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/smp_lock.h>
  25 #include <linux/sched.h>
  26 #include <linux/completion.h>
  27 #include <linux/delay.h>
  28 #include <linux/string.h>
  29 #include <linux/input.h>
  30 #include <linux/device.h>
  31 #include <linux/freezer.h>
  32 #include <linux/slab.h>
  33 #include <linux/kthread.h>
  34
  35 #include <asm/dma.h>
  36 #include <asm/semaphore.h>
  37 #include <asm/arch/collie.h>
  38 #include <asm/mach-types.h>
  39
  40 #include "ucb1x00.h"
  41
  42
  43 struct ucb1x00_ts {
  44         struct input_dev        *idev;
  45         struct ucb1x00          *ucb;
  46
  47         wait_queue_head_t       irq_wait;
  48         struct task_struct      *rtask;
  49         u16                     x_res;
  50         u16                     y_res;
  51
  52         unsigned int            restart:1;
  53         unsigned int            adcsync:1;
  54 };
  55
  56 static int adcsync;
  57
  58 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  59 {
  60         struct input_dev *idev = ts->idev;
  61
  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
  72         input_report_abs(idev, ABS_PRESSURE, 0);
  73         input_sync(idev);
  74 }
  75
  76 /*
  77  * Switch to interrupt mode.
  78  */
  79 static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
  80 {
  81         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  82                         UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
  83                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
  84                         UCB_TS_CR_MODE_INT);
  85 }
  86
  87 /*
  88  * Switch to pressure mode, and read pressure.  We don't need to wait
  89  * here, since both plates are being driven.
  90  */
  91 static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
  92 {
  93         if (machine_is_collie()) {
  94                 ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
  95                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  96                                   UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
  97                                   UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
  98
  99                 udelay(55);
 100
 101                 return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
 102         } else {
 103                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 104                                   UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 105                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 106                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 107
 108                 return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 109         }
 110 }
 111
 112 /*
 113  * Switch to X position mode and measure Y plate.  We switch the plate
 114  * configuration in pressure mode, then switch to position mode.  This
 115  * gives a faster response time.  Even so, we need to wait about 55us
 116  * for things to stabilise.
 117  */
 118 static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
 119 {
 120         if (machine_is_collie())
 121                 ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 122         else {
 123                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 124                                   UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 125                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 126                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 127                                   UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 128                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 129         }
 130         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 131                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 132                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 133
 134         udelay(55);
 135
 136         return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 137 }
 138
 139 /*
 140  * Switch to Y position mode and measure X plate.  We switch the plate
 141  * configuration in pressure mode, then switch to position mode.  This
 142  * gives a faster response time.  Even so, we need to wait about 55us
 143  * for things to stabilise.
 144  */
 145 static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
 146 {
 147         if (machine_is_collie())
 148                 ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 149         else {
 150                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 151                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 152                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 153                 ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 154                                   UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 155                                   UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 156         }
 157
 158         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 159                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 160                         UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 161
 162         udelay(55);
 163
 164         return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
 165 }
 166
 167 /*
 168  * Switch to X plate resistance mode.  Set MX to ground, PX to
 169  * supply.  Measure current.
 170  */
 171 static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
 172 {
 173         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 174                         UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 175                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 176         return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 177 }
 178
 179 /*
 180  * Switch to Y plate resistance mode.  Set MY to ground, PY to
 181  * supply.  Measure current.
 182  */
 183 static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
 184 {
 185         ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 186                         UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 187                         UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 188         return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 189 }
 190
 191 static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
 192 {
 193         unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
 194
 195         if (machine_is_collie())
 196                 return (!(val & (UCB_TS_CR_TSPX_LOW)));
 197         else
 198                 return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 199 }
 200
 201 /*
 202  * This is a RT kernel thread that handles the ADC accesses
 203  * (mainly so we can use semaphores in the UCB1200 core code
 204  * to serialise accesses to the ADC).
 205  */
 206 static int ucb1x00_thread(void *_ts)
 207 {
 208         struct ucb1x00_ts *ts = _ts;
 209         struct task_struct *tsk = current;
 210         DECLARE_WAITQUEUE(wait, tsk);
 211         int valid;
 212
 213         /*
 214          * We could run as a real-time thread.  However, thus far
 215          * this doesn't seem to be necessary.
 216          */
 217 //      tsk->policy = SCHED_FIFO;
 218 //      tsk->rt_priority = 1;
 219
 220         valid = 0;
 221
 222         add_wait_queue(&ts->irq_wait, &wait);
 223         while (!kthread_should_stop()) {
 224                 unsigned int x, y, p;
 225                 signed long timeout;
 226
 227                 ts->restart = 0;
 228
 229                 ucb1x00_adc_enable(ts->ucb);
 230
 231                 x = ucb1x00_ts_read_xpos(ts);
 232                 y = ucb1x00_ts_read_ypos(ts);
 233                 p = ucb1x00_ts_read_pressure(ts);
 234
 235                 /*
 236                  * Switch back to interrupt mode.
 237                  */
 238                 ucb1x00_ts_mode_int(ts);
 239                 ucb1x00_adc_disable(ts->ucb);
 240
 241                 msleep(10);
 242
 243                 ucb1x00_enable(ts->ucb);
 244
 245
 246                 if (ucb1x00_ts_pen_down(ts)) {
 247                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 248
 249                         ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 250                         ucb1x00_disable(ts->ucb);
 251
 252                         /*
 253                          * If we spat out a valid sample set last time,
 254                          * spit out a "pen off" sample here.
