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/hwmon.h>
  21 #include <linux/init.h>
  22 #include <linux/err.h>
  23 #include <linux/delay.h>
  24 #include <linux/input.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/slab.h>
  27 #include <linux/spi/spi.h>
  28 #include <linux/spi/ads7846.h>
  29 #include <asm/irq.h>
  30
  31 #ifdef  CONFIG_ARM
  32 #include <asm/mach-types.h>
  33 #ifdef  CONFIG_ARCH_OMAP
  34 #include <asm/arch/gpio.h>
  35 #endif
  36 #endif
  37
  38
  39 /*
  40  * This code has been heavily tested on a Nokia 770, and lightly
  41  * tested on other ads7846 devices (OSK/Mistral, Lubbock).
  42  * TSC2046 is just newer ads7846 silicon.
  43  * Support for ads7843 tested on Atmel at91sam926x-EK.
  44  * Support for ads7845 has only been stubbed in.
  45  *
  46  * IRQ handling needs a workaround because of a shortcoming in handling
  47  * edge triggered IRQs on some platforms like the OMAP1/2. These
  48  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  49  * have to maintain our own SW IRQ disabled status. This should be
  50  * removed as soon as the affected platform's IRQ handling is fixed.
  51  *
  52  * app note sbaa036 talks in more detail about accurate sampling...
  53  * that ought to help in situations like LCDs inducing noise (which
  54  * can also be helped by using synch signals) and more generally.
  55  * This driver tries to utilize the measures described in the app
  56  * note. The strength of filtering can be set in the board-* specific
  57  * files.
  58  */
  59
  60 #define TS_POLL_DELAY   (1 * 1000000)   /* ns delay before the first sample */
  61 #define TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
  62
  63 /* this driver doesn't aim at the peak continuous sample rate */
  64 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  65
  66 struct ts_event {
  67         /* For portability, we can't read 12 bit values using SPI (which
  68          * would make the controller deliver them as native byteorder u16
  69          * with msbs zeroed).  Instead, we read them as two 8-bit values,
  70          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  71          */
  72         u16     x;
  73         u16     y;
  74         u16     z1, z2;
  75         int     ignore;
  76 };
  77
  78 struct ads7846 {
  79         struct input_dev        *input;
  80         char                    phys[32];
  81
  82         struct spi_device       *spi;
  83
  84 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
  85         struct attribute_group  *attr_group;
  86         struct device           *hwmon;
  87 #endif
  88
  89         u16                     model;
  90         u16                     vref_mv;
  91         u16                     vref_delay_usecs;
  92         u16                     x_plate_ohms;
  93         u16                     pressure_max;
  94
  95         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
  96         u16                     dummy;          /* for the pwrdown read */
  97         struct ts_event         tc;
  98
  99         struct spi_transfer     xfer[18];
 100         struct spi_message      msg[5];
 101         struct spi_message      *last_msg;
 102         int                     msg_idx;
 103         int                     read_cnt;
 104         int                     read_rep;
 105         int                     last_read;
 106
 107         u16                     debounce_max;
 108         u16                     debounce_tol;
 109         u16                     debounce_rep;
 110
 111         u16                     penirq_recheck_delay_usecs;
 112
 113         spinlock_t              lock;
 114         struct hrtimer          timer;
 115         unsigned                pendown:1;      /* P: lock */
 116         unsigned                pending:1;      /* P: lock */
 117 // FIXME remove "irq_disabled"
 118         unsigned                irq_disabled:1; /* P: lock */
 119         unsigned                disabled:1;
 120         unsigned                is_suspended:1;
 121
 122         int                     (*filter)(void *data, int data_idx, int *val);
 123         void                    *filter_data;
 124         void                    (*filter_cleanup)(void *data);
 125         int                     (*get_pendown_state)(void);
 126 };
 127
 128 /* leave chip selected when we're done, for quicker re-select? */
 129 #if     0
 130 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 131 #else
 132 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 133 #endif
 134
 135 /*--------------------------------------------------------------------------*/
 136
 137 /* The ADS7846 has touchscreen and other sensors.
 138  * Earlier ads784x chips are somewhat compatible.
 139  */
 140 #define ADS_START               (1 << 7)
 141 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 142 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 143 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 144 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 145 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 146 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 147 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 148 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 149 #define ADS_8_BIT               (1 << 3)
 150 #define ADS_12_BIT              (0 << 3)
 151 #define ADS_SER                 (1 << 2)        /* non-differential */
 152 #define ADS_DFR                 (0 << 2)        /* differential */
 153 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
 154 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 155 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 156 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 157
 158 #define MAX_12BIT       ((1<<12)-1)
 159
 160 /* leave ADC powered up (disables penirq) between differential samples */
 161 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 162         | ADS_12_BIT | ADS_DFR | \
 163         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 164
 165 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 166 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 167 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 168
 169 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 170 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 171
 172 /* single-ended samples need to first power up reference voltage;
 173  * we leave both ADC and VREF powered
 174  */
 175 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 176         | ADS_12_BIT | ADS_SER)
 177
 178 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 179 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 180
 181 /*--------------------------------------------------------------------------*/
 182
 183 /*
 184  * Non-touchscreen sensors only use single-ended conversions.
