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