drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  *
   6  * Using code from:
   7  *  - corgi_ts.c
   8  *      Copyright (C) 2004-2005 Richard Purdie
   9  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  10  *      Copyright (C) 2002 MontaVista Software
  11  *      Copyright (C) 2004 Texas Instruments
  12  *      Copyright (C) 2005 Dirk Behme
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License version 2 as
  16  *  published by the Free Software Foundation.
  17  */
  18 #include <linux/device.h>
  19 #include <linux/init.h>
  20 #include <linux/delay.h>
  21 #include <linux/input.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/slab.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/spi/ads7846.h>
  26 #include <asm/irq.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 lightly tested on an ads7846.
  38  * Support for ads7843 and ads7845 has only been stubbed in.
  39  *
  40  * Not yet done:  investigate the values reported.  Are x/y/pressure
  41  * event values sane enough for X11?  How accurate are the temperature
  42  * and voltage readings?  (System-specific calibration should support
  43  * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
  44  *
  45  * app note sbaa036 talks in more detail about accurate sampling...
  46  * that ought to help in situations like LCDs inducing noise (which
  47  * can also be helped by using synch signals) and more generally.
  48  */
  49
  50 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
  51
  52 /* this driver doesn't aim at the peak continuous sample rate */
  53 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  54
  55 struct ts_event {
  56         /* For portability, we can't read 12 bit values using SPI (which
  57          * would make the controller deliver them as native byteorder u16
  58          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  59          * which need byteswapping then range adjustment.
  60          */
  61         __be16 x;
  62         __be16 y;
  63         __be16 z1, z2;
  64 };
  65
  66 struct ads7846 {
  67         struct input_dev        *input;
  68         char                    phys[32];
  69
  70         struct spi_device       *spi;
  71         u16                     model;
  72         u16                     vref_delay_usecs;
  73         u16                     x_plate_ohms;
  74
  75         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  76         u16                     dummy;          /* for the pwrdown read */
  77         struct ts_event         tc;
  78
  79         struct spi_transfer     xfer[10];
  80         struct spi_message      msg;
  81
  82         spinlock_t              lock;
  83         struct timer_list       timer;          /* P: lock */
  84         unsigned                pendown:1;      /* P: lock */
  85         unsigned                pending:1;      /* P: lock */
  86 // FIXME remove "irq_disabled"
  87         unsigned                irq_disabled:1; /* P: lock */
  88 };
  89
  90 /* leave chip selected when we're done, for quicker re-select? */
  91 #if     0
  92 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
  93 #else
  94 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
  95 #endif
  96
  97 /*--------------------------------------------------------------------------*/
  98
  99 /* The ADS7846 has touchscreen and other sensors.
 100  * Earlier ads784x chips are somewhat compatible.
 101  */
 102 #define ADS_START               (1 << 7)
 103 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 104 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 105 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 106 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 107 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 108 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 109 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 110 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 111 #define ADS_8_BIT               (1 << 3)
 112 #define ADS_12_BIT              (0 << 3)
 113 #define ADS_SER                 (1 << 2)        /* non-differential */
 114 #define ADS_DFR                 (0 << 2)        /* differential */
 115 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 116 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 117 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 118 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 119
 120 #define MAX_12BIT       ((1<<12)-1)
 121
 122 /* leave ADC powered up (disables penirq) between differential samples */
 123 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 124         | ADS_12_BIT | ADS_DFR)
 125
 126 #define READ_Y  (READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
 127 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
 128 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
 129
 130 #define READ_X  (READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)
 131 #define PWRDOWN (READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)   /* LAST */
 132
 133 /* single-ended samples need to first power up reference voltage;
 134  * we leave both ADC and VREF powered
 135  */
 136 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 137         | ADS_12_BIT | ADS_SER)
 138
 139 #define REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
 140 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 141
 142 /*--------------------------------------------------------------------------*/
 143
 144 /*
 145  * Non-touchscreen sensors only use single-ended conversions.
