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[5];
  81         int                     msg_idx;
  82         int                     read_cnt;
  83         int                     last_read;
  84
  85         u16                     debounce_max;
  86         u16                     debounce_tol;
  87
  88         spinlock_t              lock;
  89         struct timer_list       timer;          /* P: lock */
  90         unsigned                pendown:1;      /* P: lock */
  91         unsigned                pending:1;      /* P: lock */
  92 // FIXME remove "irq_disabled"
  93         unsigned                irq_disabled:1; /* P: lock */
  94 };
  95
  96 /* leave chip selected when we're done, for quicker re-select? */
  97 #if     0
  98 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
  99 #else
 100 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 101 #endif
 102
 103 /*--------------------------------------------------------------------------*/
 104
 105 /* The ADS7846 has touchscreen and other sensors.
 106  * Earlier ads784x chips are somewhat compatible.
 107  */
 108 #define ADS_START               (1 << 7)
 109 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 110 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 111 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 112 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 113 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 114 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 115 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 116 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 117 #define ADS_8_BIT               (1 << 3)
 118 #define ADS_12_BIT              (0 << 3)
 119 #define ADS_SER                 (1 << 2)        /* non-differential */
 120 #define ADS_DFR                 (0 << 2)        /* differential */
 121 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 122 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 123 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 124 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 125
 126 #define MAX_12BIT       ((1<<12)-1)
 127
 128 /* leave ADC powered up (disables penirq) between differential samples */
 129 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 130         | ADS_12_BIT | ADS_DFR)
 131
 132 #define READ_Y  (READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
 133 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
 134 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
 135
 136 #define READ_X  (READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)
 137 #define PWRDOWN (READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)   /* LAST */
 138
 139 /* single-ended samples need to first power up reference voltage;
 140  * we leave both ADC and VREF powered
 141  */
 142 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 143         | ADS_12_BIT | ADS_SER)
 144
 145 #define REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
 146 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 147
 148 /*--------------------------------------------------------------------------*/
 149
 150 /*
 151  * Non-touchscreen sensors only use single-ended conversions.
 152  */
 153
 154 struct ser_req {
 155         u8                      ref_on;
 156         u8                      command;
 157         u8                      ref_off;
 158         u16                     scratch;
 159         __be16                  sample;
 160         struct spi_message      msg;
 161         struct spi_transfer     xfer[6];
 162 };
 163
 164 static int ads7846_read12_ser(struct device *dev, unsigned command)
 165 {
 166         struct spi_device       *spi = to_spi_device(dev);
 167         struct ads7846          *ts = dev_get_drvdata(dev);
 168         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
 169         int                     status;
 170         int                     sample;
 171         int                     i;
 172
 173         if (!req)
 174                 return -ENOMEM;
 175
 176         spi_message_init(&req->msg);
 177
 178         /* activate reference, so it has time to settle; */
 179         req->ref_on = REF_ON;
 180         req->xfer[0].tx_buf = &req->ref_on;
 181         req->xfer[0].len = 1;
 182         req->xfer[1].rx_buf = &req->scratch;
 183         req->xfer[1].len = 2;
 184
 185         /*
 186          * for external VREF, 0 usec (and assume it's always on);
 187          * for 1uF, use 800 usec;
 188          * no cap, 100 usec.