 185  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 186  * ads7846 lets that pin be unconnected, to use internal vREF.
 187  */
 188
 189 struct ser_req {
 190         u8                      ref_on;
 191         u8                      command;
 192         u8                      ref_off;
 193         u16                     scratch;
 194         __be16                  sample;
 195         struct spi_message      msg;
 196         struct spi_transfer     xfer[6];
 197 };
 198
 199 static void ads7846_enable(struct ads7846 *ts);
 200 static void ads7846_disable(struct ads7846 *ts);
 201
 202 static int device_suspended(struct device *dev)
 203 {
 204         struct ads7846 *ts = dev_get_drvdata(dev);
 205         return ts->is_suspended || ts->disabled;
 206 }
 207
 208 static int ads7846_read12_ser(struct device *dev, unsigned command)
 209 {
 210         struct spi_device       *spi = to_spi_device(dev);
 211         struct ads7846          *ts = dev_get_drvdata(dev);
 212         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
 213         int                     status;
 214         int                     use_internal;
 215
 216         if (!req)
 217                 return -ENOMEM;
 218
 219         spi_message_init(&req->msg);
 220
 221         /* FIXME boards with ads7846 might use external vref instead ... */
 222         use_internal = (ts->model == 7846);
 223
 224         /* maybe turn on internal vREF, and let it settle */
 225         if (use_internal) {
 226                 req->ref_on = REF_ON;
 227                 req->xfer[0].tx_buf = &req->ref_on;
 228                 req->xfer[0].len = 1;
 229                 spi_message_add_tail(&req->xfer[0], &req->msg);
 230
 231                 req->xfer[1].rx_buf = &req->scratch;
 232                 req->xfer[1].len = 2;
 233
 234                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 235                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 236                 spi_message_add_tail(&req->xfer[1], &req->msg);
 237         }
 238
 239         /* take sample */
 240         req->command = (u8) command;
 241         req->xfer[2].tx_buf = &req->command;
 242         req->xfer[2].len = 1;
 243         spi_message_add_tail(&req->xfer[2], &req->msg);
 244
 245         req->xfer[3].rx_buf = &req->sample;
 246         req->xfer[3].len = 2;
 247         spi_message_add_tail(&req->xfer[3], &req->msg);
 248
 249         /* REVISIT:  take a few more samples, and compare ... */
 250
 251         /* converter in low power mode & enable PENIRQ */
 252         req->ref_off = PWRDOWN;
 253         req->xfer[4].tx_buf = &req->ref_off;
 254         req->xfer[4].len = 1;
 255         spi_message_add_tail(&req->xfer[4], &req->msg);
 256
 257         req->xfer[5].rx_buf = &req->scratch;
 258         req->xfer[5].len = 2;
 259         CS_CHANGE(req->xfer[5]);
 260         spi_message_add_tail(&req->xfer[5], &req->msg);
 261
 262         ts->irq_disabled = 1;
 263         disable_irq(spi->irq);
 264         status = spi_sync(spi, &req->msg);
 265         ts->irq_disabled = 0;
 266         enable_irq(spi->irq);
 267
 268         if (status == 0) {
 269                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 270                 status = be16_to_cpu(req->sample);
 271                 status = status >> 3;
 272                 status &= 0x0fff;
 273         }
 274
 275         kfree(req);
 276         return status;
 277 }
 278
 279 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
 280
 281 #define SHOW(name, var, adjust) static ssize_t \
 282 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 283 { \
 284         struct ads7846 *ts = dev_get_drvdata(dev); \
 285         ssize_t v = ads7846_read12_ser(dev, \
 286                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
 287         if (v < 0) \
 288                 return v; \
 289         return sprintf(buf, "%u\n", adjust(ts, v)); \
 290 } \
 291 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 292
 293
 294 /* Sysfs conventions report temperatures in millidegrees Celcius.
 295  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 296  * accuracy scheme without calibration data.  For now we won't try either;
 297  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 298  */
 299 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 300 {
 301         return v;
 302 }
 303
 304 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 305 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 306
 307
 308 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 309  * if we know vREF.  userspace may need to scale vAUX to match the board's
 310  * external resistors; we assume that vBATT only uses the internal ones.
