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 <linux/module.h>
  35 #include <asm/irq.h>
  36
  37 /*
  38  * This code has been heavily tested on a Nokia 770, and lightly
  39  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  40  * TSC2046 is just newer ads7846 silicon.
  41  * Support for ads7843 tested on Atmel at91sam926x-EK.
  42  * Support for ads7845 has only been stubbed in.
  43  * Support for Analog Devices AD7873 and AD7843 tested.
  44  *
  45  * IRQ handling needs a workaround because of a shortcoming in handling
  46  * edge triggered IRQs on some platforms like the OMAP1/2. These
  47  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  48  * have to maintain our own SW IRQ disabled status. This should be
  49  * removed as soon as the affected platform's IRQ handling is fixed.
  50  *
  51  * App note sbaa036 talks in more detail about accurate sampling...
  52  * that ought to help in situations like LCDs inducing noise (which
  53  * can also be helped by using synch signals) and more generally.
  54  * This driver tries to utilize the measures described in the app
  55  * note. The strength of filtering can be set in the board-* specific
  56  * files.
  57  */
  58
  59 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
  60 #define TS_POLL_PERIOD  5       /* ms delay between samples */
  61
  62 /* this driver doesn't aim at the peak continuous sample rate */
  63 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  64
  65 struct ts_event {
  66         /*
  67          * For portability, we can't read 12 bit values using SPI (which
  68          * would make the controller deliver them as native byte order u16
  69          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  70          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  71          */
  72         u16     x;
  73         u16     y;
  74         u16     z1, z2;
  75         bool    ignore;
  76         u8      x_buf[3];
  77         u8      y_buf[3];
  78 };
  79
  80 /*
  81  * We allocate this separately to avoid cache line sharing issues when
  82  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  83  * systems where main memory is not DMA-coherent (most non-x86 boards).
  84  */
  85 struct ads7846_packet {
  86         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  87         u16                     dummy;          /* for the pwrdown read */
  88         struct ts_event         tc;
  89         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
  90         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
  91 };
  92
  93 struct ads7846 {
  94         struct input_dev        *input;
  95         char                    phys[32];
  96         char                    name[32];
  97
  98         struct spi_device       *spi;
  99         struct regulator        *reg;
 100
 101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 102         struct attribute_group  *attr_group;
 103         struct device           *hwmon;
 104 #endif
 105
 106         u16                     model;
 107         u16                     vref_mv;
 108         u16                     vref_delay_usecs;
 109         u16                     x_plate_ohms;
 110         u16                     pressure_max;
 111
 112         bool                    swap_xy;
 113         bool                    use_internal;
 114
 115         struct ads7846_packet   *packet;
 116
 117         struct spi_transfer     xfer[18];
 118         struct spi_message      msg[5];
 119         int                     msg_count;
 120         wait_queue_head_t       wait;
 121
 122         bool                    pendown;
 123
 124         int                     read_cnt;
 125         int                     read_rep;
 126         int                     last_read;
 127
 128         u16                     debounce_max;
 129         u16                     debounce_tol;
 130         u16                     debounce_rep;
 131
 132         u16                     penirq_recheck_delay_usecs;
 133
 134         struct mutex            lock;
 135         bool                    stopped;        /* P: lock */
 136         bool                    disabled;       /* P: lock */
 137         bool                    suspended;      /* P: lock */
 138
 139         int                     (*filter)(void *data, int data_idx, int *val);
 140         void                    *filter_data;
 141         void                    (*filter_cleanup)(void *data);
 142         int                     (*get_pendown_state)(void);
 143         int                     gpio_pendown;
 144
 145         void                    (*wait_for_sync)(void);
 146 };
 147
 148 /* leave chip selected when we're done, for quicker re-select? */
 149 #if     0
 150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 151 #else
 152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 153 #endif
 154
 155 /*--------------------------------------------------------------------------*/
 156
 157 /* The ADS7846 has touchscreen and other sensors.
 158  * Earlier ads784x chips are somewhat compatible.
