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