drivers/input/touchscreen/ad7879.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * AD7879/AD7889 based touchscreen and GPIO driver
   4  *
   5  * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
   6  *
   7  * History:
   8  * Copyright (c) 2005 David Brownell
   9  * Copyright (c) 2006 Nokia Corporation
  10  * Various changes: Imre Deak <imre.deak@nokia.com>
  11  *
  12  * Using code from:
  13  *  - corgi_ts.c
  14  *      Copyright (C) 2004-2005 Richard Purdie
  15  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  16  *      Copyright (C) 2002 MontaVista Software
  17  *      Copyright (C) 2004 Texas Instruments
  18  *      Copyright (C) 2005 Dirk Behme
  19  *  - ad7877.c
  20  *      Copyright (C) 2006-2008 Analog Devices Inc.
  21  */
  22
  23 #include <linux/device.h>
  24 #include <linux/delay.h>
  25 #include <linux/input.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/irq.h>
  28 #include <linux/property.h>
  29 #include <linux/regmap.h>
  30 #include <linux/slab.h>
  31 #include <linux/gpio/driver.h>
  32
  33 #include <linux/input/touchscreen.h>
  34 #include <linux/module.h>
  35 #include "ad7879.h"
  36
  37 #define AD7879_REG_ZEROS                0
  38 #define AD7879_REG_CTRL1                1
  39 #define AD7879_REG_CTRL2                2
  40 #define AD7879_REG_CTRL3                3
  41 #define AD7879_REG_AUX1HIGH             4
  42 #define AD7879_REG_AUX1LOW              5
  43 #define AD7879_REG_TEMP1HIGH            6
  44 #define AD7879_REG_TEMP1LOW             7
  45 #define AD7879_REG_XPLUS                8
  46 #define AD7879_REG_YPLUS                9
  47 #define AD7879_REG_Z1                   10
  48 #define AD7879_REG_Z2                   11
  49 #define AD7879_REG_AUXVBAT              12
  50 #define AD7879_REG_TEMP                 13
  51 #define AD7879_REG_REVID                14
  52
  53 /* Control REG 1 */
  54 #define AD7879_TMR(x)                   ((x & 0xFF) << 0)
  55 #define AD7879_ACQ(x)                   ((x & 0x3) << 8)
  56 #define AD7879_MODE_NOC                 (0 << 10)       /* Do not convert */
  57 #define AD7879_MODE_SCC                 (1 << 10)       /* Single channel conversion */
  58 #define AD7879_MODE_SEQ0                (2 << 10)       /* Sequence 0 in Slave Mode */
  59 #define AD7879_MODE_SEQ1                (3 << 10)       /* Sequence 1 in Master Mode */
  60 #define AD7879_MODE_INT                 (1 << 15)       /* PENIRQ disabled INT enabled */
  61
  62 /* Control REG 2 */
  63 #define AD7879_FCD(x)                   ((x & 0x3) << 0)
  64 #define AD7879_RESET                    (1 << 4)
  65 #define AD7879_MFS(x)                   ((x & 0x3) << 5)
  66 #define AD7879_AVG(x)                   ((x & 0x3) << 7)
  67 #define AD7879_SER                      (1 << 9)        /* non-differential */
  68 #define AD7879_DFR                      (0 << 9)        /* differential */
  69 #define AD7879_GPIOPOL                  (1 << 10)
  70 #define AD7879_GPIODIR                  (1 << 11)
  71 #define AD7879_GPIO_DATA                (1 << 12)
  72 #define AD7879_GPIO_EN                  (1 << 13)
  73 #define AD7879_PM(x)                    ((x & 0x3) << 14)
  74 #define AD7879_PM_SHUTDOWN              (0)
  75 #define AD7879_PM_DYN                   (1)
  76 #define AD7879_PM_FULLON                (2)
  77
  78 /* Control REG 3 */
  79 #define AD7879_TEMPMASK_BIT             (1<<15)
  80 #define AD7879_AUXVBATMASK_BIT          (1<<14)
  81 #define AD7879_INTMODE_BIT              (1<<13)
  82 #define AD7879_GPIOALERTMASK_BIT        (1<<12)
  83 #define AD7879_AUXLOW_BIT               (1<<11)
  84 #define AD7879_AUXHIGH_BIT              (1<<10)
  85 #define AD7879_TEMPLOW_BIT              (1<<9)
  86 #define AD7879_TEMPHIGH_BIT             (1<<8)
  87 #define AD7879_YPLUS_BIT                (1<<7)
  88 #define AD7879_XPLUS_BIT                (1<<6)
  89 #define AD7879_Z1_BIT                   (1<<5)
  90 #define AD7879_Z2_BIT                   (1<<4)
  91 #define AD7879_AUX_BIT                  (1<<3)
  92 #define AD7879_VBAT_BIT                 (1<<2)
  93 #define AD7879_TEMP_BIT                 (1<<1)
  94
  95 enum {
  96         AD7879_SEQ_YPOS  = 0,
  97         AD7879_SEQ_XPOS  = 1,
  98         AD7879_SEQ_Z1    = 2,
  99         AD7879_SEQ_Z2    = 3,
 100         AD7879_NR_SENSE  = 4,
 101 };
 102
