drivers/input/touchscreen/ucb1400_ts.c

   1 /*
   2  *  Philips UCB1400 touchscreen driver
   3  *
   4  *  Author:     Nicolas Pitre
   5  *  Created:    September 25, 2006
   6  *  Copyright:  MontaVista Software, Inc.
   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 version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This code is heavily based on ucb1x00-*.c copyrighted by Russell King
  13  * covering the UCB1100, UCB1200 and UCB1300..  Support for the UCB1400 has
  14  * been made separate from ucb1x00-core/ucb1x00-ts on Russell's request.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/init.h>
  20 #include <linux/completion.h>
  21 #include <linux/delay.h>
  22 #include <linux/input.h>
  23 #include <linux/device.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/suspend.h>
  26 #include <linux/slab.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29
  30 #include <sound/driver.h>
  31 #include <sound/core.h>
  32 #include <sound/ac97_codec.h>
  33
  34
  35 /*
  36  * Interesting UCB1400 AC-link registers
  37  */
  38
  39 #define UCB_IE_RIS              0x5e
  40 #define UCB_IE_FAL              0x60
  41 #define UCB_IE_STATUS           0x62
  42 #define UCB_IE_CLEAR            0x62
  43 #define UCB_IE_ADC              (1 << 11)
  44 #define UCB_IE_TSPX             (1 << 12)
  45
  46 #define UCB_TS_CR               0x64
  47 #define UCB_TS_CR_TSMX_POW      (1 << 0)
  48 #define UCB_TS_CR_TSPX_POW      (1 << 1)
  49 #define UCB_TS_CR_TSMY_POW      (1 << 2)
  50 #define UCB_TS_CR_TSPY_POW      (1 << 3)
  51 #define UCB_TS_CR_TSMX_GND      (1 << 4)
  52 #define UCB_TS_CR_TSPX_GND      (1 << 5)
  53 #define UCB_TS_CR_TSMY_GND      (1 << 6)
  54 #define UCB_TS_CR_TSPY_GND      (1 << 7)
  55 #define UCB_TS_CR_MODE_INT      (0 << 8)
  56 #define UCB_TS_CR_MODE_PRES     (1 << 8)
  57 #define UCB_TS_CR_MODE_POS      (2 << 8)
  58 #define UCB_TS_CR_BIAS_ENA      (1 << 11)
  59 #define UCB_TS_CR_TSPX_LOW      (1 << 12)
  60 #define UCB_TS_CR_TSMX_LOW      (1 << 13)
  61
  62 #define UCB_ADC_CR              0x66
  63 #define UCB_ADC_SYNC_ENA        (1 << 0)
  64 #define UCB_ADC_VREFBYP_CON     (1 << 1)
  65 #define UCB_ADC_INP_TSPX        (0 << 2)
  66 #define UCB_ADC_INP_TSMX        (1 << 2)
  67 #define UCB_ADC_INP_TSPY        (2 << 2)
  68 #define UCB_ADC_INP_TSMY        (3 << 2)
  69 #define UCB_ADC_INP_AD0         (4 << 2)
  70 #define UCB_ADC_INP_AD1         (5 << 2)
  71 #define UCB_ADC_INP_AD2         (6 << 2)
  72 #define UCB_ADC_INP_AD3         (7 << 2)
  73 #define UCB_ADC_EXT_REF         (1 << 5)
  74 #define UCB_ADC_START           (1 << 7)
  75 #define UCB_ADC_ENA             (1 << 15)
  76
  77 #define UCB_ADC_DATA            0x68
  78 #define UCB_ADC_DAT_VALID       (1 << 15)
  79 #define UCB_ADC_DAT_VALUE(x)    ((x) & 0x3ff)
  80
  81 #define UCB_ID                  0x7e
  82 #define UCB_ID_1400             0x4304
  83
  84
  85 struct ucb1400 {
  86         struct snd_ac97         *ac97;
  87         struct input_dev        *ts_idev;
  88
  89         int                     irq;
  90
  91         wait_queue_head_t       ts_wait;
  92         struct task_struct      *ts_task;
  93
  94         unsigned int            irq_pending;    /* not bit field shared */
  95         unsigned int            ts_restart:1;
  96         unsigned int            adcsync:1;
  97 };
  98
  99 static int adcsync;
 100 static int ts_delay = 55; /* us */
 101 static int ts_delay_pressure;   /* us */
 102
 103 static inline u16 ucb1400_reg_read(struct ucb1400 *ucb, u16 reg)
 104 {
 105         return ucb->ac97->bus->ops->read(ucb->ac97, reg);
 106 }
 107
 108 static inline void ucb1400_reg_write(struct ucb1400 *ucb, u16 reg, u16 val)
 109 {
 110         ucb->ac97->bus->ops->write(ucb->ac97, reg, val);
 111 }
 112
 113 static inline void ucb1400_adc_enable(struct ucb1400 *ucb)
 114 {
 115         ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA);
 116 }
 117
 118 static unsigned int ucb1400_adc_read(struct ucb1400 *ucb, u16 adc_channel)
 119 {
 120         unsigned int val;
 121
 122         if (ucb->adcsync)
 123                 adc_channel |= UCB_ADC_SYNC_ENA;
 124
 125         ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | adc_channel);
