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
  27 #ifdef  CONFIG_ARM
  28 #include <asm/mach-types.h>
  29 #ifdef  CONFIG_ARCH_OMAP
  30 #include <asm/arch/gpio.h>
  31 #endif
  32 #endif
  33
  34
  35 /*
  36  * This code has been lightly tested on an ads7846.
  37  * Support for ads7843 and ads7845 has only been stubbed in.
  38  *
  39  * Not yet done:  investigate the values reported.  Are x/y/pressure
  40  * event values sane enough for X11?  How accurate are the temperature
  41  * and voltage readings?  (System-specific calibration should support
  42  * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
  43  *
  44  * app note sbaa036 talks in more detail about accurate sampling...
  45  * that ought to help in situations like LCDs inducing noise (which
  46  * can also be helped by using synch signals) and more generally.
  47  */
  48
  49 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
  50
  51 /* this driver doesn't aim at the peak continuous sample rate */
  52 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  53
  54 struct ts_event {
  55         /* For portability, we can't read 12 bit values using SPI (which
  56          * would make the controller deliver them as native byteorder u16
  57          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  58          * which need byteswapping then range adjustment.
  59          */
  60         __be16 x;
  61         __be16 y;
  62         __be16 z1, z2;
  63 };
  64
  65 struct ads7846 {
  66         struct input_dev        *input;
  67         char                    phys[32];
  68
  69         struct spi_device       *spi;
  70         u16                     model;
  71         u16                     vref_delay_usecs;
  72         u16                     x_plate_ohms;
  73
  74         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  75         u16                     dummy;          /* for the pwrdown read */
  76         struct ts_event         tc;
  77
  78         struct spi_transfer     xfer[10];
  79         struct spi_message      msg[5];
  80         int                     msg_idx;
  81         int                     read_cnt;
  82         int                     last_read;
  83
  84         u16                     debounce_max;
  85         u16                     debounce_tol;
  86
  87         spinlock_t              lock;
  88         struct timer_list       timer;          /* P: lock */
  89         unsigned                pendown:1;      /* P: lock */
  90         unsigned                pending:1;      /* P: lock */
  91 // FIXME remove "irq_disabled"
  92         unsigned                irq_disabled:1; /* P: lock */
  93 };
  94
  95 /* leave chip selected when we're done, for quicker re-select? */
  96 #if     0
  97 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
  98 #else
  99 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 100 #endif
 101
 102 /*--------------------------------------------------------------------------*/
 103
 104 /* The ADS7846 has touchscreen and other sensors.
 105  * Earlier ads784x chips are somewhat compatible.
 106  */
 107 #define ADS_START               (1 << 7)
 108 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 109 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 110 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 111 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 112 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 113 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 114 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 115 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 116 #define ADS_8_BIT               (1 << 3)
 117 #define ADS_12_BIT              (0 << 3)
 118 #define ADS_SER                 (1 << 2)        /* non-differential */
 119 #define ADS_DFR                 (0 << 2)        /* differential */
 120 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 121 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 122 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 123 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 124
 125 #define MAX_12BIT       ((1<<12)-1)
 126
 127 /* leave ADC powered up (disables penirq) between differential samples */
 128 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 129         | ADS_12_BIT | ADS_DFR)
 130
 131 #define READ_Y  (READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
 132 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
 133 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
 134
 135 #define READ_X  (READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)
 136 #define PWRDOWN (READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)   /* LAST */
 137
 138 /* single-ended samples need to first power up reference voltage;
 139  * we leave both ADC and VREF powered
 140  */
 141 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 142         | ADS_12_BIT | ADS_SER)
 143
 144 #define REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
 145 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 146
 147 /*--------------------------------------------------------------------------*/
 148
 149 /*
 150  * Non-touchscreen sensors only use single-ended conversions.