 103 #define MAX_12BIT                       ((1<<12)-1)
 104 #define TS_PEN_UP_TIMEOUT               msecs_to_jiffies(50)
 105
 106 struct ad7879 {
 107         struct regmap           *regmap;
 108         struct device           *dev;
 109         struct input_dev        *input;
 110         struct timer_list       timer;
 111 #ifdef CONFIG_GPIOLIB
 112         struct gpio_chip        gc;
 113         struct mutex            mutex;
 114 #endif
 115         unsigned int            irq;
 116         bool                    disabled;       /* P: input->mutex */
 117         bool                    suspended;      /* P: input->mutex */
 118         bool                    swap_xy;
 119         u16                     conversion_data[AD7879_NR_SENSE];
 120         char                    phys[32];
 121         u8                      first_conversion_delay;
 122         u8                      acquisition_time;
 123         u8                      averaging;
 124         u8                      pen_down_acc_interval;
 125         u8                      median;
 126         u16                     x_plate_ohms;
 127         u16                     cmd_crtl1;
 128         u16                     cmd_crtl2;
 129         u16                     cmd_crtl3;
 130         int                     x;
 131         int                     y;
 132         int                     Rt;
 133 };
 134
 135 static int ad7879_read(struct ad7879 *ts, u8 reg)
 136 {
 137         unsigned int val;
 138         int error;
 139
 140         error = regmap_read(ts->regmap, reg, &val);
 141         if (error) {
 142                 dev_err(ts->dev, "failed to read register %#02x: %d\n",
 143                         reg, error);
 144                 return error;
 145         }
 146
 147         return val;
 148 }
 149
 150 static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
 151 {
 152         int error;
 153
 154         error = regmap_write(ts->regmap, reg, val);
 155         if (error) {
 156                 dev_err(ts->dev,
 157                         "failed to write %#04x to register %#02x: %d\n",
 158                         val, reg, error);
 159                 return error;
 160         }
 161
 162         return 0;
 163 }
 164
 165 static int ad7879_report(struct ad7879 *ts)
 166 {
 167         struct input_dev *input_dev = ts->input;
 168         unsigned Rt;
 169         u16 x, y, z1, z2;
 170
 171         x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
 172         y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
 173         z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
 174         z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
 175
 176         if (ts->swap_xy)
 177                 swap(x, y);
 178
 179         /*
 180          * The samples processed here are already preprocessed by the AD7879.
 181          * The preprocessing function consists of a median and an averaging
 182          * filter.  The combination of these two techniques provides a robust
 183          * solution, discarding the spurious noise in the signal and keeping
 184          * only the data of interest.  The size of both filters is
 185          * programmable. (dev.platform_data, see linux/platform_data/ad7879.h)
 186          * Other user-programmable conversion controls include variable
 187          * acquisition time, and first conversion delay. Up to 16 averages can
 188          * be taken per conversion.
 189          */
 190
 191         if (likely(x && z1)) {
 192                 /* compute touch pressure resistance using equation #1 */
 193                 Rt = (z2 - z1) * x * ts->x_plate_ohms;
 194                 Rt /= z1;
 195                 Rt = (Rt + 2047) >> 12;
 196
 197                 /*
 198                  * Sample found inconsistent, pressure is beyond
 199                  * the maximum. Don't report it to user space.
 200                  */
 201                 if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE))
 202                         return -EINVAL;
 203
 204                 /*
 205                  * Note that we delay reporting events by one sample.
 206                  * This is done to avoid reporting last sample of the
 207                  * touch sequence, which may be incomplete if finger
 208                  * leaves the surface before last reading is taken.