 126         ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | adc_channel | UCB_ADC_START);
 127
 128         for (;;) {
 129                 val = ucb1400_reg_read(ucb, UCB_ADC_DATA);
 130                 if (val & UCB_ADC_DAT_VALID)
 131                         break;
 132                 /* yield to other processes */
 133                 set_current_state(TASK_INTERRUPTIBLE);
 134                 schedule_timeout(1);
 135         }
 136
 137         return UCB_ADC_DAT_VALUE(val);
 138 }
 139
 140 static inline void ucb1400_adc_disable(struct ucb1400 *ucb)
 141 {
 142         ucb1400_reg_write(ucb, UCB_ADC_CR, 0);
 143 }
 144
 145 /* Switch to interrupt mode. */
 146 static inline void ucb1400_ts_mode_int(struct ucb1400 *ucb)
 147 {
 148         ucb1400_reg_write(ucb, UCB_TS_CR,
 149                         UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 150                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 151                         UCB_TS_CR_MODE_INT);
 152 }
 153
 154 /*
 155  * Switch to pressure mode, and read pressure.  We don't need to wait
 156  * here, since both plates are being driven.
 157  */
 158 static inline unsigned int ucb1400_ts_read_pressure(struct ucb1400 *ucb)
 159 {
 160         ucb1400_reg_write(ucb, UCB_TS_CR,
 161                         UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 162                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 163                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 164         udelay(ts_delay_pressure);
 165         return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPY);
 166 }
 167
 168 /*
 169  * Switch to X position mode and measure Y plate.  We switch the plate
 170  * configuration in pressure mode, then switch to position mode.  This
 171  * gives a faster response time.  Even so, we need to wait about 55us
 172  * for things to stabilise.
 173  */
 174 static inline unsigned int ucb1400_ts_read_xpos(struct ucb1400 *ucb)
 175 {
 176         ucb1400_reg_write(ucb, UCB_TS_CR,
 177                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 178                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 179         ucb1400_reg_write(ucb, UCB_TS_CR,
 180                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 181                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 182         ucb1400_reg_write(ucb, UCB_TS_CR,
 183                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 184                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 185
 186         udelay(ts_delay);
 187
 188         return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPY);
 189 }
 190
 191 /*
 192  * Switch to Y position mode and measure X plate.  We switch the plate
 193  * configuration in pressure mode, then switch to position mode.  This
 194  * gives a faster response time.  Even so, we need to wait about 55us
 195  * for things to stabilise.
 196  */
 197 static inline unsigned int ucb1400_ts_read_ypos(struct ucb1400 *ucb)
 198 {
 199         ucb1400_reg_write(ucb, UCB_TS_CR,
 200                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 201                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 202         ucb1400_reg_write(ucb, UCB_TS_CR,
 203                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 204                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 205         ucb1400_reg_write(ucb, UCB_TS_CR,
 206                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 207                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 208
 209         udelay(ts_delay);
 210
 211         return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPX);
 212 }
 213
 214 /*
 215  * Switch to X plate resistance mode.  Set MX to ground, PX to
 216  * supply.  Measure current.
 217  */
 218 static inline unsigned int ucb1400_ts_read_xres(struct ucb1400 *ucb)
 219 {
 220         ucb1400_reg_write(ucb, UCB_TS_CR,
 221                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 222                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 223         return ucb1400_adc_read(ucb, 0);
 224 }
 225
 226 /*
 227  * Switch to Y plate resistance mode.  Set MY to ground, PY to
 228  * supply.  Measure current.
