drivers/input/touchscreen/ad7879.c

   1 /*
   2  * AD7879/AD7889 based touchscreen and GPIO driver
   3  *
   4  * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  *
   8  * History:
   9  * Copyright (c) 2005 David Brownell
  10  * Copyright (c) 2006 Nokia Corporation
  11  * Various changes: Imre Deak <imre.deak@nokia.com>
  12  *
  13  * Using code from:
  14  *  - corgi_ts.c
  15  *      Copyright (C) 2004-2005 Richard Purdie
  16  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  17  *      Copyright (C) 2002 MontaVista Software
  18  *      Copyright (C) 2004 Texas Instruments
  19  *      Copyright (C) 2005 Dirk Behme
  20  *  - ad7877.c
  21  *      Copyright (C) 2006-2008 Analog Devices Inc.
  22  */
  23
  24 #include <linux/device.h>
  25 #include <linux/init.h>
  26 #include <linux/delay.h>
  27 #include <linux/input.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/irq.h>
  30 #include <linux/slab.h>
  31 #include <linux/spi/spi.h>
  32 #include <linux/i2c.h>
  33 #include <linux/gpio.h>
  34
  35 #include <linux/spi/ad7879.h>
  36 #include "ad7879.h"
  37
  38 #define AD7879_REG_ZEROS                0
  39 #define AD7879_REG_CTRL1                1
  40 #define AD7879_REG_CTRL2                2
  41 #define AD7879_REG_CTRL3                3
  42 #define AD7879_REG_AUX1HIGH             4
  43 #define AD7879_REG_AUX1LOW              5
  44 #define AD7879_REG_TEMP1HIGH            6
  45 #define AD7879_REG_TEMP1LOW             7
  46 #define AD7879_REG_XPLUS                8
  47 #define AD7879_REG_YPLUS                9
  48 #define AD7879_REG_Z1                   10
  49 #define AD7879_REG_Z2                   11
  50 #define AD7879_REG_AUXVBAT              12
  51 #define AD7879_REG_TEMP                 13
  52 #define AD7879_REG_REVID                14
  53
  54 /* Control REG 1 */
  55 #define AD7879_TMR(x)                   ((x & 0xFF) << 0)
  56 #define AD7879_ACQ(x)                   ((x & 0x3) << 8)
  57 #define AD7879_MODE_NOC                 (0 << 10)       /* Do not convert */
  58 #define AD7879_MODE_SCC                 (1 << 10)       /* Single channel conversion */
  59 #define AD7879_MODE_SEQ0                (2 << 10)       /* Sequence 0 in Slave Mode */
  60 #define AD7879_MODE_SEQ1                (3 << 10)       /* Sequence 1 in Master Mode */
  61 #define AD7879_MODE_INT                 (1 << 15)       /* PENIRQ disabled INT enabled */
  62
  63 /* Control REG 2 */
  64 #define AD7879_FCD(x)                   ((x & 0x3) << 0)
  65 #define AD7879_RESET                    (1 << 4)
  66 #define AD7879_MFS(x)                   ((x & 0x3) << 5)
  67 #define AD7879_AVG(x)                   ((x & 0x3) << 7)
  68 #define AD7879_SER                      (1 << 9)        /* non-differential */
  69 #define AD7879_DFR                      (0 << 9)        /* differential */
  70 #define AD7879_GPIOPOL                  (1 << 10)
  71 #define AD7879_GPIODIR                  (1 << 11)
  72 #define AD7879_GPIO_DATA                (1 << 12)
  73 #define AD7879_GPIO_EN                  (1 << 13)
  74 #define AD7879_PM(x)                    ((x & 0x3) << 14)
  75 #define AD7879_PM_SHUTDOWN              (0)
  76 #define AD7879_PM_DYN                   (1)
  77 #define AD7879_PM_FULLON                (2)
  78
  79 /* Control REG 3 */
  80 #define AD7879_TEMPMASK_BIT             (1<<15)
  81 #define AD7879_AUXVBATMASK_BIT          (1<<14)
  82 #define AD7879_INTMODE_BIT              (1<<13)
  83 #define AD7879_GPIOALERTMASK_BIT        (1<<12)
  84 #define AD7879_AUXLOW_BIT               (1<<11)
  85 #define AD7879_AUXHIGH_BIT              (1<<10)