 151  */
 152
 153 struct ser_req {
 154         u8                      ref_on;
 155         u8                      command;
 156         u8                      ref_off;
 157         u16                     scratch;
 158         __be16                  sample;
 159         struct spi_message      msg;
 160         struct spi_transfer     xfer[6];
 161 };
 162
 163 static int ads7846_read12_ser(struct device *dev, unsigned command)
 164 {
 165         struct spi_device       *spi = to_spi_device(dev);
 166         struct ads7846          *ts = dev_get_drvdata(dev);
 167         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
 168         int                     status;
 169         int                     sample;
 170         int                     i;
 171
 172         if (!req)
 173                 return -ENOMEM;
 174
 175         spi_message_init(&req->msg);
 176
 177         /* activate reference, so it has time to settle; */
 178         req->ref_on = REF_ON;
 179         req->xfer[0].tx_buf = &req->ref_on;
 180         req->xfer[0].len = 1;
 181         req->xfer[1].rx_buf = &req->scratch;
 182         req->xfer[1].len = 2;
 183
 184         /*
 185          * for external VREF, 0 usec (and assume it's always on);
 186          * for 1uF, use 800 usec;
 187          * no cap, 100 usec.
 188          */
 189         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 190
 191         /* take sample */
 192         req->command = (u8) command;
 193         req->xfer[2].tx_buf = &req->command;
 194         req->xfer[2].len = 1;
 195         req->xfer[3].rx_buf = &req->sample;
 196         req->xfer[3].len = 2;
 197
 198         /* REVISIT:  take a few more samples, and compare ... */
 199
 200         /* turn off reference */
 201         req->ref_off = REF_OFF;
 202         req->xfer[4].tx_buf = &req->ref_off;
 203         req->xfer[4].len = 1;
 204         req->xfer[5].rx_buf = &req->scratch;
 205         req->xfer[5].len = 2;
 206
 207         CS_CHANGE(req->xfer[5]);
 208
 209         /* group all the transfers together, so we can't interfere with
 210          * reading touchscreen state; disable penirq while sampling
 211          */
 212         for (i = 0; i < 6; i++)
 213                 spi_message_add_tail(&req->xfer[i], &req->msg);
 214
 215         disable_irq(spi->irq);
 216         status = spi_sync(spi, &req->msg);
 217         enable_irq(spi->irq);
 218
 219         if (req->msg.status)
 220                 status = req->msg.status;
 221         sample = be16_to_cpu(req->sample);
 222         sample = sample >> 4;
 223         kfree(req);
 224
 225         return status ? status : sample;
 226 }
 227
 228 #define SHOW(name) static ssize_t \
 229 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 230 { \
 231         ssize_t v = ads7846_read12_ser(dev, \
 232                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 233         if (v < 0) \
 234                 return v; \
 235         return sprintf(buf, "%u\n", (unsigned) v); \
 236 } \
 237 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 238
 239 SHOW(temp0)
 240 SHOW(temp1)
 241 SHOW(vaux)
 242 SHOW(vbatt)
 243
 244 static int is_pen_down(struct device *dev)
 245 {
 246         struct ads7846          *ts = dev_get_drvdata(dev);
 247
 248         return ts->pendown;
 249 }
 250
 251 static ssize_t ads7846_pen_down_show(struct device *dev,
 252                                      struct device_attribute *attr, char *buf)
 253 {
 254         return sprintf(buf, "%u\n", is_pen_down(dev));
 255 }
 256
 257 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 258
 259 /*--------------------------------------------------------------------------*/
 260
 261 /*
 262  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 263  * to retrieve touchscreen status.
 264  *
 265  * The SPI transfer completion callback does the real work.  It reports
 266  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 267  */
 268
 269 static void ads7846_rx(void *ads)
 270 {
 271         struct ads7846          *ts = ads;
 272         struct input_dev        *input_dev = ts->input;
 273         unsigned                Rt;
 274         unsigned                sync = 0;
 275         u16                     x, y, z1, z2;
 276         unsigned long           flags;
 277
 278         /* adjust:  12 bit samples (left aligned), built from
 279          * two 8 bit values writen msb-first.
