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 *** and range adjustment.
  67          */
  68         u16     x;
  69         u16     y;
  70         u16     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         struct attribute_group  *attr_group;
  80         u16                     model;
  81         u16                     vref_delay_usecs;
  82         u16                     x_plate_ohms;
  83         u16                     pressure_max;
  84
  85         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  86         u16                     dummy;          /* for the pwrdown read */
  87         struct ts_event         tc;
  88
  89         struct spi_transfer     xfer[10];
  90         struct spi_message      msg[5];
  91         struct spi_message      *last_msg;
  92         int                     msg_idx;
  93         int                     read_cnt;
  94         int                     read_rep;
  95         int                     last_read;
  96
  97         u16                     debounce_max;
  98         u16                     debounce_tol;
  99         u16                     debounce_rep;
 100
 101         spinlock_t              lock;
 102         struct timer_list       timer;          /* P: lock */
 103         unsigned                pendown:1;      /* P: lock */
 104         unsigned                pending:1;      /* P: lock */
 105 // FIXME remove "irq_disabled"
 106         unsigned                irq_disabled:1; /* P: lock */
 107         unsigned                disabled:1;
 108
 109         int                     (*filter)(void *data, int data_idx, int *val);
 110         void                    *filter_data;
 111         void                    (*filter_cleanup)(void *data);
 112         int                     (*get_pendown_state)(void);
 113 };
 114
 115 /* leave chip selected when we're done, for quicker re-select? */
 116 #if     0
 117 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 118 #else
 119 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 120 #endif
 121
 122 /*--------------------------------------------------------------------------*/
 123
 124 /* The ADS7846 has touchscreen and other sensors.
 125  * Earlier ads784x chips are somewhat compatible.
 126  */
 127 #define ADS_START               (1 << 7)
 128 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 129 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 130 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 131 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 132 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 133 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 134 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 135 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 136 #define ADS_8_BIT               (1 << 3)
 137 #define ADS_12_BIT              (0 << 3)
 138 #define ADS_SER                 (1 << 2)        /* non-differential */
 139 #define ADS_DFR                 (0 << 2)        /* differential */
 140 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 141 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 142 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 143 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 144
 145 #define MAX_12BIT       ((1<<12)-1)
 146
 147 /* leave ADC powered up (disables penirq) between differential samples */
 148 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 149         | ADS_12_BIT | ADS_DFR | \
 150         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 151
 152 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 153 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 154 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 155
 156 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 157 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 158
 159 /* single-ended samples need to first power up reference voltage;
 160  * we leave both ADC and VREF powered
 161  */
 162 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 163         | ADS_12_BIT | ADS_SER)
 164
 165 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 166 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 167
 168 /*--------------------------------------------------------------------------*/
 169
 170 /*
 171  * Non-touchscreen sensors only use single-ended conversions.
 172  */
 173
 174 struct ser_req {
 175         u8                      ref_on;
 176         u8                      command;
 177         u8                      ref_off;
 178         u16                     scratch;
 179         __be16                  sample;
 180         struct spi_message      msg;
 181         struct spi_transfer     xfer[6];
 182 };
 183
 184 static void ads7846_enable(struct ads7846 *ts);
 185 static void ads7846_disable(struct ads7846 *ts);
 186
 187 static int device_suspended(struct device *dev)
 188 {
 189         struct ads7846 *ts = dev_get_drvdata(dev);
 190         return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
 191 }
 192
 193 static int ads7846_read12_ser(struct device *dev, unsigned command)
 194 {
 195         struct spi_device       *spi = to_spi_device(dev);
 196         struct ads7846          *ts = dev_get_drvdata(dev);
 197         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
 198         int                     status;
 199         int                     sample;
 200         int                     i;
 201
 202         if (!req)
 203                 return -ENOMEM;
 204
 205         spi_message_init(&req->msg);
 206
 207         /* activate reference, so it has time to settle; */
 208         req->ref_on = REF_ON;
 209         req->xfer[0].tx_buf = &req->ref_on;
 210         req->xfer[0].len = 1;
 211         req->xfer[1].rx_buf = &req->scratch;
 212         req->xfer[1].len = 2;
 213
 214         /*
 215          * for external VREF, 0 usec (and assume it's always on);
 216          * for 1uF, use 800 usec;
 217          * no cap, 100 usec.