 146  */
 147
 148 struct ser_req {
 149         u8                      ref_on;
 150         u8                      command;
 151         u8                      ref_off;
 152         u16                     scratch;
 153         __be16                  sample;
 154         struct spi_message      msg;
 155         struct spi_transfer     xfer[6];
 156 };
 157
 158 static int ads7846_read12_ser(struct device *dev, unsigned command)
 159 {
 160         struct spi_device       *spi = to_spi_device(dev);
 161         struct ads7846          *ts = dev_get_drvdata(dev);
 162         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
 163         int                     status;
 164         int                     sample;
 165         int                     i;
 166
 167         if (!req)
 168                 return -ENOMEM;
 169
 170         INIT_LIST_HEAD(&req->msg.transfers);
 171
 172         /* activate reference, so it has time to settle; */
 173         req->ref_on = REF_ON;
 174         req->xfer[0].tx_buf = &req->ref_on;
 175         req->xfer[0].len = 1;
 176         req->xfer[1].rx_buf = &req->scratch;
 177         req->xfer[1].len = 2;
 178
 179         /*
 180          * for external VREF, 0 usec (and assume it's always on);
 181          * for 1uF, use 800 usec;
 182          * no cap, 100 usec.
 183          */
 184         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 185
 186         /* take sample */
 187         req->command = (u8) command;
 188         req->xfer[2].tx_buf = &req->command;
 189         req->xfer[2].len = 1;
 190         req->xfer[3].rx_buf = &req->sample;
 191         req->xfer[3].len = 2;
 192
 193         /* REVISIT:  take a few more samples, and compare ... */
 194
 195         /* turn off reference */
 196         req->ref_off = REF_OFF;
 197         req->xfer[4].tx_buf = &req->ref_off;
 198         req->xfer[4].len = 1;
 199         req->xfer[5].rx_buf = &req->scratch;
 200         req->xfer[5].len = 2;
 201
 202         CS_CHANGE(req->xfer[5]);
 203
 204         /* group all the transfers together, so we can't interfere with
 205          * reading touchscreen state; disable penirq while sampling
 206          */
 207         for (i = 0; i < 6; i++)
 208                 spi_message_add_tail(&req->xfer[i], &req->msg);
 209
 210         disable_irq(spi->irq);
 211         status = spi_sync(spi, &req->msg);
 212         enable_irq(spi->irq);
 213
 214         if (req->msg.status)
 215                 status = req->msg.status;
 216         sample = be16_to_cpu(req->sample);
 217         sample = sample >> 4;
 218         kfree(req);
 219
 220         return status ? status : sample;
 221 }
 222
 223 #define SHOW(name) static ssize_t \
 224 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 225 { \
 226         ssize_t v = ads7846_read12_ser(dev, \
 227                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 228         if (v < 0) \
 229                 return v; \
 230         return sprintf(buf, "%u\n", (unsigned) v); \
 231 } \
 232 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 233
 234 SHOW(temp0)
 235 SHOW(temp1)
 236 SHOW(vaux)
 237 SHOW(vbatt)
 238
 239 static int is_pen_down(struct device *dev)
 240 {
 241         struct ads7846          *ts = dev_get_drvdata(dev);
 242
 243         return ts->pendown;
 244 }
 245
 246 static ssize_t ads7846_pen_down_show(struct device *dev,
 247                                      struct device_attribute *attr, char *buf)
 248 {
 249         return sprintf(buf, "%u\n", is_pen_down(dev));
 250 }
 251
 252 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 253
 254 /*--------------------------------------------------------------------------*/
 255
 256 /*
 257  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 258  * to retrieve touchscreen status.
 259  *
 260  * The SPI transfer completion callback does the real work.  It reports
 261  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 262  */
 263
 264 static void ads7846_rx(void *ads)
 265 {
 266         struct ads7846          *ts = ads;
 267         struct input_dev        *input_dev = ts->input;
 268         unsigned                Rt;
 269         unsigned                sync = 0;
 270         u16                     x, y, z1, z2;
 271         unsigned long           flags;
 272
 273         /* adjust:  12 bit samples (left aligned), built from
 274          * two 8 bit values writen msb-first.
 275          */
 276         x = be16_to_cpu(ts->tc.x) >> 4;
 277         y = be16_to_cpu(ts->tc.y) >> 4;
 278         z1 = be16_to_cpu(ts->tc.z1) >> 4;
 279         z2 = be16_to_cpu(ts->tc.z2) >> 4;
 280
 281         /* range filtering */
 282         if (x == MAX_12BIT)
 283                 x = 0;
 284
 285         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 286                 /* compute touch pressure resistance using equation #2 */
 287                 Rt = z2;
 288                 Rt -= z1;
 289                 Rt *= x;
 290                 Rt *= ts->x_plate_ohms;
 291                 Rt /= z1;
 292                 Rt = (Rt + 2047) >> 12;
 293         } else
 294                 Rt = 0;
 295
 296         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 297          * being able to check nPENIRQ status, or "friendly" trigger modes
 298          * (both-edges is much better than just-falling or low-level).
