drivers/input/touchscreen/ad7879.c

   1 /*
   2  * Copyright (C) 2008 Michael Hennerich, Analog Devices Inc.
   3  *
   4  * Description: AD7879 based touchscreen, and GPIO driver (I2C/SPI Interface)
   5  *
   6  * Bugs:        Enter bugs at http://blackfin.uclinux.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, see the file COPYING, or write
  20  * to the Free Software Foundation, Inc.,
  21  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  22  *
  23  * History:
  24  * Copyright (c) 2005 David Brownell
  25  * Copyright (c) 2006 Nokia Corporation
  26  * Various changes: Imre Deak <imre.deak@nokia.com>
  27  *
  28  * Using code from:
  29  *  - corgi_ts.c
  30  *      Copyright (C) 2004-2005 Richard Purdie
  31  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  32  *      Copyright (C) 2002 MontaVista Software
  33  *      Copyright (C) 2004 Texas Instruments
  34  *      Copyright (C) 2005 Dirk Behme
  35  *  - ad7877.c
  36  *      Copyright (C) 2006-2008 Analog Devices Inc.
  37  */
  38
  39 #include <linux/device.h>
  40 #include <linux/init.h>
  41 #include <linux/delay.h>
  42 #include <linux/input.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/irq.h>
  45 #include <linux/slab.h>
  46 #include <linux/workqueue.h>
  47 #include <linux/spi/spi.h>
  48 #include <linux/i2c.h>
  49
  50 #include <linux/spi/ad7879.h>
  51
  52 #define AD7879_REG_ZEROS                0
  53 #define AD7879_REG_CTRL1                1
  54 #define AD7879_REG_CTRL2                2
  55 #define AD7879_REG_CTRL3                3
  56 #define AD7879_REG_AUX1HIGH             4
  57 #define AD7879_REG_AUX1LOW              5
  58 #define AD7879_REG_TEMP1HIGH            6
  59 #define AD7879_REG_TEMP1LOW             7
  60 #define AD7879_REG_XPLUS                8
  61 #define AD7879_REG_YPLUS                9
  62 #define AD7879_REG_Z1                   10
  63 #define AD7879_REG_Z2                   11
  64 #define AD7879_REG_AUXVBAT              12
  65 #define AD7879_REG_TEMP                 13
  66 #define AD7879_REG_REVID                14
  67
  68 /* Control REG 1 */
  69 #define AD7879_TMR(x)                   ((x & 0xFF) << 0)
  70 #define AD7879_ACQ(x)                   ((x & 0x3) << 8)
  71 #define AD7879_MODE_NOC                 (0 << 10)       /* Do not convert */
  72 #define AD7879_MODE_SCC                 (1 << 10)       /* Single channel conversion */
  73 #define AD7879_MODE_SEQ0                (2 << 10)       /* Sequence 0 in Slave Mode */
  74 #define AD7879_MODE_SEQ1                (3 << 10)       /* Sequence 1 in Master Mode */
  75 #define AD7879_MODE_INT                 (1 << 15)       /* PENIRQ disabled INT enabled */
  76
  77 /* Control REG 2 */
  78 #define AD7879_FCD(x)                   ((x & 0x3) << 0)
  79 #define AD7879_RESET                    (1 << 4)
  80 #define AD7879_MFS(x)                   ((x & 0x3) << 5)
  81 #define AD7879_AVG(x)                   ((x & 0x3) << 7)
  82 #define AD7879_SER                      (1 << 9)        /* non-differential */
  83 #define AD7879_DFR                      (0 << 9)        /* differential */
  84 #define AD7879_GPIOPOL                  (1 << 10)
  85 #define AD7879_GPIODIR                  (1 << 11)
  86 #define AD7879_GPIO_DATA                (1 << 12)
  87 #define AD7879_GPIO_EN                  (1 << 13)
  88 #define AD7879_PM(x)                    ((x & 0x3) << 14)
  89 #define AD7879_PM_SHUTDOWN              (0)
  90 #define AD7879_PM_DYN                   (1)
  91 #define AD7879_PM_FULLON                (2)
  92
  93 /* Control REG 3 */
  94 #define AD7879_TEMPMASK_BIT             (1<<15)
  95 #define AD7879_AUXVBATMASK_BIT          (1<<14)
  96 #define AD7879_INTMODE_BIT              (1<<13)
  97 #define AD7879_GPIOALERTMASK_BIT        (1<<12)
