drivers/input/touchscreen/ad7879.c

   1 /*
   2  * Copyright (C) 2008-2009 Michael Hennerich, Analog Devices Inc.
   3  *
   4  * Description: AD7879/AD7889 based touchscreen, and GPIO driver
   5  *              (I2C/SPI Interface)
   6  *
   7  * Bugs:        Enter bugs at http://blackfin.uclinux.org/
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see the file COPYING, or write
  21  * to the Free Software Foundation, Inc.,
  22  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  23  *
  24  * History:
  25  * Copyright (c) 2005 David Brownell
  26  * Copyright (c) 2006 Nokia Corporation
  27  * Various changes: Imre Deak <imre.deak@nokia.com>
  28  *
  29  * Using code from:
  30  *  - corgi_ts.c
  31  *      Copyright (C) 2004-2005 Richard Purdie
  32  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  33  *      Copyright (C) 2002 MontaVista Software
  34  *      Copyright (C) 2004 Texas Instruments
  35  *      Copyright (C) 2005 Dirk Behme
  36  *  - ad7877.c
  37  *      Copyright (C) 2006-2008 Analog Devices Inc.
  38  */
  39
  40 #include <linux/device.h>
  41 #include <linux/init.h>
  42 #include <linux/delay.h>
  43 #include <linux/input.h>
  44 #include <linux/interrupt.h>
  45 #include <linux/irq.h>
  46 #include <linux/slab.h>
  47 #include <linux/workqueue.h>
  48 #include <linux/spi/spi.h>
  49 #include <linux/i2c.h>
  50
  51 #include <linux/spi/ad7879.h>
  52
  53 #define AD7879_REG_ZEROS                0
  54 #define AD7879_REG_CTRL1                1
  55 #define AD7879_REG_CTRL2                2
  56 #define AD7879_REG_CTRL3                3
  57 #define AD7879_REG_AUX1HIGH             4
  58 #define AD7879_REG_AUX1LOW              5
  59 #define AD7879_REG_TEMP1HIGH            6
  60 #define AD7879_REG_TEMP1LOW             7
  61 #define AD7879_REG_XPLUS                8
  62 #define AD7879_REG_YPLUS                9
  63 #define AD7879_REG_Z1                   10
  64 #define AD7879_REG_Z2                   11
  65 #define AD7879_REG_AUXVBAT              12
  66 #define AD7879_REG_TEMP                 13
  67 #define AD7879_REG_REVID                14
  68
  69 /* Control REG 1 */
  70 #define AD7879_TMR(x)                   ((x & 0xFF) << 0)
  71 #define AD7879_ACQ(x)                   ((x & 0x3) << 8)
  72 #define AD7879_MODE_NOC                 (0 << 10)       /* Do not convert */
  73 #define AD7879_MODE_SCC                 (1 << 10)       /* Single channel conversion */
  74 #define AD7879_MODE_SEQ0                (2 << 10)       /* Sequence 0 in Slave Mode */
  75 #define AD7879_MODE_SEQ1                (3 << 10)       /* Sequence 1 in Master Mode */
  76 #define AD7879_MODE_INT                 (1 << 15)       /* PENIRQ disabled INT enabled */
  77
  78 /* Control REG 2 */
  79 #define AD7879_FCD(x)                   ((x & 0x3) << 0)
  80 #define AD7879_RESET                    (1 << 4)
  81 #define AD7879_MFS(x)                   ((x & 0x3) << 5)
  82 #define AD7879_AVG(x)                   ((x & 0x3) << 7)
  83 #define AD7879_SER                      (1 << 9)        /* non-differential */
  84 #define AD7879_DFR                      (0 << 9)        /* differential */
  85 #define AD7879_GPIOPOL                  (1 << 10)
  86 #define AD7879_GPIODIR                  (1 << 11)
  87 #define AD7879_GPIO_DATA                (1 << 12)
  88 #define AD7879_GPIO_EN                  (1 << 13)
  89 #define AD7879_PM(x)                    ((x & 0x3) << 14)
  90 #define AD7879_PM_SHUTDOWN              (0)
  91 #define AD7879_PM_DYN                   (1)
  92 #define AD7879_PM_FULLON                (2)
  93
  94 /* Control REG 3 */
  95 #define AD7879_TEMPMASK_BIT             (1<<15)
  96 #define AD7879_AUXVBATMASK_BIT          (1<<14)
  97 #define AD7879_INTMODE_BIT              (1<<13)