 299          *
 300          * REVISIT:  some boards may require reading nPENIRQ; it's
 301          * needed on 7843.  and 7845 reads pressure differently...
 302          *
 303          * REVISIT:  the touchscreen might not be connected; this code
 304          * won't notice that, even if nPENIRQ never fires ...
 305          */
 306         if (!ts->pendown && Rt != 0) {
 307                 input_report_key(input_dev, BTN_TOUCH, 1);
 308                 sync = 1;
 309         } else if (ts->pendown && Rt == 0) {
 310                 input_report_key(input_dev, BTN_TOUCH, 0);
 311                 sync = 1;
 312         }
 313
 314         if (Rt) {
 315                 input_report_abs(input_dev, ABS_X, x);
 316                 input_report_abs(input_dev, ABS_Y, y);
 317                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 318                 sync = 1;
 319         }
 320         if (sync)
 321                 input_sync(input_dev);
 322
 323 #ifdef  VERBOSE
 324         if (Rt || ts->pendown)
 325                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 326                         x, y, Rt, Rt ? "" : " UP");
 327 #endif
 328
 329         /* don't retrigger while we're suspended */
 330         spin_lock_irqsave(&ts->lock, flags);
 331
 332         ts->pendown = (Rt != 0);
 333         ts->pending = 0;
 334
 335         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 336                 if (ts->pendown)
 337                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 338                 else if (ts->irq_disabled) {
 339                         ts->irq_disabled = 0;
 340                         enable_irq(ts->spi->irq);
 341                 }
 342         }
 343
 344         spin_unlock_irqrestore(&ts->lock, flags);
 345 }
 346
 347 static void ads7846_timer(unsigned long handle)
 348 {
 349         struct ads7846  *ts = (void *)handle;
 350         int             status = 0;
 351         unsigned long   flags;
 352
 353         spin_lock_irqsave(&ts->lock, flags);
 354         if (!ts->pending) {
 355                 ts->pending = 1;
 356                 if (!ts->irq_disabled) {
 357                         ts->irq_disabled = 1;
 358                         disable_irq(ts->spi->irq);
 359                 }
 360                 status = spi_async(ts->spi, &ts->msg);
 361                 if (status)
 362                         dev_err(&ts->spi->dev, "spi_async --> %d\n",
 363                                         status);
 364         }
 365         spin_unlock_irqrestore(&ts->lock, flags);
 366 }
 367
 368 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
 369 {
 370         ads7846_timer((unsigned long) handle);
 371         return IRQ_HANDLED;
 372 }
 373
 374 /*--------------------------------------------------------------------------*/
 375
 376 static int
 377 ads7846_suspend(struct spi_device *spi, pm_message_t message)
 378 {
 379         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 380         unsigned long   flags;
 381
 382         spin_lock_irqsave(&ts->lock, flags);
 383
 384         spi->dev.power.power_state = message;
 385
 386         /* are we waiting for IRQ, or polling? */
 387         if (!ts->pendown) {
 388                 if (!ts->irq_disabled) {
 389                         ts->irq_disabled = 1;
 390                         disable_irq(ts->spi->irq);
 391                 }
 392         } else {
 393                 /* polling; force a final SPI completion;
 394                  * that will clean things up neatly
 395                  */
 396                 if (!ts->pending)
 397                         mod_timer(&ts->timer, jiffies);
 398
 399                 while (ts->pendown || ts->pending) {
 400                         spin_unlock_irqrestore(&ts->lock, flags);
 401                         udelay(10);
 402                         spin_lock_irqsave(&ts->lock, flags);
 403                 }
 404         }
 405
 406         /* we know the chip's in lowpower mode since we always
 407          * leave it that way after every request
 408          */
 409
 410         spin_unlock_irqrestore(&ts->lock, flags);
 411         return 0;
 412 }
 413
 414 static int ads7846_resume(struct spi_device *spi)
 415 {
 416         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 417
 418         ts->irq_disabled = 0;
 419         enable_irq(ts->spi->irq);
 420         spi->dev.power.power_state = PMSG_ON;
 421         return 0;
 422 }
 423
 424 static int __devinit ads7846_probe(struct spi_device *spi)
 425 {
 426         struct ads7846                  *ts;
 427         struct input_dev                *input_dev;
 428         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 429         struct spi_transfer             *x;
 430         int                             err;
 431
 432         if (!spi->irq) {
 433                 dev_dbg(&spi->dev, "no IRQ?\n");
 434                 return -ENODEV;
 435         }
 436
 437         if (!pdata) {
 438                 dev_dbg(&spi->dev, "no platform data?\n");
 439                 return -ENODEV;
 440         }
 441
 442         /* don't exceed max specified sample rate */
 443         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 444                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 445                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 446                 return -EINVAL;
 447         }
 448
 449         /* We'd set the wordsize to 12 bits ... except that some controllers
 450          * will then treat the 8 bit command words as 12 bits (and drop the
 451          * four MSBs of the 12 bit result).  Result: inputs must be shifted
 452          * to discard the four garbage LSBs.