  98 #define AD7879_AUXLOW_BIT               (1<<11)
  99 #define AD7879_AUXHIGH_BIT              (1<<10)
 100 #define AD7879_TEMPLOW_BIT              (1<<9)
 101 #define AD7879_TEMPHIGH_BIT             (1<<8)
 102 #define AD7879_YPLUS_BIT                (1<<7)
 103 #define AD7879_XPLUS_BIT                (1<<6)
 104 #define AD7879_Z1_BIT                   (1<<5)
 105 #define AD7879_Z2_BIT                   (1<<4)
 106 #define AD7879_AUX_BIT                  (1<<3)
 107 #define AD7879_VBAT_BIT                 (1<<2)
 108 #define AD7879_TEMP_BIT                 (1<<1)
 109
 110 enum {
 111         AD7879_SEQ_XPOS  = 0,
 112         AD7879_SEQ_YPOS  = 1,
 113         AD7879_SEQ_Z1    = 2,
 114         AD7879_SEQ_Z2    = 3,
 115         AD7879_NR_SENSE  = 4,
 116 };
 117
 118 #define MAX_12BIT                       ((1<<12)-1)
 119 #define TS_PEN_UP_TIMEOUT               msecs_to_jiffies(50)
 120
 121 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 122 #define AD7879_DEVID            0x7A
 123 typedef struct spi_device       bus_device;
 124 #elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
 125 #define AD7879_DEVID            0x79
 126 typedef struct i2c_client       bus_device;
 127 #endif
 128
 129 struct ad7879 {
 130         bus_device              *bus;
 131         struct input_dev        *input;
 132         struct work_struct      work;
 133         struct timer_list       timer;
 134
 135         struct mutex            mutex;
 136         unsigned                disabled:1;     /* P: mutex */
 137
 138 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 139         struct spi_message      msg;
 140         struct spi_transfer     xfer[AD7879_NR_SENSE + 1];
 141         u16                     cmd;
 142 #endif
 143         u16                     conversion_data[AD7879_NR_SENSE];
 144         char                    phys[32];
 145         u8                      first_conversion_delay;
 146         u8                      acquisition_time;
 147         u8                      averaging;
 148         u8                      pen_down_acc_interval;
 149         u8                      median;
 150         u16                     x_plate_ohms;
 151         u16                     pressure_max;
 152         u16                     gpio_init;
 153         u16                     cmd_crtl1;
 154         u16                     cmd_crtl2;
 155         u16                     cmd_crtl3;
 156         unsigned                gpio:1;
 157 };
 158
 159 static int ad7879_read(bus_device *, u8);
 160 static int ad7879_write(bus_device *, u8, u16);
 161 static void ad7879_collect(struct ad7879 *);
 162
 163 static void ad7879_report(struct ad7879 *ts)
 164 {
 165         struct input_dev *input_dev = ts->input;
 166         unsigned Rt;
 167         u16 x, y, z1, z2;
 168
 169         x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
 170         y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
 171         z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
 172         z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
 173
 174         /*
 175          * The samples processed here are already preprocessed by the AD7879.
 176          * The preprocessing function consists of a median and an averaging filter.
 177          * The combination of these two techniques provides a robust solution,
 178          * discarding the spurious noise in the signal and keeping only the data of interest.
 179          * The size of both filters is programmable. (dev.platform_data, see linux/spi/ad7879.h)
 180          * Other user-programmable conversion controls include variable acquisition time,
 181          * and first conversion delay. Up to 16 averages can be taken per conversion.
