_pendown_state) {
 956                 ts->get_pendown_state = pdata->get_pendown_state;
 957         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 958
 959                 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
 960                 if (err) {
 961                         dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
 962                                 pdata->gpio_pendown);
 963                         return err;
 964                 }
 965
 966                 ts->gpio_pendown = pdata->gpio_pendown;
 967
 968         } else {
 969                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 970                 return -EINVAL;
 971         }
 972
 973         return 0;
 974 }
 975
 976 /*
 977  * Set up the transfers to read touchscreen state; this assumes we
 978  * use formula #2 for pressure, not #3.
 979  */
 980 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
 981                                 const struct ads7846_platform_data *pdata)
 982 {
 983         struct spi_message *m = &ts->msg[0];
 984         struct spi_transfer *x = ts->xfer;
 985         struct ads7846_packet *packet = ts->packet;
 986         int vref = pdata->keep_vref_on;
 987
 988         if (ts->model == 7873) {
 989                 /*
 990                  * The AD7873 is almost identical to the ADS7846
 991                  * keep VREF off during differential/ratiometric
 992                  * conversion modes.
 993                  */
 994                 ts->model = 7846;
 995                 vref = 0;
 996         }
 997
 998         ts->msg_count = 1;
 999         spi_message_init(m);
1000         m->context = ts;
1001
1002         if (ts->model == 7845) {
1003                 packet->read_y_cmd[0] = READ_Y(vref);
1004                 packet->read_y_cmd[1] = 0;
1005                 packet->read_y_cmd[2] = 0;
1006                 x->tx_buf = &packet->read_y_cmd[0];
1007                 x->rx_buf = &packet->tc.y_buf[0];
1008                 x->len = 3;
1009                 spi_message_add_tail(x, m);
1010         } else {
1011                 /* y- still on; turn on only y+ (and ADC) */
1012                 packet->read_y = READ_Y(vref);
1013                 x->tx_buf = &packet->read_y;
1014                 x->len = 1;
1015                 spi_message_add_tail(x, m);
1016
1017                 x++;
1018                 x->rx_buf = &packet->tc.y;
1019                 x->len = 2;
1020                 spi_message_add_tail(x, m);
1021         }
1022
1023         /*
1024          * The first sample after switching drivers can be low quality;
1025          * optionally discard it, using a second one after the signals
1026          * have had enough time to stabilize.
1027          */
1028         if (pdata->settle_delay_usecs) {
1029                 x->delay_usecs = pdata->settle_delay_usecs;
1030
1031                 x++;
1032                 x->tx_buf = &packet->read_y;
1033                 x->len = 1;
1034                 spi_message_add_tail(x, m);
1035
1036                 x++;
1037                 x->rx_buf = &packet->tc.y;
1038                 x->len = 2;
1039                 spi_message_add_tail(x, m);
1040         }
1041
1042         ts->msg_count++;
1043         m++;
1044         spi_message_init(m);
1045         m->context = ts;
1046
1047         if (ts->model == 7845) {
1048                 x++;
1049                 packet->read_x_cmd[0] = READ_X(vref);
1050                 packet->read_x_cmd[1] = 0;
1051                 packet->read_x_cmd[2] = 0;
1052                 x->tx_buf = &packet->read_x_cmd[0];
1053                 x->rx_buf = &packet->tc.x_buf[0];
1054                 x->len = 3;
1055                 spi_message_add_tail(x, m);
1056         } else {
1057                 /* turn y- off, x+ on, then leave in lowpower */
1058                 x++;
1059                 packet->read_x = READ_X(vref);
1060                 x->tx_buf = &packet->read_x;
1061                 x->len = 1;
1062                 spi_message_add_tail(x, m);
1063
1064                 x++;
1065                 x->rx_buf = &packet->tc.x;
1066                 x->len = 2;
1067                 spi_message_add_tail(x, m);
1068         }
1069
1070         /* ... maybe discard first sample ... */
1071         if (pdata->settle_delay_usecs) {
1072                 x->delay_usecs = pdata->settle_delay_usecs;
1073
1074                 x++;
1075                 x->tx_buf = &packet->read_x;
1076                 x->len = 1;
1077                 spi_message_add_tail(x, m);
1078
1079                 x++;
1080                 x->rx_buf = &packet->tc.x;
1081                 x->len = 2;
1082                 spi_message_add_tail(x, m);
1083         }
1084