 229  */
 230 static inline unsigned int ucb1400_ts_read_yres(struct ucb1400 *ucb)
 231 {
 232         ucb1400_reg_write(ucb, UCB_TS_CR,
 233                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 234                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 235         return ucb1400_adc_read(ucb, 0);
 236 }
 237
 238 static inline int ucb1400_ts_pen_down(struct ucb1400 *ucb)
 239 {
 240         unsigned short val = ucb1400_reg_read(ucb, UCB_TS_CR);
 241         return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 242 }
 243
 244 static inline void ucb1400_ts_irq_enable(struct ucb1400 *ucb)
 245 {
 246         ucb1400_reg_write(ucb, UCB_IE_CLEAR, UCB_IE_TSPX);
 247         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);
 248         ucb1400_reg_write(ucb, UCB_IE_FAL, UCB_IE_TSPX);
 249 }
 250
 251 static inline void ucb1400_ts_irq_disable(struct ucb1400 *ucb)
 252 {
 253         ucb1400_reg_write(ucb, UCB_IE_FAL, 0);
 254 }
 255
 256 static void ucb1400_ts_evt_add(struct input_dev *idev, u16 pressure, u16 x, u16 y)
 257 {
 258         input_report_abs(idev, ABS_X, x);
 259         input_report_abs(idev, ABS_Y, y);
 260         input_report_abs(idev, ABS_PRESSURE, pressure);
 261         input_sync(idev);
 262 }
 263
 264 static void ucb1400_ts_event_release(struct input_dev *idev)
 265 {
 266         input_report_abs(idev, ABS_PRESSURE, 0);
 267         input_sync(idev);
 268 }
 269
 270 static void ucb1400_handle_pending_irq(struct ucb1400 *ucb)
 271 {
 272         unsigned int isr;
 273
 274         isr = ucb1400_reg_read(ucb, UCB_IE_STATUS);
 275         ucb1400_reg_write(ucb, UCB_IE_CLEAR, isr);
 276         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);
 277
 278         if (isr & UCB_IE_TSPX)
 279                 ucb1400_ts_irq_disable(ucb);
 280         else
 281                 printk(KERN_ERR "ucb1400: unexpected IE_STATUS = %#x\n", isr);
 282
 283         enable_irq(ucb->irq);
 284 }
 285
 286 static int ucb1400_ts_thread(void *_ucb)
 287 {
 288         struct ucb1400 *ucb = _ucb;
 289         struct task_struct *tsk = current;
 290         int valid = 0;
 291         struct sched_param param = { .sched_priority = 1 };
 292
 293         sched_setscheduler(tsk, SCHED_FIFO, &param);
 294
 295         set_freezable();
 296         while (!kthread_should_stop()) {
 297                 unsigned int x, y, p;
 298                 long timeout;
 299
 300                 ucb->ts_restart = 0;
 301
 302                 if (ucb->irq_pending) {
 303                         ucb->irq_pending = 0;
 304                         ucb1400_handle_pending_irq(ucb);
 305                 }
 306
 307                 ucb1400_adc_enable(ucb);
 308                 x = ucb1400_ts_read_xpos(ucb);
 309                 y = ucb1400_ts_read_ypos(ucb);
 310                 p = ucb1400_ts_read_pressure(ucb);
 311                 ucb1400_adc_disable(ucb);
 312
 313                 /* Switch back to interrupt mode. */
 314                 ucb1400_ts_mode_int(ucb);
 315
 316                 msleep(10);
 317
 318                 if (ucb1400_ts_pen_down(ucb)) {
 319                         ucb1400_ts_irq_enable(ucb);
 320
 321                         /*
 322                          * If we spat out a valid sample set last time,
 323                          * spit out a "pen off" sample here.
 324                          */
 325                         if (valid) {
 326                                 ucb1400_ts_event_release(ucb->ts_idev);
 327                                 valid = 0;
 328                         }
 329
 330                         timeout = MAX_SCHEDULE_TIMEOUT;
 331                 } else {
 332                         valid = 1;
 333                         ucb1400_ts_evt_add(ucb->ts_idev, p, x, y);
 334                         timeout = msecs_to_jiffies(10);
 335                 }
 336
 337                 wait_event_interruptible_timeout(ucb->ts_wait,
 338                         ucb->irq_pending || ucb->ts_restart || kthread_should_stop(),
 339                         timeout);
 340                 try_to_freeze();
 341         }
 342
 343         /* Send the "pen off" if we are stopping with the pen still active */
 344         if (valid)
 345                 ucb1400_ts_event_release(ucb->ts_idev);
 346
 347         ucb->ts_task = NULL;
 348         return 0;
 349 }
 350
 351 /*
 352  * A restriction with interrupts exists when using the ucb1400, as
 353  * the codec read/write routines may sleep while waiting for codec
 354  * access completion and uses semaphores for access control to the
 355  * AC97 bus.  A complete codec read cycle could take  anywhere from
 356  * 60 to 100uSec so we *definitely* don't want to spin inside the
 357  * interrupt handler waiting for codec access.  So, we handle the
 358  * interrupt by scheduling a RT kernel thread to run in process
 359  * context instead of interrupt context.