 311  */
 312 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 313 {
 314         unsigned retval = v;
 315
 316         /* external resistors may scale vAUX into 0..vREF */
 317         retval *= ts->vref_mv;
 318         retval = retval >> 12;
 319         return retval;
 320 }
 321
 322 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 323 {
 324         unsigned retval = vaux_adjust(ts, v);
 325
 326         /* ads7846 has a resistor ladder to scale this signal down */
 327         if (ts->model == 7846)
 328                 retval *= 4;
 329         return retval;
 330 }
 331
 332 SHOW(in0_input, vaux, vaux_adjust)
 333 SHOW(in1_input, vbatt, vbatt_adjust)
 334
 335
 336 static struct attribute *ads7846_attributes[] = {
 337         &dev_attr_temp0.attr,
 338         &dev_attr_temp1.attr,
 339         &dev_attr_in0_input.attr,
 340         &dev_attr_in1_input.attr,
 341         NULL,
 342 };
 343
 344 static struct attribute_group ads7846_attr_group = {
 345         .attrs = ads7846_attributes,
 346 };
 347
 348 static struct attribute *ads7843_attributes[] = {
 349         &dev_attr_in0_input.attr,
 350         &dev_attr_in1_input.attr,
 351         NULL,
 352 };
 353
 354 static struct attribute_group ads7843_attr_group = {
 355         .attrs = ads7843_attributes,
 356 };
 357
 358 static struct attribute *ads7845_attributes[] = {
 359         &dev_attr_in0_input.attr,
 360         NULL,
 361 };
 362
 363 static struct attribute_group ads7845_attr_group = {
 364         .attrs = ads7845_attributes,
 365 };
 366
 367 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 368 {
 369         struct device *hwmon;
 370         int err;
 371
 372         /* hwmon sensors need a reference voltage */
 373         switch (ts->model) {
 374         case 7846:
 375                 if (!ts->vref_mv) {
 376                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 377                         ts->vref_mv = 2500;
 378                 }
 379                 break;
 380         case 7845:
 381         case 7843:
 382                 if (!ts->vref_mv) {
 383                         dev_warn(&spi->dev,
 384                                 "external vREF for ADS%d not specified\n",
 385                                 ts->model);
 386                         return 0;
 387                 }
 388                 break;
 389         }
 390
 391         /* different chips have different sensor groups */
 392         switch (ts->model) {
 393         case 7846:
 394                 ts->attr_group = &ads7846_attr_group;
 395                 break;
 396         case 7845:
 397                 ts->attr_group = &ads7845_attr_group;
 398                 break;
 399         case 7843:
 400                 ts->attr_group = &ads7843_attr_group;
 401                 break;
 402         default:
 403                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
 404                 return 0;
 405         }
 406
 407         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
 408         if (err)
 409                 return err;
 410
 411         hwmon = hwmon_device_register(&spi->dev);
 412         if (IS_ERR(hwmon)) {
 413                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 414                 return PTR_ERR(hwmon);
 415         }
 416
 417         ts->hwmon = hwmon;
 418         return 0;
 419 }
 420
 421 static void ads784x_hwmon_unregister(struct spi_device *spi,
 422                                      struct ads7846 *ts)
 423 {
 424         if (ts->hwmon) {
 425                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 426                 hwmon_device_unregister(ts->hwmon);
 427         }
 428 }
 429
 430 #else
 431 static inline int ads784x_hwmon_register(struct spi_device *spi,
 432                                          struct ads7846 *ts)
 433 {
 434         return 0;
 435 }
 436
 437 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 438                                             struct ads7846 *ts)
 439 {
 440 }
 441 #endif
 442
 443 static int is_pen_down(struct device *dev)
 444 {
 445         struct ads7846  *ts = dev_get_drvdata(dev);
 446
 447         return ts->pendown;
 448 }
 449
 450 static ssize_t ads7846_pen_down_show(struct device *dev,
 451                                      struct device_attribute *attr, char *buf)
 452 {
 453         return sprintf(buf, "%u\n", is_pen_down(dev));
 454 }
 455
 456 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 457
 458 static ssize_t ads7846_disable_show(struct device *dev,
 459                                      struct device_attribute *attr, char *buf)
 460 {
 461         struct ads7846  *ts = dev_get_drvdata(dev);
 462
 463         return sprintf(buf, "%u\n", ts->disabled);
 464 }
 465
 466 static ssize_t ads7846_disable_store(struct device *dev,
 467                                      struct device_attribute *attr,
 468                                      const char *buf, size_t count)
 469 {
 470         struct ads7846 *ts = dev_get_drvdata(dev);
 471         char *endp;
 472         int i;
 473
 474         i = simple_strtoul(buf, &endp, 10);
 475         spin_lock_irq(&ts->lock);
 476
 477         if (i)
 478                 ads7846_disable(ts);
 479         else
 480                 ads7846_enable(ts);
 481
 482         spin_unlock_irq(&ts->lock);
 483
 484         return count;
 485 }
 486
 487 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 488
 489 static struct attribute *ads784x_attributes[] = {
 490         &dev_attr_pen_down.attr,
 491         &dev_attr_disable.attr,
 492         NULL,
 493 };
 494
 495 static struct attribute_group ads784x_attr_group = {
 496         .attrs = ads784x_attributes,
 497 };
 498
 499 /*--------------------------------------------------------------------------*/
 500
 501 /*
 502  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
 503  * to retrieve touchscreen status.