 189          */
 190         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 191
 192         /* take sample */
 193         req->command = (u8) command;
 194         req->xfer[2].tx_buf = &req->command;
 195         req->xfer[2].len = 1;
 196         req->xfer[3].rx_buf = &req->sample;
 197         req->xfer[3].len = 2;
 198
 199         /* REVISIT:  take a few more samples, and compare ... */
 200
 201         /* turn off reference */
 202         req->ref_off = REF_OFF;
 203         req->xfer[4].tx_buf = &req->ref_off;
 204         req->xfer[4].len = 1;
 205         req->xfer[5].rx_buf = &req->scratch;
 206         req->xfer[5].len = 2;
 207
 208         CS_CHANGE(req->xfer[5]);
 209
 210         /* group all the transfers together, so we can't interfere with
 211          * reading touchscreen state; disable penirq while sampling
 212          */
 213         for (i = 0; i < 6; i++)
 214                 spi_message_add_tail(&req->xfer[i], &req->msg);
 215
 216         disable_irq(spi->irq);
 217         status = spi_sync(spi, &req->msg);
 218         enable_irq(spi->irq);
 219
 220         if (req->msg.status)
 221                 status = req->msg.status;
 222         sample = be16_to_cpu(req->sample);
 223         sample = sample >> 4;
 224         kfree(req);
 225
 226         return status ? status : sample;
 227 }
 228
 229 #define SHOW(name) static ssize_t \
 230 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 231 { \
 232         ssize_t v = ads7846_read12_ser(dev, \
 233                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 234         if (v < 0) \
 235                 return v; \
 236         return sprintf(buf, "%u\n", (unsigned) v); \
 237 } \
 238 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 239
 240 SHOW(temp0)
 241 SHOW(temp1)
 242 SHOW(vaux)
 243 SHOW(vbatt)
 244
 245 static int is_pen_down(struct device *dev)
 246 {
 247         struct ads7846          *ts = dev_get_drvdata(dev);
 248
 249         return ts->pendown;
 250 }
 251
 252 static ssize_t ads7846_pen_down_show(struct device *dev,
 253                                      struct device_attribute *attr, char *buf)
 254 {
 255         return sprintf(buf, "%u\n", is_pen_down(dev));
 256 }
 257
 258 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 259
 260 /*--------------------------------------------------------------------------*/
 261
 262 /*
 263  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 264  * to retrieve touchscreen status.
 265  *
 266  * The SPI transfer completion callback does the real work.  It reports
 267  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 268  */
 269
 270 static void ads7846_rx(void *ads)
 271 {
 272         struct ads7846          *ts = ads;
 273         struct input_dev        *input_dev = ts->input;
 274         unsigned                Rt;
 275         unsigned                sync = 0;
 276         u16                     x, y, z1, z2;
 277         unsigned long           flags;
 278
 279         /* adjust:  12 bit samples (left aligned), built from
 280          * two 8 bit values writen msb-first.
 281          */
 282         x = be16_to_cpu(ts->tc.x) >> 4;
 283         y = be16_to_cpu(ts->tc.y) >> 4;
 284         z1 = be16_to_cpu(ts->tc.z1) >> 4;
 285         z2 = be16_to_cpu(ts->tc.z2) >> 4;
 286
 287         /* range filtering */
 288         if (x == MAX_12BIT)
 289                 x = 0;
 290
 291         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 292                 /* compute touch pressure resistance using equation #2 */
 293                 Rt = z2;
 294                 Rt -= z1;
 295                 Rt *= x;
 296                 Rt *= ts->x_plate_ohms;
 297                 Rt /= z1;
 298                 Rt = (Rt + 2047) >> 12;
 299         } else
 300                 Rt = 0;
 301
 302         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 303          * being able to check nPENIRQ status, or "friendly" trigger modes
 304          * (both-edges is much better than just-falling or low-level).
 305          *
 306          * REVISIT:  some boards may require reading nPENIRQ; it's
 307          * needed on 7843.  and 7845 reads pressure differently...
 308          *
 309          * REVISIT:  the touchscreen might not be connected; this code
 310          * won't notice that, even if nPENIRQ never fires ...
 311          */
 312         if (!ts->pendown && Rt != 0) {
 313                 input_report_key(input_dev, BTN_TOUCH, 1);
 314                 sync = 1;
 315         } else if (ts->pendown && Rt == 0) {
 316                 input_report_key(input_dev, BTN_TOUCH, 0);
 317                 sync = 1;
 318         }
 319
 320         if (Rt) {
 321                 input_report_abs(input_dev, ABS_X, x);
 322                 input_report_abs(input_dev, ABS_Y, y);
 323                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 324                 sync = 1;
 325         }
 326         if (sync)
 327                 input_sync(input_dev);
 328
 329 #ifdef  VERBOSE
 330         if (Rt || ts->pendown)
 331                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 332                         x, y, Rt, Rt ? "" : " UP");
 333 #endif
 334
 335         /* don't retrigger while we're suspended */
 336         spin_lock_irqsave(&ts->lock, flags);
 337
 338         ts->pendown = (Rt != 0);
 339         ts->pending = 0;
 340
 341         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
 342                 if (ts->pendown)
 343                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 344                 else if (ts->irq_disabled) {
 345                         ts->irq_disabled = 0;
 346                         enable_irq(ts->spi->irq);
 347                 }
 348         }
 349