  98 #define AD7879_GPIOALERTMASK_BIT        (1<<12)
  99 #define AD7879_AUXLOW_BIT               (1<<11)
 100 #define AD7879_AUXHIGH_BIT              (1<<10)
 101 #define AD7879_TEMPLOW_BIT              (1<<9)
 102 #define AD7879_TEMPHIGH_BIT             (1<<8)
 103 #define AD7879_YPLUS_BIT                (1<<7)
 104 #define AD7879_XPLUS_BIT                (1<<6)
 105 #define AD7879_Z1_BIT                   (1<<5)
 106 #define AD7879_Z2_BIT                   (1<<4)
 107 #define AD7879_AUX_BIT                  (1<<3)
 108 #define AD7879_VBAT_BIT                 (1<<2)
 109 #define AD7879_TEMP_BIT                 (1<<1)
 110
 111 enum {
 112         AD7879_SEQ_XPOS  = 0,
 113         AD7879_SEQ_YPOS  = 1,
 114         AD7879_SEQ_Z1    = 2,
 115         AD7879_SEQ_Z2    = 3,
 116         AD7879_NR_SENSE  = 4,
 117 };
 118
 119 #define MAX_12BIT                       ((1<<12)-1)
 120 #define TS_PEN_UP_TIMEOUT               msecs_to_jiffies(50)
 121
 122 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 123 #define AD7879_DEVID            0x7A
 124 typedef struct spi_device       bus_device;
 125 #elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
 126 #define AD7879_DEVID            0x79
 127 typedef struct i2c_client       bus_device;
 128 #endif
 129
 130 struct ad7879 {
 131         bus_device              *bus;
 132         struct input_dev        *input;
 133         struct work_struct      work;
 134         struct timer_list       timer;
 135
 136         struct mutex            mutex;
 137         unsigned                disabled:1;     /* P: mutex */
 138
 139 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 140         struct spi_message      msg;
 141         struct spi_transfer     xfer[AD7879_NR_SENSE + 1];
 142         u16                     cmd;
 143 #endif
 144         u16                     conversion_data[AD7879_NR_SENSE];
 145         char                    phys[32];
 146         u8                      first_conversion_delay;
 147         u8                      acquisition_time;
 148         u8                      averaging;
 149         u8                      pen_down_acc_interval;
 150         u8                      median;
 151         u16                     x_plate_ohms;
 152         u16                     pressure_max;
 153         u16                     gpio_init;
 154         u16                     cmd_crtl1;
 155         u16                     cmd_crtl2;
 156         u16                     cmd_crtl3;
 157         unsigned                gpio:1;
 158 };
 159
 160 static int ad7879_read(bus_device *, u8);
 161 static int ad7879_write(bus_device *, u8, u16);
 162 static void ad7879_collect(struct ad7879 *);
 163
 164 static void ad7879_report(struct ad7879 *ts)
 165 {
 166         struct input_dev *input_dev = ts->input;
 167         unsigned Rt;
 168         u16 x, y, z1, z2;
 169
 170         x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
 171         y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
 172         z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
 173         z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
 174
 175         /*
 176          * The samples processed here are already preprocessed by the AD7879.
 177          * The preprocessing function consists of a median and an averaging filter.
 178          * The combination of these two techniques provides a robust solution,
 179          * discarding the spurious noise in the signal and keeping only the data of interest.
 180          * The size of both filters is programmable. (dev.platform_data, see linux/spi/ad7879.h)
 181          * Other user-programmable conversion controls include variable acquisition time,
 182          * and first conversion delay. Up to 16 averages can be taken per conversion.
