drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  * Copyright (c) 2006 Imre Deak <imre.deak@nokia.com>
   6  *
   7  * Using code from:
   8  *  - corgi_ts.c
   9  *      Copyright (C) 2004-2005 Richard Purdie
  10  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  11  *      Copyright (C) 2002 MontaVista Software
  12  *      Copyright (C) 2004 Texas Instruments
  13  *      Copyright (C) 2005 Dirk Behme
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License version 2 as
  17  *  published by the Free Software Foundation.
  18  */
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/delay.h>
  22 #include <linux/input.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/slab.h>
  25 #include <linux/spi/spi.h>
  26 #include <linux/spi/ads7846.h>
  27
  28 #ifdef  CONFIG_ARM
  29 #include <asm/mach-types.h>
  30 #ifdef  CONFIG_ARCH_OMAP
  31 #include <asm/arch/gpio.h>
  32 #endif
  33 #endif
  34
  35
  36 /*
  37  * This code has been heavily tested on a Nokia 770, and lightly
  38  * tested on an other ads7846 device.
  39  * Support for ads7843 and ads7845 has only been stubbed in.
  40  *
  41  * Not yet done:  How accurate are the temperature and voltage
  42  * readings? (System-specific calibration should support
  43  * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
  44  *
  45  * IRQ handling needs a workaround because of a shortcoming in handling
  46  * edge triggered IRQs on some platforms like the OMAP1/2. These
  47  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  48  * have to maintain our own SW IRQ disabled status. This should be
  49  * removed as soon as the affected platforms' IRQ handling is fixed.
  50  *
  51  * app note sbaa036 talks in more detail about accurate sampling...
  52  * that ought to help in situations like LCDs inducing noise (which
  53  * can also be helped by using synch signals) and more generally.
  54  * This driver tries to utilize the measures described in the app
  55  * note. The strength of filtering can be set in the board-* specific
  56  * files.
  57  */
  58
  59 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
  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         /* For portability, we can't read 12 bit values using SPI (which
  66          * would make the controller deliver them as native byteorder u16
  67          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  68          * which need byteswapping then range adjustment.
  69          */
  70         __be16 x;
  71         __be16 y;
  72         __be16 z1, z2;
  73 };
  74
  75 struct ads7846 {
  76         struct input_dev        *input;
  77         char                    phys[32];
  78
  79         struct spi_device       *spi;
  80         u16                     model;
  81         u16                     vref_delay_usecs;
  82         u16                     x_plate_ohms;
  83
  84         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  85         u16                     dummy;          /* for the pwrdown read */
  86         struct ts_event         tc;
  87
  88         struct spi_transfer     xfer[10];
  89         struct spi_message      msg[5];
  90         int                     msg_idx;
  91         int                     read_cnt;
  92         int                     last_read;
  93
  94         u16                     debounce_max;
  95         u16                     debounce_tol;
  96
  97         spinlock_t              lock;
  98         struct timer_list       timer;          /* P: lock */
  99         unsigned                pendown:1;      /* P: lock */
 100         unsigned                pending:1;      /* P: lock */
 101 // FIXME remove "irq_disabled"
 102         unsigned                irq_disabled:1; /* P: lock */
 103         unsigned                disabled:1;
 104 };
 105
 106 /* leave chip selected when we're done, for quicker re-select? */
 107 #if     0
 108 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 109 #else
 110 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 111 #endif
 112
 113 /*--------------------------------------------------------------------------*/
 114
 115 /* The ADS7846 has touchscreen and other sensors.
 116  * Earlier ads784x chips are somewhat compatible.