 360  */
 361 static irqreturn_t ucb1400_hard_irq(int irqnr, void *devid)
 362 {
 363         struct ucb1400 *ucb = devid;
 364
 365         if (irqnr == ucb->irq) {
 366                 disable_irq(ucb->irq);
 367                 ucb->irq_pending = 1;
 368                 wake_up(&ucb->ts_wait);
 369                 return IRQ_HANDLED;
 370         }
 371         return IRQ_NONE;
 372 }
 373
 374 static int ucb1400_ts_open(struct input_dev *idev)
 375 {
 376         struct ucb1400 *ucb = input_get_drvdata(idev);
 377         int ret = 0;
 378
 379         BUG_ON(ucb->ts_task);
 380
 381         ucb->ts_task = kthread_run(ucb1400_ts_thread, ucb, "UCB1400_ts");
 382         if (IS_ERR(ucb->ts_task)) {
 383                 ret = PTR_ERR(ucb->ts_task);
 384                 ucb->ts_task = NULL;
 385         }
 386
 387         return ret;
 388 }
 389
 390 static void ucb1400_ts_close(struct input_dev *idev)
 391 {
 392         struct ucb1400 *ucb = input_get_drvdata(idev);
 393
 394         if (ucb->ts_task)
 395                 kthread_stop(ucb->ts_task);
 396
 397         ucb1400_ts_irq_disable(ucb);
 398         ucb1400_reg_write(ucb, UCB_TS_CR, 0);
 399 }
 400
 401 #ifdef CONFIG_PM
 402 static int ucb1400_ts_resume(struct device *dev)
 403 {
 404         struct ucb1400 *ucb = dev_get_drvdata(dev);
 405
 406         if (ucb->ts_task) {
 407                 /*
 408                  * Restart the TS thread to ensure the
 409                  * TS interrupt mode is set up again
 410                  * after sleep.
 411                  */
 412                 ucb->ts_restart = 1;
 413                 wake_up(&ucb->ts_wait);
 414         }
 415         return 0;
 416 }
 417 #else
 418 #define ucb1400_ts_resume NULL
 419 #endif
 420
 421 #ifndef NO_IRQ
 422 #define NO_IRQ  0
 423 #endif
 424
 425 /*
 426  * Try to probe our interrupt, rather than relying on lots of
 427  * hard-coded machine dependencies.
 428  */
 429 static int ucb1400_detect_irq(struct ucb1400 *ucb)
 430 {
 431         unsigned long mask, timeout;
 432
 433         mask = probe_irq_on();
 434         if (!mask) {
 435                 probe_irq_off(mask);
 436                 return -EBUSY;
 437         }
 438
 439         /* Enable the ADC interrupt. */
 440         ucb1400_reg_write(ucb, UCB_IE_RIS, UCB_IE_ADC);
 441         ucb1400_reg_write(ucb, UCB_IE_FAL, UCB_IE_ADC);
 442         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0xffff);
 443         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);
 444
 445         /* Cause an ADC interrupt. */
 446         ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA);
 447         ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | UCB_ADC_START);
 448
 449         /* Wait for the conversion to complete. */
 450         timeout = jiffies + HZ/2;
 451         while (!(ucb1400_reg_read(ucb, UCB_ADC_DATA) & UCB_ADC_DAT_VALID)) {
 452                 cpu_relax();
 453                 if (time_after(jiffies, timeout)) {
 454                         printk(KERN_ERR "ucb1400: timed out in IRQ probe\n");
 455                         probe_irq_off(mask);
 456                         return -ENODEV;
 457                 }
 458         }
 459         ucb1400_reg_write(ucb, UCB_ADC_CR, 0);
 460
 461         /* Disable and clear interrupt. */
 462         ucb1400_reg_write(ucb, UCB_IE_RIS, 0);
 463         ucb1400_reg_write(ucb, UCB_IE_FAL, 0);
 464         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0xffff);
 465         ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);
 466
 467         /* Read triggered interrupt. */
 468         ucb->irq = probe_irq_off(mask);
 469         if (ucb->irq < 0 || ucb->irq == NO_IRQ)
 470                 return -ENODEV;
 471
 472         return 0;
 473 }
 474
 475 static int ucb1400_ts_probe(struct device *dev)
 476 {
 477         struct ucb1400 *ucb;
 478         struct input_dev *idev;
 479         int error, id, x_res, y_res;
 480