 183          */
 184
 185         if (likely(x && z1)) {
 186                 /* compute touch pressure resistance using equation #1 */
 187                 Rt = (z2 - z1) * x * ts->x_plate_ohms;
 188                 Rt /= z1;
 189                 Rt = (Rt + 2047) >> 12;
 190
 191                 input_report_abs(input_dev, ABS_X, x);
 192                 input_report_abs(input_dev, ABS_Y, y);
 193                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 194                 input_sync(input_dev);
 195         }
 196 }
 197
 198 static void ad7879_work(struct work_struct *work)
 199 {
 200         struct ad7879 *ts = container_of(work, struct ad7879, work);
 201
 202         /* use keventd context to read the result registers */
 203         ad7879_collect(ts);
 204         ad7879_report(ts);
 205         mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 206 }
 207
 208 static void ad7879_ts_event_release(struct ad7879 *ts)
 209 {
 210         struct input_dev *input_dev = ts->input;
 211
 212         input_report_abs(input_dev, ABS_PRESSURE, 0);
 213         input_sync(input_dev);
 214 }
 215
 216 static void ad7879_timer(unsigned long handle)
 217 {
 218         struct ad7879 *ts = (void *)handle;
 219
 220         ad7879_ts_event_release(ts);
 221 }
 222
 223 static irqreturn_t ad7879_irq(int irq, void *handle)
 224 {
 225         struct ad7879 *ts = handle;
 226
 227         /* The repeated conversion sequencer controlled by TMR kicked off too fast.
 228          * We ignore the last and process the sample sequence currently in the queue.
 229          * It can't be older than 9.4ms
 230          */
 231
 232         if (!work_pending(&ts->work))
 233                 schedule_work(&ts->work);
 234
 235         return IRQ_HANDLED;
 236 }
 237
 238 static void ad7879_setup(struct ad7879 *ts)
 239 {
 240         ts->cmd_crtl3 = AD7879_YPLUS_BIT |
 241                         AD7879_XPLUS_BIT |
 242                         AD7879_Z2_BIT |
 243                         AD7879_Z1_BIT |
 244                         AD7879_TEMPMASK_BIT |
 245                         AD7879_AUXVBATMASK_BIT |
 246                         AD7879_GPIOALERTMASK_BIT;
 247
 248         ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
 249                         AD7879_AVG(ts->averaging) |
 250                         AD7879_MFS(ts->median) |
 251                         AD7879_FCD(ts->first_conversion_delay) |
 252                         ts->gpio_init;
 253
 254         ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
 255                         AD7879_ACQ(ts->acquisition_time) |
 256                         AD7879_TMR(ts->pen_down_acc_interval);
 257
 258         ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
 259         ad7879_write(ts->bus, AD7879_REG_CTRL3, ts->cmd_crtl3);
 260         ad7879_write(ts->bus, AD7879_REG_CTRL1, ts->cmd_crtl1);
 261 }
 262
 263 static void ad7879_disable(struct ad7879 *ts)
 264 {
 265         mutex_lock(&ts->mutex);
 266
 267         if (!ts->disabled) {
 268
 269                 ts->disabled = 1;
 270                 disable_irq(ts->bus->irq);
 271
 272                 cancel_work_sync(&ts->work);
 273
 274                 if (del_timer_sync(&ts->timer))
 275                         ad7879_ts_event_release(ts);
 276
 277                 ad7879_write(ts->bus, AD7879_REG_CTRL2,
 278                              AD7879_PM(AD7879_PM_SHUTDOWN));
 279         }
 280
 281         mutex_unlock(&ts->mutex);
 282 }
 283
 284 static void ad7879_enable(struct ad7879 *ts)
 285 {
 286         mutex_lock(&ts->mutex);
 287
 288         if (ts->disabled) {
 289                 ad7879_setup(ts);
 290                 ts->disabled = 0;
 291                 enable_irq(ts->bus->irq);
 292         }
 293
