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