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/config.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/init.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/sched.h>
  27 #include <linux/completion.h>
  28 #include <linux/delay.h>
  29 #include <linux/string.h>
  30 #include <linux/input.h>
  31 #include <linux/device.h>
  32 #include <linux/suspend.h>
  33 #include <linux/slab.h>
  34 #include <linux/kthread.h>
  35
  36 #include <asm/dma.h>
  37 #include <asm/semaphore.h>
  38 #include <asm/arch/collie.h>
  39 #include <asm/mach-types.h>
  40
  41 #include "ucb1x00.h"
  42
  43
  44 struct ucb1x00_ts {
  45         struct input_dev        *idev;
  46         struct ucb1x00          *ucb;
  47
  48         wait_queue_head_t       irq_wait;
  49         struct task_struct      *rtask;
  50         u16                     x_res;
  51         u16                     y_res;
  52
  53         unsigned int            restart:1;
  54         unsigned int            adcsync:1;
  55 };
  56
  57 static int adcsync;
  58
  59 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  60 {
  61         struct input_dev *idev = ts->idev;
  62         input_report_abs(idev, ABS_X, x);
  63         input_report_abs(idev, ABS_Y, y);
  64         input_report_abs(idev, ABS_PRESSURE, pressure);
  65         input_sync(idev);
  66 }
  67
  68 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  69 {
  70         struct input_dev *idev = ts->idev;
  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         if (machine_is_collie())
 194                 return (!(val & (UCB_TS_CR_TSPX_LOW)));
 195         else
 196                 return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 197 }
 198
 199 /*
 200  * This is a RT kernel thread that handles the ADC accesses
 201  * (mainly so we can use semaphores in the UCB1200 core code
 202  * to serialise accesses to the ADC).
 203  */
 204 static int ucb1x00_thread(void *_ts)
 205 {
 206         struct ucb1x00_ts *ts = _ts;
 207         struct task_struct *tsk = current;
 208         DECLARE_WAITQUEUE(wait, tsk);
 209         int valid;
 210
 211         /*
 212          * We could run as a real-time thread.  However, thus far
 213          * this doesn't seem to be necessary.
 214          */
 215 //      tsk->policy = SCHED_FIFO;
 216 //      tsk->rt_priority = 1;
 217
 218         valid = 0;
 219
 220         add_wait_queue(&ts->irq_wait, &wait);
 221         while (!kthread_should_stop()) {
 222                 unsigned int x, y, p;
 223                 signed long timeout;
 224
 225                 ts->restart = 0;
 226
 227                 ucb1x00_adc_enable(ts->ucb);
 228
 229                 x = ucb1x00_ts_read_xpos(ts);
 230                 y = ucb1x00_ts_read_ypos(ts);
 231                 p = ucb1x00_ts_read_pressure(ts);
 232
 233                 /*
 234                  * Switch back to interrupt mode.
 235                  */
 236                 ucb1x00_ts_mode_int(ts);
 237                 ucb1x00_adc_disable(ts->ucb);
 238
 239                 msleep(10);
 240
 241                 ucb1x00_enable(ts->ucb);
 242
 243
 244                 if (ucb1x00_ts_pen_down(ts)) {
 245                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 246
 247                         ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 248                         ucb1x00_disable(ts->ucb);
 249
 250                         /*
 251                          * If we spat out a valid sample set last time,
 252                          * spit out a "pen off" sample here.
 253                          */
 254                         if (valid) {
 255                                 ucb1x00_ts_event_release(ts);
 256                                 valid = 0;
 257                         }
 258
 259                         timeout = MAX_SCHEDULE_TIMEOUT;
 260                 } else {
 261                         ucb1x00_disable(ts->ucb);
 262
 263                         /*
 264                          * Filtering is policy.  Policy belongs in user
 265                          * space.  We therefore leave it to user space
 266                          * to do any filtering they please.
 267                          */
 268                         if (!ts->restart) {
 269                                 ucb1x00_ts_evt_add(ts, p, x, y);
 270                                 valid = 1;
 271                         }
 272
 273                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 274                         timeout = HZ / 100;
 275                 }
 276
 277                 try_to_freeze();
 278
 279                 schedule_timeout(timeout);
 280         }
 281
 282         remove_wait_queue(&ts->irq_wait, &wait);
 283
 284         ts->rtask = NULL;
 285         return 0;
 286 }
 287
 288 /*
 289  * We only detect touch screen _touches_ with this interrupt
 290  * handler, and even then we just schedule our task.