 294         mutex_unlock(&ts->mutex);
 295 }
 296
 297 static ssize_t ad7879_disable_show(struct device *dev,
 298                                      struct device_attribute *attr, char *buf)
 299 {
 300         struct ad7879 *ts = dev_get_drvdata(dev);
 301
 302         return sprintf(buf, "%u\n", ts->disabled);
 303 }
 304
 305 static ssize_t ad7879_disable_store(struct device *dev,
 306                                      struct device_attribute *attr,
 307                                      const char *buf, size_t count)
 308 {
 309         struct ad7879 *ts = dev_get_drvdata(dev);
 310         unsigned long val;
 311         int error;
 312
 313         error = strict_strtoul(buf, 10, &val);
 314         if (error)
 315                 return error;
 316
 317         if (val)
 318                 ad7879_disable(ts);
 319         else
 320                 ad7879_enable(ts);
 321
 322         return count;
 323 }
 324
 325 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 326
 327 static ssize_t ad7879_gpio_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->gpio);
 333 }
 334
 335 static ssize_t ad7879_gpio_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         mutex_lock(&ts->mutex);
 348         ts->gpio = !!val;
 349         error = ad7879_write(ts->bus, AD7879_REG_CTRL2,
 350                            ts->gpio ?
 351                                 ts->cmd_crtl2 & ~AD7879_GPIO_DATA :
 352                                 ts->cmd_crtl2 | AD7879_GPIO_DATA);
 353         mutex_unlock(&ts->mutex);
 354
 355         return error ? : count;
 356 }
 357
 358 static DEVICE_ATTR(gpio, 0664, ad7879_gpio_show, ad7879_gpio_store);
 359
 360 static struct attribute *ad7879_attributes[] = {
 361         &dev_attr_disable.attr,
 362         &dev_attr_gpio.attr,
 363         NULL
 364 };
 365
 366 static const struct attribute_group ad7879_attr_group = {
 367         .attrs = ad7879_attributes,
 368 };
 369
 370 static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
 371 {
 372         struct input_dev *input_dev;
 373         struct ad7879_platform_data *pdata = bus->dev.platform_data;
 374         int err;
 375         u16 revid;
 376
 377         if (!bus->irq) {
 378                 dev_err(&bus->dev, "no IRQ?\n");
 379                 return -ENODEV;
 380         }
 381
 382         if (!pdata) {
 383                 dev_err(&bus->dev, "no platform data?\n");
 384                 return -ENODEV;
 385         }
 386
 387         input_dev = input_allocate_device();
 388         if (!input_dev)
 389                 return -ENOMEM;
 390
 391         ts->input = input_dev;
 392
 393         setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
 394         INIT_WORK(&ts->work, ad7879_work);
 395         mutex_init(&ts->mutex);
 396
 397         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 398         ts->pressure_max = pdata->pressure_max ? : ~0;
 399
 400         ts->first_conversion_delay = pdata->first_conversion_delay;
 401         ts->acquisition_time = pdata->acquisition_time;
 402         ts->averaging = pdata->averaging;
 403         ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
 404         ts->median = pdata->median;
 405
 406         if (pdata->gpio_output)
 407                 ts->gpio_init = AD7879_GPIO_EN |
 408                                 (pdata->gpio_default ? 0 : AD7879_GPIO_DATA);
 409         else
 410                 ts->gpio_init = AD7879_GPIO_EN | AD7879_GPIODIR;
 411
 412         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&bus->dev));
 413
 414         input_dev->name = "AD7879 Touchscreen";
 415         input_dev->phys = ts->phys;
 416         input_dev->dev.parent = &bus->dev;
 417
 418         __set_bit(EV_ABS, input_dev->evbit);
 419         __set_bit(ABS_X, input_dev->absbit);