 182          */
 183
 184         if (likely(x && z1)) {
 185                 /* compute touch pressure resistance using equation #1 */
 186                 Rt = (z2 - z1) * x * ts->x_plate_ohms;
 187                 Rt /= z1;
 188                 Rt = (Rt + 2047) >> 12;
 189
 190                 input_report_abs(input_dev, ABS_X, x);
 191                 input_report_abs(input_dev, ABS_Y, y);
 192                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
 193                 input_sync(input_dev);
 194         }
 195 }
 196
 197 static void ad7879_work(struct work_struct *work)
 198 {
 199         struct ad7879 *ts = container_of(work, struct ad7879, work);
 200
 201         /* use keventd context to read the result registers */
 202         ad7879_collect(ts);
 203         ad7879_report(ts);
 204         mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
 205 }
 206
 207 static void ad7879_ts_event_release(struct ad7879 *ts)
 208 {
 209         struct input_dev *input_dev = ts->input;
 210
 211         input_report_abs(input_dev, ABS_PRESSURE, 0);
 212         input_sync(input_dev);
 213 }
 214
 215 static void ad7879_timer(unsigned long handle)
 216 {
 217         struct ad7879 *ts = (void *)handle;
 218
 219         ad7879_ts_event_release(ts);
 220 }
 221
 222 static irqreturn_t ad7879_irq(int irq, void *handle)
 223 {
 224         struct ad7879 *ts = handle;
 225
 226         /* The repeated conversion sequencer controlled by TMR kicked off too fast.
 227          * We ignore the last and process the sample sequence currently in the queue.
 228          * It can't be older than 9.4ms
 229          */
 230
 231         if (!work_pending(&ts->work))
 232                 schedule_work(&ts->work);
 233
 234         return IRQ_HANDLED;
 235 }
 236
 237 static void ad7879_setup(struct ad7879 *ts)
 238 {
 239         ts->cmd_crtl3 = AD7879_YPLUS_BIT |
 240                         AD7879_XPLUS_BIT |
 241                         AD7879_Z2_BIT |
 242                         AD7879_Z1_BIT |
 243                         AD7879_TEMPMASK_BIT |
 244                         AD7879_AUXVBATMASK_BIT |
 245                         AD7879_GPIOALERTMASK_BIT;
 246
 247         ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
 248                         AD7879_AVG(ts->averaging) |
 249                         AD7879_MFS(ts->median) |
 250                         AD7879_FCD(ts->first_conversion_delay) |
 251                         ts->gpio_init;
 252
 253         ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
 254                         AD7879_ACQ(ts->acquisition_time) |
 255                         AD7879_TMR(ts->pen_down_acc_interval);
 256
 257         ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
 258         ad7879_write(ts->bus, AD7879_REG_CTRL3, ts->cmd_crtl3);
 259         ad7879_write(ts->bus, AD7879_REG_CTRL1, ts->cmd_crtl1);
 260 }
 261
 262 static void ad7879_disable(struct ad7879 *ts)
 263 {
 264         mutex_lock(&ts->mutex);
 265
 266         if (!ts->disabled) {
 267
 268                 ts->disabled = 1;
 269                 disable_irq(ts->bus->irq);
 270
 271                 cancel_work_sync(&ts->work);
 272
 273                 if (del_timer_sync(&ts->timer))
 274                         ad7879_ts_event_release(ts);
 275
 276                 ad7879_write(ts->bus, AD7879_REG_CTRL2,
 277                              AD7879_PM(AD7879_PM_SHUTDOWN));
 278         }
 279
 280         mutex_unlock(&ts->mutex);
 281 }
 282
 283 static void ad7879_enable(struct ad7879 *ts)
 284 {
 285         mutex_lock(&ts->mutex);
 286
 287         if (ts->disabled) {
 288                 ad7879_setup(ts);
 289                 ts->disabled = 0;
 290                 enable_irq(ts->bus->irq);
 291         }
 292
 293         mutex_unlock(&ts->mutex);
 294 }
 295
 296 static ssize_t ad7879_disable_show(struct device *dev,
 297                                      struct device_attribute *attr, char *buf)
