git.oblomov.eu Git - linux-2.6/blob - drivers/input/touchscreen/ads7846.c

   1 /*
   2  * ADS7846 based touchscreen and sensor driver
   3  *
   4  * Copyright (c) 2005 David Brownell
   5  * Copyright (c) 2006 Nokia Corporation
   6  * Various changes: Imre Deak <imre.deak@nokia.com>
   7  *
   8  * Using code from:
   9  *  - corgi_ts.c
  10  *      Copyright (C) 2004-2005 Richard Purdie
  11  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  12  *      Copyright (C) 2002 MontaVista Software
  13  *      Copyright (C) 2004 Texas Instruments
  14  *      Copyright (C) 2005 Dirk Behme
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2 as
  18  *  published by the Free Software Foundation.
  19  */
  20 #include <linux/device.h>
  21 #include <linux/init.h>
  22 #include <linux/delay.h>
  23 #include <linux/input.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/slab.h>
  26 #include <linux/spi/spi.h>
  27 #include <linux/spi/ads7846.h>
  28 #include <asm/irq.h>
  29
  30 #ifdef  CONFIG_ARM
  31 #include <asm/mach-types.h>
  32 #ifdef  CONFIG_ARCH_OMAP
  33 #include <asm/arch/gpio.h>
  34 #endif
  35 #endif
  36
  37
  38 /*
  39  * This code has been heavily tested on a Nokia 770, and lightly
  40  * tested on other ads7846 devices (OSK/Mistral, Lubbock).
  41  * Support for ads7843 and ads7845 has only been stubbed in.
  42  *
  43  * IRQ handling needs a workaround because of a shortcoming in handling
  44  * edge triggered IRQs on some platforms like the OMAP1/2. These
  45  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  46  * have to maintain our own SW IRQ disabled status. This should be
  47  * removed as soon as the affected platform's IRQ handling is fixed.
  48  *
  49  * app note sbaa036 talks in more detail about accurate sampling...
  50  * that ought to help in situations like LCDs inducing noise (which
  51  * can also be helped by using synch signals) and more generally.
  52  * This driver tries to utilize the measures described in the app
  53  * note. The strength of filtering can be set in the board-* specific
  54  * files.
  55  */
  56
  57 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
  58
  59 /* this driver doesn't aim at the peak continuous sample rate */
  60 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  61
  62 struct ts_event {
  63         /* For portability, we can't read 12 bit values using SPI (which
  64          * would make the controller deliver them as native byteorder u16
  65          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  66          * which need byteswapping then range adjustment.
  67          */
  68         __be16 x;
  69         __be16 y;
  70         __be16 z1, z2;
  71         int    ignore;
  72 };
  73
  74 struct ads7846 {
  75         struct input_dev        *input;
  76         char                    phys[32];
  77
  78         struct spi_device       *spi;
  79         u16                     model;
  80         u16                     vref_delay_usecs;
  81         u16                     x_plate_ohms;
  82         u16                     pressure_max;
  83
  84         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  85         u16                     dummy;          /* for the pwrdown read */
  86         struct ts_event         tc;
  87
  88         struct spi_transfer     xfer[10];
  89         struct spi_message      msg[5];
  90         struct spi_message      *last_msg;
  91         int                     msg_idx;
  92         int                     read_cnt;
  93         int                     read_rep;
  94         int                     last_read;
  95
  96         u16                     debounce_max;
  97         u16                     debounce_tol;
  98         u16                     debounce_rep;
  99
 100         spinlock_t              lock;
 101         struct timer_list       timer;          /* P: lock */
 102         unsigned                pendown:1;      /* P: lock */
 103         unsigned                pending:1;      /* P: lock */
 104 // FIXME remove "irq_disabled"
 105         unsigned                irq_disabled:1; /* P: lock */
 106         unsigned                disabled:1;
 107
 108         int                     (*get_pendown_state)(void);
 109 };
 110
 111 /* leave chip selected when we're done, for quicker re-select? */
 112 #if     0
 113 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 114 #else
 115 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 116 #endif
 117
 118 /*--------------------------------------------------------------------------*/
 119
 120 /* The ADS7846 has touchscreen and other sensors.
 121  * Earlier ads784x chips are somewhat compatible.
