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