1085         /* turn y+ off, x- on; we'll use formula #2 */
1086         if (ts->model == 7846) {
1087                 ts->msg_count++;
1088                 m++;
1089                 spi_message_init(m);
1090                 m->context = ts;
1091
1092                 x++;
1093                 packet->read_z1 = READ_Z1(vref);
1094                 x->tx_buf = &packet->read_z1;
1095                 x->len = 1;
1096                 spi_message_add_tail(x, m);
1097
1098                 x++;
1099                 x->rx_buf = &packet->tc.z1;
1100                 x->len = 2;
1101                 spi_message_add_tail(x, m);
1102
1103                 /* ... maybe discard first sample ... */
1104                 if (pdata->settle_delay_usecs) {
1105                         x->delay_usecs = pdata->settle_delay_usecs;
1106
1107                         x++;
1108                         x->tx_buf = &packet->read_z1;
1109                         x->len = 1;
1110                         spi_message_add_tail(x, m);
1111
1112                         x++;
1113                         x->rx_buf = &packet->tc.z1;
1114                         x->len = 2;
1115                         spi_message_add_tail(x, m);
1116                 }
1117
1118                 ts->msg_count++;
1119                 m++;
1120                 spi_message_init(m);
1121                 m->context = ts;
1122
1123                 x++;
1124                 packet->read_z2 = READ_Z2(vref);
1125                 x->tx_buf = &packet->read_z2;
1126                 x->len = 1;
1127                 spi_message_add_tail(x, m);
1128
1129                 x++;
1130                 x->rx_buf = &packet->tc.z2;
1131                 x->len = 2;
1132                 spi_message_add_tail(x, m);
1133
1134                 /* ... maybe discard first sample ... */
1135                 if (pdata->settle_delay_usecs) {
1136                         x->delay_usecs = pdata->settle_delay_usecs;
1137
1138                         x++;
1139                         x->tx_buf = &packet->read_z2;
1140                         x->len = 1;
1141                         spi_message_add_tail(x, m);
1142
1143                         x++;
1144                         x->rx_buf = &packet->tc.z2;
1145                         x->len = 2;
1146                         spi_message_add_tail(x, m);
1147                 }
1148         }
1149
1150         /* power down */
1151         ts->msg_count++;
1152         m++;
1153         spi_message_init(m);
1154         m->context = ts;
1155
1156         if (ts->model == 7845) {
1157                 x++;
1158                 packet->pwrdown_cmd[0] = PWRDOWN;
1159                 packet->pwrdown_cmd[1] = 0;
1160                 packet->pwrdown_cmd[2] = 0;
1161                 x->tx_buf = &packet->pwrdown_cmd[0];
1162                 x->len = 3;
1163         } else {
1164                 x++;
1165                 packet->pwrdown = PWRDOWN;
1166                 x->tx_buf = &packet->pwrdown;
1167                 x->len = 1;
1168                 spi_message_add_tail(x, m);
1169
1170                 x++;
1171                 x->rx_buf = &packet->dummy;
1172                 x->len = 2;
1173         }
1174
1175         CS_CHANGE(*x);
1176         spi_message_add_tail(x, m);
1177 }
1178
1179 static int __devinit ads7846_probe(struct spi_device *spi)
1180 {
1181         struct ads7846 *ts;
1182         struct ads7846_packet *packet;
1183         struct input_dev *input_dev;
1184         struct ads7846_platform_data *pdata = spi->dev.platform_data;
1185         unsigned long irq_flags;
1186         int err;
1187
1188         if (!spi->irq) {
1189                 dev_dbg(&spi->dev, "no IRQ?\n");
1190                 return -ENODEV;
1191         }
1192
1193         if (!pdata) {
1194                 dev_dbg(&spi->dev, "no platform data?\n");
1195                 return -ENODEV;
1196         }
1197
1198         /* don't exceed max specified sample rate */
1199         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1200                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1201                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1202                 return -EINVAL;
1203         }
1204
1205         /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1206          * that even if the hardware can do that, the SPI controller driver
1207          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1208          */
1209         spi->bits_per_word = 8;
1210         spi->mode = SPI_MODE_0;
1211         err = spi_setup(spi);
1212         if (err < 0)
1213                 return err;
1214
1215         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1216         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1217         input_dev = input_allocate_device();