 218          */
 219         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 220
 221         /* take sample */
 222         req->command = (u8) command;
 223         req->xfer[2].tx_buf = &req->command;
 224         req->xfer[2].len = 1;
 225         req->xfer[3].rx_buf = &req->sample;
 226         req->xfer[3].len = 2;
 227
 228         /* REVISIT:  take a few more samples, and compare ... */
 229
 230         /* turn off reference */
 231         req->ref_off = REF_OFF;
 232         req->xfer[4].tx_buf = &req->ref_off;
 233         req->xfer[4].len = 1;
 234         req->xfer[5].rx_buf = &req->scratch;
 235         req->xfer[5].len = 2;
 236
 237         CS_CHANGE(req->xfer[5]);
 238
 239         /* group all the transfers together, so we can't interfere with
 240          * reading touchscreen state; disable penirq while sampling
 241          */
 242         for (i = 0; i < 6; i++)
 243                 spi_message_add_tail(&req->xfer[i], &req->msg);
 244
 245         ts->irq_disabled = 1;
 246         disable_irq(spi->irq);
 247         status = spi_sync(spi, &req->msg);
 248         ts->irq_disabled = 0;
 249         enable_irq(spi->irq);
 250
 251         if (req->msg.status)
 252                 status = req->msg.status;
 253
 254         /* on-wire is a must-ignore bit, a BE12 value, then padding */
 255         sample = be16_to_cpu(req->sample);
 256         sample = sample >> 3;
 257         sample &= 0x0fff;
 258
 259         kfree(req);
 260         return status ? status : sample;
 261 }
 262
 263 #define SHOW(name) static ssize_t \
 264 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 265 { \
 266         ssize_t v = ads7846_read12_ser(dev, \
 267                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
 268         if (v < 0) \
 269                 return v; \
 270         return sprintf(buf, "%u\n", (unsigned) v); \
 271 } \
 272 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 273
 274 SHOW(temp0)
 275 SHOW(temp1)
 276 SHOW(vaux)
 277 SHOW(vbatt)
 278
 279 static int is_pen_down(struct device *dev)
 280 {
 281         struct ads7846          *ts = dev_get_drvdata(dev);
 282
 283         return ts->pendown;
 284 }
 285
 286 static ssize_t ads7846_pen_down_show(struct device *dev,
 287                                      struct device_attribute *attr, char *buf)
 288 {
 289         return sprintf(buf, "%u\n", is_pen_down(dev));
 290 }
 291
 292 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 293
 294 static ssize_t ads7846_disable_show(struct device *dev,
 295                                      struct device_attribute *attr, char *buf)
 296 {
 297         struct ads7846  *ts = dev_get_drvdata(dev);
 298
 299         return sprintf(buf, "%u\n", ts->disabled);
 300 }
 301
 302 static ssize_t ads7846_disable_store(struct device *dev,
 303                                      struct device_attribute *attr,
 304                                      const char *buf, size_t count)
 305 {
 306         struct ads7846 *ts = dev_get_drvdata(dev);
 307         char *endp;
 308         int i;
 309
 310         i = simple_strtoul(buf, &endp, 10);
 311         spin_lock_irq(&ts->lock);
 312
 313         if (i)
 314                 ads7846_disable(ts);
 315         else
 316                 ads7846_enable(ts);
 317
 318         spin_unlock_irq(&ts->lock);
 319
 320         return count;
 321 }
 322
 323 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 324
 325 static struct attribute *ads7846_attributes[] = {
 326         &dev_attr_temp0.attr,
 327         &dev_attr_temp1.attr,
 328         &dev_attr_vbatt.attr,
 329         &dev_attr_vaux.attr,
 330         &dev_attr_pen_down.attr,
 331         &dev_attr_disable.attr,
 332         NULL,
 333 };
 334
 335 static struct attribute_group ads7846_attr_group = {
 336         .attrs = ads7846_attributes,
 337 };
 338
 339 /*
 340  * ads7843/7845 don't have temperature sensors, and
 341  * use the other sensors a bit differently too
 342  */
 343
 344 static struct attribute *ads7843_attributes[] = {
 345         &dev_attr_vbatt.attr,
 346         &dev_attr_vaux.attr,
 347         &dev_attr_pen_down.attr,
 348         &dev_attr_disable.attr,
 349         NULL,
 350 };
 351
 352 static struct attribute_group ads7843_attr_group = {
 353         .attrs = ads7843_attributes,
 354 };
 355
 356 static struct attribute *ads7845_attributes[] = {
 357         &dev_attr_vaux.attr,
 358         &dev_attr_pen_down.attr,
 359         &dev_attr_disable.attr,
 360         NULL,
 361 };
 362
 363 static struct attribute_group ads7845_attr_group = {
 364         .attrs = ads7845_attributes,
 365 };
 366
 367 /*--------------------------------------------------------------------------*/
 368
 369 /*
 370  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 371  * to retrieve touchscreen status.