 159  */
 160 #define ADS_START               (1 << 7)
 161 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 162 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 163 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 164 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 165 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 166 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 167 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 168 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 169 #define ADS_8_BIT               (1 << 3)
 170 #define ADS_12_BIT              (0 << 3)
 171 #define ADS_SER                 (1 << 2)        /* non-differential */
 172 #define ADS_DFR                 (0 << 2)        /* differential */
 173 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 174 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 175 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 176 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 177
 178 #define MAX_12BIT       ((1<<12)-1)
 179
 180 /* leave ADC powered up (disables penirq) between differential samples */
 181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 182         | ADS_12_BIT | ADS_DFR | \
 183         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 184
 185 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 186 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 187 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 188
 189 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 190 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 191
 192 /* single-ended samples need to first power up reference voltage;
 193  * we leave both ADC and VREF powered
 194  */
 195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 196         | ADS_12_BIT | ADS_SER)
 197
 198 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 200
 201 /* Must be called with ts->lock held */
 202 static void ads7846_stop(struct ads7846 *ts)
 203 {
 204         if (!ts->disabled && !ts->suspended) {
 205                 /* Signal IRQ thread to stop polling and disable the handler. */
 206                 ts->stopped = true;
 207                 mb();
 208                 wake_up(&ts->wait);
 209                 disable_irq(ts->spi->irq);
 210         }
 211 }
 212
 213 /* Must be called with ts->lock held */
 214 static void ads7846_restart(struct ads7846 *ts)
 215 {
 216         if (!ts->disabled && !ts->suspended) {
 217                 /* Tell IRQ thread that it may poll the device. */
 218                 ts->stopped = false;
 219                 mb();
 220                 enable_irq(ts->spi->irq);
 221         }
 222 }
 223
 224 /* Must be called with ts->lock held */
 225 static void __ads7846_disable(struct ads7846 *ts)
 226 {
 227         ads7846_stop(ts);
 228         regulator_disable(ts->reg);
 229
 230         /*
 231          * We know the chip's in low power mode since we always
 232          * leave it that way after every request
 233          */
 234 }
 235
 236 /* Must be called with ts->lock held */
 237 static void __ads7846_enable(struct ads7846 *ts)
 238 {
 239         regulator_enable(ts->reg);
 240         ads7846_restart(ts);
 241 }
 242
 243 static void ads7846_disable(struct ads7846 *ts)
 244 {
 245         mutex_lock(&ts->lock);
 246
 247         if (!ts->disabled) {
 248
 249                 if  (!ts->suspended)
 250                         __ads7846_disable(ts);
 251
 252                 ts->disabled = true;
 253         }
 254
 255         mutex_unlock(&ts->lock);
 256 }
 257
 258 static void ads7846_enable(struct ads7846 *ts)
 259 {
 260         mutex_lock(&ts->lock);
 261
 262         if (ts->disabled) {
 263
 264                 ts->disabled = false;
 265
 266                 if (!ts->suspended)
 267                         __ads7846_enable(ts);
 268         }
 269
 270         mutex_unlock(&ts->lock);
 271 }
 272
 273 /*--------------------------------------------------------------------------*/
 274
 275 /*
 276  * Non-touchscreen sensors only use single-ended conversions.
 277  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 278  * ads7846 lets that pin be unconnected, to use internal vREF.
 279  */
 280
 281 struct ser_req {
 282         u8                      ref_on;
 283         u8                      command;
 284         u8                      ref_off;
 285         u16                     scratch;
 286         struct spi_message      msg;
 287         struct spi_transfer     xfer[6];
 288         /*
 289          * DMA (thus cache coherency maintenance) requires the
 290          * transfer buffers to live in their own cache lines.
 291          */
 292         __be16 sample ____cacheline_aligned;
 293 };
 294
 295 struct ads7845_ser_req {
 296         u8                      command[3];
 297         struct spi_message      msg;
 298         struct spi_transfer     xfer[2];
 299         /*
 300          * DMA (thus cache coherency maintenance) requires the
 301          * transfer buffers to live in their own cache lines.
 302          */
 303         u8 sample[3] ____cacheline_aligned;
 304 };
 305
 306 static int ads7846_read12_ser(struct device *dev, unsigned command)
 307 {
 308         struct spi_device *spi = to_spi_device(dev);
 309         struct ads7846 *ts = dev_get_drvdata(dev);
 310         struct ser_req *req;
 311         int status;
 312
 313         req = kzalloc(sizeof *req, GFP_KERNEL);
 314         if (!req)
 315                 return -ENOMEM;
 316
 317         spi_message_init(&req->msg);
 318
 319         /* maybe turn on internal vREF, and let it settle */
 320         if (ts->use_internal) {
 321                 req->ref_on = REF_ON;
 322                 req->xfer[0].tx_buf = &req->ref_on;
 323                 req->xfer[0].len = 1;
 324                 spi_message_add_tail(&req->xfer[0], &req->msg);
 325
 326                 req->xfer[1].rx_buf = &req->scratch;
 327                 req->xfer[1].len = 2;
 328
 329                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 330                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 331                 spi_message_add_tail(&req->xfer[1], &req->msg);
 332
 333                 /* Enable reference voltage */
 334                 command |= ADS_PD10_REF_ON;
 335         }
 336
 337         /* Enable ADC in every case */
 338         command |= ADS_PD10_ADC_ON;
 339
 340         /* take sample */
 341         req->command = (u8) command;
 342         req->xfer[2].tx_buf = &req->command;
 343         req->xfer[2].len = 1;
 344         spi_message_add_tail(&req->xfer[2], &req->msg);
 345
 346         req->xfer[3].rx_buf = &req->sample;
 347         req->xfer[3].len = 2;
 348         spi_message_add_tail(&req->xfer[3], &req->msg);
 349
 350         /* REVISIT:  take a few more samples, and compare ... */
 351
 352         /* converter in low power mode & enable PENIRQ */
 353         req->ref_off = PWRDOWN;
 354         req->xfer[4].tx_buf = &req->ref_off;
 355         req->xfer[4].len = 1;
 356         spi_message_add_tail(&req->xfer[4], &req->msg);
 357
 358         req->xfer[5].rx_buf = &req->scratch;
 359         req->xfer[5].len = 2;
 360         CS_CHANGE(req->xfer[5]);
 361         spi_message_add_tail(&req->xfer[5], &req->msg);
 362
 363         mutex_lock(&ts->lock);
 364         ads7846_stop(ts);
 365         status = spi_sync(spi, &req->msg);
 366         ads7846_restart(ts);
 367         mutex_unlock(&ts->lock);
 368
 369         if (status == 0) {
 370                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 371                 status = be16_to_cpu(req->sample);
 372                 status = status >> 3;
 373                 status &= 0x0fff;
 374         }
 375
 376         kfree(req);
 377         return status;
 378 }
 379
 380 static int ads7845_read12_ser(struct device *dev, unsigned command)
 381 {
 382         struct spi_device *spi = to_spi_device(dev);
 383         struct ads7846 *ts = dev_get_drvdata(dev);
 384         struct ads7845_ser_req *req;
 385         int status;
 386
 387         req = kzalloc(sizeof *req, GFP_KERNEL);
 388         if (!req)
 389                 return -ENOMEM;
 390
 391         spi_message_init(&req->msg);
 392
 393         req->command[0] = (u8) command;
 394         req->xfer[0].tx_buf = req->command;
 395         req->xfer[0].rx_buf = req->sample;
 396         req->xfer[0].len = 3;
 397         spi_message_add_tail(&req->xfer[0], &req->msg);
 398
 399         mutex_lock(&ts->lock);
 400         ads7846_stop(ts);
 401         status = spi_sync(spi, &req->msg);
 402         ads7846_restart(ts);
 403         mutex_unlock(&ts->lock);
 404
 405         if (status == 0) {
 406                 /* BE12 value, then padding */
 407                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
 408                 status = status >> 3;
 409                 status &= 0x0fff;
 410         }
 411
 412         kfree(req);
 413         return status;
 414 }
 415
 416 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 417
 418 #define SHOW(name, var, adjust) static ssize_t \
 419 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 420 { \
 421         struct ads7846 *ts = dev_get_drvdata(dev); \
 422         ssize_t v = ads7846_read12_ser(dev, \
 423                         READ_12BIT_SER(var)); \
 424         if (v < 0) \
 425                 return v; \
 426         return sprintf(buf, "%u\n", adjust(ts, v)); \
 427 } \
 428 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 429
 430
 431 /* Sysfs conventions report temperatures in millidegrees Celsius.