 504  *
 505  * The SPI transfer completion callback does the real work.  It reports
 506  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
 507  */
 508
 509 static void ads7846_rx(void *ads)
 510 {
 511         struct ads7846          *ts = ads;
 512         unsigned                Rt;
 513         u16                     x, y, z1, z2;
 514
 515         /* ads7846_rx_val() did in-place conversion (including byteswap) from
 516          * on-the-wire format as part of debouncing to get stable readings.
 517          */
 518         x = ts->tc.x;
 519         y = ts->tc.y;
 520         z1 = ts->tc.z1;
 521         z2 = ts->tc.z2;
 522
 523         /* range filtering */
 524         if (x == MAX_12BIT)
 525                 x = 0;
 526
 527         if (likely(x && z1)) {
 528                 /* compute touch pressure resistance using equation #2 */
 529                 Rt = z2;
 530                 Rt -= z1;
 531                 Rt *= x;
 532                 Rt *= ts->x_plate_ohms;
 533                 Rt /= z1;
 534                 Rt = (Rt + 2047) >> 12;
 535         } else
 536                 Rt = 0;
 537
 538         if (ts->model == 7843)
 539                 Rt = ts->pressure_max / 2;
 540
 541         /* Sample found inconsistent by debouncing or pressure is beyond
 542          * the maximum. Don't report it to user space, repeat at least
 543          * once more the measurement
 544          */
 545         if (ts->tc.ignore || Rt > ts->pressure_max) {
 546 #ifdef VERBOSE
 547                 pr_debug("%s: ignored %d pressure %d\n",
 548                         ts->spi->dev.bus_id, ts->tc.ignore, Rt);
 549 #endif
 550                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
 551                               HRTIMER_MODE_REL);
 552                 return;
 553         }
 554
 555         /* Maybe check the pendown state before reporting. This discards
 556          * false readings when the pen is lifted.
 557          */
 558         if (ts->penirq_recheck_delay_usecs) {
 559                 udelay(ts->penirq_recheck_delay_usecs);
 560                 if (!ts->get_pendown_state())
 561                         Rt = 0;
 562         }
 563
 564         /* NOTE: We can't rely on the pressure to determine the pen down
 565          * state, even this controller has a pressure sensor.  The pressure
 566          * value can fluctuate for quite a while after lifting the pen and
 567          * in some cases may not even settle at the expected value.
 568          *
 569          * The only safe way to check for the pen up condition is in the
 570          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 571          */
 572         if (Rt) {
 573                 struct input_dev *input = ts->input;
 574
 575                 if (!ts->pendown) {
 576                         input_report_key(input, BTN_TOUCH, 1);
 577                         ts->pendown = 1;
 578 #ifdef VERBOSE
 579                         dev_dbg(&ts->spi->dev, "DOWN\n");
 580 #endif
 581                 }
 582                 input_report_abs(input, ABS_X, x);
 583                 input_report_abs(input, ABS_Y, y);
 584                 input_report_abs(input, ABS_PRESSURE, Rt);
 585
 586                 input_sync(input);
 587 #ifdef VERBOSE
 588                 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 589 #endif
 590         }
 591
 592         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
 593                         HRTIMER_MODE_REL);
 594 }
 595
 596 static int ads7846_debounce(void *ads, int data_idx, int *val)
 597 {
 598         struct ads7846          *ts = ads;
 599
 600         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 601                 /* Start over collecting consistent readings. */
 602                 ts->read_rep = 0;
 603                 /* Repeat it, if this was the first read or the read
 604                  * wasn't consistent enough. */
 605                 if (ts->read_cnt < ts->debounce_max) {
 606                         ts->last_read = *val;
 607                         ts->read_cnt++;
 608                         return ADS7846_FILTER_REPEAT;
 609                 } else {
 610                         /* Maximum number of debouncing reached and still
 611                          * not enough number of consistent readings. Abort
 612                          * the whole sample, repeat it in the next sampling
 613                          * period.