 350         spin_unlock_irqrestore(&ts->lock, flags);
 351 }
 352
 353 static void ads7846_debounce(void *ads)
 354 {
 355         struct ads7846          *ts = ads;
 356         struct spi_message      *m;
 357         struct spi_transfer     *t;
 358         u16                     val;
 359         int                     status;
 360
 361         m = &ts->msg[ts->msg_idx];
 362         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 363         val = (*(u16 *)t->rx_buf) >> 3;
 364
 365         if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol
 366                                 && ts->read_cnt < ts->debounce_max)) {
 367                 /* Repeat it, if this was the first read or the read wasn't
 368                  * consistent enough
 369                  */
 370                 ts->read_cnt++;
 371                 ts->last_read = val;
 372         } else {
 373                 /* Go for the next read */
 374                 ts->msg_idx++;
 375                 ts->read_cnt = 0;
 376                 m++;
 377         }
 378         status = spi_async(ts->spi, m);
 379         if (status)
 380                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 381                                 status);
 382 }
 383
 384 static void ads7846_timer(unsigned long handle)
 385 {
 386         struct ads7846  *ts = (void *)handle;
 387         int             status = 0;
 388
 389         ts->msg_idx = 0;
 390         status = spi_async(ts->spi, &ts->msg[0]);
 391         if (status)
 392                 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 393 }
 394
 395 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
 396 {
 397         struct ads7846 *ts = handle;
 398         unsigned long flags;
 399         int r = IRQ_HANDLED;
 400
 401         spin_lock_irqsave(&ts->lock, flags);
 402         if (ts->irq_disabled)
 403                 r = IRQ_HANDLED;
 404         else {
 405                 if (!ts->irq_disabled) {
 406                         /* REVISIT irq logic for many ARM chips has cloned a
 407                          * bug wherein disabling an irq in its handler won't
 408                          * work;(it's disabled lazily, and too late to work.
 409                          * until all their irq logic is fixed, we must shadow
 410                          * that state here.
 411                          */
 412                         ts->irq_disabled = 1;
 413
 414                         disable_irq(ts->spi->irq);
 415                 }
 416                 if (!ts->pending) {
 417                         ts->pending = 1;
 418                         mod_timer(&ts->timer, jiffies);
 419                 }
 420         }
 421         spin_unlock_irqrestore(&ts->lock, flags);
 422         return r;
 423 }
 424
 425 /*--------------------------------------------------------------------------*/
 426
 427 static int
 428 ads7846_suspend(struct spi_device *spi, pm_message_t message)
 429 {
 430         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 431         unsigned long   flags;
 432
 433         spin_lock_irqsave(&ts->lock, flags);
 434
 435         spi->dev.power.power_state = message;
 436
 437         /* are we waiting for IRQ, or polling? */
 438         if (!ts->pendown) {
 439                 if (!ts->irq_disabled) {
 440                         ts->irq_disabled = 1;
 441                         disable_irq(ts->spi->irq);
 442                 }
 443         } else {
 444                 /* polling; force a final SPI completion;
 445                  * that will clean things up neatly
 446                  */
 447                 if (!ts->pending)
 448                         mod_timer(&ts->timer, jiffies);
 449
 450                 while (ts->pendown || ts->pending) {
 451                         spin_unlock_irqrestore(&ts->lock, flags);
 452                         udelay(10);
 453                         spin_lock_irqsave(&ts->lock, flags);
 454                 }
 455         }
 456
 457         /* we know the chip's in lowpower mode since we always
 458          * leave it that way after every request
 459          */
 460
 461         spin_unlock_irqrestore(&ts->lock, flags);
 462         return 0;
 463 }
 464
 465 static int ads7846_resume(struct spi_device *spi)
 466 {
 467         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 468
 469         ts->irq_disabled = 0;
 470         enable_irq(ts->spi->irq);
 471         spi->dev.power.power_state = PMSG_ON;
 472         return 0;
 473 }
 474
 475 static int __devinit ads7846_probe(struct spi_device *spi)
 476 {
 477         struct ads7846                  *ts;
 478         struct input_dev                *input_dev;
 479         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 480         struct spi_message              *m;
 481         struct spi_transfer             *x;
 482         int                             err;
 483
 484         if (!spi->irq) {
 485                 dev_dbg(&spi->dev, "no IRQ?\n");
 486                 return -ENODEV;
 487         }
 488
 489         if (!pdata) {
 490                 dev_dbg(&spi->dev, "no platform data?\n");
 491                 return -ENODEV;
 492         }
 493
 494         /* don't exceed max specified sample rate */
 495         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 496                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 497                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 498                 return -EINVAL;
 499         }
 500
 501         /* We'd set the wordsize to 12 bits ... except that some controllers
 502          * will then treat the 8 bit command words as 12 bits (and drop the
 503          * four MSBs of the 12 bit result).  Result: inputs must be shifted
 504          * to discard the four garbage LSBs.