 420         __set_bit(ABS_Y, input_dev->absbit);
 421         __set_bit(ABS_PRESSURE, input_dev->absbit);
 422
 423         input_set_abs_params(input_dev, ABS_X,
 424                         pdata->x_min ? : 0,
 425                         pdata->x_max ? : MAX_12BIT,
 426                         0, 0);
 427         input_set_abs_params(input_dev, ABS_Y,
 428                         pdata->y_min ? : 0,
 429                         pdata->y_max ? : MAX_12BIT,
 430                         0, 0);
 431         input_set_abs_params(input_dev, ABS_PRESSURE,
 432                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 433
 434         err = ad7879_write(bus, AD7879_REG_CTRL2, AD7879_RESET);
 435
 436         if (err < 0) {
 437                 dev_err(&bus->dev, "Failed to write %s\n", input_dev->name);
 438                 goto err_free_mem;
 439         }
 440
 441         revid = ad7879_read(bus, AD7879_REG_REVID);
 442
 443         if ((revid & 0xFF) != AD7879_DEVID) {
 444                 dev_err(&bus->dev, "Failed to probe %s\n", input_dev->name);
 445                 err = -ENODEV;
 446                 goto err_free_mem;
 447         }
 448
 449         ad7879_setup(ts);
 450
 451         err = request_irq(bus->irq, ad7879_irq,
 452                           IRQF_TRIGGER_FALLING, bus->dev.driver->name, ts);
 453
 454         if (err) {
 455                 dev_err(&bus->dev, "irq %d busy?\n", bus->irq);
 456                 goto err_free_mem;
 457         }
 458
 459         err = sysfs_create_group(&bus->dev.kobj, &ad7879_attr_group);
 460         if (err)
 461                 goto err_free_irq;
 462
 463         err = input_register_device(input_dev);
 464         if (err)
 465                 goto err_remove_attr;
 466
 467         dev_info(&bus->dev, "Rev.%d touchscreen, irq %d\n",
 468                  revid >> 8, bus->irq);
 469
 470         return 0;
 471
 472 err_remove_attr:
 473         sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
 474 err_free_irq:
 475         free_irq(bus->irq, ts);
 476 err_free_mem:
 477         input_free_device(input_dev);
 478
 479         return err;
 480 }
 481
 482 static int __devexit ad7879_destroy(bus_device *bus, struct ad7879 *ts)
 483 {
 484         ad7879_disable(ts);
 485         sysfs_remove_group(&ts->bus->dev.kobj, &ad7879_attr_group);
 486         free_irq(ts->bus->irq, ts);
 487         input_unregister_device(ts->input);
 488         dev_dbg(&bus->dev, "unregistered touchscreen\n");
 489
 490         return 0;
 491 }
 492
 493 #ifdef CONFIG_PM
 494 static int ad7879_suspend(bus_device *bus, pm_message_t message)
 495 {
 496         struct ad7879 *ts = dev_get_drvdata(&bus->dev);
 497
 498         ad7879_disable(ts);
 499
 500         return 0;
 501 }
 502
 503 static int ad7879_resume(bus_device *bus)
 504 {
 505         struct ad7879 *ts = dev_get_drvdata(&bus->dev);
 506
 507         ad7879_enable(ts);
 508
 509         return 0;
 510 }
 511 #else
 512 #define ad7879_suspend NULL
 513 #define ad7879_resume  NULL
 514 #endif
 515
 516 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 517 #define MAX_SPI_FREQ_HZ         5000000
 518 #define AD7879_CMD_MAGIC        0xE000
 519 #define AD7879_CMD_READ         (1 << 10)
 520 #define AD7879_WRITECMD(reg)    (AD7879_CMD_MAGIC | (reg & 0xF))
 521 #define AD7879_READCMD(reg)     (AD7879_CMD_MAGIC | AD7879_CMD_READ | (reg & 0xF))
 522
 523 struct ser_req {
 524         u16                     command;
 525         u16                     data;
 526         struct spi_message      msg;
 527         struct spi_transfer     xfer[2];
 528 };
 529
 530 /*
 531  * ad7879_read/write are only used for initial setup and for sysfs controls.
 532  * The main traffic is done in ad7879_collect().