 372  *
 373  * The SPI transfer completion callback does the real work.  It reports
 374  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 375  */
 376
 377 static void ads7846_rx(void *ads)
 378 {
 379         struct ads7846          *ts = ads;
 380         struct input_dev        *input_dev = ts->input;
 381         unsigned                Rt;
 382         unsigned                sync = 0;
 383         u16                     x, y, z1, z2;
 384         unsigned long           flags;
 385
 386         /* ads7846_rx_val() did in-place conversion (including byteswap) from
 387          * on-the-wire format as part of debouncing to get stable readings.
 388          */
 389         x = ts->tc.x;
 390         y = ts->tc.y;
 391         z1 = ts->tc.z1;
 392         z2 = ts->tc.z2;
 393
 394         /* range filtering */
 395         if (x == MAX_12BIT)
 396                 x = 0;
 397
 398         if (likely(x && z1 && !device_suspended(&ts->spi->dev))) {
 399                 /* compute touch pressure resistance using equation #2 */
 400                 Rt = z2;
 401                 Rt -= z1;
 402                 Rt *= x;
 403                 Rt *= ts->x_plate_ohms;
 404                 Rt /= z1;
 405                 Rt = (Rt + 2047) >> 12;
 406         } else
 407                 Rt = 0;
 408
 409         /* Sample found inconsistent by debouncing or pressure is beyond
 410         * the maximum. Don't report it to user space, repeat at least
 411         * once more the measurement */
 412         if (ts->tc.ignore || Rt > ts->pressure_max) {
 413                 mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 414                 return;
 415         }
 416
 417         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
 418          * being able to check nPENIRQ status, or "friendly" trigger modes
 419          * (both-edges is much better than just-falling or low-level).
 420          *
 421          * REVISIT:  some boards may require reading nPENIRQ; it's
 422          * needed on 7843.  and 7845 reads pressure differently...
 423          *
 424          * REVISIT:  the touchscreen might not be connected; this code
 425          * won't notice that, even if nPENIRQ never fires ...
 426          */
 427         if (!ts->pendown && Rt != 0) {
 428                 input_report_key(input_dev, BTN_TOUCH, 1);
 429                 sync = 1;
 430         } else if (ts->pendown && Rt == 0) {
 431                 input_report_key(input_dev, BTN_TOUCH, 0);
 432                 sync = 1;
 433         }
 434
 435         if (Rt) {
 436                 input_report_abs(input_dev, ABS_X, x);
 437                 input_report_abs(input_dev, ABS_Y, y);
 438                 sync = 1;
 439         }
 440
 441         if (sync) {
 442                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 443                 input_sync(input_dev);
 444         }
 445
 446 #ifdef  VERBOSE
 447         if (Rt || ts->pendown)
 448                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
 449                         x, y, Rt, Rt ? "" : " UP");
 450 #endif
 451
 452         spin_lock_irqsave(&ts->lock, flags);
 453
 454         ts->pendown = (Rt != 0);
 455         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
 456
 457         spin_unlock_irqrestore(&ts->lock, flags);
 458 }
 459
 460 static int ads7846_debounce(void *ads, int data_idx, int *val)
 461 {
 462         struct ads7846          *ts = ads;
 463
 464         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 465                 /* Start over collecting consistent readings. */
 466                 ts->read_rep = 0;
 467                 /* Repeat it, if this was the first read or the read
 468                  * wasn't consistent enough. */
 469                 if (ts->read_cnt < ts->debounce_max) {
 470                         ts->last_read = *val;
 471                         ts->read_cnt++;
 472                         return ADS7846_FILTER_REPEAT;
 473                 } else {
 474                         /* Maximum number of debouncing reached and still
 475                          * not enough number of consistent readings. Abort
 476                          * the whole sample, repeat it in the next sampling
 477                          * period.