1218         if (!ts || !packet || !input_dev) {
1219                 err = -ENOMEM;
1220                 goto err_free_mem;
1221         }
1222
1223         dev_set_drvdata(&spi->dev, ts);
1224
1225         ts->packet = packet;
1226         ts->spi = spi;
1227         ts->input = input_dev;
1228         ts->vref_mv = pdata->vref_mv;
1229         ts->swap_xy = pdata->swap_xy;
1230
1231         mutex_init(&ts->lock);
1232         init_waitqueue_head(&ts->wait);
1233
1234         ts->model = pdata->model ? : 7846;
1235         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1236         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1237         ts->pressure_max = pdata->pressure_max ? : ~0;
1238
1239         if (pdata->filter != NULL) {
1240                 if (pdata->filter_init != NULL) {
1241                         err = pdata->filter_init(pdata, &ts->filter_data);
1242                         if (err < 0)
1243                                 goto err_free_mem;
1244                 }
1245                 ts->filter = pdata->filter;
1246                 ts->filter_cleanup = pdata->filter_cleanup;
1247         } else if (pdata->debounce_max) {
1248                 ts->debounce_max = pdata->debounce_max;
1249                 if (ts->debounce_max < 2)
1250                         ts->debounce_max = 2;
1251                 ts->debounce_tol = pdata->debounce_tol;
1252                 ts->debounce_rep = pdata->debounce_rep;
1253                 ts->filter = ads7846_debounce_filter;
1254                 ts->filter_data = ts;
1255         } else {
1256                 ts->filter = ads7846_no_filter;
1257         }
1258
1259         err = ads7846_setup_pendown(spi, ts);
1260         if (err)
1261                 goto err_cleanup_filter;
1262
1263         if (pdata->penirq_recheck_delay_usecs)
1264                 ts->penirq_recheck_delay_usecs =
1265                                 pdata->penirq_recheck_delay_usecs;
1266
1267         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1268
1269         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1270         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1271
1272         input_dev->name = ts->name;
1273         input_dev->phys = ts->phys;
1274         input_dev->dev.parent = &spi->dev;
1275
1276         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1277         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1278         input_set_abs_params(input_dev, ABS_X,
1279                         pdata->x_min ? : 0,
1280                         pdata->x_max ? : MAX_12BIT,
1281                         0, 0);
1282         input_set_abs_params(input_dev, ABS_Y,
1283                         pdata->y_min ? : 0,
1284                         pdata->y_max ? : MAX_12BIT,
1285                         0, 0);
1286         input_set_abs_params(input_dev, ABS_PRESSURE,
1287                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1288
1289         ads7846_setup_spi_msg(ts, pdata);
1290
1291         ts->reg = regulator_get(&spi->dev, "vcc");
1292         if (IS_ERR(ts->reg)) {
1293                 err = PTR_ERR(ts->reg);
1294                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1295                 goto err_free_gpio;
1296         }
1297
1298         err = regulator_enable(ts->reg);
1299         if (err) {
1300                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1301                 goto err_put_regulator;
1302         }
1303
1304         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1305         irq_flags |= IRQF_ONESHOT;
1306
1307         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1308                                    irq_flags, spi->dev.driver->name, ts);
1309         if (err && !pdata->irq_flags) {
1310                 dev_info(&spi->dev,
1311                         "trying pin change workaround on irq %d\n", spi->irq);
1312                 irq_flags |= IRQF_TRIGGER_RISING;
1313                 err = request_threaded_irq(spi->irq,
1314                                   ads7846_hard_irq, ads7846_irq,
1315                                   irq_flags, spi->dev.driver->name, ts);
1316         }
1317
1318         if (err) {
1319                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1320                 goto err_disable_regulator;
1321         }
1322
1323         err = ads784x_hwmon_register(spi, ts);
1324         if (err)
1325                 goto err_free_irq;
1326
1327         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1328
1329         /*
1330          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1331          * the touchscreen, in case it's not connected.
