drivers/mfd/ucb1x00-ts.c

   1 /*
   2  *  Touchscreen driver for UCB1x00-based touchscreens
   3  *
   4  *  Copyright (C) 2001 Russell King, All Rights Reserved.
   5  *  Copyright (C) 2005 Pavel Machek
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * 21-Jan-2002 <jco@ict.es> :
  12  *
  13  * Added support for synchronous A/D mode. This mode is useful to
  14  * avoid noise induced in the touchpanel by the LCD, provided that
  15  * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
  16  * It is important to note that the signal connected to the ADCSYNC
  17  * pin should provide pulses even when the LCD is blanked, otherwise
  18  * a pen touch needed to unblank the LCD will never be read.
  19  */
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/init.h>
  23 #include <linux/smp.h>
  24 #include <linux/sched.h>
  25 #include <linux/completion.h>
  26 #include <linux/delay.h>
  27 #include <linux/string.h>
  28 #include <linux/input.h>
  29 #include <linux/device.h>
  30 #include <linux/freezer.h>
  31 #include <linux/slab.h>
  32 #include <linux/kthread.h>
  33
  34 #include <asm/dma.h>
  35 #include <asm/semaphore.h>
  36 #include <asm/arch/collie.h>
  37 #include <asm/mach-types.h>
  38
  39 #include "ucb1x00.h"
  40
  41
  42 struct ucb1x00_ts {
  43         struct input_dev        *idev;
  44         struct ucb1x00          *ucb;
  45
  46         wait_queue_head_t       irq_wait;
  47         struct task_struct      *rtask;
  48         u16                     x_res;
  49         u16                     y_res;
  50
  51         unsigned int            restart:1;
  52         unsigned int            adcsync:1;
  53 };
  54
  55 static int adcsync;
  56
  57 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  58 {
  59         struct input_dev *idev = ts->idev;
  60
  61         input_report_abs(idev, ABS_X, x);
  62         input_report_abs(idev, ABS_Y, y);
  63         input_report_abs(idev, ABS_PRESSURE, pressure);
  64         input_sync(idev);
  65 }
  66
  67 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  68 {
  69         struct input_dev *idev = ts->idev;
  70
  71         input_report_abs(idev, ABS_PRESSURE, 0);
  72         input_sync(idev);
  73 }
  74
  75 /*
  76  * Switch to interrupt mode.
  77  */
  78 static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
  79 {
  80         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  81                         UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
  82                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
  83                         UCB_TS_CR_MODE_INT);
  84 }
  85
  86 /*
  87  * Switch to pressure mode, and read pressure.  We don't need to wait
  88  * here, since both plates are being driven.
  89  */
  90 static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
  91 {
  92         if (machine_is_collie()) {
  93                 ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
  94                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  95                                   UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
  96                                   UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
  97
  98                 udelay(55);
  99
 100                 return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
 101         } else {
 102                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 103                                   UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 104                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 105                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 106
 107                 return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 108         }
 109 }
 110
 111 /*
 112  * Switch to X position mode and measure Y plate.  We switch the plate
 113  * configuration in pressure mode, then switch to position mode.  This
 114  * gives a faster response time.  Even so, we need to wait about 55us
 115  * for things to stabilise.
 116  */
 117 static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
 118 {
 119         if (machine_is_collie())
 120                 ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 121         else {
 122                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 123                                   UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 124                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 125                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 126                                   UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 127                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 128         }
 129         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 130                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 131                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 132
 133         udelay(55);
 134
 135         return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 136 }
 137
 138 /*
 139  * Switch to Y position mode and measure X plate.  We switch the plate
 140  * configuration in pressure mode, then switch to position mode.  This
 141  * gives a faster response time.  Even so, we need to wait about 55us
 142  * for things to stabilise.
