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