 209                  */
 210                 if (timer_pending(&ts->timer)) {
 211                         /* Touch continues */
 212                         input_report_key(input_dev, BTN_TOUCH, 1);
 213                         input_report_abs(input_dev, ABS_X, ts->x);
 214                         input_report_abs(input_dev, ABS_Y, ts->y);
 215                         input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
 216                         input_sync(input_dev);
 217                 }
 218
 219                 ts->x = x;
 220                 ts->y = y;
 221                 ts->Rt = Rt;
 222
 223                 return 0;
 224         }
 225
 226         return -EINVAL;
 227 }
 228
 229 static void ad7879_ts_event_release(struct ad7879 *ts)
 230 {
 231         struct input_dev *input_dev = ts->input;
 232
 233         input_report_abs(input_dev, ABS_PRESSURE, 0);
 234         input_report_key(input_dev, BTN_TOUCH, 0);
 235         input_sync(input_dev);
 236 }
 237
 238 static void ad7879_timer(struct timer_list *t)
 239 {
 240         struct ad7879 *ts = from_timer(ts, t, timer);
 241
 242         ad7879_ts_event_release(ts);
 243 }
 244
 245 static irqreturn_t ad7879_irq(int irq, void *handle)
 246 {
 247         struct ad7879 *ts = handle;
 248         int error;
 249
 250         error = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
 251                                  ts->conversion_data, AD7879_NR_SENSE);
 252         if (error)
 253                 dev_err_ratelimited(ts->dev, "failed to read %#02x: %d\n",
 254                                     AD7879_REG_XPLUS, error);
 255         else if (!ad7879_report(ts))
 256                 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 257
 258         return IRQ_HANDLED;
 259 }
 260
 261 static void __ad7879_enable(struct ad7879 *ts)
 262 {
 263         ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 264         ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
 265         ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
 266
 267         enable_irq(ts->irq);
 268 }
 269
 270 static void __ad7879_disable(struct ad7879 *ts)
 271 {
 272         u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
 273                 AD7879_PM(AD7879_PM_SHUTDOWN);
 274         disable_irq(ts->irq);
 275
 276         if (del_timer_sync(&ts->timer))
 277                 ad7879_ts_event_release(ts);
 278
 279         ad7879_write(ts, AD7879_REG_CTRL2, reg);
 280 }
 281
 282
 283 static int ad7879_open(struct input_dev *input)
 284 {
 285         struct ad7879 *ts = input_get_drvdata(input);
 286
 287         /* protected by input->mutex */
 288         if (!ts->disabled && !ts->suspended)
 289                 __ad7879_enable(ts);
 290
 291         return 0;
 292 }
 293
 294 static void ad7879_close(struct input_dev *input)
 295 {
 296         struct ad7879 *ts = input_get_drvdata(input);
 297
 298         /* protected by input->mutex */
 299         if (!ts->disabled && !ts->suspended)
 300                 __ad7879_disable(ts);
 301 }
 302
 303 static int __maybe_unused ad7879_suspend(struct device *dev)
 304 {
 305         struct ad7879 *ts = dev_get_drvdata(dev);
 306
 307         mutex_lock(&ts->input->mutex);
 308
 309         if (!ts->suspended && !ts->disabled && input_device_enabled(ts->input))
 310                 __ad7879_disable(ts);
 311
 312         ts->suspended = true;
 313
 314         mutex_unlock(&ts->input->mutex);
 315
 316         return 0;
 317 }
 318
 319 static int __maybe_unused ad7879_resume(struct device *dev)
 320 {
 321         struct ad7879 *ts = dev_get_drvdata(dev);
 322
 323         mutex_lock(&ts->input->mutex);
 324
 325         if (ts->suspended && !ts->disabled && input_device_enabled(ts->input))
 326                 __ad7879_enable(ts);
 327
 328         ts->suspended = false;
 329
 330         mutex_unlock(&ts->input->mutex);
 331
 332         return 0;
 333 }
 334
 335 SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
 336 EXPORT_SYMBOL(ad7879_pm_ops);
 337
 338 static void ad7879_toggle(struct ad7879 *ts, bool disable)
 339 {
 340         mutex_lock(&ts->input->mutex);
 341
 342         if (!ts->suspended && input_device_enabled(ts->input)) {
 343
 344                 if (disable) {
 345                         if (ts->disabled)
 346                                 __ad7879_enable(ts);
 347                 } else {
 348                         if (!ts->disabled)
 349                                 __ad7879_disable(ts);
 350                 }
 351         }
 352
 353         ts->disabled = disable;
 354
 355         mutex_unlock(&ts->input->mutex);
 356 }
 357
 358 static ssize_t ad7879_disable_show(struct device *dev,
 359                                      struct device_attribute *attr, char *buf)
 360 {