 478                          */
 479                         ts->read_cnt = 0;
 480                         return ADS7846_FILTER_IGNORE;
 481                 }
 482         } else {
 483                 if (++ts->read_rep > ts->debounce_rep) {
 484                         /* Got a good reading for this coordinate,
 485                          * go for the next one. */
 486                         ts->read_cnt = 0;
 487                         ts->read_rep = 0;
 488                         return ADS7846_FILTER_OK;
 489                 } else {
 490                         /* Read more values that are consistent. */
 491                         ts->read_cnt++;
 492                         return ADS7846_FILTER_REPEAT;
 493                 }
 494         }
 495 }
 496
 497 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 498 {
 499         return ADS7846_FILTER_OK;
 500 }
 501
 502 static void ads7846_rx_val(void *ads)
 503 {
 504         struct ads7846 *ts = ads;
 505         struct spi_message *m;
 506         struct spi_transfer *t;
 507         u16 *rx_val;
 508         int val;
 509         int action;
 510         int status;
 511
 512         m = &ts->msg[ts->msg_idx];
 513         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 514         rx_val = t->rx_buf;
 515
 516         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
 517          * built from two 8 bit values written msb-first.
 518          */
 519         val = be16_to_cpu(*rx_val) >> 3;
 520
 521         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
 522         switch (action) {
 523         case ADS7846_FILTER_REPEAT:
 524                 break;
 525         case ADS7846_FILTER_IGNORE:
 526                 ts->tc.ignore = 1;
 527                 /* Last message will contain ads7846_rx() as the
 528                  * completion function.
 529                  */
 530                 m = ts->last_msg;
 531                 break;
 532         case ADS7846_FILTER_OK:
 533                 *rx_val = val;
 534                 ts->tc.ignore = 0;
 535                 m = &ts->msg[++ts->msg_idx];
 536                 break;
 537         default:
 538                 BUG();
 539         }
 540         status = spi_async(ts->spi, m);
 541         if (status)
 542                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 543                                 status);
 544 }
 545
 546 static void ads7846_timer(unsigned long handle)
 547 {
 548         struct ads7846  *ts = (void *)handle;
 549         int             status = 0;
 550
 551         spin_lock_irq(&ts->lock);
 552
 553         if (unlikely(ts->msg_idx && !ts->pendown)) {
 554                 /* measurement cycle ended */
 555                 if (!device_suspended(&ts->spi->dev)) {
 556                         ts->irq_disabled = 0;
 557                         enable_irq(ts->spi->irq);
 558                 }
 559                 ts->pending = 0;
 560                 ts->msg_idx = 0;
 561         } else {
 562                 /* pen is still down, continue with the measurement */
 563                 ts->msg_idx = 0;
 564                 status = spi_async(ts->spi, &ts->msg[0]);
 565                 if (status)
 566                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 567         }
 568
 569         spin_unlock_irq(&ts->lock);
 570 }
 571
 572 static irqreturn_t ads7846_irq(int irq, void *handle)
 573 {
 574         struct ads7846 *ts = handle;
 575         unsigned long flags;
 576
 577         spin_lock_irqsave(&ts->lock, flags);
 578         if (likely(ts->get_pendown_state())) {
 579                 if (!ts->irq_disabled) {
 580                         /* The ARM do_simple_IRQ() dispatcher doesn't act
 581                          * like the other dispatchers:  it will report IRQs
 582                          * even after they've been disabled.  We work around
 583                          * that here.  (The "generic irq" framework may help...)