 533  */
 534
 535 static int ad7879_read(struct spi_device *spi, u8 reg)
 536 {
 537         struct ser_req *req;
 538         int status, ret;
 539
 540         req = kzalloc(sizeof *req, GFP_KERNEL);
 541         if (!req)
 542                 return -ENOMEM;
 543
 544         spi_message_init(&req->msg);
 545
 546         req->command = (u16) AD7879_READCMD(reg);
 547         req->xfer[0].tx_buf = &req->command;
 548         req->xfer[0].len = 2;
 549
 550         req->xfer[1].rx_buf = &req->data;
 551         req->xfer[1].len = 2;
 552
 553         spi_message_add_tail(&req->xfer[0], &req->msg);
 554         spi_message_add_tail(&req->xfer[1], &req->msg);
 555
 556         status = spi_sync(spi, &req->msg);
 557         ret = status ? : req->data;
 558
 559         kfree(req);
 560
 561         return ret;
 562 }
 563
 564 static int ad7879_write(struct spi_device *spi, u8 reg, u16 val)
 565 {
 566         struct ser_req *req;
 567         int status;
 568
 569         req = kzalloc(sizeof *req, GFP_KERNEL);
 570         if (!req)
 571                 return -ENOMEM;
 572
 573         spi_message_init(&req->msg);
 574
 575         req->command = (u16) AD7879_WRITECMD(reg);
 576         req->xfer[0].tx_buf = &req->command;
 577         req->xfer[0].len = 2;
 578
 579         req->data = val;
 580         req->xfer[1].tx_buf = &req->data;
 581         req->xfer[1].len = 2;
 582
 583         spi_message_add_tail(&req->xfer[0], &req->msg);
 584         spi_message_add_tail(&req->xfer[1], &req->msg);
 585
 586         status = spi_sync(spi, &req->msg);
 587
 588         kfree(req);
 589
 590         return status;
 591 }
 592
 593 static void ad7879_collect(struct ad7879 *ts)
 594 {
 595         int status = spi_sync(ts->bus, &ts->msg);
 596
 597         if (status)
 598                 dev_err(&ts->bus->dev, "spi_sync --> %d\n", status);
 599 }
 600
 601 static void ad7879_setup_ts_def_msg(struct ad7879 *ts)
 602 {
 603         struct spi_message *m;
 604         int i;
 605
 606         ts->cmd = (u16) AD7879_READCMD(AD7879_REG_XPLUS);
 607
 608         m = &ts->msg;
 609         spi_message_init(m);
 610         ts->xfer[0].tx_buf = &ts->cmd;
 611         ts->xfer[0].len = 2;
 612
 613         spi_message_add_tail(&ts->xfer[0], m);
 614
 615         for (i = 0; i < AD7879_NR_SENSE; i++) {
 616                 ts->xfer[i + 1].rx_buf = &ts->conversion_data[i];
 617                 ts->xfer[i + 1].len = 2;
 618                 spi_message_add_tail(&ts->xfer[i + 1], m);
 619         }
 620 }
 621
 622 static int __devinit ad7879_probe(struct spi_device *spi)
 623 {
 624         struct ad7879 *ts;
 625         int error;
 626
 627         /* don't exceed max specified SPI CLK frequency */
 628         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
 629                 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
 630                 return -EINVAL;
 631         }
 632
 633         ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
 634         if (!ts)
 635                 return -ENOMEM;
 636
 637         dev_set_drvdata(&spi->dev, ts);
 638         ts->bus = spi;
 639
 640         ad7879_setup_ts_def_msg(ts);
 641
 642         error = ad7879_construct(spi, ts);
 643         if (error) {
 644                 dev_set_drvdata(&spi->dev, NULL);
 645                 kfree(ts);
 646         }
 647
 648         return error;
 649 }
 650
 651 static int __devexit ad7879_remove(struct spi_device *spi)
 652 {
 653         struct ad7879 *ts = dev_get_drvdata(&spi->dev);
 654
 655         ad7879_destroy(spi, ts);
 656         dev_set_drvdata(&spi->dev, NULL);
 657         kfree(ts);
 658
 659         return 0;
 660 }
 661
 662 static struct spi_driver ad7879_driver = {
 663         .driver = {
 664                 .name   = "ad7879",
 665                 .bus    = &spi_bus_type,
 666                 .owner  = THIS_MODULE,
 667         },
 668         .probe          = ad7879_probe,
 669         .remove         = __devexit_p(ad7879_remove),
 670         .suspend        = ad7879_suspend,
 671         .resume         = ad7879_resume,
 672 };
 673
 674 static int __init ad7879_init(void)
 675 {
 676         return spi_register_driver(&ad7879_driver);
 677 }
 678 module_init(ad7879_init);
 679
 680 static void __exit ad7879_exit(void)
 681 {
 682         spi_unregister_driver(&ad7879_driver);
 683 }
 684 module_exit(ad7879_exit);
 685
 686 #elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
 687
 688 /* All registers are word-sized.