 117  */
 118 #define ADS_START               (1 << 7)
 119 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 120 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 121 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 122 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 123 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 124 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 125 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 126 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 127 #define ADS_8_BIT               (1 << 3)
 128 #define ADS_12_BIT              (0 << 3)
 129 #define ADS_SER                 (1 << 2)        /* non-differential */
 130 #define ADS_DFR                 (0 << 2)        /* differential */
 131 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 132 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 133 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 134 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 135
 136 #define MAX_12BIT       ((1<<12)-1)
 137
 138 /* leave ADC powered up (disables penirq) between differential samples */
 139 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 140         | ADS_12_BIT | ADS_DFR)
 141
 142 #define READ_Y  (READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
 143 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
 144 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
 145
 146 #define READ_X  (READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)
 147 #define PWRDOWN (READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)   /* LAST */
 148
 149 /* single-ended samples need to first power up reference voltage;
 150  * we leave both ADC and VREF powered
 151  */
 152 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 153         | ADS_12_BIT | ADS_SER)
 154
 155 #define REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
 156 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 157
 158 /*--------------------------------------------------------------------------*/
 159
 160 /*
 161  * Non-touchscreen sensors only use single-ended conversions.
 162  */
 163
 164 struct ser_req {
 165         u8                      ref_on;
 166         u8                      command;
 167         u8                      ref_off;
 168         u16                     scratch;
 169         __be16                  sample;
 170         struct spi_message      msg;
 171         struct spi_transfer     xfer[6];
 172 };
 173
 174 static void ads7846_enable(struct ads7846 *ts);
 175 static void ads7846_disable(struct ads7846 *ts);
 176
 177 static int ads7846_read12_ser(struct device *dev, unsigned command)
 178 {
 179         struct spi_device       *spi = to_spi_device(dev);
 180         struct ads7846          *ts = dev_get_drvdata(dev);
 181         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
 182         int                     status;
 183         int                     sample;
 184         int                     i;
 185
 186         if (!req)
 187                 return -ENOMEM;
 188
 189         spi_message_init(&req->msg);
 190
 191         /* activate reference, so it has time to settle; */
 192         req->ref_on = REF_ON;
 193         req->xfer[0].tx_buf = &req->ref_on;
 194         req->xfer[0].len = 1;
 195         req->xfer[1].rx_buf = &req->scratch;
 196         req->xfer[1].len = 2;
 197
 198         /*
 199          * for external VREF, 0 usec (and assume it's always on);
 200          * for 1uF, use 800 usec;
 201          * no cap, 100 usec.
 202          */
 203         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 204
 205         /* take sample */
 206         req->command = (u8) command;
 207         req->xfer[2].tx_buf = &req->command;
 208         req->xfer[2].len = 1;
 209         req->xfer[3].rx_buf = &req->sample;
 210         req->xfer[3].len = 2;
 211
 212         /* REVISIT:  take a few more samples, and compare ... */
 213
 214         /* turn off reference */
 215         req->ref_off = REF_OFF;
 216         req->xfer[4].tx_buf = &req->ref_off;
 217         req->xfer[4].len = 1;
 218         req->xfer[5].rx_buf = &req->scratch;
 219         req->xfer[5].len = 2;
 220
 221         CS_CHANGE(req->xfer[5]);
 222
 223         /* group all the transfers together, so we can't interfere with
 224          * reading touchscreen state; disable penirq while sampling
 225          */
 226         for (i = 0; i < 6; i++)