 280          */
 281         x = ts->tc.x >> 3;
 282         y = ts->tc.y >> 3;
 283         z1 = ts->tc.z1 >> 3;
 284         z2 = ts->tc.z2 >> 3;
 285
 286         /* range filtering */
 287         if (x == MAX_12BIT)
 288                 x = 0;
 289
 290         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 291                 /* compute touch pressure resistance using equation #2 */
 292                 Rt = z2;
 293                 Rt -= z1;
 294                 Rt *= x;
 295                 Rt *= ts->x_plate_ohms;
 296                 Rt /= z1;
 297                 Rt = (Rt + 2047) >> 12;
 298         } else
 299                 Rt = 0;
 300
 301         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 302          * being able to check nPENIRQ status, or "friendly" trigger modes
 303          * (both-edges is much better than just-falling or low-level).
 304          *
 305          * REVISIT:  some boards may require reading nPENIRQ; it's
 306          * needed on 7843.  and 7845 reads pressure differently...
 307          *
 308          * REVISIT:  the touchscreen might not be connected; this code
 309          * won't notice that, even if nPENIRQ never fires ...
 310          */
 311         if (!ts->pendown && Rt != 0) {
 312                 input_report_key(input_dev, BTN_TOUCH, 1);
 313                 sync = 1;
 314         } else if (ts->pendown && Rt == 0) {
 315                 input_report_key(input_dev, BTN_TOUCH, 0);
 316                 sync = 1;
 317         }
 318
 319         if (Rt) {
 320                 input_report_abs(input_dev, ABS_X, x);
 321                 input_report_abs(input_dev, ABS_Y, y);
 322                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 323                 sync = 1;
 324         }
 325         if (sync)
 326                 input_sync(input_dev);
 327
 328 #ifdef  VERBOSE
 329         if (Rt || ts->pendown)
 330                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 331                         x, y, Rt, Rt ? "" : " UP");
 332 #endif
 333
 334         /* don't retrigger while we're suspended */
 335         spin_lock_irqsave(&ts->lock, flags);
 336
 337         ts->pendown = (Rt != 0);
 338         ts->pending = 0;
 339
 340         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 341                 if (ts->pendown)
 342                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 343                 else if (ts->irq_disabled) {
 344                         ts->irq_disabled = 0;
 345                         enable_irq(ts->spi->irq);
 346                 }
 347         }
 348
 349         spin_unlock_irqrestore(&ts->lock, flags);
 350 }
 351
 352 static void ads7846_debounce(void *ads)
 353 {
 354         struct ads7846          *ts = ads;
 355         struct spi_message      *m;
 356         struct spi_transfer     *t;
 357         u16                     val;
 358         int                     status;
 359
 360         m = &ts->msg[ts->msg_idx];
 361         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 362         val = (*(u16 *)t->rx_buf) >> 3;
 363
 364         if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol &&
 365                               ts->read_cnt < ts->debounce_max)) {
 366                 /* Repeat it, if this was the first read or the read wasn't
 367                  * consistent enough */
 368                 ts->read_cnt++;
 369                 ts->last_read = val;
 370         } else {
 371                 /* Go for the next read */
 372                 ts->msg_idx++;
 373                 ts->read_cnt = 0;
 374                 m++;
 375         }
 376         status = spi_async(ts->spi, m);
 377         if (status)
 378                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 379                                 status);
 380 }
 381
 382 static void ads7846_timer(unsigned long handle)
 383 {
 384         struct ads7846  *ts = (void *)handle;
 385         int             status = 0;
 386
 387         ts->msg_idx = 0;
 388         status = spi_async(ts->spi, &ts->msg[0]);
 389         if (status)