 298 {
 299         struct ad7879 *ts = dev_get_drvdata(dev);
 300
 301         return sprintf(buf, "%u\n", ts->disabled);
 302 }
 303
 304 static ssize_t ad7879_disable_store(struct device *dev,
 305                                      struct device_attribute *attr,
 306                                      const char *buf, size_t count)
 307 {
 308         struct ad7879 *ts = dev_get_drvdata(dev);
 309         unsigned long val;
 310         int error;
 311
 312         error = strict_strtoul(buf, 10, &val);
 313         if (error)
 314                 return error;
 315
 316         if (val)
 317                 ad7879_disable(ts);
 318         else
 319                 ad7879_enable(ts);
 320
 321         return count;
 322 }
 323
 324 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 325
 326 static ssize_t ad7879_gpio_show(struct device *dev,
 327                                      struct device_attribute *attr, char *buf)
 328 {
 329         struct ad7879 *ts = dev_get_drvdata(dev);
 330
 331         return sprintf(buf, "%u\n", ts->gpio);
 332 }
 333
 334 static ssize_t ad7879_gpio_store(struct device *dev,
 335                                      struct device_attribute *attr,
 336                                      const char *buf, size_t count)
 337 {
 338         struct ad7879 *ts = dev_get_drvdata(dev);
 339         unsigned long val;
 340         int error;
 341
 342         error = strict_strtoul(buf, 10, &val);
 343         if (error)
 344                 return error;
 345
 346         mutex_lock(&ts->mutex);
 347         ts->gpio = !!val;
 348         error = ad7879_write(ts->bus, AD7879_REG_CTRL2,
 349                            ts->gpio ?
 350                                 ts->cmd_crtl2 & ~AD7879_GPIO_DATA :
 351                                 ts->cmd_crtl2 | AD7879_GPIO_DATA);
 352         mutex_unlock(&ts->mutex);
 353
 354         return error ? : count;
 355 }
 356
 357 static DEVICE_ATTR(gpio, 0664, ad7879_gpio_show, ad7879_gpio_store);
 358
 359 static struct attribute *ad7879_attributes[] = {
 360         &dev_attr_disable.attr,
 361         &dev_attr_gpio.attr,
 362         NULL
 363 };
 364
 365 static const struct attribute_group ad7879_attr_group = {
 366         .attrs = ad7879_attributes,
 367 };
 368
 369 static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
 370 {
 371         struct input_dev *input_dev;
 372         struct ad7879_platform_data *pdata = bus->dev.platform_data;
 373         int err;
 374         u16 revid;
 375
 376         if (!bus->irq) {
 377                 dev_err(&bus->dev, "no IRQ?\n");
 378                 return -ENODEV;
 379         }
 380
 381         if (!pdata) {
 382                 dev_err(&bus->dev, "no platform data?\n");
 383                 return -ENODEV;
 384         }
 385
 386         input_dev = input_allocate_device();
 387         if (!input_dev)
 388                 return -ENOMEM;
 389
 390         ts->input = input_dev;
 391
 392         setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
 393         INIT_WORK(&ts->work, ad7879_work);
 394         mutex_init(&ts->mutex);
 395
 396         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
 397         ts->pressure_max = pdata->pressure_max ? : ~0;
 398
 399         ts->first_conversion_delay = pdata->first_conversion_delay;
 400         ts->acquisition_time = pdata->acquisition_time;
 401         ts->averaging = pdata->averaging;
 402         ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
 403         ts->median = pdata->median;
 404
 405         if (pdata->gpio_output)
 406                 ts->gpio_init = AD7879_GPIO_EN |
 407                                 (pdata->gpio_default ? 0 : AD7879_GPIO_DATA);
 408         else
 409                 ts->gpio_init = AD7879_GPIO_EN | AD7879_GPIODIR;
 410
 411         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&bus->dev));
 412