 227                 spi_message_add_tail(&req->xfer[i], &req->msg);
 228
 229         disable_irq(spi->irq);
 230         status = spi_sync(spi, &req->msg);
 231         enable_irq(spi->irq);
 232
 233         if (req->msg.status)
 234                 status = req->msg.status;
 235         sample = be16_to_cpu(req->sample);
 236         sample = sample >> 4;
 237         kfree(req);
 238
 239         return status ? status : sample;
 240 }
 241
 242 #define SHOW(name) static ssize_t \
 243 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 244 { \
 245         ssize_t v = ads7846_read12_ser(dev, \
 246                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 247         if (v < 0) \
 248                 return v; \
 249         return sprintf(buf, "%u\n", (unsigned) v); \
 250 } \
 251 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 252
 253 SHOW(temp0)
 254 SHOW(temp1)
 255 SHOW(vaux)
 256 SHOW(vbatt)
 257
 258 static int is_pen_down(struct device *dev)
 259 {
 260         struct ads7846          *ts = dev_get_drvdata(dev);
 261
 262         return ts->pendown;
 263 }
 264
 265 static ssize_t ads7846_pen_down_show(struct device *dev,
 266                                      struct device_attribute *attr, char *buf)
 267 {
 268         return sprintf(buf, "%u\n", is_pen_down(dev));
 269 }
 270
 271 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 272
 273 static ssize_t ads7846_disable_show(struct device *dev,
 274                                      struct device_attribute *attr, char *buf)
 275 {
 276         struct ads7846  *ts = dev_get_drvdata(dev);
 277
 278         return sprintf(buf, "%u\n", ts->disabled);
 279 }
 280
 281 static ssize_t ads7846_disable_store(struct device *dev,
 282                                      struct device_attribute *attr,
 283                                      const char *buf, size_t count)
 284 {
 285         struct ads7846 *ts = dev_get_drvdata(dev);
 286         unsigned long flags;
 287         char *endp;
 288         int i;
 289
 290         i = simple_strtoul(buf, &endp, 10);
 291         spin_lock_irqsave(&ts->lock, flags);
 292
 293         if (i)
 294                 ads7846_disable(ts);
 295         else
 296                 ads7846_enable(ts);
 297
 298         spin_unlock_irqrestore(&ts->lock, flags);
 299
 300         return count;
 301 }
 302
 303 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 304
 305 /*--------------------------------------------------------------------------*/
 306
 307 /*
 308  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 309  * to retrieve touchscreen status.
 310  *
 311  * The SPI transfer completion callback does the real work.  It reports
 312  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 313  */
 314
 315 static void ads7846_rx(void *ads)
 316 {
 317         struct ads7846          *ts = ads;
 318         struct input_dev        *input_dev = ts->input;
 319         unsigned                Rt;
 320         unsigned                sync = 0;
 321         u16                     x, y, z1, z2;
 322         unsigned long           flags;
 323
 324         /* adjust:  12 bit samples (left aligned), built from
 325          * two 8 bit values writen msb-first.
 326          */
 327         x = ts->tc.x >> 3;
 328         y = ts->tc.y >> 3;
 329         z1 = ts->tc.z1 >> 3;
 330         z2 = ts->tc.z2 >> 3;
 331
 332         /* range filtering */
 333         if (x == MAX_12BIT)
 334                 x = 0;
 335
 336         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 337                 /* compute touch pressure resistance using equation #2 */
 338                 Rt = z2;
 339                 Rt -= z1;
 340                 Rt *= x;
 341                 Rt *= ts->x_plate_ohms;
 342                 Rt /= z1;
 343                 Rt = (Rt + 2047) >> 12;
 344         } else
 345                 Rt = 0;
 346
 347         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 348          * being able to check nPENIRQ status, or "friendly" trigger modes
 349          * (both-edges is much better than just-falling or low-level).
 350          *
 351          * REVISIT:  some boards may require reading nPENIRQ; it's
 352          * needed on 7843.  and 7845 reads pressure differently...
 353          *
 354          * REVISIT:  the touchscreen might not be connected; this code
 355          * won't notice that, even if nPENIRQ never fires ...