 390                 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 391 }
 392
 393 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
 394 {
 395         struct ads7846 *ts = handle;
 396         unsigned long flags;
 397         int r = IRQ_HANDLED;
 398
 399         spin_lock_irqsave(&ts->lock, flags);
 400         if (ts->irq_disabled)
 401                 r = IRQ_HANDLED;
 402         else {
 403                 if (!ts->irq_disabled) {
 404                         ts->irq_disabled = 1;
 405                         /* The following has at the moment no effect whatsoever
 406                          * on OMAP, that's why we maintain the disabled
 407                          * state ourselves */
 408                         disable_irq(ts->spi->irq);
 409                 }
 410                 if (!ts->pending) {
 411                         ts->pending = 1;
 412                         mod_timer(&ts->timer, jiffies);
 413                 }
 414         }
 415         spin_unlock_irqrestore(&ts->lock, flags);
 416         return r;
 417 }
 418
 419 /*--------------------------------------------------------------------------*/
 420
 421 static int
 422 ads7846_suspend(struct spi_device *spi, pm_message_t message)
 423 {
 424         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 425         unsigned long   flags;
 426
 427         spin_lock_irqsave(&ts->lock, flags);
 428
 429         spi->dev.power.power_state = message;
 430
 431         /* are we waiting for IRQ, or polling? */
 432         if (!ts->pendown) {
 433                 if (!ts->irq_disabled) {
 434                         ts->irq_disabled = 1;
 435                         disable_irq(ts->spi->irq);
 436                 }
 437         } else {
 438                 /* polling; force a final SPI completion;
 439                  * that will clean things up neatly
 440                  */
 441                 if (!ts->pending)
 442                         mod_timer(&ts->timer, jiffies);
 443
 444                 while (ts->pendown || ts->pending) {
 445                         spin_unlock_irqrestore(&ts->lock, flags);
 446                         msleep(1);
 447                         spin_lock_irqsave(&ts->lock, flags);
 448                 }
 449         }
 450
 451         /* we know the chip's in lowpower mode since we always
 452          * leave it that way after every request
 453          */
 454
 455         spin_unlock_irqrestore(&ts->lock, flags);
 456         return 0;
 457 }
 458
 459 static int ads7846_resume(struct spi_device *spi)
 460 {
 461         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 462
 463         ts->irq_disabled = 0;
 464         enable_irq(ts->spi->irq);
 465         spi->dev.power.power_state = PMSG_ON;
 466         return 0;
 467 }
 468
 469 static int __devinit ads7846_probe(struct spi_device *spi)
 470 {
 471         struct ads7846                  *ts;
 472         struct input_dev                *input_dev;
 473         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 474         struct spi_message              *m;
 475         struct spi_transfer             *x;
 476         int                             err;
 477
 478         if (!spi->irq) {
 479                 dev_dbg(&spi->dev, "no IRQ?\n");
 480                 return -ENODEV;
 481         }
 482
 483         if (!pdata) {
 484                 dev_dbg(&spi->dev, "no platform data?\n");
 485                 return -ENODEV;
 486         }
 487
 488         /* don't exceed max specified sample rate */
 489         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 490                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 491                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 492                 return -EINVAL;
 493         }
 494
 495         /* We'd set the wordsize to 12 bits ... except that some controllers
 496          * will then treat the 8 bit command words as 12 bits (and drop the
 497          * four MSBs of the 12 bit result).  Result: inputs must be shifted
 498          * to discard the four garbage LSBs.