 689  * AD7879 uses a high-byte first convention.
 690  */
 691 static int ad7879_read(struct i2c_client *client, u8 reg)
 692 {
 693         return swab16(i2c_smbus_read_word_data(client, reg));
 694 }
 695
 696 static int ad7879_write(struct i2c_client *client, u8 reg, u16 val)
 697 {
 698         return i2c_smbus_write_word_data(client, reg, swab16(val));
 699 }
 700
 701 static void ad7879_collect(struct ad7879 *ts)
 702 {
 703         int i;
 704
 705         for (i = 0; i < AD7879_NR_SENSE; i++)
 706                 ts->conversion_data[i] = ad7879_read(ts->bus,
 707                                                      AD7879_REG_XPLUS + i);
 708 }
 709
 710 static int __devinit ad7879_probe(struct i2c_client *client,
 711                                         const struct i2c_device_id *id)
 712 {
 713         struct ad7879 *ts;
 714         int error;
 715
 716         if (!i2c_check_functionality(client->adapter,
 717                                         I2C_FUNC_SMBUS_WORD_DATA)) {
 718                 dev_err(&client->dev, "SMBUS Word Data not Supported\n");
 719                 return -EIO;
 720         }
 721
 722         ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
 723         if (!ts)
 724                 return -ENOMEM;
 725
 726         i2c_set_clientdata(client, ts);
 727         ts->bus = client;
 728
 729         error = ad7879_construct(client, ts);
 730         if (error) {
 731                 i2c_set_clientdata(client, NULL);
 732                 kfree(ts);
 733         }
 734
 735         return error;
 736 }
 737
 738 static int __devexit ad7879_remove(struct i2c_client *client)
 739 {
 740         struct ad7879 *ts = dev_get_drvdata(&client->dev);
 741
 742         ad7879_destroy(client, ts);
 743         i2c_set_clientdata(client, NULL);
 744         kfree(ts);
 745
 746         return 0;
 747 }
 748
 749 static const struct i2c_device_id ad7879_id[] = {
 750         { "ad7879", 0 },
 751         { "ad7889", 0 },
 752         { }
 753 };
 754 MODULE_DEVICE_TABLE(i2c, ad7879_id);
 755
 756 static struct i2c_driver ad7879_driver = {
 757         .driver = {
 758                 .name   = "ad7879",
 759                 .owner  = THIS_MODULE,
 760         },
 761         .probe          = ad7879_probe,
 762         .remove         = __devexit_p(ad7879_remove),
 763         .suspend        = ad7879_suspend,
 764         .resume         = ad7879_resume,
 765         .id_table       = ad7879_id,
 766 };
 767
 768 static int __init ad7879_init(void)
 769 {
 770         return i2c_add_driver(&ad7879_driver);
 771 }
 772 module_init(ad7879_init);
 773
 774 static void __exit ad7879_exit(void)
 775 {
 776         i2c_del_driver(&ad7879_driver);
 777 }
 778 module_exit(ad7879_exit);
 779 #endif
 780
 781 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 782 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 783 MODULE_LICENSE("GPL");
 784 MODULE_ALIAS("spi:ad7879");