 356          */
 357         if (!ts->pendown && Rt != 0) {
 358                 input_report_key(input_dev, BTN_TOUCH, 1);
 359                 sync = 1;
 360         } else if (ts->pendown && Rt == 0) {
 361                 input_report_key(input_dev, BTN_TOUCH, 0);
 362                 sync = 1;
 363         }
 364
 365         if (Rt) {
 366                 input_report_abs(input_dev, ABS_X, x);
 367                 input_report_abs(input_dev, ABS_Y, y);
 368                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 369                 sync = 1;
 370         }
 371         if (sync)
 372                 input_sync(input_dev);
 373
 374 #ifdef  VERBOSE
 375         if (Rt || ts->pendown)
 376                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 377                         x, y, Rt, Rt ? "" : " UP");
 378 #endif
 379
 380         /* don't retrigger while we're suspended */
 381         spin_lock_irqsave(&ts->lock, flags);
 382
 383         ts->pendown = (Rt != 0);
 384         ts->pending = 0;
 385
 386         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 387                 if (ts->pendown)
 388                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 389                 else if (ts->irq_disabled) {
 390                         ts->irq_disabled = 0;
 391                         enable_irq(ts->spi->irq);
 392                 }
 393         }
 394
 395         spin_unlock_irqrestore(&ts->lock, flags);
 396 }
 397
 398 static void ads7846_debounce(void *ads)
 399 {
 400         struct ads7846          *ts = ads;
 401         struct spi_message      *m;
 402         struct spi_transfer     *t;
 403         u16                     val;
 404         int                     status;
 405
 406         m = &ts->msg[ts->msg_idx];
 407         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 408         val = (*(u16 *)t->rx_buf) >> 3;
 409
 410         if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol &&
 411                               ts->read_cnt < ts->debounce_max)) {
 412                 /* Repeat it, if this was the first read or the read wasn't
 413                  * consistent enough */
 414                 ts->read_cnt++;
 415                 ts->last_read = val;
 416         } else {
 417                 /* Go for the next read */
 418                 ts->msg_idx++;
 419                 ts->read_cnt = 0;
 420                 m++;
 421         }
 422         status = spi_async(ts->spi, m);
 423         if (status)
 424                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 425                                 status);
 426 }
 427
 428 static void ads7846_timer(unsigned long handle)
 429 {
 430         struct ads7846  *ts = (void *)handle;
 431         int             status = 0;
 432
 433         ts->msg_idx = 0;
 434         status = spi_async(ts->spi, &ts->msg[0]);
 435         if (status)
 436                 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 437 }
 438
 439 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
 440 {
 441         struct ads7846 *ts = handle;
 442         unsigned long flags;
 443
 444         spin_lock_irqsave(&ts->lock, flags);
 445         if (likely(!ts->irq_disabled && !ts->disabled)) {
 446                 if (!ts->irq_disabled) {
 447                         ts->irq_disabled = 1;
 448                         /* The following has at the moment no effect whatsoever
 449                          * on OMAP, that's why we maintain the disabled
 450                          * state ourselves */
 451                         disable_irq(ts->spi->irq);
 452                 }
 453                 if (!ts->pending) {
 454                         ts->pending = 1;
 455                         mod_timer(&ts->timer, jiffies);
 456                 }
 457         }
 458         spin_unlock_irqrestore(&ts->lock, flags);
 459
 460         return IRQ_HANDLED;
 461 }
 462
 463 /*--------------------------------------------------------------------------*/
 464
 465 /* Must be called with ts->lock held */
 466 static void ads7846_disable(struct ads7846 *ts)
 467 {
 468         if (ts->disabled)
 469                 return;
 470
 471         /* are we waiting for IRQ, or polling? */
 472         if (!ts->pendown) {
 473                 if (!ts->irq_disabled) {
 474                         ts->irq_disabled = 1;
 475                         disable_irq(ts->spi->irq);
 476                 }
 477         } else {
 478                 unsigned long flags;
 479
 480                 /* polling; force a final SPI completion;
 481                  * that will clean things up neatly
 482                  */
 483                 if (!ts->pending)
 484                         mod_timer(&ts->timer, jiffies);
 485