 453          */
 454
 455         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 456         input_dev = input_allocate_device();
 457         if (!ts || !input_dev) {
 458                 err = -ENOMEM;
 459                 goto err_free_mem;
 460         }
 461
 462         dev_set_drvdata(&spi->dev, ts);
 463         spi->dev.power.power_state = PMSG_ON;
 464
 465         ts->spi = spi;
 466         ts->input = input_dev;
 467
 468         init_timer(&ts->timer);
 469         ts->timer.data = (unsigned long) ts;
 470         ts->timer.function = ads7846_timer;
 471
 472         ts->model = pdata->model ? : 7846;
 473         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 474         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 475
 476         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 477
 478         input_dev->name = "ADS784x Touchscreen";
 479         input_dev->phys = ts->phys;
 480         input_dev->cdev.dev = &spi->dev;
 481
 482         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 483         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 484         input_set_abs_params(input_dev, ABS_X,
 485                         pdata->x_min ? : 0,
 486                         pdata->x_max ? : MAX_12BIT,
 487                         0, 0);
 488         input_set_abs_params(input_dev, ABS_Y,
 489                         pdata->y_min ? : 0,
 490                         pdata->y_max ? : MAX_12BIT,
 491                         0, 0);
 492         input_set_abs_params(input_dev, ABS_PRESSURE,
 493                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 494
 495         /* set up the transfers to read touchscreen state; this assumes we
 496          * use formula #2 for pressure, not #3.
 497          */
 498         INIT_LIST_HEAD(&ts->msg.transfers);
 499         x = ts->xfer;
 500
 501         /* y- still on; turn on only y+ (and ADC) */
 502         ts->read_y = READ_Y;
 503         x->tx_buf = &ts->read_y;
 504         x->len = 1;
 505         spi_message_add_tail(x, &ts->msg);
 506
 507         x++;
 508         x->rx_buf = &ts->tc.y;
 509         x->len = 2;
 510         spi_message_add_tail(x, &ts->msg);
 511
 512         /* turn y+ off, x- on; we'll use formula #2 */
 513         if (ts->model == 7846) {
 514                 x++;
 515                 ts->read_z1 = READ_Z1;
 516                 x->tx_buf = &ts->read_z1;
 517                 x->len = 1;
 518                 spi_message_add_tail(x, &ts->msg);
 519
 520                 x++;
 521                 x->rx_buf = &ts->tc.z1;
 522                 x->len = 2;
 523                 spi_message_add_tail(x, &ts->msg);
 524
 525                 x++;
 526                 ts->read_z2 = READ_Z2;
 527                 x->tx_buf = &ts->read_z2;
 528                 x->len = 1;
 529                 spi_message_add_tail(x, &ts->msg);
 530
 531                 x++;
 532                 x->rx_buf = &ts->tc.z2;
 533                 x->len = 2;
 534                 spi_message_add_tail(x, &ts->msg);
 535         }
 536
 537         /* turn y- off, x+ on, then leave in lowpower */
 538         x++;
 539         ts->read_x = READ_X;
 540         x->tx_buf = &ts->read_x;
 541         x->len = 1;
 542         spi_message_add_tail(x, &ts->msg);
 543
 544         x++;
 545         x->rx_buf = &ts->tc.x;
 546         x->len = 2;
 547         spi_message_add_tail(x, &ts->msg);
 548
 549         /* power down */
 550         x++;
 551         ts->pwrdown = PWRDOWN;
 552         x->tx_buf = &ts->pwrdown;
 553         x->len = 1;
 554         spi_message_add_tail(x, &ts->msg);
 555
 556         x++;
 557         x->rx_buf = &ts->dummy;
 558         x->len = 2;
 559         CS_CHANGE(*x);
 560         spi_message_add_tail(x, &ts->msg);
 561
 562         ts->msg.complete = ads7846_rx;
 563         ts->msg.context = ts;
 564
 565         if (request_irq(spi->irq, ads7846_irq,
 566                         SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
 567                         spi->dev.bus_id, ts)) {
 568                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 569                 err = -EBUSY;
 570                 goto err_free_mem;
 571         }
 572
 573         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 574
 575         /* take a first sample, leaving nPENIRQ active; avoid
 576          * the touchscreen, in case it's not connected.