  86 #define AD7879_TEMPLOW_BIT              (1<<9)
  87 #define AD7879_TEMPHIGH_BIT             (1<<8)
  88 #define AD7879_YPLUS_BIT                (1<<7)
  89 #define AD7879_XPLUS_BIT                (1<<6)
  90 #define AD7879_Z1_BIT                   (1<<5)
  91 #define AD7879_Z2_BIT                   (1<<4)
  92 #define AD7879_AUX_BIT                  (1<<3)
  93 #define AD7879_VBAT_BIT                 (1<<2)
  94 #define AD7879_TEMP_BIT                 (1<<1)
  95
  96 enum {
  97         AD7879_SEQ_XPOS  = 0,
  98         AD7879_SEQ_YPOS  = 1,
  99         AD7879_SEQ_Z1    = 2,
 100         AD7879_SEQ_Z2    = 3,
 101         AD7879_NR_SENSE  = 4,
 102 };
 103
 104 #define MAX_12BIT                       ((1<<12)-1)
 105 #define TS_PEN_UP_TIMEOUT               msecs_to_jiffies(50)
 106
 107 struct ad7879 {
 108         const struct ad7879_bus_ops *bops;
 109
 110         struct device           *dev;
 111         struct input_dev        *input;
 112         struct timer_list       timer;
 113 #ifdef CONFIG_GPIOLIB
 114         struct gpio_chip        gc;
 115         struct mutex            mutex;
 116 #endif
 117         unsigned int            irq;
 118         bool                    disabled;       /* P: input->mutex */
 119         bool                    suspended;      /* P: input->mutex */
 120         u16                     conversion_data[AD7879_NR_SENSE];
 121         char                    phys[32];
 122         u8                      first_conversion_delay;
 123         u8                      acquisition_time;
 124         u8                      averaging;
 125         u8                      pen_down_acc_interval;
 126         u8                      median;
 127         u16                     x_plate_ohms;
 128         u16                     pressure_max;
 129         u16                     cmd_crtl1;
 130         u16                     cmd_crtl2;
 131         u16                     cmd_crtl3;
 132         int                     x;
 133         int                     y;
 134         int                     Rt;
 135 };
 136
 137 static int ad7879_read(struct ad7879 *ts, u8 reg)
 138 {
 139         return ts->bops->read(ts->dev, reg);
 140 }
 141
 142 static int ad7879_multi_read(struct ad7879 *ts, u8 first_reg, u8 count, u16 *buf)
 143 {
 144         return ts->bops->multi_read(ts->dev, first_reg, count, buf);
 145 }
 146
 147 static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
 148 {
 149         return ts->bops->write(ts->dev, reg, val);
 150 }
 151
 152 static int ad7879_report(struct ad7879 *ts)
 153 {
 154         struct input_dev *input_dev = ts->input;
 155         unsigned Rt;
 156         u16 x, y, z1, z2;
 157
 158         x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
 159         y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
 160         z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
 161         z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
 162
 163         /*
 164          * The samples processed here are already preprocessed by the AD7879.
 165          * The preprocessing function consists of a median and an averaging
 166          * filter.  The combination of these two techniques provides a robust
 167          * solution, discarding the spurious noise in the signal and keeping
 168          * only the data of interest.  The size of both filters is
 169          * programmable. (dev.platform_data, see linux/spi/ad7879.h) Other
 170          * user-programmable conversion controls include variable acquisition
 171          * time, and first conversion delay. Up to 16 averages can be taken
 172          * per conversion.
