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#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
  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_report_key(idev, BTN_TOUCH, 1);
  64        input_sync(idev);
  65}
  66
  67static 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 */
  79static 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 */
  91static 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 */
 118static 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 */
 145static 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 */
 171static 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 */
 183static 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
 191static 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 */
 206static 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 */
 285static 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
 293static 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 */
 330static 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
 344static 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 */
 367static 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
 417static 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
 425static struct ucb1x00_driver ucb1x00_ts_driver = {
 426        .add            = ucb1x00_ts_add,
 427        .remove         = ucb1x00_ts_remove,
 428        .resume         = ucb1x00_ts_resume,
 429};
 430
 431static int __init ucb1x00_ts_init(void)
 432{
 433        return ucb1x00_register_driver(&ucb1x00_ts_driver);
 434}
 435
 436static void __exit ucb1x00_ts_exit(void)
 437{
 438        ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 439}
 440
 441module_param(adcsync, int, 0444);
 442module_init(ucb1x00_ts_init);
 443module_exit(ucb1x00_ts_exit);
 444
 445MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 446MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 447MODULE_LICENSE("GPL");
 448