 577          */
 578         (void) ads7846_read12_ser(&spi->dev,
 579                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 580
 581         /* ads7843/7845 don't have temperature sensors, and
 582          * use the other sensors a bit differently too
 583          */
 584         if (ts->model == 7846) {
 585                 device_create_file(&spi->dev, &dev_attr_temp0);
 586                 device_create_file(&spi->dev, &dev_attr_temp1);
 587         }
 588         if (ts->model != 7845)
 589                 device_create_file(&spi->dev, &dev_attr_vbatt);
 590         device_create_file(&spi->dev, &dev_attr_vaux);
 591
 592         device_create_file(&spi->dev, &dev_attr_pen_down);
 593
 594         err = input_register_device(input_dev);
 595         if (err)
 596                 goto err_free_irq;
 597
 598         return 0;
 599
 600  err_free_irq:
 601         free_irq(spi->irq, ts);
 602  err_free_mem:
 603         input_free_device(input_dev);
 604         kfree(ts);
 605         return err;
 606 }
 607
 608 static int __devexit ads7846_remove(struct spi_device *spi)
 609 {
 610         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 611
 612         ads7846_suspend(spi, PMSG_SUSPEND);
 613         free_irq(ts->spi->irq, ts);
 614         if (ts->irq_disabled)
 615                 enable_irq(ts->spi->irq);
 616
 617         device_remove_file(&spi->dev, &dev_attr_pen_down);
 618
 619         if (ts->model == 7846) {
 620                 device_remove_file(&spi->dev, &dev_attr_temp0);
 621                 device_remove_file(&spi->dev, &dev_attr_temp1);
 622         }
 623         if (ts->model != 7845)
 624                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 625         device_remove_file(&spi->dev, &dev_attr_vaux);
 626
 627         input_unregister_device(ts->input);
 628         kfree(ts);
 629
 630         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 631         return 0;
 632 }
 633
 634 static struct spi_driver ads7846_driver = {
 635         .driver = {
 636                 .name   = "ads7846",
 637                 .bus    = &spi_bus_type,
 638                 .owner  = THIS_MODULE,
 639         },
 640         .probe          = ads7846_probe,
 641         .remove         = __devexit_p(ads7846_remove),
 642         .suspend        = ads7846_suspend,
 643         .resume         = ads7846_resume,
 644 };
 645
 646 static int __init ads7846_init(void)
 647 {
 648         /* grr, board-specific init should stay out of drivers!! */
 649
 650 #ifdef  CONFIG_ARCH_OMAP
 651         if (machine_is_omap_osk()) {
 652                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 653                 omap_request_gpio(4);
 654                 omap_set_gpio_direction(4, 1);
 655                 omap_request_gpio(6);
 656                 omap_set_gpio_direction(6, 1);
 657         }
 658         // also TI 1510 Innovator, bitbanging through FPGA
 659         // also Nokia 770
 660         // also Palm Tungsten T2
 661 #endif
 662
 663         // PXA:
 664         // also Dell Axim X50
 665         // also HP iPaq H191x/H192x/H415x/H435x
 666         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 667         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 668
 669         // Atmel at91sam9261-EK uses ads7843
 670
 671         // also various AMD Au1x00 devel boards
 672
 673         return spi_register_driver(&ads7846_driver);
 674 }
 675 module_init(ads7846_init);
 676
 677 static void __exit ads7846_exit(void)
 678 {
 679         spi_unregister_driver(&ads7846_driver);
 680
 681 #ifdef  CONFIG_ARCH_OMAP
 682         if (machine_is_omap_osk()) {
 683                 omap_free_gpio(4);
 684                 omap_free_gpio(6);
 685         }
 686 #endif
 687
 688 }
 689 module_exit(ads7846_exit);
 690
 691 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 692 MODULE_LICENSE("GPL");