 614                          */
 615                         ts->read_cnt = 0;
 616                         return ADS7846_FILTER_IGNORE;
 617                 }
 618         } else {
 619                 if (++ts->read_rep > ts->debounce_rep) {
 620                         /* Got a good reading for this coordinate,
 621                          * go for the next one. */
 622                         ts->read_cnt = 0;
 623                         ts->read_rep = 0;
 624                         return ADS7846_FILTER_OK;
 625                 } else {
 626                         /* Read more values that are consistent. */
 627                         ts->read_cnt++;
 628                         return ADS7846_FILTER_REPEAT;
 629                 }
 630         }
 631 }
 632
 633 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 634 {
 635         return ADS7846_FILTER_OK;
 636 }
 637
 638 static void ads7846_rx_val(void *ads)
 639 {
 640         struct ads7846 *ts = ads;
 641         struct spi_message *m;
 642         struct spi_transfer *t;
 643         u16 *rx_val;
 644         int val;
 645         int action;
 646         int status;
 647
 648         m = &ts->msg[ts->msg_idx];
 649         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 650         rx_val = t->rx_buf;
 651
 652         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
 653          * built from two 8 bit values written msb-first.
 654          */
 655         val = be16_to_cpu(*rx_val) >> 3;
 656
 657         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
 658         switch (action) {
 659         case ADS7846_FILTER_REPEAT:
 660                 break;
 661         case ADS7846_FILTER_IGNORE:
 662                 ts->tc.ignore = 1;
 663                 /* Last message will contain ads7846_rx() as the
 664                  * completion function.
 665                  */
 666                 m = ts->last_msg;
 667                 break;
 668         case ADS7846_FILTER_OK:
 669                 *rx_val = val;
 670                 ts->tc.ignore = 0;
 671                 m = &ts->msg[++ts->msg_idx];
 672                 break;
 673         default:
 674                 BUG();
 675         }
 676         status = spi_async(ts->spi, m);
 677         if (status)
 678                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
 679                                 status);
 680 }
 681
 682 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
 683 {
 684         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
 685         int             status = 0;
 686
 687         spin_lock_irq(&ts->lock);
 688
 689         if (unlikely(!ts->get_pendown_state() ||
 690                      device_suspended(&ts->spi->dev))) {
 691                 if (ts->pendown) {
 692                         struct input_dev *input = ts->input;
 693
 694                         input_report_key(input, BTN_TOUCH, 0);
 695                         input_report_abs(input, ABS_PRESSURE, 0);
 696                         input_sync(input);
 697
 698                         ts->pendown = 0;
 699 #ifdef VERBOSE
 700                         dev_dbg(&ts->spi->dev, "UP\n");
 701 #endif
 702                 }
 703
 704                 /* measurement cycle ended */
 705                 if (!device_suspended(&ts->spi->dev)) {
 706                         ts->irq_disabled = 0;
 707                         enable_irq(ts->spi->irq);
 708                 }
 709                 ts->pending = 0;
 710         } else {
 711                 /* pen is still down, continue with the measurement */
 712                 ts->msg_idx = 0;
 713                 status = spi_async(ts->spi, &ts->msg[0]);
 714                 if (status)
 715                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
 716         }
 717
 718         spin_unlock_irq(&ts->lock);
 719         return HRTIMER_NORESTART;
 720 }
 721
 722 static irqreturn_t ads7846_irq(int irq, void *handle)
 723 {
 724         struct ads7846 *ts = handle;
 725         unsigned long flags;
 726
 727         spin_lock_irqsave(&ts->lock, flags);
 728         if (likely(ts->get_pendown_state())) {
 729                 if (!ts->irq_disabled) {
 730                         /* The ARM do_simple_IRQ() dispatcher doesn't act
 731                          * like the other dispatchers:  it will report IRQs
 732                          * even after they've been disabled.  We work around
 733                          * that here.  (The "generic irq" framework may help...)