 122  */
 123 #define ADS_START               (1 << 7)
 124 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 125 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 126 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 127 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 128 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 129 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 130 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 131 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 132 #define ADS_8_BIT               (1 << 3)
 133 #define ADS_12_BIT              (0 << 3)
 134 #define ADS_SER                 (1 << 2)        /* non-differential */
 135 #define ADS_DFR                 (0 << 2)        /* differential */
 136 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 137 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 138 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 139 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 140
 141 #define MAX_12BIT       ((1<<12)-1)
 142
 143 /* leave ADC powered up (disables penirq) between differential samples */
 144 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
 145         | ADS_12_BIT | ADS_DFR)
 146
 147 #define READ_Y  (READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)
 148 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
 149 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
 150
 151 #define READ_X  (READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)
 152 #define PWRDOWN (READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)   /* LAST */
 153
 154 /* single-ended samples need to first power up reference voltage;
 155  * we leave both ADC and VREF powered
 156  */
 157 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 158         | ADS_12_BIT | ADS_SER)
 159
 160 #define REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
 161 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 162
 163 /*--------------------------------------------------------------------------*/
 164
 165 /*
 166  * Non-touchscreen sensors only use single-ended conversions.
 167  */
 168
 169 struct ser_req {
 170         u8                      ref_on;
 171         u8                      command;
 172         u8                      ref_off;
 173         u16                     scratch;
 174         __be16                  sample;
 175         struct spi_message      msg;
 176         struct spi_transfer     xfer[6];
 177 };
 178
 179 static void ads7846_enable(struct ads7846 *ts);
 180 static void ads7846_disable(struct ads7846 *ts);
 181
 182 static int device_suspended(struct device *dev)
 183 {
 184         struct ads7846 *ts = dev_get_drvdata(dev);
 185         return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
 186 }
 187
 188 static int ads7846_read12_ser(struct device *dev, unsigned command)
 189 {
 190         struct spi_device       *spi = to_spi_device(dev);
 191         struct ads7846          *ts = dev_get_drvdata(dev);
 192         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
 193         int                     status;
 194         int                     sample;
 195         int                     i;
 196
 197         if (!req)
 198                 return -ENOMEM;
 199
 200         spi_message_init(&req->msg);
 201
 202         /* activate reference, so it has time to settle; */
 203         req->ref_on = REF_ON;
 204         req->xfer[0].tx_buf = &req->ref_on;
 205         req->xfer[0].len = 1;
 206         req->xfer[1].rx_buf = &req->scratch;
 207         req->xfer[1].len = 2;
 208
 209         /*
 210          * for external VREF, 0 usec (and assume it's always on);
 211          * for 1uF, use 800 usec;
 212          * no cap, 100 usec.
 213          */
 214         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 215
 216         /* take sample */
 217         req->command = (u8) command;
 218         req->xfer[2].tx_buf = &req->command;
 219         req->xfer[2].len = 1;
 220         req->xfer[3].rx_buf = &req->sample;
 221         req->xfer[3].len = 2;
 222
 223         /* REVISIT:  take a few more samples, and compare ... */
 224
 225         /* turn off reference */
 226         req->ref_off = REF_OFF;
 227         req->xfer[4].tx_buf = &req->ref_off;
 228         req->xfer[4].len = 1;
 229         req->xfer[5].rx_buf = &req->scratch;
 230         req->xfer[5].len = 2;
 231
 232         CS_CHANGE(req->xfer[5]);
 233
 234         /* group all the transfers together, so we can't interfere with
 235          * reading touchscreen state; disable penirq while sampling
 236          */
 237         for (i = 0; i < 6; i++)
 238                 spi_message_add_tail(&req->xfer[i], &req->msg);
 239
 240         ts->irq_disabled = 1;
 241         disable_irq(spi->irq);
 242         status = spi_sync(spi, &req->msg);
 243         ts->irq_disabled = 0;