 291  */
 292 static void ucb1x00_ts_irq(int idx, void *id)
 293 {
 294         struct ucb1x00_ts *ts = id;
 295         ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 296         wake_up(&ts->irq_wait);
 297 }
 298
 299 static int ucb1x00_ts_open(struct input_dev *idev)
 300 {
 301         struct ucb1x00_ts *ts = idev->private;
 302         int ret = 0;
 303
 304         BUG_ON(ts->rtask);
 305
 306         init_waitqueue_head(&ts->irq_wait);
 307         ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 308         if (ret < 0)
 309                 goto out;
 310
 311         /*
 312          * If we do this at all, we should allow the user to
 313          * measure and read the X and Y resistance at any time.
 314          */
 315         ucb1x00_adc_enable(ts->ucb);
 316         ts->x_res = ucb1x00_ts_read_xres(ts);
 317         ts->y_res = ucb1x00_ts_read_yres(ts);
 318         ucb1x00_adc_disable(ts->ucb);
 319
 320         ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 321         if (!IS_ERR(ts->rtask)) {
 322                 ret = 0;
 323         } else {
 324                 ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 325                 ts->rtask = NULL;
 326                 ret = -EFAULT;
 327         }
 328
 329  out:
 330         return ret;
 331 }
 332
 333 /*
 334  * Release touchscreen resources.  Disable IRQs.
 335  */
 336 static void ucb1x00_ts_close(struct input_dev *idev)
 337 {
 338         struct ucb1x00_ts *ts = idev->private;
 339
 340         if (ts->rtask)
 341                 kthread_stop(ts->rtask);
 342
 343         ucb1x00_enable(ts->ucb);
 344         ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 345         ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 346         ucb1x00_disable(ts->ucb);
 347 }
 348
 349 #ifdef CONFIG_PM
 350 static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 351 {
 352         struct ucb1x00_ts *ts = dev->priv;
 353
 354         if (ts->rtask != NULL) {
 355                 /*
 356                  * Restart the TS thread to ensure the
 357                  * TS interrupt mode is set up again
 358                  * after sleep.
 359                  */
 360                 ts->restart = 1;
 361                 wake_up(&ts->irq_wait);
 362         }
 363         return 0;
 364 }
 365 #else
 366 #define ucb1x00_ts_resume NULL
 367 #endif
 368
 369
 370 /*
 371  * Initialisation.
 372  */
 373 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 374 {
 375         struct ucb1x00_ts *ts;
 376
 377         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 378         if (!ts)
 379                 return -ENOMEM;
 380
 381         ts->idev = input_allocate_device();
 382         if (!ts->idev) {
 383                 kfree(ts);
 384                 return -ENOMEM;
 385         }
 386
 387         ts->ucb = dev->ucb;
 388         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 389
 390         ts->idev->private = ts;
 391         ts->idev->name       = "Touchscreen panel";
 392         ts->idev->id.product = ts->ucb->id;
 393         ts->idev->open       = ucb1x00_ts_open;
 394         ts->idev->close      = ucb1x00_ts_close;
 395
 396         __set_bit(EV_ABS, ts->idev->evbit);
 397         __set_bit(ABS_X, ts->idev->absbit);
 398         __set_bit(ABS_Y, ts->idev->absbit);
 399         __set_bit(ABS_PRESSURE, ts->idev->absbit);
 400
 401         input_register_device(ts->idev);
 402
 403         dev->priv = ts;
 404
 405         return 0;
 406 }
 407
 408 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 409 {
 410         struct ucb1x00_ts *ts = dev->priv;
 411
 412         input_unregister_device(ts->idev);
 413         kfree(ts);
 414 }
 415
 416 static struct ucb1x00_driver ucb1x00_ts_driver = {
 417         .add            = ucb1x00_ts_add,
 418         .remove         = ucb1x00_ts_remove,
 419         .resume         = ucb1x00_ts_resume,
 420 };
 421
 422 static int __init ucb1x00_ts_init(void)
 423 {
 424         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 425 }
 426
 427 static void __exit ucb1x00_ts_exit(void)
 428 {
 429         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 430 }
 431
 432 module_param(adcsync, int, 0444);
 433 module_init(ucb1x00_ts_init);
 434 module_exit(ucb1x00_ts_exit);
 435
 436 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 437 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 438 MODULE_LICENSE("GPL");