linux/drivers/input/touchscreen/ad7879.c
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   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
 111enum {
 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
 124typedef struct spi_device       bus_device;
 125#elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
 126#define AD7879_DEVID            0x79
 127typedef struct i2c_client       bus_device;
 128#endif
 129
 130struct 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
 160static int ad7879_read(bus_device *, u8);
 161static int ad7879_write(bus_device *, u8, u16);
 162static void ad7879_collect(struct ad7879 *);
 163
 164static 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
 198static 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
 208static 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
 216static void ad7879_timer(unsigned long handle)
 217{
 218        struct ad7879 *ts = (void *)handle;
 219
 220        ad7879_ts_event_release(ts);
 221}
 222
 223static 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
 238static 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
 263static 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
 284static 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
 297static 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
 305static 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
 325static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 326
 327static 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
 335static 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
 358static DEVICE_ATTR(gpio, 0664, ad7879_gpio_show, ad7879_gpio_store);
 359
 360static struct attribute *ad7879_attributes[] = {
 361        &dev_attr_disable.attr,
 362        &dev_attr_gpio.attr,
 363        NULL
 364};
 365
 366static const struct attribute_group ad7879_attr_group = {
 367        .attrs = ad7879_attributes,
 368};
 369
 370static 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
 472err_remove_attr:
 473        sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
 474err_free_irq:
 475        free_irq(bus->irq, ts);
 476err_free_mem:
 477        input_free_device(input_dev);
 478
 479        return err;
 480}
 481
 482static 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
 494static 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
 503static 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
 523struct 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
 535static 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
 564static 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
 593static 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
 601static 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
 622static 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
 651static 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
 662static 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
 674static int __init ad7879_init(void)
 675{
 676        return spi_register_driver(&ad7879_driver);
 677}
 678module_init(ad7879_init);
 679
 680static void __exit ad7879_exit(void)
 681{
 682        spi_unregister_driver(&ad7879_driver);
 683}
 684module_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 */
 691static int ad7879_read(struct i2c_client *client, u8 reg)
 692{
 693        return swab16(i2c_smbus_read_word_data(client, reg));
 694}
 695
 696static 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
 701static 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
 710static 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
 738static 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
 749static const struct i2c_device_id ad7879_id[] = {
 750        { "ad7879", 0 },
 751        { "ad7889", 0 },
 752        { }
 753};
 754MODULE_DEVICE_TABLE(i2c, ad7879_id);
 755
 756static 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
 768static int __init ad7879_init(void)
 769{
 770        return i2c_add_driver(&ad7879_driver);
 771}
 772module_init(ad7879_init);
 773
 774static void __exit ad7879_exit(void)
 775{
 776        i2c_del_driver(&ad7879_driver);
 777}
 778module_exit(ad7879_exit);
 779#endif
 780
 781MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 782MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 783MODULE_LICENSE("GPL");
 784MODULE_ALIAS("spi:ad7879");
 785