 432  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 433  * accuracy scheme without calibration data.  For now we won't try either;
 434  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 435  */
 436 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 437 {
 438         return v;
 439 }
 440
 441 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 442 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 443
 444
 445 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 446  * if we know vREF.  userspace may need to scale vAUX to match the board's
 447  * external resistors; we assume that vBATT only uses the internal ones.
 448  */
 449 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 450 {
 451         unsigned retval = v;
 452
 453         /* external resistors may scale vAUX into 0..vREF */
 454         retval *= ts->vref_mv;
 455         retval = retval >> 12;
 456
 457         return retval;
 458 }
 459
 460 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 461 {
 462         unsigned retval = vaux_adjust(ts, v);
 463
 464         /* ads7846 has a resistor ladder to scale this signal down */
 465         if (ts->model == 7846)
 466                 retval *= 4;
 467
 468         return retval;
 469 }
 470
 471 SHOW(in0_input, vaux, vaux_adjust)
 472 SHOW(in1_input, vbatt, vbatt_adjust)
 473
 474 static struct attribute *ads7846_attributes[] = {
 475         &dev_attr_temp0.attr,
 476         &dev_attr_temp1.attr,
 477         &dev_attr_in0_input.attr,
 478         &dev_attr_in1_input.attr,
 479         NULL,
 480 };
 481
 482 static struct attribute_group ads7846_attr_group = {
 483         .attrs = ads7846_attributes,
 484 };
 485
 486 static struct attribute *ads7843_attributes[] = {
 487         &dev_attr_in0_input.attr,
 488         &dev_attr_in1_input.attr,
 489         NULL,
 490 };
 491
 492 static struct attribute_group ads7843_attr_group = {
 493         .attrs = ads7843_attributes,
 494 };
 495
 496 static struct attribute *ads7845_attributes[] = {
 497         &dev_attr_in0_input.attr,
 498         NULL,
 499 };
 500
 501 static struct attribute_group ads7845_attr_group = {
 502         .attrs = ads7845_attributes,
 503 };
 504
 505 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 506 {
 507         struct device *hwmon;
 508         int err;
 509
 510         /* hwmon sensors need a reference voltage */
 511         switch (ts->model) {
 512         case 7846:
 513                 if (!ts->vref_mv) {
 514                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 515                         ts->vref_mv = 2500;
 516                         ts->use_internal = true;
 517                 }
 518                 break;
 519         case 7845:
 520         case 7843:
 521                 if (!ts->vref_mv) {
 522                         dev_warn(&spi->dev,
 523                                 "external vREF for ADS%d not specified\n",
 524                                 ts->model);
 525                         return 0;
 526                 }
 527                 break;
 528         }
 529
 530         /* different chips have different sensor groups */
 531         switch (ts->model) {
 532         case 7846:
 533                 ts->attr_group = &ads7846_attr_group;
 534                 break;
 535         case 7845:
 536                 ts->attr_group = &ads7845_attr_group;
 537                 break;
 538         case 7843:
 539                 ts->attr_group = &ads7843_attr_group;
 540                 break;
 541         default:
 542                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 543                 return 0;
 544         }
 545
 546         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 547         if (err)
 548                 return err;
 549
 550         hwmon = hwmon_device_register(&spi->dev);
 551         if (IS_ERR(hwmon)) {
 552                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 553                 return PTR_ERR(hwmon);
 554         }
 555
 556         ts->hwmon = hwmon;
 557         return 0;
 558 }
 559
 560 static void ads784x_hwmon_unregister(struct spi_device *spi,
 561                                      struct ads7846 *ts)
 562 {
 563         if (ts->hwmon) {
 564                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 565                 hwmon_device_unregister(ts->hwmon);
 566         }
 567 }
 568
 569 #else
 570 static inline int ads784x_hwmon_register(struct spi_device *spi,
 571                                          struct ads7846 *ts)
 572 {
 573         return 0;
 574 }
 575
 576 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 577                                             struct ads7846 *ts)
 578 {
 579 }
 580 #endif
 581
 582 static ssize_t ads7846_pen_down_show(struct device *dev,
 583                                      struct device_attribute *attr, char *buf)
 584 {
 585         struct ads7846 *ts = dev_get_drvdata(dev);
 586
 587         return sprintf(buf, "%u\n", ts->pendown);
 588 }
 589
 590 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 591
 592 static ssize_t ads7846_disable_show(struct device *dev,
 593                                      struct device_attribute *attr, char *buf)
 594 {
 595         struct ads7846 *ts = dev_get_drvdata(dev);
 596
 597         return sprintf(buf, "%u\n", ts->disabled);
 598 }
 599
 600 static ssize_t ads7846_disable_store(struct device *dev,
 601                                      struct device_attribute *attr,
 602                                      const char *buf, size_t count)
 603 {
 604         struct ads7846 *ts = dev_get_drvdata(dev);
 605         unsigned long i;
 606
 607         if (strict_strtoul(buf, 10, &i))
 608                 return -EINVAL;
 609
 610         if (i)
 611                 ads7846_disable(ts);
 612         else
 613                 ads7846_enable(ts);
 614
 615         return count;