 584                          */
 585                         ts->irq_disabled = 1;
 586                         disable_irq(ts->spi->irq);
 587                         ts->pending = 1;
 588                         mod_timer(&ts->timer, jiffies);
 589                 }
 590         }
 591         spin_unlock_irqrestore(&ts->lock, flags);
 592
 593         return IRQ_HANDLED;
 594 }
 595
 596 /*--------------------------------------------------------------------------*/
 597
 598 /* Must be called with ts->lock held */
 599 static void ads7846_disable(struct ads7846 *ts)
 600 {
 601         if (ts->disabled)
 602                 return;
 603
 604         ts->disabled = 1;
 605
 606         /* are we waiting for IRQ, or polling? */
 607         if (!ts->pending) {
 608                 ts->irq_disabled = 1;
 609                 disable_irq(ts->spi->irq);
 610         } else {
 611                 /* the timer will run at least once more, and
 612                  * leave everything in a clean state, IRQ disabled
 613                  */
 614                 while (ts->pending) {
 615                         spin_unlock_irq(&ts->lock);
 616                         msleep(1);
 617                         spin_lock_irq(&ts->lock);
 618                 }
 619         }
 620
 621         /* we know the chip's in lowpower mode since we always
 622          * leave it that way after every request
 623          */
 624
 625 }
 626
 627 /* Must be called with ts->lock held */
 628 static void ads7846_enable(struct ads7846 *ts)
 629 {
 630         if (!ts->disabled)
 631                 return;
 632
 633         ts->disabled = 0;
 634         ts->irq_disabled = 0;
 635         enable_irq(ts->spi->irq);
 636 }
 637
 638 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 639 {
 640         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 641
 642         spin_lock_irq(&ts->lock);
 643
 644         spi->dev.power.power_state = message;
 645         ads7846_disable(ts);
 646
 647         spin_unlock_irq(&ts->lock);
 648
 649         return 0;
 650
 651 }
 652
 653 static int ads7846_resume(struct spi_device *spi)
 654 {
 655         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 656
 657         spin_lock_irq(&ts->lock);
 658
 659         spi->dev.power.power_state = PMSG_ON;
 660         ads7846_enable(ts);
 661
 662         spin_unlock_irq(&ts->lock);
 663
 664         return 0;
 665 }
 666
 667 static int __devinit ads7846_probe(struct spi_device *spi)
 668 {
 669         struct ads7846                  *ts;
 670         struct input_dev                *input_dev;
 671         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 672         struct spi_message              *m;
 673         struct spi_transfer             *x;
 674         int                             vref;
 675         int                             err;
 676
 677         if (!spi->irq) {
 678                 dev_dbg(&spi->dev, "no IRQ?\n");
 679                 return -ENODEV;
 680         }
 681
 682         if (!pdata) {
 683                 dev_dbg(&spi->dev, "no platform data?\n");
 684                 return -ENODEV;
 685         }
 686
 687         /* don't exceed max specified sample rate */
 688         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 689                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 690                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 691                 return -EINVAL;
 692         }
 693
 694         /* REVISIT when the irq can be triggered active-low, or if for some
 695          * reason the touchscreen isn't hooked up, we don't need to access
 696          * the pendown state.
 697          */
 698         if (pdata->get_pendown_state == NULL) {
 699                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
 700                 return -EINVAL;
 701         }
 702
 703         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
 704          * that even if the hardware can do that, the SPI controller driver
 705          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
 706          */
 707         spi->bits_per_word = 8;
 708
 709         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 710         input_dev = input_allocate_device();
 711         if (!ts || !input_dev) {
 712                 err = -ENOMEM;
 713                 goto err_free_mem;
 714         }
 715
 716         dev_set_drvdata(&spi->dev, ts);
 717         spi->dev.power.power_state = PMSG_ON;
 718
 719         ts->spi = spi;
 720         ts->input = input_dev;
 721
 722         init_timer(&ts->timer);
 723         ts->timer.data = (unsigned long) ts;
 724         ts->timer.function = ads7846_timer;
 725
 726         spin_lock_init(&ts->lock);
 727
 728         ts->model = pdata->model ? : 7846;
 729         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 730         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 731         ts->pressure_max = pdata->pressure_max ? : ~0;
 732
 733         if (pdata->filter != NULL) {
 734                 if (pdata->filter_init != NULL) {