1332          */
1333         if (ts->model == 7845)
1334                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1335         else
1336                 (void) ads7846_read12_ser(&spi->dev,
1337                                 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1338
1339         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1340         if (err)
1341                 goto err_remove_hwmon;
1342
1343         err = input_register_device(input_dev);
1344         if (err)
1345                 goto err_remove_attr_group;
1346
1347         device_init_wakeup(&spi->dev, pdata->wakeup);
1348
1349         return 0;
1350
1351  err_remove_attr_group:
1352         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1353  err_remove_hwmon:
1354         ads784x_hwmon_unregister(spi, ts);
1355  err_free_irq:
1356         free_irq(spi->irq, ts);
1357  err_disable_regulator:
1358         regulator_disable(ts->reg);
1359  err_put_regulator:
1360         regulator_put(ts->reg);
1361  err_free_gpio:
1362         if (!ts->get_pendown_state)
1363                 gpio_free(ts->gpio_pendown);
1364  err_cleanup_filter:
1365         if (ts->filter_cleanup)
1366                 ts->filter_cleanup(ts->filter_data);
1367  err_free_mem:
1368         input_free_device(input_dev);
1369         kfree(packet);
1370         kfree(ts);
1371         return err;
1372 }
1373
1374 static int __devexit ads7846_remove(struct spi_device *spi)
1375 {
1376         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1377
1378         device_init_wakeup(&spi->dev, false);
1379
1380         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1381
1382         ads7846_disable(ts);
1383         free_irq(ts->spi->irq, ts);
1384
1385         input_unregister_device(ts->input);
1386
1387         ads784x_hwmon_unregister(spi, ts);
1388
1389         regulator_disable(ts->reg);
1390         regulator_put(ts->reg);
1391
1392         if (!ts->get_pendown_state) {
1393                 /*
1394                  * If we are not using specialized pendown method we must
1395                  * have been relying on gpio we set up ourselves.
1396                  */
1397                 gpio_free(ts->gpio_pendown);
1398         }
1399
1400         if (ts->filter_cleanup)
1401                 ts->filter_cleanup(ts->filter_data);
1402
1403         kfree(ts->packet);
1404         kfree(ts);
1405
1406         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1407
1408         return 0;
1409 }
1410
1411 static struct spi_driver ads7846_driver = {
1412         .driver = {
1413                 .name   = "ads7846",
1414                 .bus    = &spi_bus_type,
1415                 .owner  = THIS_MODULE,
1416                 .pm     = &ads7846_pm,
1417         },
1418         .probe          = ads7846_probe,
1419         .remove         = __devexit_p(ads7846_remove),
1420 };
1421
1422 static int __init ads7846_init(void)
1423 {
1424         return spi_register_driver(&ads7846_driver);
1425 }
1426 module_init(ads7846_init);
1427
1428 static void __exit ads7846_exit(void)
1429 {
1430         spi_unregister_driver(&ads7846_driver);
1431 }
1432 module_exit(ads7846_exit);
1433
1434 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1435 MODULE_LICENSE("GPL");
1436 MODULE_ALIAS("spi:ads7846");