 244         enable_irq(spi->irq);
 245
 246         if (req->msg.status)
 247                 status = req->msg.status;
 248
 249         /* on-wire is a must-ignore bit, a BE12 value, then padding */
 250         sample = be16_to_cpu(req->sample);
 251         sample = sample >> 3;
 252         sample &= 0x0fff;
 253
 254         kfree(req);
 255         return status ? status : sample;
 256 }
 257
 258 #define SHOW(name) static ssize_t \
 259 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 260 { \
 261         ssize_t v = ads7846_read12_ser(dev, \
 262                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 263         if (v < 0) \
 264                 return v; \
 265         return sprintf(buf, "%u\n", (unsigned) v); \
 266 } \
 267 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 268
 269 SHOW(temp0)
 270 SHOW(temp1)
 271 SHOW(vaux)
 272 SHOW(vbatt)
 273
 274 static int is_pen_down(struct device *dev)
 275 {
 276         struct ads7846          *ts = dev_get_drvdata(dev);
 277
 278         return ts->pendown;
 279 }
 280
 281 static ssize_t ads7846_pen_down_show(struct device *dev,
 282                                      struct device_attribute *attr, char *buf)
 283 {
 284         return sprintf(buf, "%u\n", is_pen_down(dev));
 285 }
 286
 287 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 288
 289 static ssize_t ads7846_disable_show(struct device *dev,
 290                                      struct device_attribute *attr, char *buf)
 291 {
 292         struct ads7846  *ts = dev_get_drvdata(dev);
 293
 294         return sprintf(buf, "%u\n", ts->disabled);
 295 }
 296
 297 static ssize_t ads7846_disable_store(struct device *dev,
 298                                      struct device_attribute *attr,
 299                                      const char *buf, size_t count)
 300 {
 301         struct ads7846 *ts = dev_get_drvdata(dev);
 302         char *endp;
 303         int i;
 304
 305         i = simple_strtoul(buf, &endp, 10);
 306         spin_lock_irq(&ts->lock);
 307
 308         if (i)
 309                 ads7846_disable(ts);
 310         else
 311                 ads7846_enable(ts);
 312
 313         spin_unlock_irq(&ts->lock);
 314
 315         return count;
 316 }
 317
 318 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 319
 320 /*--------------------------------------------------------------------------*/
 321
 322 /*
 323  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 324  * to retrieve touchscreen status.
 325  *
 326  * The SPI transfer completion callback does the real work.  It reports
 327  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 328  */
 329
 330 static void ads7846_rx(void *ads)
 331 {
 332         struct ads7846          *ts = ads;
 333         struct input_dev        *input_dev = ts->input;
 334         unsigned                Rt;
 335         unsigned                sync = 0;
 336         u16                     x, y, z1, z2;
 337         unsigned long           flags;
 338
 339         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
 340          * built from two 8 bit values written msb-first.
 341          */
 342         x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff;
 343         y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff;
 344         z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff;
 345         z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff;
 346
 347         /* range filtering */
 348         if (x == MAX_12BIT)
 349                 x = 0;
 350
 351         if (likely(x && z1 && !device_suspended(&ts->spi->dev))) {
 352                 /* compute touch pressure resistance using equation #2 */
 353                 Rt = z2;
 354                 Rt -= z1;
 355                 Rt *= x;
 356                 Rt *= ts->x_plate_ohms;
 357                 Rt /= z1;
 358                 Rt = (Rt + 2047) >> 12;
 359         } else
 360                 Rt = 0;
 361
 362         /* Sample found inconsistent by debouncing or pressure is beyond
 363         * the maximum. Don't report it to user space, repeat at least
 364         * once more the measurement */
 365         if (ts->tc.ignore || Rt > ts->pressure_max) {
 366                 mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 367                 return;
 368         }
 369
 370         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 371          * being able to check nPENIRQ status, or "friendly" trigger modes
 372          * (both-edges is much better than just-falling or low-level).
 373          *
 374          * REVISIT:  some boards may require reading nPENIRQ; it's
 375          * needed on 7843.  and 7845 reads pressure differently...
 376          *
 377          * REVISIT:  the touchscreen might not be connected; this code
 378          * won't notice that, even if nPENIRQ never fires ...