 735                         err = pdata->filter_init(pdata, &ts->filter_data);
 736                         if (err < 0)
 737                                 goto err_free_mem;
 738                 }
 739                 ts->filter = pdata->filter;
 740                 ts->filter_cleanup = pdata->filter_cleanup;
 741         } else if (pdata->debounce_max) {
 742                 ts->debounce_max = pdata->debounce_max;
 743                 if (ts->debounce_max < 2)
 744                         ts->debounce_max = 2;
 745                 ts->debounce_tol = pdata->debounce_tol;
 746                 ts->debounce_rep = pdata->debounce_rep;
 747                 ts->filter = ads7846_debounce;
 748                 ts->filter_data = ts;
 749         } else
 750                 ts->filter = ads7846_no_filter;
 751         ts->get_pendown_state = pdata->get_pendown_state;
 752
 753         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 754
 755         input_dev->name = "ADS784x Touchscreen";
 756         input_dev->phys = ts->phys;
 757         input_dev->cdev.dev = &spi->dev;
 758
 759         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
 760         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
 761         input_set_abs_params(input_dev, ABS_X,
 762                         pdata->x_min ? : 0,
 763                         pdata->x_max ? : MAX_12BIT,
 764                         0, 0);
 765         input_set_abs_params(input_dev, ABS_Y,
 766                         pdata->y_min ? : 0,
 767                         pdata->y_max ? : MAX_12BIT,
 768                         0, 0);
 769         input_set_abs_params(input_dev, ABS_PRESSURE,
 770                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 771
 772         vref = pdata->keep_vref_on;
 773
 774         /* set up the transfers to read touchscreen state; this assumes we
 775          * use formula #2 for pressure, not #3.
 776          */
 777         m = &ts->msg[0];
 778         x = ts->xfer;
 779
 780         spi_message_init(m);
 781
 782         /* y- still on; turn on only y+ (and ADC) */
 783         ts->read_y = READ_Y(vref);
 784         x->tx_buf = &ts->read_y;
 785         x->len = 1;
 786         spi_message_add_tail(x, m);
 787
 788         x++;
 789         x->rx_buf = &ts->tc.y;
 790         x->len = 2;
 791         spi_message_add_tail(x, m);
 792
 793         m->complete = ads7846_rx_val;
 794         m->context = ts;
 795
 796         m++;
 797         spi_message_init(m);
 798
 799         /* turn y- off, x+ on, then leave in lowpower */
 800         x++;
 801         ts->read_x = READ_X(vref);
 802         x->tx_buf = &ts->read_x;
 803         x->len = 1;
 804         spi_message_add_tail(x, m);
 805
 806         x++;
 807         x->rx_buf = &ts->tc.x;
 808         x->len = 2;
 809         spi_message_add_tail(x, m);
 810
 811         m->complete = ads7846_rx_val;
 812         m->context = ts;
 813
 814         /* turn y+ off, x- on; we'll use formula #2 */
 815         if (ts->model == 7846) {
 816                 m++;
 817                 spi_message_init(m);
 818
 819                 x++;
 820                 ts->read_z1 = READ_Z1(vref);
 821                 x->tx_buf = &ts->read_z1;
 822                 x->len = 1;
 823                 spi_message_add_tail(x, m);
 824
 825                 x++;
 826                 x->rx_buf = &ts->tc.z1;
 827                 x->len = 2;
 828                 spi_message_add_tail(x, m);
 829
 830                 m->complete = ads7846_rx_val;
 831                 m->context = ts;
 832
 833                 m++;
 834                 spi_message_init(m);
 835
 836                 x++;
 837                 ts->read_z2 = READ_Z2(vref);
 838                 x->tx_buf = &ts->read_z2;
 839                 x->len = 1;
 840                 spi_message_add_tail(x, m);
 841
 842                 x++;
 843                 x->rx_buf = &ts->tc.z2;
 844                 x->len = 2;
 845                 spi_message_add_tail(x, m);
 846
 847                 m->complete = ads7846_rx_val;
 848                 m->context = ts;
 849         }
 850
 851         /* power down */
 852         m++;
 853         spi_message_init(m);
 854
 855         x++;
 856         ts->pwrdown = PWRDOWN;
 857         x->tx_buf = &ts->pwrdown;
 858         x->len = 1;
 859         spi_message_add_tail(x, m);
 860
 861         x++;
 862         x->rx_buf = &ts->dummy;
 863         x->len = 2;
 864         CS_CHANGE(*x);
 865         spi_message_add_tail(x, m);
 866
 867         m->complete = ads7846_rx;
 868         m->context = ts;
 869
 870         ts->last_msg = m;
 871
 872         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
 873                         spi->dev.driver->name, ts)) {
 874                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
 875                 err = -EBUSY;
 876                 goto err_cleanup_filter;
 877         }
 878
 879         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 880
 881         /* take a first sample, leaving nPENIRQ active; avoid
 882          * the touchscreen, in case it's not connected.