 616 }
 617
 618 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 619
 620 static struct attribute *ads784x_attributes[] = {
 621         &dev_attr_pen_down.attr,
 622         &dev_attr_disable.attr,
 623         NULL,
 624 };
 625
 626 static struct attribute_group ads784x_attr_group = {
 627         .attrs = ads784x_attributes,
 628 };
 629
 630 /*--------------------------------------------------------------------------*/
 631
 632 static int get_pendown_state(struct ads7846 *ts)
 633 {
 634         if (ts->get_pendown_state)
 635                 return ts->get_pendown_state();
 636
 637         return !gpio_get_value(ts->gpio_pendown);
 638 }
 639
 640 static void null_wait_for_sync(void)
 641 {
 642 }
 643
 644 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 645 {
 646         struct ads7846 *ts = ads;
 647
 648         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 649                 /* Start over collecting consistent readings. */
 650                 ts->read_rep = 0;
 651                 /*
 652                  * Repeat it, if this was the first read or the read
 653                  * wasn't consistent enough.
 654                  */
 655                 if (ts->read_cnt < ts->debounce_max) {
 656                         ts->last_read = *val;
 657                         ts->read_cnt++;
 658                         return ADS7846_FILTER_REPEAT;
 659                 } else {
 660                         /*
 661                          * Maximum number of debouncing reached and still
 662                          * not enough number of consistent readings. Abort
 663                          * the whole sample, repeat it in the next sampling
 664                          * period.
 665                          */
 666                         ts->read_cnt = 0;
 667                         return ADS7846_FILTER_IGNORE;
 668                 }
 669         } else {
 670                 if (++ts->read_rep > ts->debounce_rep) {
 671                         /*
 672                          * Got a good reading for this coordinate,
 673                          * go for the next one.
 674                          */
 675                         ts->read_cnt = 0;
 676                         ts->read_rep = 0;
 677                         return ADS7846_FILTER_OK;
 678                 } else {
 679                         /* Read more values that are consistent. */
 680                         ts->read_cnt++;
 681                         return ADS7846_FILTER_REPEAT;
 682                 }
 683         }
 684 }
 685
 686 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 687 {
 688         return ADS7846_FILTER_OK;
 689 }
 690
 691 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 692 {
 693         struct spi_transfer *t =
 694                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 695
 696         if (ts->model == 7845) {
 697                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
 698         } else {
 699                 /*
 700                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
 701                  * padding; built from two 8 bit values written msb-first.
 702                  */
 703                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
 704         }
 705 }
 706
 707 static void ads7846_update_value(struct spi_message *m, int val)
 708 {
 709         struct spi_transfer *t =
 710                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 711
 712         *(u16 *)t->rx_buf = val;
 713 }
 714
 715 static void ads7846_read_state(struct ads7846 *ts)
 716 {
 717         struct ads7846_packet *packet = ts->packet;
 718         struct spi_message *m;
 719         int msg_idx = 0;
 720         int val;
 721         int action;
 722         int error;
 723
 724         while (msg_idx < ts->msg_count) {
 725
 726                 ts->wait_for_sync();
 727
 728                 m = &ts->msg[msg_idx];
 729                 error = spi_sync(ts->spi, m);
 730                 if (error) {
 731                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
 732                         packet->tc.ignore = true;
 733                         return;
 734                 }
 735
 736                 /*
 737                  * Last message is power down request, no need to convert
 738                  * or filter the value.
 739                  */
 740                 if (msg_idx < ts->msg_count - 1) {
 741
 742                         val = ads7846_get_value(ts, m);
 743
 744                         action = ts->filter(ts->filter_data, msg_idx, &val);
 745                         switch (action) {
 746                         case ADS7846_FILTER_REPEAT:
 747                                 continue;
 748
 749                         case ADS7846_FILTER_IGNORE:
 750                                 packet->tc.ignore = true;
 751                                 msg_idx = ts->msg_count - 1;
 752                                 continue;
 753
 754                         case ADS7846_FILTER_OK:
 755                                 ads7846_update_value(m, val);
 756                                 packet->tc.ignore = false;
 757                                 msg_idx++;
 758                                 break;
 759
 760                         default:
 761                                 BUG();
 762                         }
 763                 } else {
 764                         msg_idx++;
 765                 }
 766         }
 767 }
 768
 769 static void ads7846_report_state(struct ads7846 *ts)
 770 {
 771         struct ads7846_packet *packet = ts->packet;
 772         unsigned int Rt;
 773         u16 x, y, z1, z2;
 774
 775         /*
 776          * ads7846_get_value() does in-place conversion (including byte swap)
 777          * from on-the-wire format as part of debouncing to get stable
 778          * readings.