 379          */
 380         if (!ts->pendown && Rt != 0) {
 381                 input_report_key(input_dev, BTN_TOUCH, 1);
 382                 sync = 1;
 383         } else if (ts->pendown && Rt == 0) {
 384                 input_report_key(input_dev, BTN_TOUCH, 0);
 385                 sync = 1;
 386         }
 387
 388         if (Rt) {
 389                 input_report_abs(input_dev, ABS_X, x);
 390                 input_report_abs(input_dev, ABS_Y, y);
 391                 sync = 1;
 392         }
 393
 394         if (sync) {
 395                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 396                 input_sync(input_dev);
 397         }
 398
 399 #ifdef  VERBOSE
 400         if (Rt || ts->pendown)
 401                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 402                         x, y, Rt, Rt ? "" : " UP");
 403 #endif
 404
 405         spin_lock_irqsave(&ts->lock, flags);
 406
 407         ts->pendown = (Rt != 0);
 408         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 409
 410         spin_unlock_irqrestore(&ts->lock, flags);
 411 }
 412
 413 static void ads7846_debounce(void *ads)
 414 {
 415         struct ads7846          *ts = ads;
 416         struct spi_message      *m;
 417         struct spi_transfer     *t;
 418         int                     val;
 419         int                     status;
 420
 421         m = &ts->msg[ts->msg_idx];
 422         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 423         val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff;
 424         if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) {
 425                 /* Repeat it, if this was the first read or the read
 426                  * wasn't consistent enough. */
 427                 if (ts->read_cnt < ts->debounce_max) {
 428                         ts->last_read = val;
 429                         ts->read_cnt++;
 430                 } else {
 431                         /* Maximum number of debouncing reached and still
 432                          * not enough number of consistent readings. Abort
 433                          * the whole sample, repeat it in the next sampling
 434                          * period.
 435                          */
 436                         ts->tc.ignore = 1;
 437                         ts->read_cnt = 0;
 438                         /* Last message will contain ads7846_rx() as the
 439                          * completion function.
 440                          */
 441                         m = ts->last_msg;
 442                 }
 443                 /* Start over collecting consistent readings. */
 444                 ts->read_rep = 0;
 445         } else {
 446                 if (++ts->read_rep > ts->debounce_rep) {
 447                         /* Got a good reading for this coordinate,
 448                          * go for the next one. */
 449                         ts->tc.ignore = 0;
 450                         ts->msg_idx++;
 451                         ts->read_cnt = 0;
 452                         ts->read_rep = 0;
 453                         m++;
 454                 } else
 455                         /* Read more values that are consistent. */
 456                         ts->read_cnt++;
 457         }
 458         status = spi_async(ts->spi, m);
 459         if (status)
 460                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 461                                 status);
 462 }
 463
 464 static void ads7846_timer(unsigned long handle)
 465 {
 466         struct ads7846  *ts = (void *)handle;
 467         int             status = 0;
 468
 469         spin_lock_irq(&ts->lock);
 470
 471         if (unlikely(ts->msg_idx && !ts->pendown)) {
 472                 /* measurement cycle ended */
 473                 if (!device_suspended(&ts->spi->dev)) {
 474                         ts->irq_disabled = 0;
 475                         enable_irq(ts->spi->irq);
 476                 }
 477                 ts->pending = 0;
 478                 ts->msg_idx = 0;
 479         } else {
 480                 /* pen is still down, continue with the measurement */
 481                 ts->msg_idx = 0;
 482                 status = spi_async(ts->spi, &ts->msg[0]);
 483                 if (status)
 484                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 485         }
 486
 487         spin_unlock_irq(&ts->lock);
 488 }
 489
 490 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
 491 {
 492         struct ads7846 *ts = handle;
 493         unsigned long flags;
 494
 495         spin_lock_irqsave(&ts->lock, flags);
 496         if (likely(ts->get_pendown_state())) {
 497                 if (!ts->irq_disabled) {
 498                         /* The ARM do_simple_IRQ() dispatcher doesn't act
 499                          * like the other dispatchers:  it will report IRQs
 500                          * even after they've been disabled.  We work around
 501                          * that here.  (The "generic irq" framework may help...)