 505          */
 506
 507         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 508         input_dev = input_allocate_device();
 509         if (!ts || !input_dev) {
 510                 err = -ENOMEM;
 511                 goto err_free_mem;
 512         }
 513
 514         dev_set_drvdata(&spi->dev, ts);
 515         spi->dev.power.power_state = PMSG_ON;
 516
 517         ts->spi = spi;
 518         ts->input = input_dev;
 519
 520         init_timer(&ts->timer);
 521         ts->timer.data = (unsigned long) ts;
 522         ts->timer.function = ads7846_timer;
 523
 524         ts->model = pdata->model ? : 7846;
 525         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 526         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 527         ts->debounce_max = pdata->debounce_max ? : 1;
 528         ts->debounce_tol = pdata->debounce_tol ? : 10;
 529
 530         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 531
 532         input_dev->name = "ADS784x Touchscreen";
 533         input_dev->phys = ts->phys;
 534         input_dev->cdev.dev = &spi->dev;
 535
 536         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 537         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 538         input_set_abs_params(input_dev, ABS_X,
 539                         pdata->x_min ? : 0,
 540                         pdata->x_max ? : MAX_12BIT,
 541                         0, 0);
 542         input_set_abs_params(input_dev, ABS_Y,
 543                         pdata->y_min ? : 0,
 544                         pdata->y_max ? : MAX_12BIT,
 545                         0, 0);
 546         input_set_abs_params(input_dev, ABS_PRESSURE,
 547                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 548
 549         /* set up the transfers to read touchscreen state; this assumes we
 550          * use formula #2 for pressure, not #3.
 551          */
 552         m = &ts->msg[0];
 553         x = ts->xfer;
 554
 555         spi_message_init(m);
 556
 557         /* y- still on; turn on only y+ (and ADC) */
 558         ts->read_y = READ_Y;
 559         x->tx_buf = &ts->read_y;
 560         x->len = 1;
 561         spi_message_add_tail(x, m);
 562
 563         x++;
 564         x->rx_buf = &ts->tc.y;
 565         x->len = 2;
 566         spi_message_add_tail(x, m);
 567
 568         m->complete = ads7846_debounce;
 569         m->context = ts;
 570
 571         m++;
 572         spi_message_init(m);
 573
 574         /* turn y- off, x+ on, then leave in lowpower */
 575         x++;
 576         ts->read_x = READ_X;
 577         x->tx_buf = &ts->read_x;
 578         x->len = 1;
 579         spi_message_add_tail(x, m);
 580
 581         x++;
 582         x->rx_buf = &ts->tc.x;
 583         x->len = 2;
 584         spi_message_add_tail(x, m);
 585
 586         m->complete = ads7846_debounce;
 587         m->context = ts;
 588
 589         /* turn y+ off, x- on; we'll use formula #2 */
 590         if (ts->model == 7846) {
 591                 m++;
 592                 spi_message_init(m);
 593
 594                 x++;
 595                 ts->read_z1 = READ_Z1;
 596                 x->tx_buf = &ts->read_z1;
 597                 x->len = 1;
 598                 spi_message_add_tail(x, m);
 599
 600                 x++;
 601                 x->rx_buf = &ts->tc.z1;
 602                 x->len = 2;
 603                 spi_message_add_tail(x, m);
 604
 605                 m->complete = ads7846_debounce;
 606                 m->context = ts;
 607
 608                 m++;
 609                 spi_message_init(m);
 610
 611                 x++;
 612                 ts->read_z2 = READ_Z2;
 613                 x->tx_buf = &ts->read_z2;
 614                 x->len = 1;
 615                 spi_message_add_tail(x, m);
 616
 617                 x++;
 618                 x->rx_buf = &ts->tc.z2;
 619                 x->len = 2;
 620                 spi_message_add_tail(x, m);
 621
 622                 m->complete = ads7846_debounce;
 623                 m->context = ts;
 624         }
 625
 626         /* power down */
 627         m++;
 628         spi_message_init(m);
 629
 630         x++;
 631         ts->pwrdown = PWRDOWN;
 632         x->tx_buf = &ts->pwrdown;
 633         x->len = 1;
 634         spi_message_add_tail(x, m);
 635
 636         x++;
 637         x->rx_buf = &ts->dummy;
 638         x->len = 2;
 639         CS_CHANGE(*x);
 640         spi_message_add_tail(x, m);
 641
 642         m->complete = ads7846_rx;
 643         m->context = ts;
 644
 645         if (request_irq(spi->irq, ads7846_irq,
 646                         SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
 647                         spi->dev.bus_id, ts)) {
 648                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 649                 err = -EBUSY;
 650                 goto err_free_mem;
 651         }
 652
 653         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 654
 655         /* take a first sample, leaving nPENIRQ active; avoid
 656          * the touchscreen, in case it's not connected.