 486                 while (ts->pendown || ts->pending) {
 487                         spin_unlock_irqrestore(&ts->lock, flags);
 488                         msleep(1);
 489                         spin_lock_irqsave(&ts->lock, flags);
 490                 }
 491         }
 492
 493         /* we know the chip's in lowpower mode since we always
 494          * leave it that way after every request
 495          */
 496
 497         ts->disabled = 1;
 498 }
 499
 500 /* Must be called with ts->lock held */
 501 static void ads7846_enable(struct ads7846 *ts)
 502 {
 503         if (!ts->disabled)
 504                 return;
 505
 506         ts->disabled = 0;
 507         ts->irq_disabled = 0;
 508         enable_irq(ts->spi->irq);
 509 }
 510
 511 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 512 {
 513         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 514         unsigned long   flags;
 515
 516         spin_lock_irqsave(&ts->lock, flags);
 517
 518         spi->dev.power.power_state = message;
 519         ads7846_disable(ts);
 520
 521         spin_unlock_irqrestore(&ts->lock, flags);
 522
 523         return 0;
 524
 525 }
 526
 527 static int ads7846_resume(struct spi_device *spi)
 528 {
 529         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 530         unsigned long flags;
 531
 532         spin_lock_irqsave(&ts->lock, flags);
 533
 534         spi->dev.power.power_state = PMSG_ON;
 535         ads7846_enable(ts);
 536
 537         spin_unlock_irqrestore(&ts->lock, flags);
 538
 539         return 0;
 540 }
 541
 542 static int __devinit ads7846_probe(struct spi_device *spi)
 543 {
 544         struct ads7846                  *ts;
 545         struct input_dev                *input_dev;
 546         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 547         struct spi_message              *m;
 548         struct spi_transfer             *x;
 549         int                             err;
 550
 551         if (!spi->irq) {
 552                 dev_dbg(&spi->dev, "no IRQ?\n");
 553                 return -ENODEV;
 554         }
 555
 556         if (!pdata) {
 557                 dev_dbg(&spi->dev, "no platform data?\n");
 558                 return -ENODEV;
 559         }
 560
 561         /* don't exceed max specified sample rate */
 562         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 563                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 564                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 565                 return -EINVAL;
 566         }
 567
 568         /* We'd set the wordsize to 12 bits ... except that some controllers
 569          * will then treat the 8 bit command words as 12 bits (and drop the
 570          * four MSBs of the 12 bit result).  Result: inputs must be shifted
 571          * to discard the four garbage LSBs.
 572          */
 573
 574         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 575         input_dev = input_allocate_device();
 576         if (!ts || !input_dev) {
 577                 err = -ENOMEM;
 578                 goto err_free_mem;
 579         }
 580
 581         dev_set_drvdata(&spi->dev, ts);
 582         spi->dev.power.power_state = PMSG_ON;
 583
 584         ts->spi = spi;
 585         ts->input = input_dev;
 586
 587         init_timer(&ts->timer);
 588         ts->timer.data = (unsigned long) ts;
 589         ts->timer.function = ads7846_timer;
 590
 591         spin_lock_init(&ts->lock);
 592
 593         ts->model = pdata->model ? : 7846;
 594         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 595         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 596         ts->debounce_max = pdata->debounce_max ? : 1;
 597         ts->debounce_tol = pdata->debounce_tol ? : 10;
 598
 599         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 600
 601         input_dev->name = "ADS784x Touchscreen";
 602         input_dev->phys = ts->phys;
 603         input_dev->cdev.dev = &spi->dev;
 604
 605         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 606         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 607         input_set_abs_params(input_dev, ABS_X,
 608                         pdata->x_min ? : 0,
 609                         pdata->x_max ? : MAX_12BIT,
 610                         0, 0);
 611         input_set_abs_params(input_dev, ABS_Y,
 612                         pdata->y_min ? : 0,
 613                         pdata->y_max ? : MAX_12BIT,
 614                         0, 0);
 615         input_set_abs_params(input_dev, ABS_PRESSURE,
 616                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 617
 618         /* set up the transfers to read touchscreen state; this assumes we
 619          * use formula #2 for pressure, not #3.