 502                          */
 503                         ts->irq_disabled = 1;
 504                         disable_irq(ts->spi->irq);
 505                         ts->pending = 1;
 506                         mod_timer(&ts->timer, jiffies);
 507                 }
 508         }
 509         spin_unlock_irqrestore(&ts->lock, flags);
 510
 511         return IRQ_HANDLED;
 512 }
 513
 514 /*--------------------------------------------------------------------------*/
 515
 516 /* Must be called with ts->lock held */
 517 static void ads7846_disable(struct ads7846 *ts)
 518 {
 519         if (ts->disabled)
 520                 return;
 521
 522         ts->disabled = 1;
 523
 524         /* are we waiting for IRQ, or polling? */
 525         if (!ts->pending) {
 526                 ts->irq_disabled = 1;
 527                 disable_irq(ts->spi->irq);
 528         } else {
 529                 /* the timer will run at least once more, and
 530                  * leave everything in a clean state, IRQ disabled
 531                  */
 532                 while (ts->pending) {
 533                         spin_unlock_irq(&ts->lock);
 534                         msleep(1);
 535                         spin_lock_irq(&ts->lock);
 536                 }
 537         }
 538
 539         /* we know the chip's in lowpower mode since we always
 540          * leave it that way after every request
 541          */
 542
 543 }
 544
 545 /* Must be called with ts->lock held */
 546 static void ads7846_enable(struct ads7846 *ts)
 547 {
 548         if (!ts->disabled)
 549                 return;
 550
 551         ts->disabled = 0;
 552         ts->irq_disabled = 0;
 553         enable_irq(ts->spi->irq);
 554 }
 555
 556 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 557 {
 558         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 559
 560         spin_lock_irq(&ts->lock);
 561
 562         spi->dev.power.power_state = message;
 563         ads7846_disable(ts);
 564
 565         spin_unlock_irq(&ts->lock);
 566
 567         return 0;
 568
 569 }
 570
 571 static int ads7846_resume(struct spi_device *spi)
 572 {
 573         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 574
 575         spin_lock_irq(&ts->lock);
 576
 577         spi->dev.power.power_state = PMSG_ON;
 578         ads7846_enable(ts);
 579
 580         spin_unlock_irq(&ts->lock);
 581
 582         return 0;
 583 }
 584
 585 static int __devinit ads7846_probe(struct spi_device *spi)
 586 {
 587         struct ads7846                  *ts;
 588         struct input_dev                *input_dev;
 589         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 590         struct spi_message              *m;
 591         struct spi_transfer             *x;
 592         int                             err;
 593
 594         if (!spi->irq) {
 595                 dev_dbg(&spi->dev, "no IRQ?\n");
 596                 return -ENODEV;
 597         }
 598
 599         if (!pdata) {
 600                 dev_dbg(&spi->dev, "no platform data?\n");
 601                 return -ENODEV;
 602         }
 603
 604         /* don't exceed max specified sample rate */
 605         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 606                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 607                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 608                 return -EINVAL;
 609         }
 610
 611         /* REVISIT when the irq can be triggered active-low, or if for some
 612          * reason the touchscreen isn't hooked up, we don't need to access
 613          * the pendown state.
 614          */
 615         if (pdata->get_pendown_state == NULL) {
 616                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
 617                 return -EINVAL;
 618         }
 619
 620         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
 621          * that even if the hardware can do that, the SPI controller driver
 622          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
 623          */
 624         spi->bits_per_word = 8;
 625
 626         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 627         input_dev = input_allocate_device();
 628         if (!ts || !input_dev) {
 629                 err = -ENOMEM;
 630                 goto err_free_mem;
 631         }
 632
 633         dev_set_drvdata(&spi->dev, ts);
 634         spi->dev.power.power_state = PMSG_ON;
 635
 636         ts->spi = spi;
 637         ts->input = input_dev;
 638
 639         init_timer(&ts->timer);
 640         ts->timer.data = (unsigned long) ts;
 641         ts->timer.function = ads7846_timer;
 642
 643         spin_lock_init(&ts->lock);
 644
 645         ts->model = pdata->model ? : 7846;
 646         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 647         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 648         ts->pressure_max = pdata->pressure_max ? : ~0;
 649         if (pdata->debounce_max) {
 650                 ts->debounce_max = pdata->debounce_max;
 651                 ts->debounce_tol = pdata->debounce_tol;
 652                 ts->debounce_rep = pdata->debounce_rep;
 653                 if (ts->debounce_rep > ts->debounce_max + 1)
 654                         ts->debounce_rep = ts->debounce_max - 1;
 655         } else
 656                 ts->debounce_tol = ~0;
 657         ts->get_pendown_state = pdata->get_pendown_state;
 658
 659         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 660
 661         input_dev->name = "ADS784x Touchscreen";
 662         input_dev->phys = ts->phys;
 663         input_dev->cdev.dev = &spi->dev;
 664
 665         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 666         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 667         input_set_abs_params(input_dev, ABS_X,
 668                         pdata->x_min ? : 0,
 669                         pdata->x_max ? : MAX_12BIT,
 670                         0, 0);
 671         input_set_abs_params(input_dev, ABS_Y,
 672                         pdata->y_min ? : 0,
 673                         pdata->y_max ? : MAX_12BIT,
 674                         0, 0);
 675         input_set_abs_params(input_dev, ABS_PRESSURE,
 676                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 677
 678         /* set up the transfers to read touchscreen state; this assumes we
 679          * use formula #2 for pressure, not #3.