 481         ucb = kzalloc(sizeof(struct ucb1400), GFP_KERNEL);
 482         idev = input_allocate_device();
 483         if (!ucb || !idev) {
 484                 error = -ENOMEM;
 485                 goto err_free_devs;
 486         }
 487
 488         ucb->ts_idev = idev;
 489         ucb->adcsync = adcsync;
 490         ucb->ac97 = to_ac97_t(dev);
 491         init_waitqueue_head(&ucb->ts_wait);
 492
 493         id = ucb1400_reg_read(ucb, UCB_ID);
 494         if (id != UCB_ID_1400) {
 495                 error = -ENODEV;
 496                 goto err_free_devs;
 497         }
 498
 499         error = ucb1400_detect_irq(ucb);
 500         if (error) {
 501                 printk(KERN_ERR "UCB1400: IRQ probe failed\n");
 502                 goto err_free_devs;
 503         }
 504
 505         error = request_irq(ucb->irq, ucb1400_hard_irq, IRQF_TRIGGER_RISING,
 506                                 "UCB1400", ucb);
 507         if (error) {
 508                 printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n",
 509                                 ucb->irq, error);
 510                 goto err_free_devs;
 511         }
 512         printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq);
 513
 514         input_set_drvdata(idev, ucb);
 515
 516         idev->dev.parent        = dev;
 517         idev->name              = "UCB1400 touchscreen interface";
 518         idev->id.vendor         = ucb1400_reg_read(ucb, AC97_VENDOR_ID1);
 519         idev->id.product        = id;
 520         idev->open              = ucb1400_ts_open;
 521         idev->close             = ucb1400_ts_close;
 522         idev->evbit[0]          = BIT(EV_ABS);
 523
 524         ucb1400_adc_enable(ucb);
 525         x_res = ucb1400_ts_read_xres(ucb);
 526         y_res = ucb1400_ts_read_yres(ucb);
 527         ucb1400_adc_disable(ucb);
 528         printk(KERN_DEBUG "UCB1400: x/y = %d/%d\n", x_res, y_res);
 529
 530         input_set_abs_params(idev, ABS_X, 0, x_res, 0, 0);
 531         input_set_abs_params(idev, ABS_Y, 0, y_res, 0, 0);
 532         input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
 533
 534         error = input_register_device(idev);
 535         if (error)
 536                 goto err_free_irq;
 537
 538         dev_set_drvdata(dev, ucb);
 539         return 0;
 540
 541  err_free_irq:
 542         free_irq(ucb->irq, ucb);
 543  err_free_devs:
 544         input_free_device(idev);
 545         kfree(ucb);
 546         return error;
 547 }
 548
 549 static int ucb1400_ts_remove(struct device *dev)
 550 {
 551         struct ucb1400 *ucb = dev_get_drvdata(dev);
 552
 553         free_irq(ucb->irq, ucb);
 554         input_unregister_device(ucb->ts_idev);
 555         dev_set_drvdata(dev, NULL);
 556         kfree(ucb);
 557         return 0;
 558 }
 559
 560 static struct device_driver ucb1400_ts_driver = {
 561         .name           = "ucb1400_ts",
 562         .owner          = THIS_MODULE,
 563         .bus            = &ac97_bus_type,
 564         .probe          = ucb1400_ts_probe,
 565         .remove         = ucb1400_ts_remove,
 566         .resume         = ucb1400_ts_resume,
 567 };
 568
 569 static int __init ucb1400_ts_init(void)
 570 {
 571         return driver_register(&ucb1400_ts_driver);
 572 }
 573
 574 static void __exit ucb1400_ts_exit(void)
 575 {
 576         driver_unregister(&ucb1400_ts_driver);
 577 }
 578
 579 module_param(adcsync, bool, 0444);
 580 MODULE_PARM_DESC(adcsync, "Synchronize touch readings with ADCSYNC pin.");
 581
 582 module_param(ts_delay, int, 0444);
 583 MODULE_PARM_DESC(ts_delay, "Delay between panel setup and position read. Default = 55us.");
 584
 585 module_param(ts_delay_pressure, int, 0444);
 586 MODULE_PARM_DESC(ts_delay_pressure,
 587                   "delay between panel setup and pressure read.  Default = 0us.");
 588
 589 module_init(ucb1400_ts_init);
 590 module_exit(ucb1400_ts_exit);
 591
 592 MODULE_DESCRIPTION("Philips UCB1400 touchscreen driver");
 593 MODULE_LICENSE("GPL");