 734                          */
 735                         ts->irq_disabled = 1;
 736                         disable_irq(ts->spi->irq);
 737                         ts->pending = 1;
 738                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
 739                                         HRTIMER_MODE_REL);
 740                 }
 741         }
 742         spin_unlock_irqrestore(&ts->lock, flags);
 743
 744         return IRQ_HANDLED;
 745 }
 746
 747 /*--------------------------------------------------------------------------*/
 748
 749 /* Must be called with ts->lock held */
 750 static void ads7846_disable(struct ads7846 *ts)
 751 {
 752         if (ts->disabled)
 753                 return;
 754
 755         ts->disabled = 1;
 756
 757         /* are we waiting for IRQ, or polling? */
 758         if (!ts->pending) {
 759                 ts->irq_disabled = 1;
 760                 disable_irq(ts->spi->irq);
 761         } else {
 762                 /* the timer will run at least once more, and
 763                  * leave everything in a clean state, IRQ disabled
 764                  */
 765                 while (ts->pending) {
 766                         spin_unlock_irq(&ts->lock);
 767                         msleep(1);
 768                         spin_lock_irq(&ts->lock);
 769                 }
 770         }
 771
 772         /* we know the chip's in lowpower mode since we always
 773          * leave it that way after every request
 774          */
 775
 776 }
 777
 778 /* Must be called with ts->lock held */
 779 static void ads7846_enable(struct ads7846 *ts)
 780 {
 781         if (!ts->disabled)
 782                 return;
 783
 784         ts->disabled = 0;
 785         ts->irq_disabled = 0;
 786         enable_irq(ts->spi->irq);
 787 }
 788
 789 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
 790 {
 791         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 792
 793         spin_lock_irq(&ts->lock);
 794
 795         ts->is_suspended = 1;
 796         ads7846_disable(ts);
 797
 798         spin_unlock_irq(&ts->lock);
 799
 800         return 0;
 801
 802 }
 803
 804 static int ads7846_resume(struct spi_device *spi)
 805 {
 806         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
 807
 808         spin_lock_irq(&ts->lock);
 809
 810         ts->is_suspended = 0;
 811         ads7846_enable(ts);
 812
 813         spin_unlock_irq(&ts->lock);
 814
 815         return 0;
 816 }
 817
 818 static int __devinit ads7846_probe(struct spi_device *spi)
 819 {
 820         struct ads7846                  *ts;
 821         struct input_dev                *input_dev;
 822         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
 823         struct spi_message              *m;
 824         struct spi_transfer             *x;
 825         int                             vref;
 826         int                             err;
 827
 828         if (!spi->irq) {
 829                 dev_dbg(&spi->dev, "no IRQ?\n");
 830                 return -ENODEV;
 831         }
 832
 833         if (!pdata) {
 834                 dev_dbg(&spi->dev, "no platform data?\n");
 835                 return -ENODEV;
 836         }
 837
 838         /* don't exceed max specified sample rate */
 839         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
 840                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
 841                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
 842                 return -EINVAL;
 843         }
 844
 845         /* REVISIT when the irq can be triggered active-low, or if for some
 846          * reason the touchscreen isn't hooked up, we don't need to access
 847          * the pendown state.
 848          */
 849         if (pdata->get_pendown_state == NULL) {
 850                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
 851                 return -EINVAL;
 852         }
 853
 854         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
 855          * that even if the hardware can do that, the SPI controller driver
 856          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
 857          */
 858         spi->bits_per_word = 8;
 859         spi->mode = SPI_MODE_0;
 860         err = spi_setup(spi);
 861         if (err < 0)
 862                 return err;
 863
 864         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
 865         input_dev = input_allocate_device();
 866         if (!ts || !input_dev) {
 867                 err = -ENOMEM;
 868                 goto err_free_mem;
 869         }
 870
 871         dev_set_drvdata(&spi->dev, ts);
 872
 873         ts->spi = spi;
 874         ts->input = input_dev;
 875         ts->vref_mv = pdata->vref_mv;
 876
 877         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 878         ts->timer.function = ads7846_timer;
 879
 880         spin_lock_init(&ts->lock);
 881
 882         ts->model = pdata->model ? : 7846;
 883         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
 884         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 885         ts->pressure_max = pdata->pressure_max ? : ~0;
 886
 887         if (pdata->filter != NULL) {
 888                 if (pdata->filter_init != NULL) {
 889                         err = pdata->filter_init(pdata, &ts->filter_data);
 890                         if (err < 0)
 891                                 goto err_free_mem;
 892                 }
 893                 ts->filter = pdata->filter;
 894                 ts->filter_cleanup = pdata->filter_cleanup;
 895         } else if (pdata->debounce_max) {
 896                 ts->debounce_max = pdata->debounce_max;
 897                 if (ts->debounce_max < 2)
 898                         ts->debounce_max = 2;
 899                 ts->debounce_tol = pdata->debounce_tol;
 900                 ts->debounce_rep = pdata->debounce_rep;
 901                 ts->filter = ads7846_debounce;
 902                 ts->filter_data = ts;
 903         } else
 904                 ts->filter = ads7846_no_filter;
 905         ts->get_pendown_state = pdata->get_pendown_state;
 906
 907         if (pdata->penirq_recheck_delay_usecs)
 908                 ts->penirq_recheck_delay_usecs =
 909                                 pdata->penirq_recheck_delay_usecs;
 910
 911         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
 912
 913         input_dev->name = "ADS784x Touchscreen";
 914         input_dev->phys = ts->phys;
 915         input_dev->dev.parent = &spi->dev;
 916
 917         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 918         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 919         input_set_abs_params(input_dev, ABS_X,
 920                         pdata->x_min ? : 0,
 921                         pdata->x_max ? : MAX_12BIT,
 922                         0, 0);
 923         input_set_abs_params(input_dev, ABS_Y,
 924                         pdata->y_min ? : 0,
 925                         pdata->y_max ? : MAX_12BIT,
 926                         0, 0);
 927         input_set_abs_params(input_dev, ABS_PRESSURE,
 928                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 929
 930         vref = pdata->keep_vref_on;
 931
 932         /* set up the transfers to read touchscreen state; this assumes we
 933          * use formula #2 for pressure, not #3.
