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            restart:1;
  51         unsigned int            adcsync:1;
  52 };
  53
  54 static int adcsync;
  55
  56 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  57 {
  58         struct input_dev *idev = ts->idev;
  59
  60         input_report_abs(idev, ABS_X, x);
  61         input_report_abs(idev, ABS_Y, y);
  62         input_report_abs(idev, ABS_PRESSURE, pressure);
  63         input_report_key(idev, BTN_TOUCH, 1);
  64         input_sync(idev);
  65 }
  66
  67 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  68 {
  69         struct input_dev *idev = ts->idev;
  70
  71         input_report_abs(idev, ABS_PRESSURE, 0);
  72         input_report_key(idev, BTN_TOUCH, 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         DECLARE_WAITQUEUE(wait, current);
 210         int valid = 0;
 211
 212         set_freezable();
 213         add_wait_queue(&ts->irq_wait, &wait);
 214         while (!kthread_should_stop()) {
 215                 unsigned int x, y, p;
 216                 signed long timeout;
 217
 218                 ts->restart = 0;
 219
 220                 ucb1x00_adc_enable(ts->ucb);
 221
 222                 x = ucb1x00_ts_read_xpos(ts);
 223                 y = ucb1x00_ts_read_ypos(ts);
 224                 p = ucb1x00_ts_read_pressure(ts);
 225
 226                 /*
 227                  * Switch back to interrupt mode.
 228                  */
 229                 ucb1x00_ts_mode_int(ts);
 230                 ucb1x00_adc_disable(ts->ucb);
 231
 232                 msleep(10);
 233
 234                 ucb1x00_enable(ts->ucb);
 235
 236
 237                 if (ucb1x00_ts_pen_down(ts)) {
 238                         set_current_state(TASK_INTERRUPTIBLE);
 239
 240                         ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 241                         ucb1x00_disable(ts->ucb);
 242
 243                         /*
 244                          * If we spat out a valid sample set last time,
 245                          * spit out a "pen off" sample here.
 246                          */
 247                         if (valid) {
 248                                 ucb1x00_ts_event_release(ts);
 249                                 valid = 0;
 250                         }
 251
 252                         timeout = MAX_SCHEDULE_TIMEOUT;
 253                 } else {
 254                         ucb1x00_disable(ts->ucb);
 255
 256                         /*
 257                          * Filtering is policy.  Policy belongs in user
 258                          * space.  We therefore leave it to user space
 259                          * to do any filtering they please.
 260                          */
 261                         if (!ts->restart) {
 262                                 ucb1x00_ts_evt_add(ts, p, x, y);
 263                                 valid = 1;
 264                         }
 265
 266                         set_current_state(TASK_INTERRUPTIBLE);
 267                         timeout = HZ / 100;
 268                 }
 269
 270                 try_to_freeze();
 271
 272                 schedule_timeout(timeout);
 273         }
 274
 275         remove_wait_queue(&ts->irq_wait, &wait);
 276
 277         ts->rtask = NULL;
 278         return 0;
 279 }
 280
 281 /*
 282  * We only detect touch screen _touches_ with this interrupt
 283  * handler, and even then we just schedule our task.
 284  */
 285 static void ucb1x00_ts_irq(int idx, void *id)
 286 {
 287         struct ucb1x00_ts *ts = id;
 288
 289         ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 290         wake_up(&ts->irq_wait);
 291 }
 292
 293 static int ucb1x00_ts_open(struct input_dev *idev)
 294 {
 295         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 296         int ret = 0;
 297
 298         BUG_ON(ts->rtask);
 299
 300         init_waitqueue_head(&ts->irq_wait);
 301         ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 302         if (ret < 0)
 303                 goto out;
 304
 305         /*
 306          * If we do this at all, we should allow the user to
 307          * measure and read the X and Y resistance at any time.
 308          */
 309         ucb1x00_adc_enable(ts->ucb);
 310         ts->x_res = ucb1x00_ts_read_xres(ts);
 311         ts->y_res = ucb1x00_ts_read_yres(ts);
 312         ucb1x00_adc_disable(ts->ucb);
 313
 314         ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 315         if (!IS_ERR(ts->rtask)) {
 316                 ret = 0;
 317         } else {
 318                 ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 319                 ts->rtask = NULL;
 320                 ret = -EFAULT;
 321         }
 322
 323  out:
 324         return ret;
 325 }
 326
 327 /*
 328  * Release touchscreen resources.  Disable IRQs.
 329  */
 330 static void ucb1x00_ts_close(struct input_dev *idev)
 331 {
 332         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 333
 334         if (ts->rtask)
 335                 kthread_stop(ts->rtask);
 336
 337         ucb1x00_enable(ts->ucb);
 338         ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 339         ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 340         ucb1x00_disable(ts->ucb);
 341 }
 342
 343 #ifdef CONFIG_PM
 344 static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 345 {
 346         struct ucb1x00_ts *ts = dev->priv;
 347
 348         if (ts->rtask != NULL) {
 349                 /*
 350                  * Restart the TS thread to ensure the
 351                  * TS interrupt mode is set up again
 352                  * after sleep.
 353                  */
 354                 ts->restart = 1;
 355                 wake_up(&ts->irq_wait);
 356         }
 357         return 0;
 358 }
 359 #else
 360 #define ucb1x00_ts_resume NULL
 361 #endif
 362
 363
 364 /*
 365  * Initialisation.
 366  */
 367 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 368 {
 369         struct ucb1x00_ts *ts;
 370         struct input_dev *idev;
 371         int err;
 372
 373         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 374         idev = input_allocate_device();
 375         if (!ts || !idev) {
 376                 err = -ENOMEM;
 377                 goto fail;
 378         }
 379
 380         ts->ucb = dev->ucb;
 381         ts->idev = idev;
 382         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 383
 384         idev->name       = "Touchscreen panel";
 385         idev->id.product = ts->ucb->id;
 386         idev->open       = ucb1x00_ts_open;
 387         idev->close      = ucb1x00_ts_close;
 388
 389         idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
 390         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 391
 392         input_set_drvdata(idev, ts);
 393
 394         ucb1x00_adc_enable(ts->ucb);
 395         ts->x_res = ucb1x00_ts_read_xres(ts);
 396         ts->y_res = ucb1x00_ts_read_yres(ts);
 397         ucb1x00_adc_disable(ts->ucb);
 398
 399         input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
 400         input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
 401         input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
 402
 403         err = input_register_device(idev);
 404         if (err)
 405                 goto fail;
 406
 407         dev->priv = ts;
 408
 409         return 0;
 410
 411  fail:
 412         input_free_device(idev);
 413         kfree(ts);
 414         return err;
 415 }
 416
 417 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 418 {
 419         struct ucb1x00_ts *ts = dev->priv;
 420
 421         input_unregister_device(ts->idev);
 422         kfree(ts);
 423 }
 424
 425 static struct ucb1x00_driver ucb1x00_ts_driver = {
 426         .add            = ucb1x00_ts_add,
 427         .remove         = ucb1x00_ts_remove,
 428         .resume         = ucb1x00_ts_resume,
 429 };
 430
 431 static int __init ucb1x00_ts_init(void)
 432 {
 433         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 434 }
 435
 436 static void __exit ucb1x00_ts_exit(void)
 437 {
 438         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 439 }
 440
 441 module_param(adcsync, int, 0444);
 442 module_init(ucb1x00_ts_init);
 443 module_exit(ucb1x00_ts_exit);
 444
 445 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 446 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 447 MODULE_LICENSE("GPL");