 779          */
 780         if (ts->model == 7845) {
 781                 x = *(u16 *)packet->tc.x_buf;
 782                 y = *(u16 *)packet->tc.y_buf;
 783                 z1 = 0;
 784                 z2 = 0;
 785         } else {
 786                 x = packet->tc.x;
 787                 y = packet->tc.y;
 788                 z1 = packet->tc.z1;
 789                 z2 = packet->tc.z2;
 790         }
 791
 792         /* range filtering */
 793         if (x == MAX_12BIT)
 794                 x = 0;
 795
 796         if (ts->model == 7843) {
 797                 Rt = ts->pressure_max / 2;
 798         } else if (ts->model == 7845) {
 799                 if (get_pendown_state(ts))
 800                         Rt = ts->pressure_max / 2;
 801                 else
 802                         Rt = 0;
 803                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 804         } else if (likely(x && z1)) {
 805                 /* compute touch pressure resistance using equation #2 */
 806                 Rt = z2;
 807                 Rt -= z1;
 808                 Rt *= x;
 809                 Rt *= ts->x_plate_ohms;
 810                 Rt /= z1;
 811                 Rt = (Rt + 2047) >> 12;
 812         } else {
 813                 Rt = 0;
 814         }
 815
 816         /*
 817          * Sample found inconsistent by debouncing or pressure is beyond
 818          * the maximum. Don't report it to user space, repeat at least
 819          * once more the measurement
 820          */
 821         if (packet->tc.ignore || Rt > ts->pressure_max) {
 822                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 823                          packet->tc.ignore, Rt);
 824                 return;
 825         }
 826
 827         /*
 828          * Maybe check the pendown state before reporting. This discards
 829          * false readings when the pen is lifted.
 830          */
 831         if (ts->penirq_recheck_delay_usecs) {
 832                 udelay(ts->penirq_recheck_delay_usecs);
 833                 if (!get_pendown_state(ts))
 834                         Rt = 0;
 835         }
 836
 837         /*
 838          * NOTE: We can't rely on the pressure to determine the pen down
 839          * state, even this controller has a pressure sensor. The pressure
 840          * value can fluctuate for quite a while after lifting the pen and
 841          * in some cases may not even settle at the expected value.
 842          *
 843          * The only safe way to check for the pen up condition is in the
 844          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 845          */
 846         if (Rt) {
 847                 struct input_dev *input = ts->input;
 848
 849                 if (ts->swap_xy)
 850                         swap(x, y);
 851
 852                 if (!ts->pendown) {
 853                         input_report_key(input, BTN_TOUCH, 1);
 854                         ts->pendown = true;
 855                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 856                 }
 857
 858                 input_report_abs(input, ABS_X, x);
 859                 input_report_abs(input, ABS_Y, y);
 860                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 861
 862                 input_sync(input);
 863                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 864         }
 865 }
 866
 867 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 868 {
 869         struct ads7846 *ts = handle;
 870
 871         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 872 }
 873
 874
 875 static irqreturn_t ads7846_irq(int irq, void *handle)
 876 {
 877         struct ads7846 *ts = handle;
 878
 879         disable_irq_nosync(ts->spi->irq);
 880
 881         /* Start with a small delay before checking pendown state */
 882         msleep(TS_POLL_DELAY);
 883
 884         while (!ts->stopped && get_pendown_state(ts)) {
 885
 886                 /* pen is down, continue with the measurement */
 887                 ads7846_read_state(ts);
 888
 889                 if (!ts->stopped)
 890                         ads7846_report_state(ts);
 891
 892                 wait_event_timeout(ts->wait, ts->stopped,
 893                                    msecs_to_jiffies(TS_POLL_PERIOD));
 894         }
 895
 896         if (ts->pendown) {
 897                 struct input_dev *input = ts->input;
 898
 899                 input_report_key(input, BTN_TOUCH, 0);
 900                 input_report_abs(input, ABS_PRESSURE, 0);
 901                 input_sync(input);
 902
 903                 ts->pendown = false;
 904                 dev_vdbg(&ts->spi->dev, "UP\n");
 905         }
 906
 907         mutex_lock(&ts->lock);
 908         if (!ts->stopped)
 909                 enable_irq(ts->spi->irq);
 910         mutex_unlock(&ts->lock);
 911
 912         return IRQ_HANDLED;
 913 }
 914
 915 #ifdef CONFIG_PM_SLEEP
 916 static int ads7846_suspend(struct device *dev)
 917 {
 918         struct ads7846 *ts = dev_get_drvdata(dev);
 919
 920         mutex_lock(&ts->lock);
 921
 922         if (!ts->suspended) {
 923
 924                 if (!ts->disabled)
 925                         __ads7846_disable(ts);
 926
 927                 if (device_may_wakeup(&ts->spi->dev))
 928                         enable_irq_wake(ts->spi->irq);
 929
 930                 ts->suspended = true;
 931         }
 932
 933         mutex_unlock(&ts->lock);
 934
 935         return 0;
 936 }
 937
 938 static int ads7846_resume(struct device *dev)
 939 {
 940         struct ads7846 *ts = dev_get_drvdata(dev);
 941
 942         mutex_lock(&ts->lock);
 943
 944         if (ts->suspended) {
 945
 946                 ts->suspended = false;
 947
 948                 if (device_may_wakeup(&ts->spi->dev))
 949                         disable_irq_wake(ts->spi->irq);
 950
 951                 if (!ts->disabled)
 952                         __ads7846_enable(ts);
 953         }
 954
 955         mutex_unlock(&ts->lock);
 956
 957         return 0;
 958 }
 959 #endif
 960
 961 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 962
 963 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
 964 {
 965         struct ads7846_platform_data *pdata = spi->dev.platform_data;
 966         int err;
 967
 968         /*
 969          * REVISIT when the irq can be triggered active-low, or if for some
 970          * reason the touchscreen isn't hooked up, we don't need to access
 971          * the pendown state.