 934          */
 935         m = &ts->msg[0];
 936         x = ts->xfer;
 937
 938         spi_message_init(m);
 939
 940         /* y- still on; turn on only y+ (and ADC) */
 941         ts->read_y = READ_Y(vref);
 942         x->tx_buf = &ts->read_y;
 943         x->len = 1;
 944         spi_message_add_tail(x, m);
 945
 946         x++;
 947         x->rx_buf = &ts->tc.y;
 948         x->len = 2;
 949         spi_message_add_tail(x, m);
 950
 951         /* the first sample after switching drivers can be low quality;
 952          * optionally discard it, using a second one after the signals
 953          * have had enough time to stabilize.
 954          */
 955         if (pdata->settle_delay_usecs) {
 956                 x->delay_usecs = pdata->settle_delay_usecs;
 957
 958                 x++;
 959                 x->tx_buf = &ts->read_y;
 960                 x->len = 1;
 961                 spi_message_add_tail(x, m);
 962
 963                 x++;
 964                 x->rx_buf = &ts->tc.y;
 965                 x->len = 2;
 966                 spi_message_add_tail(x, m);
 967         }
 968
 969         m->complete = ads7846_rx_val;
 970         m->context = ts;
 971
 972         m++;
 973         spi_message_init(m);
 974
 975         /* turn y- off, x+ on, then leave in lowpower */
 976         x++;
 977         ts->read_x = READ_X(vref);
 978         x->tx_buf = &ts->read_x;
 979         x->len = 1;
 980         spi_message_add_tail(x, m);
 981
 982         x++;
 983         x->rx_buf = &ts->tc.x;
 984         x->len = 2;
 985         spi_message_add_tail(x, m);
 986
 987         /* ... maybe discard first sample ... */
 988         if (pdata->settle_delay_usecs) {
 989                 x->delay_usecs = pdata->settle_delay_usecs;
 990
 991                 x++;
 992                 x->tx_buf = &ts->read_x;
 993                 x->len = 1;
 994                 spi_message_add_tail(x, m);
 995
 996                 x++;
 997                 x->rx_buf = &ts->tc.x;
 998                 x->len = 2;
 999                 spi_message_add_tail(x, m);
1000         }
1001
1002         m->complete = ads7846_rx_val;
1003         m->context = ts;
1004
1005         /* turn y+ off, x- on; we'll use formula #2 */
1006         if (ts->model == 7846) {
1007                 m++;
1008                 spi_message_init(m);
1009
1010                 x++;
1011                 ts->read_z1 = READ_Z1(vref);
1012                 x->tx_buf = &ts->read_z1;
1013                 x->len = 1;
1014                 spi_message_add_tail(x, m);
1015
1016                 x++;
1017                 x->rx_buf = &ts->tc.z1;
1018                 x->len = 2;
1019                 spi_message_add_tail(x, m);
1020
1021                 /* ... maybe discard first sample ... */
1022                 if (pdata->settle_delay_usecs) {
1023                         x->delay_usecs = pdata->settle_delay_usecs;
1024
1025                         x++;
1026                         x->tx_buf = &ts->read_z1;
1027                         x->len = 1;
1028                         spi_message_add_tail(x, m);
1029
1030                         x++;
1031                         x->rx_buf = &ts->tc.z1;
1032                         x->len = 2;
1033                         spi_message_add_tail(x, m);
1034                 }
1035
1036                 m->complete = ads7846_rx_val;
1037                 m->context = ts;
1038
1039                 m++;
1040                 spi_message_init(m);
1041
1042                 x++;
1043                 ts->read_z2 = READ_Z2(vref);
1044                 x->tx_buf = &ts->read_z2;
1045                 x->len = 1;
1046                 spi_message_add_tail(x, m);
1047
1048                 x++;
1049                 x->rx_buf = &ts->tc.z2;
1050                 x->len = 2;
1051                 spi_message_add_tail(x, m);
1052
1053                 /* ... maybe discard first sample ... */
1054                 if (pdata->settle_delay_usecs) {
1055                         x->delay_usecs = pdata->settle_delay_usecs;
1056
1057                         x++;
1058                         x->tx_buf = &ts->read_z2;
1059                         x->len = 1;
1060                         spi_message_add_tail(x, m);
1061
1062                         x++;
1063                         x->rx_buf = &ts->tc.z2;
1064                         x->len = 2;
1065                         spi_message_add_tail(x, m);
1066                 }
1067
1068                 m->complete = ads7846_rx_val;
1069                 m->context = ts;
1070         }
1071
1072         /* power down */
1073         m++;
1074         spi_message_init(m);
1075
1076         x++;
1077         ts->pwrdown = PWRDOWN;
1078         x->tx_buf = &ts->pwrdown;
1079         x->len = 1;
1080         spi_message_add_tail(x, m);
1081
1082         x++;
1083         x->rx_buf = &ts->dummy;
1084         x->len = 2;
1085         CS_CHANGE(*x);
1086         spi_message_add_tail(x, m);
1087
1088         m->complete = ads7846_rx;
1089         m->context = ts;
1090
1091         ts->last_msg = m;
1092
1093         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1094                         spi->dev.driver->name, ts)) {
1095                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1096                 err = -EBUSY;
1097                 goto err_cleanup_filter;
1098         }
1099
1100         err = ads784x_hwmon_register(spi, ts);
1101         if (err)
1102                 goto err_free_irq;
1103
1104         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1105
1106         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1107          * the touchscreen, in case it's not connected.