 173          */
 174
 175         if (likely(x && z1)) {
 176                 /* compute touch pressure resistance using equation #1 */
 177                 Rt = (z2 - z1) * x * ts->x_plate_ohms;
 178                 Rt /= z1;
 179                 Rt = (Rt + 2047) >> 12;
 180
 181                 /*
 182                  * Sample found inconsistent, pressure is beyond
 183                  * the maximum. Don't report it to user space.
 184                  */
 185                 if (Rt > ts->pressure_max)
 186                         return -EINVAL;
 187
 188                 /*
 189                  * Note that we delay reporting events by one sample.
 190                  * This is done to avoid reporting last sample of the
 191                  * touch sequence, which may be incomplete if finger
 192                  * leaves the surface before last reading is taken.
 193                  */
 194                 if (timer_pending(&ts->timer)) {
 195                         /* Touch continues */
 196                         input_report_key(input_dev, BTN_TOUCH, 1);
 197                         input_report_abs(input_dev, ABS_X, ts->x);
 198                         input_report_abs(input_dev, ABS_Y, ts->y);
 199                         input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
 200                         input_sync(input_dev);
 201                 }
 202
 203                 ts->x = x;
 204                 ts->y = y;
 205                 ts->Rt = Rt;
 206
 207                 return 0;
 208         }
 209
 210         return -EINVAL;
 211 }
 212
 213 static void ad7879_ts_event_release(struct ad7879 *ts)
 214 {
 215         struct input_dev *input_dev = ts->input;
 216
 217         input_report_abs(input_dev, ABS_PRESSURE, 0);
 218         input_report_key(input_dev, BTN_TOUCH, 0);
 219         input_sync(input_dev);
 220 }
 221
 222 static void ad7879_timer(unsigned long handle)
 223 {
 224         struct ad7879 *ts = (void *)handle;
 225
 226         ad7879_ts_event_release(ts);
 227 }
 228
 229 static irqreturn_t ad7879_irq(int irq, void *handle)
 230 {
 231         struct ad7879 *ts = handle;
 232
 233         ad7879_multi_read(ts, AD7879_REG_XPLUS, AD7879_NR_SENSE, ts->conversion_data);
 234
 235         if (!ad7879_report(ts))
 236                 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 237
 238         return IRQ_HANDLED;
 239 }
 240
 241 static void __ad7879_enable(struct ad7879 *ts)
 242 {
 243         ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 244         ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
 245         ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
 246
 247         enable_irq(ts->irq);
 248 }
 249
 250 static void __ad7879_disable(struct ad7879 *ts)
 251 {
 252         disable_irq(ts->irq);
 253
 254         if (del_timer_sync(&ts->timer))
 255                 ad7879_ts_event_release(ts);
 256
 257         ad7879_write(ts, AD7879_REG_CTRL2, AD7879_PM(AD7879_PM_SHUTDOWN));
 258 }
 259
 260
 261 static int ad7879_open(struct input_dev *input)
 262 {
 263         struct ad7879 *ts = input_get_drvdata(input);
 264
 265         /* protected by input->mutex */
 266         if (!ts->disabled && !ts->suspended)
 267                 __ad7879_enable(ts);
 268
 269         return 0;
 270 }
 271
 272 static void ad7879_close(struct input_dev* input)
 273 {
 274         struct ad7879 *ts = input_get_drvdata(input);
 275
 276         /* protected by input->mutex */
 277         if (!ts->disabled && !ts->suspended)
 278                 __ad7879_disable(ts);
 279 }
 280
 281 void ad7879_suspend(struct ad7879 *ts)
 282 {
 283         mutex_lock(&ts->input->mutex);
 284
 285         if (!ts->suspended && !ts->disabled && ts->input->users)
 286                 __ad7879_disable(ts);
 287
 288         ts->suspended = true;
 289
 290         mutex_unlock(&ts->input->mutex);
 291 }
 292 EXPORT_SYMBOL(ad7879_suspend);
 293