 255                          */
 256                         if (valid) {
 257                                 ucb1x00_ts_event_release(ts);
 258                                 valid = 0;
 259                         }
 260
 261                         timeout = MAX_SCHEDULE_TIMEOUT;
 262                 } else {
 263                         ucb1x00_disable(ts->ucb);
 264
 265                         /*
 266                          * Filtering is policy.  Policy belongs in user
 267                          * space.  We therefore leave it to user space
 268                          * to do any filtering they please.
 269                          */
 270                         if (!ts->restart) {
 271                                 ucb1x00_ts_evt_add(ts, p, x, y);
 272                                 valid = 1;
 273                         }
 274
 275                         set_task_state(tsk, TASK_INTERRUPTIBLE);
 276                         timeout = HZ / 100;
 277                 }
 278
 279                 try_to_freeze();
 280
 281                 schedule_timeout(timeout);
 282         }
 283
 284         remove_wait_queue(&ts->irq_wait, &wait);
 285
 286         ts->rtask = NULL;
 287         return 0;
 288 }
 289
 290 /*
 291  * We only detect touch screen _touches_ with this interrupt
 292  * handler, and even then we just schedule our task.
 293  */
 294 static void ucb1x00_ts_irq(int idx, void *id)
 295 {
 296         struct ucb1x00_ts *ts = id;
 297
 298         ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 299         wake_up(&ts->irq_wait);
 300 }
 301
 302 static int ucb1x00_ts_open(struct input_dev *idev)
 303 {
 304         struct ucb1x00_ts *ts = idev->private;
 305         int ret = 0;
 306
 307         BUG_ON(ts->rtask);
 308
 309         init_waitqueue_head(&ts->irq_wait);
 310         ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 311         if (ret < 0)
 312                 goto out;
 313
 314         /*
 315          * If we do this at all, we should allow the user to
 316          * measure and read the X and Y resistance at any time.
 317          */
 318         ucb1x00_adc_enable(ts->ucb);
 319         ts->x_res = ucb1x00_ts_read_xres(ts);
 320         ts->y_res = ucb1x00_ts_read_yres(ts);
 321         ucb1x00_adc_disable(ts->ucb);
 322
 323         ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 324         if (!IS_ERR(ts->rtask)) {
 325                 ret = 0;
 326         } else {
 327                 ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 328                 ts->rtask = NULL;
 329                 ret = -EFAULT;
 330         }
 331
 332  out:
 333         return ret;
 334 }
 335
 336 /*
 337  * Release touchscreen resources.  Disable IRQs.
 338  */
 339 static void ucb1x00_ts_close(struct input_dev *idev)
 340 {
 341         struct ucb1x00_ts *ts = idev->private;
 342
 343         if (ts->rtask)
 344                 kthread_stop(ts->rtask);
 345
 346         ucb1x00_enable(ts->ucb);
 347         ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 348         ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 349         ucb1x00_disable(ts->ucb);
 350 }
 351
 352 #ifdef CONFIG_PM
 353 static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 354 {
 355         struct ucb1x00_ts *ts = dev->priv;
 356
 357         if (ts->rtask != NULL) {
 358                 /*
 359                  * Restart the TS thread to ensure the
 360                  * TS interrupt mode is set up again
 361                  * after sleep.
 362                  */
 363                 ts->restart = 1;
 364                 wake_up(&ts->irq_wait);
 365         }
 366         return 0;
 367 }
 368 #else
 369 #define ucb1x00_ts_resume NULL
 370 #endif
 371
 372
 373 /*
 374  * Initialisation.
 375  */
 376 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 377 {
 378         struct ucb1x00_ts *ts;
 379         struct input_dev *idev;
 380         int err;
 381
 382         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 383         idev = input_allocate_device();
 384         if (!ts || !idev) {
 385                 err = -ENOMEM;
 386                 goto fail;
 387         }
 388
 389         ts->ucb = dev->ucb;
 390         ts->idev = idev;
 391         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 392
 393         idev->private    = ts;
 394         idev->name       = "Touchscreen panel";
 395         idev->id.product = ts->ucb->id;
 396         idev->open       = ucb1x00_ts_open;
 397         idev->close      = ucb1x00_ts_close;
 398
 399         __set_bit(EV_ABS, idev->evbit);
 400         __set_bit(ABS_X, idev->absbit);
 401         __set_bit(ABS_Y, idev->absbit);
 402         __set_bit(ABS_PRESSURE, idev->absbit);
 403
 404         err = input_register_device(idev);
 405         if (err)
 406                 goto fail;
 407
 408         dev->priv = ts;
 409
 410         return 0;
 411
 412  fail:
 413         input_free_device(idev);
 414         kfree(ts);
 415         return err;
 416 }
 417
 418 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 419 {
 420         struct ucb1x00_ts *ts = dev->priv;
 421
 422         input_unregister_device(ts->idev);
 423         kfree(ts);
 424 }
 425
 426 static struct ucb1x00_driver ucb1x00_ts_driver = {
 427         .add            = ucb1x00_ts_add,
 428         .remove         = ucb1x00_ts_remove,
 429         .resume         = ucb1x00_ts_resume,
 430 };
 431
 432 static int __init ucb1x00_ts_init(void)
 433 {
 434         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 435 }
 436
 437 static void __exit ucb1x00_ts_exit(void)
 438 {
 439         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 440 }
 441
 442 module_param(adcsync, int, 0444);
 443 module_init(ucb1x00_ts_init);
 444 module_exit(ucb1x00_ts_exit);
 445
 446 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 447 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 448 MODULE_LICENSE("GPL");