 143  */
 144 static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
 145 {
 146         if (machine_is_collie())
 147                 ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 148         else {
 149                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 150                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 151                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 152                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 153                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 154                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 155         }
 156
 157         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 158                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 159                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 160
 161         udelay(55);
 162
 163         return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
 164 }
 165
 166 /*
 167  * Switch to X plate resistance mode.  Set MX to ground, PX to
 168  * supply.  Measure current.
 169  */
 170 static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
 171 {
 172         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 173                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 174                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 175         return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 176 }
 177
 178 /*
 179  * Switch to Y plate resistance mode.  Set MY to ground, PY to
 180  * supply.  Measure current.
 181  */
 182 static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
 183 {
 184         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 185                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 186                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 187         return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 188 }
 189
 190 static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
 191 {
 192         unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
 193
 194         if (machine_is_collie())
 195                 return (!(val & (UCB_TS_CR_TSPX_LOW)));
 196         else
 197                 return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 198 }
 199
 200 /*
 201  * This is a RT kernel thread that handles the ADC accesses
 202  * (mainly so we can use semaphores in the UCB1200 core code
 203  * to serialise accesses to the ADC).
 204  */
 205 static int ucb1x00_thread(void *_ts)
 206 {
 207         struct ucb1x00_ts *ts = _ts;
 208         struct task_struct *tsk = current;
 209         DECLARE_WAITQUEUE(wait, tsk);
 210         int valid = 0;
 211
 212         add_wait_queue(&ts->irq_wait, &wait);
 213         while (!kthread_should_stop()) {
 214                 unsigned int x, y, p;
 215                 signed long timeout;
 216
 217                 ts->restart = 0;
 218
 219                 ucb1x00_adc_enable(ts->ucb);
 220
 221                 x = ucb1x00_ts_read_xpos(ts);
 222                 y = ucb1x00_ts_read_ypos(ts);
 223                 p = ucb1x00_ts_read_pressure(ts);
 224
 225                 /*
 226                  * Switch back to interrupt mode.
 227                  */
 228                 ucb1x00_ts_mode_int(ts);
 229                 ucb1x00_adc_disable(ts->ucb);
 230
 231                 msleep(10);
 232
 233                 ucb1x00_enable(ts->ucb);
 234
 235
 236                 if (ucb1x00_ts_pen_down(ts)) {
 237                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 238
 239                         ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 240                         ucb1x00_disable(ts->ucb);
 241
 242                         /*
 243                          * If we spat out a valid sample set last time,
 244                          * spit out a "pen off" sample here.
 245                          */
 246                         if (valid) {
 247                                 ucb1x00_ts_event_release(ts);
 248                                 valid = 0;
 249                         }
 250
 251                         timeout = MAX_SCHEDULE_TIMEOUT;
 252                 } else {
 253                         ucb1x00_disable(ts->ucb);
 254
 255                         /*
 256                          * Filtering is policy.  Policy belongs in user
 257                          * space.  We therefore leave it to user space
 258                          * to do any filtering they please.
 259                          */
 260                         if (!ts->restart) {
 261                                 ucb1x00_ts_evt_add(ts, p, x, y);
 262                                 valid = 1;
 263                         }
 264
 265                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 266                         timeout = HZ / 100;
 267                 }
 268
 269                 try_to_freeze();
 270
 271                 schedule_timeout(timeout);
 272         }
 273
 274         remove_wait_queue(&ts->irq_wait, &wait);
 275
 276         ts->rtask = NULL;
 277         return 0;
 278 }
 279
 280 /*
 281  * We only detect touch screen _touches_ with this interrupt
 282  * handler, and even then we just schedule our task.
 283  */
 284 static void ucb1x00_ts_irq(int idx, void *id)
 285 {
 286         struct ucb1x00_ts *ts = id;
 287
 288         ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 289         wake_up(&ts->irq_wait);
 290 }
 291
 292 static int ucb1x00_ts_open(struct input_dev *idev)
 293 {
 294         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 295         int ret = 0;
 296
 297         BUG_ON(ts->rtask);
 298
 299         init_waitqueue_head(&ts->irq_wait);
 300         ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 301         if (ret < 0)
 302                 goto out;
 303
 304         /*
 305          * If we do this at all, we should allow the user to
 306          * measure and read the X and Y resistance at any time.