 294 void ad7879_resume(struct ad7879 *ts)
 295 {
 296         mutex_lock(&ts->input->mutex);
 297
 298         if (ts->suspended && !ts->disabled && ts->input->users)
 299                 __ad7879_enable(ts);
 300
 301         ts->suspended = false;
 302
 303         mutex_unlock(&ts->input->mutex);
 304 }
 305 EXPORT_SYMBOL(ad7879_resume);
 306
 307 static void ad7879_toggle(struct ad7879 *ts, bool disable)
 308 {
 309         mutex_lock(&ts->input->mutex);
 310
 311         if (!ts->suspended && ts->input->users != 0) {
 312
 313                 if (disable) {
 314                         if (ts->disabled)
 315                                 __ad7879_enable(ts);
 316                 } else {
 317                         if (!ts->disabled)
 318                                 __ad7879_disable(ts);
 319                 }
 320         }
 321
 322         ts->disabled = disable;
 323
 324         mutex_unlock(&ts->input->mutex);
 325 }
 326
 327 static ssize_t ad7879_disable_show(struct device *dev,
 328                                      struct device_attribute *attr, char *buf)
 329 {
 330         struct ad7879 *ts = dev_get_drvdata(dev);
 331
 332         return sprintf(buf, "%u\n", ts->disabled);
 333 }
 334
 335 static ssize_t ad7879_disable_store(struct device *dev,
 336                                      struct device_attribute *attr,
 337                                      const char *buf, size_t count)
 338 {
 339         struct ad7879 *ts = dev_get_drvdata(dev);
 340         unsigned long val;
 341         int error;
 342
 343         error = strict_strtoul(buf, 10, &val);
 344         if (error)
 345                 return error;
 346
 347         ad7879_toggle(ts, val);
 348
 349         return count;
 350 }
 351
 352 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 353
 354 static struct attribute *ad7879_attributes[] = {
 355         &dev_attr_disable.attr,
 356         NULL
 357 };
 358
 359 static const struct attribute_group ad7879_attr_group = {
 360         .attrs = ad7879_attributes,
 361 };
 362
 363 #ifdef CONFIG_GPIOLIB
 364 static int ad7879_gpio_direction_input(struct gpio_chip *chip,
 365                                         unsigned gpio)
 366 {
 367         struct ad7879 *ts = container_of(chip, struct ad7879, gc);
 368         int err;
 369
 370         mutex_lock(&ts->mutex);
 371         ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
 372         err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 373         mutex_unlock(&ts->mutex);
 374
 375         return err;
 376 }
 377
 378 static int ad7879_gpio_direction_output(struct gpio_chip *chip,
 379                                         unsigned gpio, int level)
 380 {
 381         struct ad7879 *ts = container_of(chip, struct ad7879, gc);
 382         int err;
 383
 384         mutex_lock(&ts->mutex);
 385         ts->cmd_crtl2 &= ~AD7879_GPIODIR;
 386         ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
 387         if (level)
 388                 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
 389         else
 390                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 391
 392         err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 393         mutex_unlock(&ts->mutex);
 394
 395         return err;
 396 }
 397
 398 static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
 399 {
 400         struct ad7879 *ts = container_of(chip, struct ad7879, gc);
 401         u16 val;
 402
 403         mutex_lock(&ts->mutex);
 404         val = ad7879_read(ts, AD7879_REG_CTRL2);
 405         mutex_unlock(&ts->mutex);
 406
 407         return !!(val & AD7879_GPIO_DATA);
 408 }
 409
 410 static void ad7879_gpio_set_value(struct gpio_chip *chip,
 411                                   unsigned gpio, int value)
 412 {
 413         struct ad7879 *ts = container_of(chip, struct ad7879, gc);
 414
 415         mutex_lock(&ts->mutex);
 416         if (value)