 620          */
 621         m = &ts->msg[0];
 622         x = ts->xfer;
 623
 624         spi_message_init(m);
 625
 626         /* y- still on; turn on only y+ (and ADC) */
 627         ts->read_y = READ_Y;
 628         x->tx_buf = &ts->read_y;
 629         x->len = 1;
 630         spi_message_add_tail(x, m);
 631
 632         x++;
 633         x->rx_buf = &ts->tc.y;
 634         x->len = 2;
 635         spi_message_add_tail(x, m);
 636
 637         m->complete = ads7846_debounce;
 638         m->context = ts;
 639
 640         m++;
 641         spi_message_init(m);
 642
 643         /* turn y- off, x+ on, then leave in lowpower */
 644         x++;
 645         ts->read_x = READ_X;
 646         x->tx_buf = &ts->read_x;
 647         x->len = 1;
 648         spi_message_add_tail(x, m);
 649
 650         x++;
 651         x->rx_buf = &ts->tc.x;
 652         x->len = 2;
 653         spi_message_add_tail(x, m);
 654
 655         m->complete = ads7846_debounce;
 656         m->context = ts;
 657
 658         /* turn y+ off, x- on; we'll use formula #2 */
 659         if (ts->model == 7846) {
 660                 m++;
 661                 spi_message_init(m);
 662
 663                 x++;
 664                 ts->read_z1 = READ_Z1;
 665                 x->tx_buf = &ts->read_z1;
 666                 x->len = 1;
 667                 spi_message_add_tail(x, m);
 668
 669                 x++;
 670                 x->rx_buf = &ts->tc.z1;
 671                 x->len = 2;
 672                 spi_message_add_tail(x, m);
 673
 674                 m->complete = ads7846_debounce;
 675                 m->context = ts;
 676
 677                 m++;
 678                 spi_message_init(m);
 679
 680                 x++;
 681                 ts->read_z2 = READ_Z2;
 682                 x->tx_buf = &ts->read_z2;
 683                 x->len = 1;
 684                 spi_message_add_tail(x, m);
 685
 686                 x++;
 687                 x->rx_buf = &ts->tc.z2;
 688                 x->len = 2;
 689                 spi_message_add_tail(x, m);
 690
 691                 m->complete = ads7846_debounce;
 692                 m->context = ts;
 693         }
 694
 695         /* power down */
 696         m++;
 697         spi_message_init(m);
 698
 699         x++;
 700         ts->pwrdown = PWRDOWN;
 701         x->tx_buf = &ts->pwrdown;
 702         x->len = 1;
 703         spi_message_add_tail(x, m);
 704
 705         x++;
 706         x->rx_buf = &ts->dummy;
 707         x->len = 2;
 708         CS_CHANGE(*x);
 709         spi_message_add_tail(x, m);
 710
 711         m->complete = ads7846_rx;
 712         m->context = ts;
 713
 714         if (request_irq(spi->irq, ads7846_irq,
 715                         SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
 716                         spi->dev.bus_id, ts)) {
 717                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 718                 err = -EBUSY;
 719                 goto err_free_mem;
 720         }
 721
 722         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 723
 724         /* take a first sample, leaving nPENIRQ active; avoid
 725          * the touchscreen, in case it's not connected.
