linux/drivers/mfd/ucb1x00-ts.c
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   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
  34#include <asm/dma.h>
  35#include <mach/collie.h>
  36#include <asm/mach-types.h>
  37
  38#include "ucb1x00.h"
  39
  40
  41struct 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
  54static int adcsync;
  55
  56static 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_sync(idev);
  64}
  65
  66static 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_sync(idev);
  72}
  73
  74/*
  75 * Switch to interrupt mode.
  76 */
  77static 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 */
  89static 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 */
 116static 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 */
 143static 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 */
 169static 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 */
 181static 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
 189static 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 */
 204static int ucb1x00_thread(void *_ts)
 205{
 206        struct ucb1x00_ts *ts = _ts;
 207        DECLARE_WAITQUEUE(wait, current);
 208        int valid = 0;
 209
 210        set_freezable();
 211        add_wait_queue(&ts->irq_wait, &wait);
 212        while (!kthread_should_stop()) {
 213                unsigned int x, y, p;
 214                signed long timeout;
 215
 216                ts->restart = 0;
 217
 218                ucb1x00_adc_enable(ts->ucb);
 219
 220                x = ucb1x00_ts_read_xpos(ts);
 221                y = ucb1x00_ts_read_ypos(ts);
 222                p = ucb1x00_ts_read_pressure(ts);
 223
 224                /*
 225                 * Switch back to interrupt mode.
 226                 */
 227                ucb1x00_ts_mode_int(ts);
 228                ucb1x00_adc_disable(ts->ucb);
 229
 230                msleep(10);
 231
 232                ucb1x00_enable(ts->ucb);
 233
 234
 235                if (ucb1x00_ts_pen_down(ts)) {
 236                        set_current_state(TASK_INTERRUPTIBLE);
 237
 238                        ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, machine_is_collie() ? UCB_RISING : UCB_FALLING);
 239                        ucb1x00_disable(ts->ucb);
 240
 241                        /*
 242                         * If we spat out a valid sample set last time,
 243                         * spit out a "pen off" sample here.
 244                         */
 245                        if (valid) {
 246                                ucb1x00_ts_event_release(ts);
 247                                valid = 0;
 248                        }
 249
 250                        timeout = MAX_SCHEDULE_TIMEOUT;
 251                } else {
 252                        ucb1x00_disable(ts->ucb);
 253
 254                        /*
 255                         * Filtering is policy.  Policy belongs in user
 256                         * space.  We therefore leave it to user space
 257                         * to do any filtering they please.
 258                         */
 259                        if (!ts->restart) {
 260                                ucb1x00_ts_evt_add(ts, p, x, y);
 261                                valid = 1;
 262                        }
 263
 264                        set_current_state(TASK_INTERRUPTIBLE);
 265                        timeout = HZ / 100;
 266                }
 267
 268                try_to_freeze();
 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 */
 283static 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
 291static 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 */
 328static 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#ifdef CONFIG_PM
 342static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
 343{
 344        struct ucb1x00_ts *ts = dev->priv;
 345
 346        if (ts->rtask != NULL) {
 347                /*
 348                 * Restart the TS thread to ensure the
 349                 * TS interrupt mode is set up again
 350                 * after sleep.
 351                 */
 352                ts->restart = 1;
 353                wake_up(&ts->irq_wait);
 354        }
 355        return 0;
 356}
 357#else
 358#define ucb1x00_ts_resume NULL
 359#endif
 360
 361
 362/*
 363 * Initialisation.
 364 */
 365static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
 366{
 367        struct ucb1x00_ts *ts;
 368        struct input_dev *idev;
 369        int err;
 370
 371        ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
 372        idev = input_allocate_device();
 373        if (!ts || !idev) {
 374                err = -ENOMEM;
 375                goto fail;
 376        }
 377
 378        ts->ucb = dev->ucb;
 379        ts->idev = idev;
 380        ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
 381
 382        idev->name       = "Touchscreen panel";
 383        idev->id.product = ts->ucb->id;
 384        idev->open       = ucb1x00_ts_open;
 385        idev->close      = ucb1x00_ts_close;
 386
 387        __set_bit(EV_ABS, idev->evbit);
 388        __set_bit(ABS_X, idev->absbit);
 389        __set_bit(ABS_Y, idev->absbit);
 390        __set_bit(ABS_PRESSURE, idev->absbit);
 391
 392        input_set_drvdata(idev, ts);
 393
 394        err = input_register_device(idev);
 395        if (err)
 396                goto fail;
 397
 398        dev->priv = ts;
 399
 400        return 0;
 401
 402 fail:
 403        input_free_device(idev);
 404        kfree(ts);
 405        return err;
 406}
 407
 408static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 409{
 410        struct ucb1x00_ts *ts = dev->priv;
 411
 412        input_unregister_device(ts->idev);
 413        kfree(ts);
 414}
 415
 416static struct ucb1x00_driver ucb1x00_ts_driver = {
 417        .add            = ucb1x00_ts_add,
 418        .remove         = ucb1x00_ts_remove,
 419        .resume         = ucb1x00_ts_resume,
 420};
 421
 422static int __init ucb1x00_ts_init(void)
 423{
 424        return ucb1x00_register_driver(&ucb1x00_ts_driver);
 425}
 426
 427static void __exit ucb1x00_ts_exit(void)
 428{
 429        ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 430}
 431
 432module_param(adcsync, int, 0444);
 433module_init(ucb1x00_ts_init);
 434module_exit(ucb1x00_ts_exit);
 435
 436MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 437MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 438MODULE_LICENSE("GPL");
 439