 417                 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
 418         else
 419                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 420
 421         ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 422         mutex_unlock(&ts->mutex);
 423 }
 424
 425 static int ad7879_gpio_add(struct ad7879 *ts,
 426                            const struct ad7879_platform_data *pdata)
 427 {
 428         int ret = 0;
 429
 430         mutex_init(&ts->mutex);
 431
 432         if (pdata->gpio_export) {
 433                 ts->gc.direction_input = ad7879_gpio_direction_input;
 434                 ts->gc.direction_output = ad7879_gpio_direction_output;
 435                 ts->gc.get = ad7879_gpio_get_value;
 436                 ts->gc.set = ad7879_gpio_set_value;
 437                 ts->gc.can_sleep = 1;
 438                 ts->gc.base = pdata->gpio_base;
 439                 ts->gc.ngpio = 1;
 440                 ts->gc.label = "AD7879-GPIO";
 441                 ts->gc.owner = THIS_MODULE;
 442                 ts->gc.dev = ts->dev;
 443
 444                 ret = gpiochip_add(&ts->gc);
 445                 if (ret)
 446                         dev_err(ts->dev, "failed to register gpio %d\n",
 447                                 ts->gc.base);
 448         }
 449
 450         return ret;
 451 }
 452
 453 static void ad7879_gpio_remove(struct ad7879 *ts)
 454 {
 455         const struct ad7879_platform_data *pdata = ts->dev->platform_data;
 456         int ret;
 457
 458         if (pdata->gpio_export) {
 459                 ret = gpiochip_remove(&ts->gc);
 460                 if (ret)
 461                         dev_err(ts->dev, "failed to remove gpio %d\n",
 462                                 ts->gc.base);
 463         }
 464 }
 465 #else
 466 static inline int ad7879_gpio_add(struct ad7879 *ts,
 467                                   const struct ad7879_platform_data *pdata)
 468 {
 469         return 0;
 470 }
 471
 472 static inline void ad7879_gpio_remove(struct ad7879 *ts)
 473 {
 474 }
 475 #endif
 476
 477 struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
 478                             const struct ad7879_bus_ops *bops)
 479 {
 480         struct ad7879_platform_data *pdata = dev->platform_data;
 481         struct ad7879 *ts;
 482         struct input_dev *input_dev;
 483         int err;
 484         u16 revid;
 485
 486         if (!irq) {
 487                 dev_err(dev, "no IRQ?\n");
 488                 err = -EINVAL;
 489                 goto err_out;
 490         }
 491
 492         if (!pdata) {
 493                 dev_err(dev, "no platform data?\n");
 494                 err = -EINVAL;
 495                 goto err_out;
 496         }
 497
 498         ts = kzalloc(sizeof(*ts), GFP_KERNEL);
 499         input_dev = input_allocate_device();
 500         if (!ts || !input_dev) {
 501                 err = -ENOMEM;
 502                 goto err_free_mem;
 503         }
 504
 505         ts->bops = bops;
 506         ts->dev = dev;
 507         ts->input = input_dev;
 508         ts->irq = irq;
 509
 510         setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
 511
 512         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 513         ts->pressure_max = pdata->pressure_max ? : ~0;
 514
 515         ts->first_conversion_delay = pdata->first_conversion_delay;
 516         ts->acquisition_time = pdata->acquisition_time;
 517         ts->averaging = pdata->averaging;
 518         ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
 519         ts->median = pdata->median;
 520
 521         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
 522
 523         input_dev->name = "AD7879 Touchscreen";
 524         input_dev->phys = ts->phys;
 525         input_dev->dev.parent = dev;
 526         input_dev->id.bustype = bops->bustype;
 527
 528         input_dev->open = ad7879_open;
 529         input_dev->close = ad7879_close;
 530
 531         input_set_drvdata(input_dev, ts);