 680          */
 681         m = &ts->msg[0];
 682         x = ts->xfer;
 683
 684         spi_message_init(m);
 685
 686         /* y- still on; turn on only y+ (and ADC) */
 687         ts->read_y = READ_Y;
 688         x->tx_buf = &ts->read_y;
 689         x->len = 1;
 690         spi_message_add_tail(x, m);
 691
 692         x++;
 693         x->rx_buf = &ts->tc.y;
 694         x->len = 2;
 695         spi_message_add_tail(x, m);
 696
 697         m->complete = ads7846_debounce;
 698         m->context = ts;
 699
 700         m++;
 701         spi_message_init(m);
 702
 703         /* turn y- off, x+ on, then leave in lowpower */
 704         x++;
 705         ts->read_x = READ_X;
 706         x->tx_buf = &ts->read_x;
 707         x->len = 1;
 708         spi_message_add_tail(x, m);
 709
 710         x++;
 711         x->rx_buf = &ts->tc.x;
 712         x->len = 2;
 713         spi_message_add_tail(x, m);
 714
 715         m->complete = ads7846_debounce;
 716         m->context = ts;
 717
 718         /* turn y+ off, x- on; we'll use formula #2 */
 719         if (ts->model == 7846) {
 720                 m++;
 721                 spi_message_init(m);
 722
 723                 x++;
 724                 ts->read_z1 = READ_Z1;
 725                 x->tx_buf = &ts->read_z1;
 726                 x->len = 1;
 727                 spi_message_add_tail(x, m);
 728
 729                 x++;
 730                 x->rx_buf = &ts->tc.z1;
 731                 x->len = 2;
 732                 spi_message_add_tail(x, m);
 733
 734                 m->complete = ads7846_debounce;
 735                 m->context = ts;
 736
 737                 m++;
 738                 spi_message_init(m);
 739
 740                 x++;
 741                 ts->read_z2 = READ_Z2;
 742                 x->tx_buf = &ts->read_z2;
 743                 x->len = 1;
 744                 spi_message_add_tail(x, m);
 745
 746                 x++;
 747                 x->rx_buf = &ts->tc.z2;
 748                 x->len = 2;
 749                 spi_message_add_tail(x, m);
 750
 751                 m->complete = ads7846_debounce;
 752                 m->context = ts;
 753         }
 754
 755         /* power down */
 756         m++;
 757         spi_message_init(m);
 758
 759         x++;
 760         ts->pwrdown = PWRDOWN;
 761         x->tx_buf = &ts->pwrdown;
 762         x->len = 1;
 763         spi_message_add_tail(x, m);
 764
 765         x++;
 766         x->rx_buf = &ts->dummy;
 767         x->len = 2;
 768         CS_CHANGE(*x);
 769         spi_message_add_tail(x, m);
 770
 771         m->complete = ads7846_rx;
 772         m->context = ts;
 773
 774         ts->last_msg = m;
 775
 776         if (request_irq(spi->irq, ads7846_irq, SA_TRIGGER_FALLING,
 777                         spi->dev.driver->name, ts)) {
 778                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 779                 err = -EBUSY;
 780                 goto err_free_mem;
 781         }
 782
 783         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 784
 785         /* take a first sample, leaving nPENIRQ active; avoid
 786          * the touchscreen, in case it's not connected.
