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 #include <linux/mfd/ucb1x00.h>
  34
  35 #include <mach/dma.h>
  36 #include <mach/collie.h>
  37 #include <asm/mach-types.h>
  38
  39
  40
  41 struct ucb1x00_ts {
  42         struct input_dev        *idev;
  43         struct ucb1x00          *ucb;
  44
  45         wait_queue_head_t       irq_wait;
  46         struct task_struct      *rtask;
  47         u16                     x_res;
  48         u16                     y_res;
  49
  50         unsigned int            adcsync:1;
  51 };
  52
  53 static int adcsync;
  54
  55 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  56 {
  57         struct input_dev *idev = ts->idev;
  58
  59         input_report_abs(idev, ABS_X, x);
  60         input_report_abs(idev, ABS_Y, y);
  61         input_report_abs(idev, ABS_PRESSURE, pressure);
  62         input_report_key(idev, BTN_TOUCH, 1);
  63         input_sync(idev);
  64 }
  65
  66 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  67 {
  68         struct input_dev *idev = ts->idev;
  69
  70         input_report_abs(idev, ABS_PRESSURE, 0);
  71         input_report_key(idev, BTN_TOUCH, 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         DECLARE_WAITQUEUE(wait, current);
 209         bool frozen, ignore = false;
 210         int valid = 0;
 211
 212         set_freezable();
 213         add_wait_queue(&ts->irq_wait, &wait);
 214         while (!kthread_freezable_should_stop(&frozen)) {
 215                 unsigned int x, y, p;
 216                 signed long timeout;
 217
 218                 if (frozen)
 219                         ignore = true;
 220
 221                 ucb1x00_adc_enable(ts->ucb);
 222
 223                 x = ucb1x00_ts_read_xpos(ts);
 224                 y = ucb1x00_ts_read_ypos(ts);
 225                 p = ucb1x00_ts_read_pressure(ts);
 226
 227                 /*
 228                  * Switch back to interrupt mode.
 229                  */
 230                 ucb1x00_ts_mode_int(ts);
 231                 ucb1x00_adc_disable(ts->ucb);
 232
 233                 msleep(10);
 234
 235                 ucb1x00_enable(ts->ucb);
 236
 237
 238                 if (ucb1x00_ts_pen_down(ts)) {
 239                         set_current_state(TASK_INTERRUPTIBLE);
 240
 241                         ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 242                         ucb1x00_disable(ts->ucb);
 243
 244                         /*
 245                          * If we spat out a valid sample set last time,
 246                          * spit out a "pen off" sample here.
 247                          */
 248                         if (valid) {
 249                                 ucb1x00_ts_event_release(ts);
 250                                 valid = 0;
 251                         }
 252
 253                         timeout = MAX_SCHEDULE_TIMEOUT;
 254                 } else {
 255                         ucb1x00_disable(ts->ucb);
 256
 257                         /*
 258                          * Filtering is policy.  Policy belongs in user
 259                          * space.  We therefore leave it to user space
 260                          * to do any filtering they please.
 261                          */
 262                         if (!ignore) {
 263                                 ucb1x00_ts_evt_add(ts, p, x, y);
 264                                 valid = 1;
 265                         }
 266
 267                         set_current_state(TASK_INTERRUPTIBLE);
 268                         timeout = HZ / 100;
 269                 }
 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
 343 /*
 344  * Initialisation.
 345  */
 346 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 347 {
 348         struct ucb1x00_ts *ts;
 349         struct input_dev *idev;
 350         int err;
 351
 352         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 353         idev = input_allocate_device();
 354         if (!ts || !idev) {
 355                 err = -ENOMEM;
 356                 goto fail;
 357         }
 358
 359         ts->ucb = dev->ucb;
 360         ts->idev = idev;
 361         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 362
 363         idev->name       = "Touchscreen panel";
 364         idev->id.product = ts->ucb->id;
 365         idev->open       = ucb1x00_ts_open;
 366         idev->close      = ucb1x00_ts_close;
 367
 368         idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
 369         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 370
 371         input_set_drvdata(idev, ts);
 372
 373         ucb1x00_adc_enable(ts->ucb);
 374         ts->x_res = ucb1x00_ts_read_xres(ts);
 375         ts->y_res = ucb1x00_ts_read_yres(ts);
 376         ucb1x00_adc_disable(ts->ucb);
 377
 378         input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
 379         input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
 380         input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
 381
 382         err = input_register_device(idev);
 383         if (err)
 384                 goto fail;
 385
 386         dev->priv = ts;
 387
 388         return 0;
 389
 390  fail:
 391         input_free_device(idev);
 392         kfree(ts);
 393         return err;
 394 }
 395
 396 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 397 {
 398         struct ucb1x00_ts *ts = dev->priv;
 399
 400         input_unregister_device(ts->idev);
 401         kfree(ts);
 402 }
 403
 404 static struct ucb1x00_driver ucb1x00_ts_driver = {
 405         .add            = ucb1x00_ts_add,
 406         .remove         = ucb1x00_ts_remove,
 407 };
 408
 409 static int __init ucb1x00_ts_init(void)
 410 {
 411         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 412 }
 413
 414 static void __exit ucb1x00_ts_exit(void)
 415 {
 416         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 417 }
 418
 419 module_param(adcsync, int, 0444);
 420 module_init(ucb1x00_ts_init);
 421 module_exit(ucb1x00_ts_exit);
 422
 423 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 424 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 425 MODULE_LICENSE("GPL");