 883          */
 884         (void) ads7846_read12_ser(&spi->dev,
 885                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 886
 887         switch (ts->model) {
 888         case 7846:
 889                 ts->attr_group = &ads7846_attr_group;
 890                 break;
 891         case 7845:
 892                 ts->attr_group = &ads7845_attr_group;
 893                 break;
 894         default:
 895                 ts->attr_group = &ads7843_attr_group;
 896                 break;
 897         }
 898         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 899         if (err)
 900                 goto err_free_irq;
 901
 902         err = input_register_device(input_dev);
 903         if (err)
 904                 goto err_remove_attr_group;
 905
 906         return 0;
 907
 908  err_remove_attr_group:
 909         sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 910  err_free_irq:
 911         free_irq(spi->irq, ts);
 912  err_cleanup_filter:
 913         if (ts->filter_cleanup)
 914                 ts->filter_cleanup(ts->filter_data);
 915  err_free_mem:
 916         input_free_device(input_dev);
 917         kfree(ts);
 918         return err;
 919 }
 920
 921 static int __devexit ads7846_remove(struct spi_device *spi)
 922 {
 923         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 924
 925         input_unregister_device(ts->input);
 926
 927         ads7846_suspend(spi, PMSG_SUSPEND);
 928
 929         sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 930
 931         free_irq(ts->spi->irq, ts);
 932         /* suspend left the IRQ disabled */
 933         enable_irq(ts->spi->irq);
 934
 935         if (ts->filter_cleanup)
 936                 ts->filter_cleanup(ts->filter_data);
 937
 938         kfree(ts);
 939
 940         dev_dbg(&spi->dev, "unregistered touchscreen\n");
 941         return 0;
 942 }
 943
 944 static struct spi_driver ads7846_driver = {
 945         .driver = {
 946                 .name   = "ads7846",
 947                 .bus    = &spi_bus_type,
 948                 .owner  = THIS_MODULE,
 949         },
 950         .probe          = ads7846_probe,
 951         .remove         = __devexit_p(ads7846_remove),
 952         .suspend        = ads7846_suspend,
 953         .resume         = ads7846_resume,
 954 };
 955
 956 static int __init ads7846_init(void)
 957 {
 958         /* grr, board-specific init should stay out of drivers!! */
 959
 960 #ifdef  CONFIG_ARCH_OMAP
 961         if (machine_is_omap_osk()) {
 962                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
 963                 omap_request_gpio(4);
 964                 omap_set_gpio_direction(4, 1);
 965                 omap_request_gpio(6);
 966                 omap_set_gpio_direction(6, 1);
 967         }
 968         // also TI 1510 Innovator, bitbanging through FPGA
 969         // also Nokia 770
 970         // also Palm Tungsten T2
 971 #endif
 972
 973         // PXA:
 974         // also Dell Axim X50
 975         // also HP iPaq H191x/H192x/H415x/H435x
 976         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
 977         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
 978
 979         // Atmel at91sam9261-EK uses ads7843
 980
 981         // also various AMD Au1x00 devel boards
 982
 983         return spi_register_driver(&ads7846_driver);
 984 }
 985 module_init(ads7846_init);
 986
 987 static void __exit ads7846_exit(void)
 988 {
 989         spi_unregister_driver(&ads7846_driver);
 990
 991 #ifdef  CONFIG_ARCH_OMAP
 992         if (machine_is_omap_osk()) {
 993                 omap_free_gpio(4);
 994                 omap_free_gpio(6);
 995         }
 996 #endif
 997
 998 }
 999 module_exit(ads7846_exit);
1000
1001 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1002 MODULE_LICENSE("GPL");