 787          */
 788         (void) ads7846_read12_ser(&spi->dev,
 789                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 790
 791         /* ads7843/7845 don't have temperature sensors, and
 792          * use the other sensors a bit differently too
 793          */
 794         if (ts->model == 7846) {
 795                 device_create_file(&spi->dev, &dev_attr_temp0);
 796                 device_create_file(&spi->dev, &dev_attr_temp1);
 797         }
 798         if (ts->model != 7845)
 799                 device_create_file(&spi->dev, &dev_attr_vbatt);
 800         device_create_file(&spi->dev, &dev_attr_vaux);
 801
 802         device_create_file(&spi->dev, &dev_attr_pen_down);
 803
 804         device_create_file(&spi->dev, &dev_attr_disable);
 805
 806         err = input_register_device(input_dev);
 807         if (err)
 808                 goto err_remove_attr;
 809
 810         return 0;
 811
 812  err_remove_attr:
 813         device_remove_file(&spi->dev, &dev_attr_disable);
 814         device_remove_file(&spi->dev, &dev_attr_pen_down);
 815         if (ts->model == 7846) {
 816                 device_remove_file(&spi->dev, &dev_attr_temp1);
 817                 device_remove_file(&spi->dev, &dev_attr_temp0);
 818         }
 819         if (ts->model != 7845)
 820                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 821         device_remove_file(&spi->dev, &dev_attr_vaux);
 822
 823         free_irq(spi->irq, ts);
 824  err_free_mem:
 825         input_free_device(input_dev);
 826         kfree(ts);
 827         return err;
 828 }
 829
 830 static int __devexit ads7846_remove(struct spi_device *spi)
 831 {
 832         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 833
 834         input_unregister_device(ts->input);
 835
 836         ads7846_suspend(spi, PMSG_SUSPEND);
 837
 838         device_remove_file(&spi->dev, &dev_attr_disable);
 839         device_remove_file(&spi->dev, &dev_attr_pen_down);
 840         if (ts->model == 7846) {
 841                 device_remove_file(&spi->dev, &dev_attr_temp1);
 842                 device_remove_file(&spi->dev, &dev_attr_temp0);
 843         }
 844         if (ts->model != 7845)
 845                 device_remove_file(&spi->dev, &dev_attr_vbatt);
 846         device_remove_file(&spi->dev, &dev_attr_vaux);
 847
 848         free_irq(ts->spi->irq, ts);
 849         /* suspend left the IRQ disabled */
 850         enable_irq(ts->spi->irq);
 851
 852         kfree(ts);
 853
 854         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 855         return 0;
 856 }
 857
 858 static struct spi_driver ads7846_driver = {
 859         .driver = {
 860                 .name   = "ads7846",
 861                 .bus    = &spi_bus_type,
 862                 .owner  = THIS_MODULE,
 863         },
 864         .probe          = ads7846_probe,
 865         .remove         = __devexit_p(ads7846_remove),
 866         .suspend        = ads7846_suspend,
 867         .resume         = ads7846_resume,
 868 };
 869
 870 static int __init ads7846_init(void)
 871 {
 872         /* grr, board-specific init should stay out of drivers!! */
 873
 874 #ifdef  CONFIG_ARCH_OMAP
 875         if (machine_is_omap_osk()) {
 876                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 877                 omap_request_gpio(4);
 878                 omap_set_gpio_direction(4, 1);
 879                 omap_request_gpio(6);
 880                 omap_set_gpio_direction(6, 1);
 881         }
 882         // also TI 1510 Innovator, bitbanging through FPGA
 883         // also Nokia 770
 884         // also Palm Tungsten T2
 885 #endif
 886
 887         // PXA:
 888         // also Dell Axim X50
 889         // also HP iPaq H191x/H192x/H415x/H435x
 890         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 891         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 892
 893         // Atmel at91sam9261-EK uses ads7843
 894
 895         // also various AMD Au1x00 devel boards
 896
 897         return spi_register_driver(&ads7846_driver);
 898 }
 899 module_init(ads7846_init);
 900
 901 static void __exit ads7846_exit(void)
 902 {
 903         spi_unregister_driver(&ads7846_driver);
 904
 905 #ifdef  CONFIG_ARCH_OMAP
 906         if (machine_is_omap_osk()) {
 907                 omap_free_gpio(4);
 908                 omap_free_gpio(6);
 909         }
 910 #endif
 911
 912 }
 913 module_exit(ads7846_exit);
 914
 915 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 916 MODULE_LICENSE("GPL");