 657          */
 658         (void) ads7846_read12_ser(&spi->dev,
 659                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 660
 661         /* ads7843/7845 don't have temperature sensors, and
 662          * use the other sensors a bit differently too
 663          */
 664         if (ts->model == 7846) {
 665                 device_create_file(&spi->dev, &dev_attr_temp0);
 666                 device_create_file(&spi->dev, &dev_attr_temp1);
 667         }
 668         if (ts->model != 7845)
 669                 device_create_file(&spi->dev, &dev_attr_vbatt);
 670         device_create_file(&spi->dev, &dev_attr_vaux);
 671
 672         device_create_file(&spi->dev, &dev_attr_pen_down);
 673
 674         err = input_register_device(input_dev);
 675         if (err)
 676                 goto err_free_irq;
 677
 678         return 0;
 679
 680  err_free_irq:
 681         free_irq(spi->irq, ts);
 682  err_free_mem:
 683         input_free_device(input_dev);
 684         kfree(ts);
 685         return err;
 686 }
 687
 688 static int __devexit ads7846_remove(struct spi_device *spi)
 689 {
 690         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 691
 692         ads7846_suspend(spi, PMSG_SUSPEND);
 693         free_irq(ts->spi->irq, ts);
 694         if (ts->irq_disabled)
 695                 enable_irq(ts->spi->irq);
 696
 697         device_remove_file(&spi->dev, &dev_attr_pen_down);
 698
 699         if (ts->model == 7846) {
 700                 device_remove_file(&spi->dev, &dev_attr_temp0);
 701                 device_remove_file(&spi->dev, &dev_attr_temp1);
 702         }
 703         if (ts->model != 7845)
 704                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 705         device_remove_file(&spi->dev, &dev_attr_vaux);
 706
 707         input_unregister_device(ts->input);
 708         kfree(ts);
 709
 710         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 711         return 0;
 712 }
 713
 714 static struct spi_driver ads7846_driver = {
 715         .driver = {
 716                 .name   = "ads7846",
 717                 .bus    = &spi_bus_type,
 718                 .owner  = THIS_MODULE,
 719         },
 720         .probe          = ads7846_probe,
 721         .remove         = __devexit_p(ads7846_remove),
 722         .suspend        = ads7846_suspend,
 723         .resume         = ads7846_resume,
 724 };
 725
 726 static int __init ads7846_init(void)
 727 {
 728         /* grr, board-specific init should stay out of drivers!! */
 729
 730 #ifdef  CONFIG_ARCH_OMAP
 731         if (machine_is_omap_osk()) {
 732                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 733                 omap_request_gpio(4);
 734                 omap_set_gpio_direction(4, 1);
 735                 omap_request_gpio(6);
 736                 omap_set_gpio_direction(6, 1);
 737         }
 738         // also TI 1510 Innovator, bitbanging through FPGA
 739         // also Nokia 770
 740         // also Palm Tungsten T2
 741 #endif
 742
 743         // PXA:
 744         // also Dell Axim X50
 745         // also HP iPaq H191x/H192x/H415x/H435x
 746         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 747         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 748
 749         // Atmel at91sam9261-EK uses ads7843
 750
 751         // also various AMD Au1x00 devel boards
 752
 753         return spi_register_driver(&ads7846_driver);
 754 }
 755 module_init(ads7846_init);
 756
 757 static void __exit ads7846_exit(void)
 758 {
 759         spi_unregister_driver(&ads7846_driver);
 760
 761 #ifdef  CONFIG_ARCH_OMAP
 762         if (machine_is_omap_osk()) {
 763                 omap_free_gpio(4);
 764                 omap_free_gpio(6);
 765         }
 766 #endif
 767
 768 }
 769 module_exit(ads7846_exit);
 770
 771 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 772 MODULE_LICENSE("GPL");