 532
 533         __set_bit(EV_ABS, input_dev->evbit);
 534         __set_bit(ABS_X, input_dev->absbit);
 535         __set_bit(ABS_Y, input_dev->absbit);
 536         __set_bit(ABS_PRESSURE, input_dev->absbit);
 537
 538         __set_bit(EV_KEY, input_dev->evbit);
 539         __set_bit(BTN_TOUCH, input_dev->keybit);
 540
 541         input_set_abs_params(input_dev, ABS_X,
 542                         pdata->x_min ? : 0,
 543                         pdata->x_max ? : MAX_12BIT,
 544                         0, 0);
 545         input_set_abs_params(input_dev, ABS_Y,
 546                         pdata->y_min ? : 0,
 547                         pdata->y_max ? : MAX_12BIT,
 548                         0, 0);
 549         input_set_abs_params(input_dev, ABS_PRESSURE,
 550                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 551
 552         err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
 553         if (err < 0) {
 554                 dev_err(dev, "Failed to write %s\n", input_dev->name);
 555                 goto err_free_mem;
 556         }
 557
 558         revid = ad7879_read(ts, AD7879_REG_REVID);
 559         input_dev->id.product = (revid & 0xff);
 560         input_dev->id.version = revid >> 8;
 561         if (input_dev->id.product != devid) {
 562                 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
 563                         input_dev->name, devid, revid);
 564                 err = -ENODEV;
 565                 goto err_free_mem;
 566         }
 567
 568         ts->cmd_crtl3 = AD7879_YPLUS_BIT |
 569                         AD7879_XPLUS_BIT |
 570                         AD7879_Z2_BIT |
 571                         AD7879_Z1_BIT |
 572                         AD7879_TEMPMASK_BIT |
 573                         AD7879_AUXVBATMASK_BIT |
 574                         AD7879_GPIOALERTMASK_BIT;
 575
 576         ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
 577                         AD7879_AVG(ts->averaging) |
 578                         AD7879_MFS(ts->median) |
 579                         AD7879_FCD(ts->first_conversion_delay);
 580
 581         ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
 582                         AD7879_ACQ(ts->acquisition_time) |
 583                         AD7879_TMR(ts->pen_down_acc_interval);
 584
 585         err = request_threaded_irq(ts->irq, NULL, ad7879_irq,
 586                                    IRQF_TRIGGER_FALLING,
 587                                    dev_name(dev), ts);
 588         if (err) {
 589                 dev_err(dev, "irq %d busy?\n", ts->irq);
 590                 goto err_free_mem;
 591         }
 592
 593         __ad7879_disable(ts);
 594
 595         err = sysfs_create_group(&dev->kobj, &ad7879_attr_group);
 596         if (err)
 597                 goto err_free_irq;
 598
 599         err = ad7879_gpio_add(ts, pdata);
 600         if (err)
 601                 goto err_remove_attr;
 602
 603         err = input_register_device(input_dev);
 604         if (err)
 605                 goto err_remove_gpio;
 606
 607         return ts;
 608
 609 err_remove_gpio:
 610         ad7879_gpio_remove(ts);
 611 err_remove_attr:
 612         sysfs_remove_group(&dev->kobj, &ad7879_attr_group);
 613 err_free_irq:
 614         free_irq(ts->irq, ts);
 615 err_free_mem:
 616         input_free_device(input_dev);
 617         kfree(ts);
 618 err_out:
 619         return ERR_PTR(err);
 620 }
 621 EXPORT_SYMBOL(ad7879_probe);
 622
 623 void ad7879_remove(struct ad7879 *ts)
 624 {
 625         ad7879_gpio_remove(ts);
 626         sysfs_remove_group(&ts->dev->kobj, &ad7879_attr_group);
 627         free_irq(ts->irq, ts);
 628         input_unregister_device(ts->input);
 629         kfree(ts);
 630 }
 631 EXPORT_SYMBOL(ad7879_remove);
 632
 633 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 634 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 635 MODULE_LICENSE("GPL");