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/collie.h>
  36 #include <asm/mach-types.h>
  37
  38
  39
  40 struct ucb1x00_ts {
  41         struct input_dev        *idev;
  42         struct ucb1x00          *ucb;
  43
  44         wait_queue_head_t       irq_wait;
  45         struct task_struct      *rtask;
  46         u16                     x_res;
  47         u16                     y_res;
  48
  49         unsigned int            adcsync:1;
  50 };
  51
  52 static int adcsync;
  53
  54 static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  55 {
  56         struct input_dev *idev = ts->idev;
  57
  58         input_report_abs(idev, ABS_X, x);
  59         input_report_abs(idev, ABS_Y, y);
  60         input_report_abs(idev, ABS_PRESSURE, pressure);
  61         input_report_key(idev, BTN_TOUCH, 1);
  62         input_sync(idev);
  63 }
  64
  65 static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  66 {
  67         struct input_dev *idev = ts->idev;
  68
  69         input_report_abs(idev, ABS_PRESSURE, 0);
  70         input_report_key(idev, BTN_TOUCH, 0);
  71         input_sync(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
 193         if (machine_is_collie())
 194                 return (!(val & (UCB_TS_CR_TSPX_LOW)));
 195         else
 196                 return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 197 }
 198
 199 /*
 200  * This is a RT kernel thread that handles the ADC accesses
 201  * (mainly so we can use semaphores in the UCB1200 core code
 202  * to serialise accesses to the ADC).
 203  */
 204 static int ucb1x00_thread(void *_ts)
 205 {
 206         struct ucb1x00_ts *ts = _ts;
 207         DECLARE_WAITQUEUE(wait, current);
 208         bool frozen, ignore = false;
 209         int valid = 0;
 210
 211         set_freezable();
 212         add_wait_queue(&ts->irq_wait, &wait);
 213         while (!kthread_freezable_should_stop(&frozen)) {
 214                 unsigned int x, y, p;
 215                 signed long timeout;
 216
 217                 if (frozen)
 218                         ignore = true;
 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 (!ignore) {
 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                 schedule_timeout(timeout);
 271         }
 272
 273         remove_wait_queue(&ts->irq_wait, &wait);
 274
 275         ts->rtask = NULL;
 276         return 0;
 277 }
 278
 279 /*
 280  * We only detect touch screen _touches_ with this interrupt
 281  * handler, and even then we just schedule our task.
 282  */
 283 static void ucb1x00_ts_irq(int idx, void *id)
 284 {
 285         struct ucb1x00_ts *ts = id;
 286
 287         ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
 288         wake_up(&ts->irq_wait);
 289 }
 290
 291 static int ucb1x00_ts_open(struct input_dev *idev)
 292 {
 293         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 294         int ret = 0;
 295
 296         BUG_ON(ts->rtask);
 297
 298         init_waitqueue_head(&ts->irq_wait);
 299         ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
 300         if (ret < 0)
 301                 goto out;
 302
 303         /*
 304          * If we do this at all, we should allow the user to
 305          * measure and read the X and Y resistance at any time.
 306          */
 307         ucb1x00_adc_enable(ts->ucb);
 308         ts->x_res = ucb1x00_ts_read_xres(ts);
 309         ts->y_res = ucb1x00_ts_read_yres(ts);
 310         ucb1x00_adc_disable(ts->ucb);
 311
 312         ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 313         if (!IS_ERR(ts->rtask)) {
 314                 ret = 0;
 315         } else {
 316                 ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 317                 ts->rtask = NULL;
 318                 ret = -EFAULT;
 319         }
 320
 321  out:
 322         return ret;
 323 }
 324
 325 /*
 326  * Release touchscreen resources.  Disable IRQs.
 327  */
 328 static void ucb1x00_ts_close(struct input_dev *idev)
 329 {
 330         struct ucb1x00_ts *ts = input_get_drvdata(idev);
 331
 332         if (ts->rtask)
 333                 kthread_stop(ts->rtask);
 334
 335         ucb1x00_enable(ts->ucb);
 336         ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
 337         ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 338         ucb1x00_disable(ts->ucb);
 339 }
 340
 341
 342 /*
 343  * Initialisation.
 344  */
 345 static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 346 {
 347         struct ucb1x00_ts *ts;
 348         struct input_dev *idev;
 349         int err;
 350
 351         ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 352         idev = input_allocate_device();
 353         if (!ts || !idev) {
 354                 err = -ENOMEM;
 355                 goto fail;
 356         }
 357
 358         ts->ucb = dev->ucb;
 359         ts->idev = idev;
 360         ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 361
 362         idev->name       = "Touchscreen panel";
 363         idev->id.product = ts->ucb->id;
 364         idev->open       = ucb1x00_ts_open;
 365         idev->close      = ucb1x00_ts_close;
 366
 367         idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
 368         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 369
 370         input_set_drvdata(idev, ts);
 371
 372         ucb1x00_adc_enable(ts->ucb);
 373         ts->x_res = ucb1x00_ts_read_xres(ts);
 374         ts->y_res = ucb1x00_ts_read_yres(ts);
 375         ucb1x00_adc_disable(ts->ucb);
 376
 377         input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
 378         input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
 379         input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
 380
 381         err = input_register_device(idev);
 382         if (err)
 383                 goto fail;
 384
 385         dev->priv = ts;
 386
 387         return 0;
 388
 389  fail:
 390         input_free_device(idev);
 391         kfree(ts);
 392         return err;
 393 }
 394
 395 static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 396 {
 397         struct ucb1x00_ts *ts = dev->priv;
 398
 399         input_unregister_device(ts->idev);
 400         kfree(ts);
 401 }
 402
 403 static struct ucb1x00_driver ucb1x00_ts_driver = {
 404         .add            = ucb1x00_ts_add,
 405         .remove         = ucb1x00_ts_remove,
 406 };
 407
 408 static int __init ucb1x00_ts_init(void)
 409 {
 410         return ucb1x00_register_driver(&ucb1x00_ts_driver);
 411 }
 412
 413 static void __exit ucb1x00_ts_exit(void)
 414 {
 415         ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 416 }
 417
 418 module_param(adcsync, int, 0444);
 419 module_init(ucb1x00_ts_init);
 420 module_exit(ucb1x00_ts_exit);
 421
 422 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 423 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 424 MODULE_LICENSE("GPL");