 413         input_dev->name = "AD7879 Touchscreen";
 414         input_dev->phys = ts->phys;
 415         input_dev->dev.parent = &bus->dev;
 416
 417         __set_bit(EV_ABS, input_dev->evbit);
 418         __set_bit(ABS_X, input_dev->absbit);
 419         __set_bit(ABS_Y, input_dev->absbit);
 420         __set_bit(ABS_PRESSURE, input_dev->absbit);
 421
 422         input_set_abs_params(input_dev, ABS_X,
 423                         pdata->x_min ? : 0,
 424                         pdata->x_max ? : MAX_12BIT,
 425                         0, 0);
 426         input_set_abs_params(input_dev, ABS_Y,
 427                         pdata->y_min ? : 0,
 428                         pdata->y_max ? : MAX_12BIT,
 429                         0, 0);
 430         input_set_abs_params(input_dev, ABS_PRESSURE,
 431                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 432
 433         err = ad7879_write(bus, AD7879_REG_CTRL2, AD7879_RESET);
 434
 435         if (err < 0) {
 436                 dev_err(&bus->dev, "Failed to write %s\n", input_dev->name);
 437                 goto err_free_mem;
 438         }
 439
 440         revid = ad7879_read(bus, AD7879_REG_REVID);
 441
 442         if ((revid & 0xFF) != AD7879_DEVID) {
 443                 dev_err(&bus->dev, "Failed to probe %s\n", input_dev->name);
 444                 err = -ENODEV;
 445                 goto err_free_mem;
 446         }
 447
 448         ad7879_setup(ts);
 449
 450         err = request_irq(bus->irq, ad7879_irq,
 451                           IRQF_TRIGGER_FALLING, bus->dev.driver->name, ts);
 452
 453         if (err) {
 454                 dev_err(&bus->dev, "irq %d busy?\n", bus->irq);
 455                 goto err_free_mem;
 456         }
 457
 458         err = sysfs_create_group(&bus->dev.kobj, &ad7879_attr_group);
 459         if (err)
 460                 goto err_free_irq;
 461
 462         err = input_register_device(input_dev);
 463         if (err)
 464                 goto err_remove_attr;
 465
 466         dev_info(&bus->dev, "Rev.%d touchscreen, irq %d\n",
 467                  revid >> 8, bus->irq);
 468
 469         return 0;
 470
 471 err_remove_attr:
 472         sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
 473 err_free_irq:
 474         free_irq(bus->irq, ts);
 475 err_free_mem:
 476         input_free_device(input_dev);
 477
 478         return err;
 479 }
 480
 481 static int __devexit ad7879_destroy(bus_device *bus, struct ad7879 *ts)
 482 {
 483         ad7879_disable(ts);
 484         sysfs_remove_group(&ts->bus->dev.kobj, &ad7879_attr_group);
 485         free_irq(ts->bus->irq, ts);
 486         input_unregister_device(ts->input);
 487         dev_dbg(&bus->dev, "unregistered touchscreen\n");
 488
 489         return 0;
 490 }
 491
 492 #ifdef CONFIG_PM
 493 static int ad7879_suspend(bus_device *bus, pm_message_t message)
 494 {
 495         struct ad7879 *ts = dev_get_drvdata(&bus->dev);
 496
 497         ad7879_disable(ts);
 498
 499         return 0;
 500 }
 501
 502 static int ad7879_resume(bus_device *bus)
 503 {
 504         struct ad7879 *ts = dev_get_drvdata(&bus->dev);
 505
 506         ad7879_enable(ts);
 507
 508         return 0;
 509 }
 510 #else
 511 #define ad7879_suspend NULL
 512 #define ad7879_resume  NULL
 513 #endif
 514
 515 #if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
 516 #define MAX_SPI_FREQ_HZ         5000000
 517 #define AD7879_CMD_MAGIC        0xE000
 518 #define AD7879_CMD_READ         (1 << 10)
 519 #define AD7879_WRITECMD(reg)    (AD7879_CMD_MAGIC | (reg & 0xF))
 520 #define AD7879_READCMD(reg)     (AD7879_CMD_MAGIC | AD7879_CMD_READ | (reg & 0xF))
 521
 522 struct ser_req {
 523         u16                     command;
 524         u16                     data;
 525         struct spi_message      msg;
 526         struct spi_transfer     xfer[2];
 527 };
 528
 529 /*
 530  * ad7879_read/write are only used for initial setup and for sysfs controls.