 972          */
 973
 974         if (pdata->get_pendown_state) {
 975                 ts->get_pendown_state = pdata->get_pendown_state;
 976         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 977
 978                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 979                                        "ads7846_pendown");
 980                 if (err) {
 981                         dev_err(&spi->dev,
 982                                 "failed to request/setup pendown GPIO%d: %d\n",
 983                                 pdata->gpio_pendown, err);
 984                         return err;
 985                 }
 986
 987                 ts->gpio_pendown = pdata->gpio_pendown;
 988
 989         } else {
 990                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 991                 return -EINVAL;
 992         }
 993
 994         return 0;
 995 }
 996
 997 /*
 998  * Set up the transfers to read touchscreen state; this assumes we
 999  * use formula #2 for pressure, not #3.
1000  */
1001 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
1002                                 const struct ads7846_platform_data *pdata)
1003 {
1004         struct spi_message *m = &ts->msg[0];
1005         struct spi_transfer *x = ts->xfer;
1006         struct ads7846_packet *packet = ts->packet;
1007         int vref = pdata->keep_vref_on;
1008
1009         if (ts->model == 7873) {
1010                 /*
1011                  * The AD7873 is almost identical to the ADS7846
1012                  * keep VREF off during differential/ratiometric
1013                  * conversion modes.
1014                  */
1015                 ts->model = 7846;
1016                 vref = 0;
1017         }
1018
1019         ts->msg_count = 1;
1020         spi_message_init(m);
1021         m->context = ts;
1022
1023         if (ts->model == 7845) {
1024                 packet->read_y_cmd[0] = READ_Y(vref);
1025                 packet->read_y_cmd[1] = 0;
1026                 packet->read_y_cmd[2] = 0;
1027                 x->tx_buf = &packet->read_y_cmd[0];
1028                 x->rx_buf = &packet->tc.y_buf[0];
1029                 x->len = 3;
1030                 spi_message_add_tail(x, m);
1031         } else {
1032                 /* y- still on; turn on only y+ (and ADC) */
1033                 packet->read_y = READ_Y(vref);
1034                 x->tx_buf = &packet->read_y;
1035                 x->len = 1;
1036                 spi_message_add_tail(x, m);
1037
1038                 x++;
1039                 x->rx_buf = &packet->tc.y;
1040                 x->len = 2;
1041                 spi_message_add_tail(x, m);
1042         }
1043
1044         /*
1045          * The first sample after switching drivers can be low quality;
1046          * optionally discard it, using a second one after the signals
1047          * have had enough time to stabilize.
1048          */
1049         if (pdata->settle_delay_usecs) {
1050                 x->delay_usecs = pdata->settle_delay_usecs;
1051
1052                 x++;
1053                 x->tx_buf = &packet->read_y;
1054                 x->len = 1;
1055                 spi_message_add_tail(x, m);
1056
1057                 x++;
1058                 x->rx_buf = &packet->tc.y;
1059                 x->len = 2;
1060                 spi_message_add_tail(x, m);
1061         }
1062
1063         ts->msg_count++;
1064         m++;
1065         spi_message_init(m);
1066         m->context = ts;
1067
1068         if (ts->model == 7845) {
1069                 x++;
1070                 packet->read_x_cmd[0] = READ_X(vref);
1071                 packet->read_x_cmd[1] = 0;
1072                 packet->read_x_cmd[2] = 0;
1073                 x->tx_buf = &packet->read_x_cmd[0];
1074                 x->rx_buf = &packet->tc.x_buf[0];
1075                 x->len = 3;
1076                 spi_message_add_tail(x, m);
1077         } else {
1078                 /* turn y- off, x+ on, then leave in lowpower */
1079                 x++;
1080                 packet->read_x = READ_X(vref);
1081                 x->tx_buf = &packet->read_x;
1082                 x->len = 1;
1083                 spi_message_add_tail(x, m);
1084
1085                 x++;
1086                 x->rx_buf = &packet->tc.x;
1087                 x->len = 2;
1088                 spi_message_add_tail(x, m);
1089         }
1090
1091         /* ... maybe discard first sample ... */
1092         if (pdata->settle_delay_usecs) {
1093                 x->delay_usecs = pdata->settle_delay_usecs;
1094
1095                 x++;
1096                 x->tx_buf = &packet->read_x;
1097                 x->len = 1;
1098                 spi_message_add_tail(x, m);
1099
1100                 x++;
1101                 x->rx_buf = &packet->tc.x;
1102                 x->len = 2;
1103                 spi_message_add_tail(x, m);
1104         }
1105
1106         /* turn y+ off, x- on; we'll use formula #2 */
1107         if (ts->model == 7846) {
1108                 ts->msg_count++;
1109                 m++;
1110                 spi_message_init(m);
1111                 m->context = ts;
1112
1113                 x++;
1114                 packet->read_z1 = READ_Z1(vref);
1115                 x->tx_buf = &packet->read_z1;
1116                 x->len = 1;
1117                 spi_message_add_tail(x, m);
1118
1119                 x++;
1120                 x->rx_buf = &packet->tc.z1;
1121                 x->len = 2;
1122                 spi_message_add_tail(x, m);
1123
1124                 /* ... maybe discard first sample ... */
1125                 if (pdata->settle_delay_usecs) {
1126                         x->delay_usecs = pdata->settle_delay_usecs;
1127
1128                         x++;
1129                         x->tx_buf = &packet->read_z1;
1130                         x->len = 1;
1131                         spi_message_add_tail(x, m);
