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/interrupt.h>
  24#include <linux/sched.h>
  25#include <linux/spinlock.h>
  26#include <linux/completion.h>
  27#include <linux/delay.h>
  28#include <linux/string.h>
  29#include <linux/input.h>
  30#include <linux/device.h>
  31#include <linux/freezer.h>
  32#include <linux/slab.h>
  33#include <linux/kthread.h>
  34#include <linux/mfd/ucb1x00.h>
  35
  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        spinlock_t              irq_lock;
  46        unsigned                irq_disabled;
  47        wait_queue_head_t       irq_wait;
  48        struct task_struct      *rtask;
  49        u16                     x_res;
  50        u16                     y_res;
  51
  52        unsigned int            adcsync:1;
  53};
  54
  55static int adcsync;
  56
  57static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
  58{
  59        struct input_dev *idev = ts->idev;
  60
  61        input_report_abs(idev, ABS_X, x);
  62        input_report_abs(idev, ABS_Y, y);
  63        input_report_abs(idev, ABS_PRESSURE, pressure);
  64        input_report_key(idev, BTN_TOUCH, 1);
  65        input_sync(idev);
  66}
  67
  68static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
  69{
  70        struct input_dev *idev = ts->idev;
  71
  72        input_report_abs(idev, ABS_PRESSURE, 0);
  73        input_report_key(idev, BTN_TOUCH, 0);
  74        input_sync(idev);
  75}
  76
  77/*
  78 * Switch to interrupt mode.
  79 */
  80static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
  81{
  82        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  83                        UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
  84                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
  85                        UCB_TS_CR_MODE_INT);
  86}
  87
  88/*
  89 * Switch to pressure mode, and read pressure.  We don't need to wait
  90 * here, since both plates are being driven.
  91 */
  92static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
  93{
  94        if (machine_is_collie()) {
  95                ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
  96                ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
  97                                  UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
  98                                  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
  99
 100                udelay(55);
 101
 102                return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
 103        } else {
 104                ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 105                                  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 106                                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 107                                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 108
 109                return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 110        }
 111}
 112
 113/*
 114 * Switch to X position mode and measure Y plate.  We switch the plate
 115 * configuration in pressure mode, then switch to position mode.  This
 116 * gives a faster response time.  Even so, we need to wait about 55us
 117 * for things to stabilise.
 118 */
 119static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
 120{
 121        if (machine_is_collie())
 122                ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 123        else {
 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                ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 128                                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 129                                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 130        }
 131        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 132                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 133                        UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 134
 135        udelay(55);
 136
 137        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
 138}
 139
 140/*
 141 * Switch to Y position mode and measure X plate.  We switch the plate
 142 * configuration in pressure mode, then switch to position mode.  This
 143 * gives a faster response time.  Even so, we need to wait about 55us
 144 * for things to stabilise.
 145 */
 146static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
 147{
 148        if (machine_is_collie())
 149                ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
 150        else {
 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                ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 155                                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 156                                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 157        }
 158
 159        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 160                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 161                        UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 162
 163        udelay(55);
 164
 165        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
 166}
 167
 168/*
 169 * Switch to X plate resistance mode.  Set MX to ground, PX to
 170 * supply.  Measure current.
 171 */
 172static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
 173{
 174        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 175                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
 176                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 177        return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 178}
 179
 180/*
 181 * Switch to Y plate resistance mode.  Set MY to ground, PY to
 182 * supply.  Measure current.
 183 */
 184static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
 185{
 186        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 187                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
 188                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
 189        return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
 190}
 191
 192static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
 193{
 194        unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
 195
 196        if (machine_is_collie())
 197                return (!(val & (UCB_TS_CR_TSPX_LOW)));
 198        else
 199                return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
 200}
 201
 202/*
 203 * This is a RT kernel thread that handles the ADC accesses
 204 * (mainly so we can use semaphores in the UCB1200 core code
 205 * to serialise accesses to the ADC).
 206 */
 207static int ucb1x00_thread(void *_ts)
 208{
 209        struct ucb1x00_ts *ts = _ts;
 210        DECLARE_WAITQUEUE(wait, current);
 211        bool frozen, ignore = false;
 212        int valid = 0;
 213
 214        set_freezable();
 215        add_wait_queue(&ts->irq_wait, &wait);
 216        while (!kthread_freezable_should_stop(&frozen)) {
 217                unsigned int x, y, p;
 218                signed long timeout;
 219
 220                if (frozen)
 221                        ignore = true;
 222
 223                ucb1x00_adc_enable(ts->ucb);
 224
 225                x = ucb1x00_ts_read_xpos(ts);
 226                y = ucb1x00_ts_read_ypos(ts);
 227                p = ucb1x00_ts_read_pressure(ts);
 228
 229                /*
 230                 * Switch back to interrupt mode.