 531  * The main traffic is done in ad7879_collect().
 532  */
 533
 534 static int ad7879_read(struct spi_device *spi, u8 reg)
 535 {
 536         struct ser_req *req;
 537         int status, ret;
 538
 539         req = kzalloc(sizeof *req, GFP_KERNEL);
 540         if (!req)
 541                 return -ENOMEM;
 542
 543         spi_message_init(&req->msg);
 544
 545         req->command = (u16) AD7879_READCMD(reg);
 546         req->xfer[0].tx_buf = &req->command;
 547         req->xfer[0].len = 2;
 548
 549         req->xfer[1].rx_buf = &req->data;
 550         req->xfer[1].len = 2;
 551
 552         spi_message_add_tail(&req->xfer[0], &req->msg);
 553         spi_message_add_tail(&req->xfer[1], &req->msg);
 554
 555         status = spi_sync(spi, &req->msg);
 556         ret = status ? : req->data;
 557
 558         kfree(req);
 559
 560         return ret;
 561 }
 562
 563 static int ad7879_write(struct spi_device *spi, u8 reg, u16 val)
 564 {
 565         struct ser_req *req;
 566         int status;
 567
 568         req = kzalloc(sizeof *req, GFP_KERNEL);
 569         if (!req)
 570                 return -ENOMEM;
 571
 572         spi_message_init(&req->msg);
 573
 574         req->command = (u16) AD7879_WRITECMD(reg);
 575         req->xfer[0].tx_buf = &req->command;
 576         req->xfer[0].len = 2;
 577
 578         req->data = val;
 579         req->xfer[1].tx_buf = &req->data;
 580         req->xfer[1].len = 2;
 581
 582         spi_message_add_tail(&req->xfer[0], &req->msg);
 583         spi_message_add_tail(&req->xfer[1], &req->msg);
 584
 585         status = spi_sync(spi, &req->msg);
 586
 587         kfree(req);
 588
 589         return status;
 590 }
 591
 592 static void ad7879_collect(struct ad7879 *ts)
 593 {
 594         int status = spi_sync(ts->bus, &ts->msg);
 595
 596         if (status)
 597                 dev_err(&ts->bus->dev, "spi_sync --> %d\n", status);
 598 }
 599
 600 static void ad7879_setup_ts_def_msg(struct ad7879 *ts)
 601 {
 602         struct spi_message *m;
 603         int i;
 604
 605         ts->cmd = (u16) AD7879_READCMD(AD7879_REG_XPLUS);
 606
 607         m = &ts->msg;
 608         spi_message_init(m);
 609         ts->xfer[0].tx_buf = &ts->cmd;
 610         ts->xfer[0].len = 2;
 611
 612         spi_message_add_tail(&ts->xfer[0], m);
 613
 614         for (i = 0; i < AD7879_NR_SENSE; i++) {
 615                 ts->xfer[i + 1].rx_buf = &ts->conversion_data[i];
 616                 ts->xfer[i + 1].len = 2;
 617                 spi_message_add_tail(&ts->xfer[i + 1], m);
 618         }
 619 }
 620
 621 static int __devinit ad7879_probe(struct spi_device *spi)
 622 {
 623         struct ad7879 *ts;
 624         int error;
 625
 626         /* don't exceed max specified SPI CLK frequency */
 627         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
 628                 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
 629                 return -EINVAL;
 630         }
 631
 632         ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
 633         if (!ts)
 634                 return -ENOMEM;
 635
 636         dev_set_drvdata(&spi->dev, ts);
 637         ts->bus = spi;
 638
 639         ad7879_setup_ts_def_msg(ts);
 640
 641         error = ad7879_construct(spi, ts);
 642         if (error) {
 643                 dev_set_drvdata(&spi->dev, NULL);
 644                 kfree(ts);
 645         }
 646
 647         return 0;
 648 }
 649
 650 static int __devexit ad7879_remove(struct spi_device *spi)
 651 {
 652         struct ad7879 *ts = dev_get_drvdata(&spi->dev);
 653
 654         ad7879_destroy(spi, ts);
 655         dev_set_drvdata(&spi->dev, NULL);
 656         kfree(ts);
 657
 658         return 0;
 659 }
 660
 661 static struct spi_driver ad7879_driver = {
 662         .driver = {
 663                 .name   = "ad7879",
 664                 .bus    = &spi_bus_type,
 665                 .owner  = THIS_MODULE,
 666         },
 667         .probe          = ad7879_probe,
 668         .remove         = __devexit_p(ad7879_remove),
 669         .suspend        = ad7879_suspend,
 670         .resume         = ad7879_resume,
 671 };
 672
 673 static int __init ad7879_init(void)
 674 {
 675         return spi_register_driver(&ad7879_driver);
 676 }
 677 module_init(ad7879_init);
 678
 679 static void __exit ad7879_exit(void)
 680 {
 681         spi_unregister_driver(&ad7879_driver);
 682 }
 683 module_exit(ad7879_exit);
 684
 685 #elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
 686
 687 /* All registers are word-sized.