1132
1133                         x++;
1134                         x->rx_buf = &packet->tc.z1;
1135                         x->len = 2;
1136                         spi_message_add_tail(x, m);
1137                 }
1138
1139                 ts->msg_count++;
1140                 m++;
1141                 spi_message_init(m);
1142                 m->context = ts;
1143
1144                 x++;
1145                 packet->read_z2 = READ_Z2(vref);
1146                 x->tx_buf = &packet->read_z2;
1147                 x->len = 1;
1148                 spi_message_add_tail(x, m);
1149
1150                 x++;
1151                 x->rx_buf = &packet->tc.z2;
1152                 x->len = 2;
1153                 spi_message_add_tail(x, m);
1154
1155                 /* ... maybe discard first sample ... */
1156                 if (pdata->settle_delay_usecs) {
1157                         x->delay_usecs = pdata->settle_delay_usecs;
1158
1159                         x++;
1160                         x->tx_buf = &packet->read_z2;
1161                         x->len = 1;
1162                         spi_message_add_tail(x, m);
1163
1164                         x++;
1165                         x->rx_buf = &packet->tc.z2;
1166                         x->len = 2;
1167                         spi_message_add_tail(x, m);
1168                 }
1169         }
1170
1171         /* power down */
1172         ts->msg_count++;
1173         m++;
1174         spi_message_init(m);
1175         m->context = ts;
1176
1177         if (ts->model == 7845) {
1178                 x++;
1179                 packet->pwrdown_cmd[0] = PWRDOWN;
1180                 packet->pwrdown_cmd[1] = 0;
1181                 packet->pwrdown_cmd[2] = 0;
1182                 x->tx_buf = &packet->pwrdown_cmd[0];
1183                 x->len = 3;
1184         } else {
1185                 x++;
1186                 packet->pwrdown = PWRDOWN;
1187                 x->tx_buf = &packet->pwrdown;
1188                 x->len = 1;
1189                 spi_message_add_tail(x, m);
1190
1191                 x++;
1192                 x->rx_buf = &packet->dummy;
1193                 x->len = 2;
1194         }
1195
1196         CS_CHANGE(*x);
1197         spi_message_add_tail(x, m);
1198 }
1199
1200 static int __devinit ads7846_probe(struct spi_device *spi)
1201 {
1202         struct ads7846 *ts;
1203         struct ads7846_packet *packet;
1204         struct input_dev *input_dev;
1205         struct ads7846_platform_data *pdata = spi->dev.platform_data;
1206         unsigned long irq_flags;
1207         int err;
1208
1209         if (!spi->irq) {
1210                 dev_dbg(&spi->dev, "no IRQ?\n");
1211                 return -ENODEV;
1212         }
1213
1214         if (!pdata) {
1215                 dev_dbg(&spi->dev, "no platform data?\n");
1216                 return -ENODEV;
1217         }
1218
1219         /* don't exceed max specified sample rate */
1220         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1221                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1222                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1223                 return -EINVAL;
1224         }
1225
1226         /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1227          * that even if the hardware can do that, the SPI controller driver
1228          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1229          */
1230         spi->bits_per_word = 8;
1231         spi->mode = SPI_MODE_0;
1232         err = spi_setup(spi);
1233         if (err < 0)
1234                 return err;
1235
1236         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1237         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1238         input_dev = input_allocate_device();
1239         if (!ts || !packet || !input_dev) {
1240                 err = -ENOMEM;
1241                 goto err_free_mem;
1242         }
1243
1244         dev_set_drvdata(&spi->dev, ts);
1245
1246         ts->packet = packet;
1247         ts->spi = spi;
1248         ts->input = input_dev;
1249         ts->vref_mv = pdata->vref_mv;
1250         ts->swap_xy = pdata->swap_xy;
1251
1252         mutex_init(&ts->lock);
1253         init_waitqueue_head(&ts->wait);
1254
1255         ts->model = pdata->model ? : 7846;
1256         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1257         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1258         ts->pressure_max = pdata->pressure_max ? : ~0;
1259
1260         if (pdata->filter != NULL) {
1261                 if (pdata->filter_init != NULL) {
1262                         err = pdata->filter_init(pdata, &ts->filter_data);
1263                         if (err < 0)
1264                                 goto err_free_mem;
1265                 }
1266                 ts->filter = pdata->filter;
1267                 ts->filter_cleanup = pdata->filter_cleanup;
1268         } else if (pdata->debounce_max) {
1269                 ts->debounce_max = pdata->debounce_max;
1270                 if (ts->debounce_max < 2)
1271                         ts->debounce_max = 2;
1272                 ts->debounce_tol = pdata->debounce_tol;
1273                 ts->debounce_rep = pdata->debounce_rep;
1274                 ts->filter = ads7846_debounce_filter;
1275                 ts->filter_data = ts;
1276         } else {
1277                 ts->filter = ads7846_no_filter;
1278         }
1279
1280         err = ads7846_setup_pendown(spi, ts);
1281         if (err)
1282                 goto err_cleanup_filter;
1283
1284         if (pdata->penirq_recheck_delay_usecs)
1285                 ts->penirq_recheck_delay_usecs =
1286                                 pdata->penirq_recheck_delay_usecs;
1287
1288         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1289