 499          */
 500
 501         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 502         input_dev = input_allocate_device();
 503         if (!ts || !input_dev) {
 504                 err = -ENOMEM;
 505                 goto err_free_mem;
 506         }
 507
 508         dev_set_drvdata(&spi->dev, ts);
 509         spi->dev.power.power_state = PMSG_ON;
 510
 511         ts->spi = spi;
 512         ts->input = input_dev;
 513
 514         init_timer(&ts->timer);
 515         ts->timer.data = (unsigned long) ts;
 516         ts->timer.function = ads7846_timer;
 517
 518         ts->model = pdata->model ? : 7846;
 519         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 520         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 521         ts->debounce_max = pdata->debounce_max ? : 1;
 522         ts->debounce_tol = pdata->debounce_tol ? : 10;
 523
 524         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 525
 526         input_dev->name = "ADS784x Touchscreen";
 527         input_dev->phys = ts->phys;
 528         input_dev->cdev.dev = &spi->dev;
 529
 530         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 531         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 532         input_set_abs_params(input_dev, ABS_X,
 533                         pdata->x_min ? : 0,
 534                         pdata->x_max ? : MAX_12BIT,
 535                         0, 0);
 536         input_set_abs_params(input_dev, ABS_Y,
 537                         pdata->y_min ? : 0,
 538                         pdata->y_max ? : MAX_12BIT,
 539                         0, 0);
 540         input_set_abs_params(input_dev, ABS_PRESSURE,
 541                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 542
 543         /* set up the transfers to read touchscreen state; this assumes we
 544          * use formula #2 for pressure, not #3.
 545          */
 546         m = &ts->msg[0];
 547         x = ts->xfer;
 548
 549         spi_message_init(m);
 550
 551         /* y- still on; turn on only y+ (and ADC) */
 552         ts->read_y = READ_Y;
 553         x->tx_buf = &ts->read_y;
 554         x->len = 1;
 555         spi_message_add_tail(x, m);
 556
 557         x++;
 558         x->rx_buf = &ts->tc.y;
 559         x->len = 2;
 560         spi_message_add_tail(x, m);
 561
 562         m->complete = ads7846_debounce;
 563         m->context = ts;
 564
 565         m++;
 566         spi_message_init(m);
 567
 568         /* turn y- off, x+ on, then leave in lowpower */
 569         x++;
 570         ts->read_x = READ_X;
 571         x->tx_buf = &ts->read_x;
 572         x->len = 1;
 573         spi_message_add_tail(x, m);
 574
 575         x++;
 576         x->rx_buf = &ts->tc.x;
 577         x->len = 2;
 578         spi_message_add_tail(x, m);
 579
 580         m->complete = ads7846_debounce;
 581         m->context = ts;
 582
 583         /* turn y+ off, x- on; we'll use formula #2 */
 584         if (ts->model == 7846) {
 585                 m++;
 586                 spi_message_init(m);
 587
 588                 x++;
 589                 ts->read_z1 = READ_Z1;
 590                 x->tx_buf = &ts->read_z1;
 591                 x->len = 1;
 592                 spi_message_add_tail(x, m);
 593
 594                 x++;
 595                 x->rx_buf = &ts->tc.z1;
 596                 x->len = 2;
 597                 spi_message_add_tail(x, m);
 598
 599                 m->complete = ads7846_debounce;
 600                 m->context = ts;
 601
 602                 m++;
 603                 spi_message_init(m);
 604
 605                 x++;
 606                 ts->read_z2 = READ_Z2;
 607                 x->tx_buf = &ts->read_z2;
 608                 x->len = 1;
 609                 spi_message_add_tail(x, m);
 610
 611                 x++;
 612                 x->rx_buf = &ts->tc.z2;
 613                 x->len = 2;
 614                 spi_message_add_tail(x, m);
 615
 616                 m->complete = ads7846_debounce;
 617                 m->context = ts;
 618         }
 619
 620         /* power down */
 621         m++;
 622         spi_message_init(m);
 623
 624         x++;
 625         ts->pwrdown = PWRDOWN;
 626         x->tx_buf = &ts->pwrdown;
 627         x->len = 1;
 628         spi_message_add_tail(x, m);
 629
 630         x++;
 631         x->rx_buf = &ts->dummy;
 632         x->len = 2;
 633         CS_CHANGE(*x);
 634         spi_message_add_tail(x, m);
 635
 636         m->complete = ads7846_rx;
 637         m->context = ts;
 638
 639         if (request_irq(spi->irq, ads7846_irq,
 640                         SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
 641                         spi->dev.bus_id, ts)) {
 642                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 643                 err = -EBUSY;
 644                 goto err_free_mem;
 645         }
 646
 647         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 648
 649         /* take a first sample, leaving nPENIRQ active; avoid
 650          * the touchscreen, in case it's not connected.