 688  * AD7879 uses a high-byte first convention.
 689  */
 690 static int ad7879_read(struct i2c_client *client, u8 reg)
 691 {
 692         return swab16(i2c_smbus_read_word_data(client, reg));
 693 }
 694
 695 static int ad7879_write(struct i2c_client *client, u8 reg, u16 val)
 696 {
 697         return i2c_smbus_write_word_data(client, reg, swab16(val));
 698 }
 699
 700 static void ad7879_collect(struct ad7879 *ts)
 701 {
 702         int i;
 703
 704         for (i = 0; i < AD7879_NR_SENSE; i++)
 705                 ts->conversion_data[i] = ad7879_read(ts->bus,
 706                                                      AD7879_REG_XPLUS + i);
 707 }
 708
 709 static int __devinit ad7879_probe(struct i2c_client *client,
 710                                         const struct i2c_device_id *id)
 711 {
 712         struct ad7879 *ts;
 713         int error;
 714
 715         if (!i2c_check_functionality(client->adapter,
 716                                         I2C_FUNC_SMBUS_WORD_DATA)) {
 717                 dev_err(&client->dev, "SMBUS Word Data not Supported\n");
 718                 return -EIO;
 719         }
 720
 721         ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
 722         if (!ts)
 723                 return -ENOMEM;
 724
 725         i2c_set_clientdata(client, ts);
 726         ts->bus = client;
 727
 728         error = ad7879_construct(client, ts);
 729         if (error) {
 730                 i2c_set_clientdata(client, NULL);
 731                 kfree(ts);
 732         }
 733
 734         return 0;
 735 }
 736
 737 static int __devexit ad7879_remove(struct i2c_client *client)
 738 {
 739         struct ad7879 *ts = dev_get_drvdata(&client->dev);
 740
 741         ad7879_destroy(client, ts);
 742         i2c_set_clientdata(client, NULL);
 743         kfree(ts);
 744
 745         return 0;
 746 }
 747
 748 static const struct i2c_device_id ad7879_id[] = {
 749         { "ad7879", 0 },
 750         { }
 751 };
 752 MODULE_DEVICE_TABLE(i2c, ad7879_id);
 753
 754 static struct i2c_driver ad7879_driver = {
 755         .driver = {
 756                 .name   = "ad7879",
 757                 .owner  = THIS_MODULE,
 758         },
 759         .probe          = ad7879_probe,
 760         .remove         = __devexit_p(ad7879_remove),
 761         .suspend        = ad7879_suspend,
 762         .resume         = ad7879_resume,
 763         .id_table       = ad7879_id,
 764 };
 765
 766 static int __init ad7879_init(void)
 767 {
 768         return i2c_add_driver(&ad7879_driver);
 769 }
 770 module_init(ad7879_init);
 771
 772 static void __exit ad7879_exit(void)
 773 {
 774         i2c_del_driver(&ad7879_driver);
 775 }
 776 module_exit(ad7879_exit);
 777 #endif
 778
 779 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 780 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 781 MODULE_LICENSE("GPL");