 726          */
 727         (void) ads7846_read12_ser(&spi->dev,
 728                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 729
 730         /* ads7843/7845 don't have temperature sensors, and
 731          * use the other sensors a bit differently too
 732          */
 733         if (ts->model == 7846) {
 734                 device_create_file(&spi->dev, &dev_attr_temp0);
 735                 device_create_file(&spi->dev, &dev_attr_temp1);
 736         }
 737         if (ts->model != 7845)
 738                 device_create_file(&spi->dev, &dev_attr_vbatt);
 739         device_create_file(&spi->dev, &dev_attr_vaux);
 740
 741         device_create_file(&spi->dev, &dev_attr_pen_down);
 742
 743         device_create_file(&spi->dev, &dev_attr_disable);
 744
 745         err = input_register_device(input_dev);
 746         if (err)
 747                 goto err_remove_attr;
 748
 749         return 0;
 750
 751  err_remove_attr:
 752         device_remove_file(&spi->dev, &dev_attr_disable);
 753         device_remove_file(&spi->dev, &dev_attr_pen_down);
 754         if (ts->model == 7846) {
 755                 device_remove_file(&spi->dev, &dev_attr_temp1);
 756                 device_remove_file(&spi->dev, &dev_attr_temp0);
 757         }
 758         if (ts->model != 7845)
 759                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 760         device_remove_file(&spi->dev, &dev_attr_vaux);
 761
 762         free_irq(spi->irq, ts);
 763  err_free_mem:
 764         input_free_device(input_dev);
 765         kfree(ts);
 766         return err;
 767 }
 768
 769 static int __devexit ads7846_remove(struct spi_device *spi)
 770 {
 771         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 772
 773         input_unregister_device(ts->input);
 774
 775         ads7846_suspend(spi, PMSG_SUSPEND);
 776
 777         device_remove_file(&spi->dev, &dev_attr_disable);
 778         device_remove_file(&spi->dev, &dev_attr_pen_down);
 779         if (ts->model == 7846) {
 780                 device_remove_file(&spi->dev, &dev_attr_temp1);
 781                 device_remove_file(&spi->dev, &dev_attr_temp0);
 782         }
 783         if (ts->model != 7845)
 784                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 785         device_remove_file(&spi->dev, &dev_attr_vaux);
 786
 787         free_irq(ts->spi->irq, ts);
 788         if (ts->irq_disabled)
 789                 enable_irq(ts->spi->irq);
 790
 791         kfree(ts);
 792
 793         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 794         return 0;
 795 }
 796
 797 static struct spi_driver ads7846_driver = {
 798         .driver = {
 799                 .name   = "ads7846",
 800                 .bus    = &spi_bus_type,
 801                 .owner  = THIS_MODULE,
 802         },
 803         .probe          = ads7846_probe,
 804         .remove         = __devexit_p(ads7846_remove),
 805         .suspend        = ads7846_suspend,
 806         .resume         = ads7846_resume,
 807 };
 808
 809 static int __init ads7846_init(void)
 810 {
 811         /* grr, board-specific init should stay out of drivers!! */
 812
 813 #ifdef  CONFIG_ARCH_OMAP
 814         if (machine_is_omap_osk()) {
 815                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 816                 omap_request_gpio(4);
 817                 omap_set_gpio_direction(4, 1);
 818                 omap_request_gpio(6);
 819                 omap_set_gpio_direction(6, 1);
 820         }
 821         // also TI 1510 Innovator, bitbanging through FPGA
 822         // also Nokia 770
 823         // also Palm Tungsten T2
 824 #endif
 825
 826         // PXA:
 827         // also Dell Axim X50
 828         // also HP iPaq H191x/H192x/H415x/H435x
 829         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 830         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 831
 832         // Atmel at91sam9261-EK uses ads7843
 833
 834         // also various AMD Au1x00 devel boards
 835
 836         return spi_register_driver(&ads7846_driver);
 837 }
 838 module_init(ads7846_init);
 839
 840 static void __exit ads7846_exit(void)
 841 {
 842         spi_unregister_driver(&ads7846_driver);
 843
 844 #ifdef  CONFIG_ARCH_OMAP
 845         if (machine_is_omap_osk()) {
 846                 omap_free_gpio(4);
 847                 omap_free_gpio(6);
 848         }
 849 #endif
 850
 851 }
 852 module_exit(ads7846_exit);
 853
 854 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 855 MODULE_LICENSE("GPL");