 651          */
 652         (void) ads7846_read12_ser(&spi->dev,
 653                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 654
 655         /* ads7843/7845 don't have temperature sensors, and
 656          * use the other sensors a bit differently too
 657          */
 658         if (ts->model == 7846) {
 659                 device_create_file(&spi->dev, &dev_attr_temp0);
 660                 device_create_file(&spi->dev, &dev_attr_temp1);
 661         }
 662         if (ts->model != 7845)
 663                 device_create_file(&spi->dev, &dev_attr_vbatt);
 664         device_create_file(&spi->dev, &dev_attr_vaux);
 665
 666         device_create_file(&spi->dev, &dev_attr_pen_down);
 667
 668         err = input_register_device(input_dev);
 669         if (err)
 670                 goto err_free_irq;
 671
 672         return 0;
 673
 674  err_free_irq:
 675         free_irq(spi->irq, ts);
 676  err_free_mem:
 677         input_free_device(input_dev);
 678         kfree(ts);
 679         return err;
 680 }
 681
 682 static int __devexit ads7846_remove(struct spi_device *spi)
 683 {
 684         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 685
 686         ads7846_suspend(spi, PMSG_SUSPEND);
 687         free_irq(ts->spi->irq, ts);
 688         if (ts->irq_disabled)
 689                 enable_irq(ts->spi->irq);
 690
 691         device_remove_file(&spi->dev, &dev_attr_pen_down);
 692
 693         if (ts->model == 7846) {
 694                 device_remove_file(&spi->dev, &dev_attr_temp0);
 695                 device_remove_file(&spi->dev, &dev_attr_temp1);
 696         }
 697         if (ts->model != 7845)
 698                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 699         device_remove_file(&spi->dev, &dev_attr_vaux);
 700
 701         input_unregister_device(ts->input);
 702         kfree(ts);
 703
 704         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 705         return 0;
 706 }
 707
 708 static struct spi_driver ads7846_driver = {
 709         .driver = {
 710                 .name   = "ads7846",
 711                 .bus    = &spi_bus_type,
 712                 .owner  = THIS_MODULE,
 713         },
 714         .probe          = ads7846_probe,
 715         .remove         = __devexit_p(ads7846_remove),
 716         .suspend        = ads7846_suspend,
 717         .resume         = ads7846_resume,
 718 };
 719
 720 static int __init ads7846_init(void)
 721 {
 722         /* grr, board-specific init should stay out of drivers!! */
 723
 724 #ifdef  CONFIG_ARCH_OMAP
 725         if (machine_is_omap_osk()) {
 726                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 727                 omap_request_gpio(4);
 728                 omap_set_gpio_direction(4, 1);
 729                 omap_request_gpio(6);
 730                 omap_set_gpio_direction(6, 1);
 731         }
 732         // also TI 1510 Innovator, bitbanging through FPGA
 733         // also Nokia 770
 734         // also Palm Tungsten T2
 735 #endif
 736
 737         // PXA:
 738         // also Dell Axim X50
 739         // also HP iPaq H191x/H192x/H415x/H435x
 740         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 741         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 742
 743         // Atmel at91sam9261-EK uses ads7843
 744
 745         // also various AMD Au1x00 devel boards
 746
 747         return spi_register_driver(&ads7846_driver);
 748 }
 749 module_init(ads7846_init);
 750
 751 static void __exit ads7846_exit(void)
 752 {
 753         spi_unregister_driver(&ads7846_driver);
 754
 755 #ifdef  CONFIG_ARCH_OMAP
 756         if (machine_is_omap_osk()) {
 757                 omap_free_gpio(4);
 758                 omap_free_gpio(6);
 759         }
 760 #endif
 761
 762 }
 763 module_exit(ads7846_exit);
 764
 765 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 766 MODULE_LICENSE("GPL");