 307          */
 308         ucb1x00_adc_enable(ts->ucb);
 309         ts->x_res = ucb1x00_ts_read_xres(ts);
 310         ts->y_res = ucb1x00_ts_read_yres(ts);
 311         ucb1x00_adc_disable(ts->ucb);
 312
 313         ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 314         if (!IS_ERR(ts->rtask)) {
 315                 ret = 0;
 316         } else {
 317                 ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 318                 ts->rtask = NULL;
 319                 ret = -EFAULT;
 320         }
 321
 322  out:
 323         return ret;
 324 }
 325
 326 /*
 327  * Release touchscreen resources.  Disable IRQs.
 328  */
 329 static void ucb1x00_ts_close(struct input_dev *idev)
 330 {
 331         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 332
 333         if (ts->rtask)
 334                 kthread_stop(ts->rtask);
 335
 336         ucb1x00_enable(ts->ucb);
 337         ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 338         ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 339         ucb1x00_disable(ts->ucb);
 340 }
 341
 342 #ifdef CONFIG_PM
 343 static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 344 {
 345         struct ucb1x00_ts *ts = dev->priv;
 346
 347         if (ts->rtask != NULL) {
 348                 /*
 349                  * Restart the TS thread to ensure the
 350                  * TS interrupt mode is set up again
 351                  * after sleep.
 352                  */
 353                 ts->restart = 1;
 354                 wake_up(&ts->irq_wait);
 355         }
 356         return 0;
 357 }
 358 #else
 359 #define ucb1x00_ts_resume NULL
 360 #endif
 361
 362
 363 /*
 364  * Initialisation.
 365  */
 366 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 367 {
 368         struct ucb1x00_ts *ts;
 369         struct input_dev *idev;
 370         int err;
 371
 372         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 373         idev = input_allocate_device();
 374         if (!ts || !idev) {
 375                 err = -ENOMEM;
 376                 goto fail;
 377         }
 378
 379         ts->ucb = dev->ucb;
 380         ts->idev = idev;
 381         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 382
 383         idev->name       = "Touchscreen panel";
 384         idev->id.product = ts->ucb->id;
 385         idev->open       = ucb1x00_ts_open;
 386         idev->close      = ucb1x00_ts_close;
 387
 388         __set_bit(EV_ABS, idev->evbit);
 389         __set_bit(ABS_X, idev->absbit);
 390         __set_bit(ABS_Y, idev->absbit);
 391         __set_bit(ABS_PRESSURE, idev->absbit);
 392
 393         input_set_drvdata(idev, ts);
 394
 395         err = input_register_device(idev);
 396         if (err)
 397                 goto fail;
 398
 399         dev->priv = ts;
 400
 401         return 0;
 402
 403  fail:
 404         input_free_device(idev);
 405         kfree(ts);
 406         return err;
 407 }
 408
 409 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 410 {
 411         struct ucb1x00_ts *ts = dev->priv;
 412
 413         input_unregister_device(ts->idev);
 414         kfree(ts);
 415 }
 416
 417 static struct ucb1x00_driver ucb1x00_ts_driver = {
 418         .add            = ucb1x00_ts_add,
 419         .remove         = ucb1x00_ts_remove,
 420         .resume         = ucb1x00_ts_resume,
 421 };
 422
 423 static int __init ucb1x00_ts_init(void)
 424 {
 425         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 426 }
 427
 428 static void __exit ucb1x00_ts_exit(void)
 429 {
 430         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 431 }
 432
 433 module_param(adcsync, int, 0444);
 434 module_init(ucb1x00_ts_init);
 435 module_exit(ucb1x00_ts_exit);
 436
 437 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 438 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 439 MODULE_LICENSE("GPL");