1108          */
1109         (void) ads7846_read12_ser(&spi->dev,
1110                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1111
1112         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1113         if (err)
1114                 goto err_remove_hwmon;
1115
1116         err = input_register_device(input_dev);
1117         if (err)
1118                 goto err_remove_attr_group;
1119
1120         return 0;
1121
1122  err_remove_attr_group:
1123         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1124  err_remove_hwmon:
1125         ads784x_hwmon_unregister(spi, ts);
1126  err_free_irq:
1127         free_irq(spi->irq, ts);
1128  err_cleanup_filter:
1129         if (ts->filter_cleanup)
1130                 ts->filter_cleanup(ts->filter_data);
1131  err_free_mem:
1132         input_free_device(input_dev);
1133         kfree(ts);
1134         return err;
1135 }
1136
1137 static int __devexit ads7846_remove(struct spi_device *spi)
1138 {
1139         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1140
1141         ads784x_hwmon_unregister(spi, ts);
1142         input_unregister_device(ts->input);
1143
1144         ads7846_suspend(spi, PMSG_SUSPEND);
1145
1146         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1147
1148         free_irq(ts->spi->irq, ts);
1149         /* suspend left the IRQ disabled */
1150         enable_irq(ts->spi->irq);
1151
1152         if (ts->filter_cleanup)
1153                 ts->filter_cleanup(ts->filter_data);
1154
1155         kfree(ts);
1156
1157         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1158         return 0;
1159 }
1160
1161 static struct spi_driver ads7846_driver = {
1162         .driver = {
1163                 .name   = "ads7846",
1164                 .bus    = &spi_bus_type,
1165                 .owner  = THIS_MODULE,
1166         },
1167         .probe          = ads7846_probe,
1168         .remove         = __devexit_p(ads7846_remove),
1169         .suspend        = ads7846_suspend,
1170         .resume         = ads7846_resume,
1171 };
1172
1173 static int __init ads7846_init(void)
1174 {
1175         /* grr, board-specific init should stay out of drivers!! */
1176
1177 #ifdef  CONFIG_ARCH_OMAP
1178         if (machine_is_omap_osk()) {
1179                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
1180                 omap_request_gpio(4);
1181                 omap_set_gpio_direction(4, 1);
1182                 omap_request_gpio(6);
1183                 omap_set_gpio_direction(6, 1);
1184         }
1185         // also TI 1510 Innovator, bitbanging through FPGA
1186         // also Nokia 770
1187         // also Palm Tungsten T2
1188 #endif
1189
1190         // PXA:
1191         // also Dell Axim X50
1192         // also HP iPaq H191x/H192x/H415x/H435x
1193         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
1194         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
1195
1196         // Atmel at91sam9261-EK uses ads7843
1197
1198         // also various AMD Au1x00 devel boards
1199
1200         return spi_register_driver(&ads7846_driver);
1201 }
1202 module_init(ads7846_init);
1203
1204 static void __exit ads7846_exit(void)
1205 {
1206         spi_unregister_driver(&ads7846_driver);
1207
1208 #ifdef  CONFIG_ARCH_OMAP
1209         if (machine_is_omap_osk()) {
1210                 omap_free_gpio(4);
1211                 omap_free_gpio(6);
1212         }
1213 #endif
1214
1215 }
1216 module_exit(ads7846_exit);
1217
1218 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1219 MODULE_LICENSE("GPL");