1290         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1291         snprintf(ts->name, sizeof(ts->name), "touchscreen");
1292
1293         input_dev->name = ts->name;
1294         input_dev->phys = ts->phys;
1295         input_dev->dev.parent = &spi->dev;
1296
1297         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1298         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1299         input_set_abs_params(input_dev, ABS_X,
1300                         pdata->x_min ? : 0,
1301                         pdata->x_max ? : MAX_12BIT,
1302                         0, 0);
1303         input_set_abs_params(input_dev, ABS_Y,
1304                         pdata->y_min ? : 0,
1305                         pdata->y_max ? : MAX_12BIT,
1306                         0, 0);
1307         input_set_abs_params(input_dev, ABS_PRESSURE,
1308                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1309
1310         ads7846_setup_spi_msg(ts, pdata);
1311
1312         ts->reg = regulator_get(&spi->dev, "vcc");
1313         if (IS_ERR(ts->reg)) {
1314                 err = PTR_ERR(ts->reg);
1315                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1316                 goto err_free_gpio;
1317         }
1318
1319         err = regulator_enable(ts->reg);
1320         if (err) {
1321                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1322                 goto err_put_regulator;
1323         }
1324
1325         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1326         irq_flags |= IRQF_ONESHOT;
1327
1328         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1329                                    irq_flags, spi->dev.driver->name, ts);
1330         if (err && !pdata->irq_flags) {
1331                 dev_info(&spi->dev,
1332                         "trying pin change workaround on irq %d\n", spi->irq);
1333                 irq_flags |= IRQF_TRIGGER_RISING;
1334                 err = request_threaded_irq(spi->irq,
1335                                   ads7846_hard_irq, ads7846_irq,
1336                                   irq_flags, spi->dev.driver->name, ts);
1337         }
1338
1339         if (err) {
1340                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1341                 goto err_disable_regulator;
1342         }
1343
1344         err = ads784x_hwmon_register(spi, ts);
1345         if (err)
1346                 goto err_free_irq;
1347
1348         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1349
1350         /*
1351          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1352          * the touchscreen, in case it's not connected.
1353          */
1354         if (ts->model == 7845)
1355                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1356         else
1357                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1358
1359         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1360         if (err)
1361                 goto err_remove_hwmon;
1362
1363         err = input_register_device(input_dev);
1364         if (err)
1365                 goto err_remove_attr_group;
1366
1367         device_init_wakeup(&spi->dev, pdata->wakeup);
1368
1369         return 0;
1370
1371  err_remove_attr_group:
1372         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1373  err_remove_hwmon:
1374         ads784x_hwmon_unregister(spi, ts);
1375  err_free_irq:
1376         free_irq(spi->irq, ts);
1377  err_disable_regulator:
1378         regulator_disable(ts->reg);
1379  err_put_regulator:
1380         regulator_put(ts->reg);
1381  err_free_gpio:
1382         if (!ts->get_pendown_state)
1383                 gpio_free(ts->gpio_pendown);
1384  err_cleanup_filter:
1385         if (ts->filter_cleanup)
1386                 ts->filter_cleanup(ts->filter_data);
1387  err_free_mem:
1388         input_free_device(input_dev);
1389         kfree(packet);
1390         kfree(ts);
1391         return err;
1392 }
1393
1394 static int __devexit ads7846_remove(struct spi_device *spi)
1395 {
1396         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1397
1398         device_init_wakeup(&spi->dev, false);
1399
1400         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1401
1402         ads7846_disable(ts);
1403         free_irq(ts->spi->irq, ts);
1404
1405         input_unregister_device(ts->input);
1406
1407         ads784x_hwmon_unregister(spi, ts);
1408
1409         regulator_disable(ts->reg);
1410         regulator_put(ts->reg);
1411
1412         if (!ts->get_pendown_state) {
1413                 /*
1414                  * If we are not using specialized pendown method we must
1415                  * have been relying on gpio we set up ourselves.
1416                  */
1417                 gpio_free(ts->gpio_pendown);
1418         }
1419
1420         if (ts->filter_cleanup)
1421                 ts->filter_cleanup(ts->filter_data);
1422
1423         kfree(ts->packet);
1424         kfree(ts);
1425
1426         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1427
1428         return 0;
1429 }
1430
1431 static struct spi_driver ads7846_driver = {
1432         .driver = {
1433                 .name   = "ads7846",
1434                 .bus    = &spi_bus_type,
1435                 .owner  = THIS_MODULE,
1436                 .pm     = &ads7846_pm,
1437         },
1438         .probe          = ads7846_probe,
1439         .remove         = __devexit_p(ads7846_remove),
1440 };
1441
1442 static int __init ads7846_init(void)
1443 {
1444         return spi_register_driver(&ads7846_driver);
1445 }
1446 module_init(ads7846_init);
1447
1448 static void __exit ads7846_exit(void)
1449 {
1450         spi_unregister_driver(&ads7846_driver);
1451 }
1452 module_exit(ads7846_exit);
1453
1454 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1455 MODULE_LICENSE("GPL");
1456 MODULE_ALIAS("spi:ads7846");