 361         struct ad7879 *ts = dev_get_drvdata(dev);
 362
 363         return sprintf(buf, "%u\n", ts->disabled);
 364 }
 365
 366 static ssize_t ad7879_disable_store(struct device *dev,
 367                                      struct device_attribute *attr,
 368                                      const char *buf, size_t count)
 369 {
 370         struct ad7879 *ts = dev_get_drvdata(dev);
 371         unsigned int val;
 372         int error;
 373
 374         error = kstrtouint(buf, 10, &val);
 375         if (error)
 376                 return error;
 377
 378         ad7879_toggle(ts, val);
 379
 380         return count;
 381 }
 382
 383 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 384
 385 static struct attribute *ad7879_attributes[] = {
 386         &dev_attr_disable.attr,
 387         NULL
 388 };
 389
 390 static const struct attribute_group ad7879_attr_group = {
 391         .attrs = ad7879_attributes,
 392 };
 393
 394 #ifdef CONFIG_GPIOLIB
 395 static int ad7879_gpio_direction_input(struct gpio_chip *chip,
 396                                         unsigned gpio)
 397 {
 398         struct ad7879 *ts = gpiochip_get_data(chip);
 399         int err;
 400
 401         mutex_lock(&ts->mutex);
 402         ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
 403         err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 404         mutex_unlock(&ts->mutex);
 405
 406         return err;
 407 }
 408
 409 static int ad7879_gpio_direction_output(struct gpio_chip *chip,
 410                                         unsigned gpio, int level)
 411 {
 412         struct ad7879 *ts = gpiochip_get_data(chip);
 413         int err;
 414
 415         mutex_lock(&ts->mutex);
 416         ts->cmd_crtl2 &= ~AD7879_GPIODIR;
 417         ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
 418         if (level)
 419                 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
 420         else
 421                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 422
 423         err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 424         mutex_unlock(&ts->mutex);
 425
 426         return err;
 427 }
 428
 429 static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
 430 {
 431         struct ad7879 *ts = gpiochip_get_data(chip);
 432         u16 val;
 433
 434         mutex_lock(&ts->mutex);
 435         val = ad7879_read(ts, AD7879_REG_CTRL2);
 436         mutex_unlock(&ts->mutex);
 437
 438         return !!(val & AD7879_GPIO_DATA);
 439 }
 440
 441 static void ad7879_gpio_set_value(struct gpio_chip *chip,
 442                                   unsigned gpio, int value)
 443 {
 444         struct ad7879 *ts = gpiochip_get_data(chip);
 445
 446         mutex_lock(&ts->mutex);
 447         if (value)
 448                 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
 449         else
 450                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 451
 452         ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
 453         mutex_unlock(&ts->mutex);
 454 }
 455
 456 static int ad7879_gpio_add(struct ad7879 *ts)
 457 {
 458         int ret = 0;
 459
 460         mutex_init(&ts->mutex);
 461
 462         /* Do not create a chip unless flagged for it */
 463         if (!device_property_read_bool(ts->dev, "gpio-controller"))
 464                 return 0;
 465
 466         ts->gc.direction_input = ad7879_gpio_direction_input;
 467         ts->gc.direction_output = ad7879_gpio_direction_output;
 468         ts->gc.get = ad7879_gpio_get_value;
 469         ts->gc.set = ad7879_gpio_set_value;
 470         ts->gc.can_sleep = 1;
 471         ts->gc.base = -1;
 472         ts->gc.ngpio = 1;
 473         ts->gc.label = "AD7879-GPIO";
 474         ts->gc.owner = THIS_MODULE;
 475         ts->gc.parent = ts->dev;
 476
 477         ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts);
 478         if (ret)
 479                 dev_err(ts->dev, "failed to register gpio %d\n",
 480                         ts->gc.base);
 481
 482         return ret;
 483 }
 484 #else
 485 static int ad7879_gpio_add(struct ad7879 *ts)
 486 {
 487         return 0;
 488 }
 489 #endif
 490
 491 static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts)
 492 {
 493         int err;
 494         u32 tmp;
 495
 496         err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp);
 497         if (err) {
 498                 dev_err(dev, "failed to get resistance-plate-x property\n");
 499                 return err;
 500         }
 501         ts->x_plate_ohms = (u16)tmp;
 502
 503         device_property_read_u8(dev, "adi,first-conversion-delay",
 504                                 &ts->first_conversion_delay);
 505         device_property_read_u8(dev, "adi,acquisition-time",
 506                                 &ts->acquisition_time);
