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