 507         device_property_read_u8(dev, "adi,median-filter-size", &ts->median);
 508         device_property_read_u8(dev, "adi,averaging", &ts->averaging);
 509         device_property_read_u8(dev, "adi,conversion-interval",
 510                                 &ts->pen_down_acc_interval);
 511
 512         ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y");
 513
 514         return 0;
 515 }
 516
 517 int ad7879_probe(struct device *dev, struct regmap *regmap,
 518                  int irq, u16 bustype, u8 devid)
 519 {
 520         struct ad7879 *ts;
 521         struct input_dev *input_dev;
 522         int err;
 523         u16 revid;
 524
 525         if (irq <= 0) {
 526                 dev_err(dev, "No IRQ specified\n");
 527                 return -EINVAL;
 528         }
 529
 530         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 531         if (!ts)
 532                 return -ENOMEM;
 533
 534         err = ad7879_parse_dt(dev, ts);
 535         if (err)
 536                 return err;
 537
 538         input_dev = devm_input_allocate_device(dev);
 539         if (!input_dev) {
 540                 dev_err(dev, "Failed to allocate input device\n");
 541                 return -ENOMEM;
 542         }
 543
 544         ts->dev = dev;
 545         ts->input = input_dev;
 546         ts->irq = irq;
 547         ts->regmap = regmap;
 548
 549         timer_setup(&ts->timer, ad7879_timer, 0);
 550         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
 551
 552         input_dev->name = "AD7879 Touchscreen";
 553         input_dev->phys = ts->phys;
 554         input_dev->dev.parent = dev;
 555         input_dev->id.bustype = bustype;
 556
 557         input_dev->open = ad7879_open;
 558         input_dev->close = ad7879_close;
 559
 560         input_set_drvdata(input_dev, ts);
 561
 562         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 563
 564         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 565         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 566         input_set_capability(input_dev, EV_ABS, ABS_PRESSURE);
 567         touchscreen_parse_properties(input_dev, false, NULL);
 568         if (!input_abs_get_max(input_dev, ABS_PRESSURE)) {
 569                 dev_err(dev, "Touchscreen pressure is not specified\n");
 570                 return -EINVAL;
 571         }
 572
 573         err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
 574         if (err < 0) {
 575                 dev_err(dev, "Failed to write %s\n", input_dev->name);
 576                 return err;
 577         }
 578
 579         revid = ad7879_read(ts, AD7879_REG_REVID);
 580         input_dev->id.product = (revid & 0xff);
 581         input_dev->id.version = revid >> 8;
 582         if (input_dev->id.product != devid) {
 583                 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
 584                         input_dev->name, devid, revid);
 585                 return -ENODEV;
 586         }
 587
 588         ts->cmd_crtl3 = AD7879_YPLUS_BIT |
 589                         AD7879_XPLUS_BIT |
 590                         AD7879_Z2_BIT |
 591                         AD7879_Z1_BIT |
 592                         AD7879_TEMPMASK_BIT |
 593                         AD7879_AUXVBATMASK_BIT |
 594                         AD7879_GPIOALERTMASK_BIT;
 595
 596         ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
 597                         AD7879_AVG(ts->averaging) |
 598                         AD7879_MFS(ts->median) |
 599                         AD7879_FCD(ts->first_conversion_delay);
 600
 601         ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
 602                         AD7879_ACQ(ts->acquisition_time) |
 603                         AD7879_TMR(ts->pen_down_acc_interval);
 604
 605         err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq,
 606                                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 607                                         dev_name(dev), ts);
 608         if (err) {
 609                 dev_err(dev, "Failed to request IRQ: %d\n", err);
 610                 return err;
 611         }
 612
 613         __ad7879_disable(ts);
 614
 615         err = devm_device_add_group(dev, &ad7879_attr_group);
 616         if (err)
 617                 return err;
 618
 619         err = ad7879_gpio_add(ts);
 620         if (err)
 621                 return err;
 622
 623         err = input_register_device(input_dev);
 624         if (err)
 625                 return err;
 626
 627         dev_set_drvdata(dev, ts);
 628
 629         return 0;
 630 }
 631 EXPORT_SYMBOL(ad7879_probe);
 632
 633 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 634 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 635 MODULE_LICENSE("GPL");