 231                 */
 232                ucb1x00_ts_mode_int(ts);
 233                ucb1x00_adc_disable(ts->ucb);
 234
 235                msleep(10);
 236
 237                ucb1x00_enable(ts->ucb);
 238
 239
 240                if (ucb1x00_ts_pen_down(ts)) {
 241                        set_current_state(TASK_INTERRUPTIBLE);
 242
 243                        spin_lock_irq(&ts->irq_lock);
 244                        if (ts->irq_disabled) {
 245                                ts->irq_disabled = 0;
 246                                enable_irq(ts->ucb->irq_base + UCB_IRQ_TSPX);
 247                        }
 248                        spin_unlock_irq(&ts->irq_lock);
 249                        ucb1x00_disable(ts->ucb);
 250
 251                        /*
 252                         * If we spat out a valid sample set last time,
 253                         * spit out a "pen off" sample here.
 254                         */
 255                        if (valid) {
 256                                ucb1x00_ts_event_release(ts);
 257                                valid = 0;
 258                        }
 259
 260                        timeout = MAX_SCHEDULE_TIMEOUT;
 261                } else {
 262                        ucb1x00_disable(ts->ucb);
 263
 264                        /*
 265                         * Filtering is policy.  Policy belongs in user
 266                         * space.  We therefore leave it to user space
 267                         * to do any filtering they please.
 268                         */
 269                        if (!ignore) {
 270                                ucb1x00_ts_evt_add(ts, p, x, y);
 271                                valid = 1;
 272                        }
 273
 274                        set_current_state(TASK_INTERRUPTIBLE);
 275                        timeout = HZ / 100;
 276                }
 277
 278                schedule_timeout(timeout);
 279        }
 280
 281        remove_wait_queue(&ts->irq_wait, &wait);
 282
 283        ts->rtask = NULL;
 284        return 0;
 285}
 286
 287/*
 288 * We only detect touch screen _touches_ with this interrupt
 289 * handler, and even then we just schedule our task.
 290 */
 291static irqreturn_t ucb1x00_ts_irq(int irq, void *id)
 292{
 293        struct ucb1x00_ts *ts = id;
 294
 295        spin_lock(&ts->irq_lock);
 296        ts->irq_disabled = 1;
 297        disable_irq_nosync(ts->ucb->irq_base + UCB_IRQ_TSPX);
 298        spin_unlock(&ts->irq_lock);
 299        wake_up(&ts->irq_wait);
 300
 301        return IRQ_HANDLED;
 302}
 303
 304static int ucb1x00_ts_open(struct input_dev *idev)
 305{
 306        struct ucb1x00_ts *ts = input_get_drvdata(idev);
 307        unsigned long flags = 0;
 308        int ret = 0;
 309
 310        BUG_ON(ts->rtask);
 311
 312        if (machine_is_collie())
 313                flags = IRQF_TRIGGER_RISING;
 314        else
 315                flags = IRQF_TRIGGER_FALLING;
 316
 317        ts->irq_disabled = 0;
 318
 319        init_waitqueue_head(&ts->irq_wait);
 320        ret = request_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ucb1x00_ts_irq,
 321                          flags, "ucb1x00-ts", ts);
 322        if (ret < 0)
 323                goto out;
 324
 325        /*
 326         * If we do this at all, we should allow the user to
 327         * measure and read the X and Y resistance at any time.
 328         */
 329        ucb1x00_adc_enable(ts->ucb);
 330        ts->x_res = ucb1x00_ts_read_xres(ts);
 331        ts->y_res = ucb1x00_ts_read_yres(ts);
 332        ucb1x00_adc_disable(ts->ucb);
 333
 334        ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
 335        if (!IS_ERR(ts->rtask)) {
 336                ret = 0;
 337        } else {
 338                free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
 339                ts->rtask = NULL;
 340                ret = -EFAULT;
 341        }
 342
 343 out:
 344        return ret;
 345}
 346
 347/*
 348 * Release touchscreen resources.  Disable IRQs.
 349 */
 350static void ucb1x00_ts_close(struct input_dev *idev)
 351{
 352        struct ucb1x00_ts *ts = input_get_drvdata(idev);
 353
 354        if (ts->rtask)
 355                kthread_stop(ts->rtask);
 356
 357        ucb1x00_enable(ts->ucb);
 358        free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
 359        ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
 360        ucb1x00_disable(ts->ucb);
 361}
 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        spin_lock_init(&ts->irq_lock);
 384
 385        idev->name       = "Touchscreen panel";
 386        idev->id.product = ts->ucb->id;
 387        idev->open       = ucb1x00_ts_open;
 388        idev->close      = ucb1x00_ts_close;
 389        idev->dev.parent = &ts->ucb->dev;
 390
 391        idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
 392        idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 393
 394        input_set_drvdata(idev, ts);
 395
 396        ucb1x00_adc_enable(ts->ucb);
 397        ts->x_res = ucb1x00_ts_read_xres(ts);
 398        ts->y_res = ucb1x00_ts_read_yres(ts);
 399        ucb1x00_adc_disable(ts->ucb);
 400
 401        input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
 402        input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
 403        input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
 404
 405        err = input_register_device(idev);
 406        if (err)
 407                goto fail;
 408
 409        dev->priv = ts;
 410
 411        return 0;
 412
 413 fail:
 414        input_free_device(idev);
 415        kfree(ts);
 416        return err;
 417}
 418
 419static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
 420{
 421        struct ucb1x00_ts *ts = dev->priv;
 422
 423        input_unregister_device(ts->idev);
 424        kfree(ts);
 425}
 426
 427static struct ucb1x00_driver ucb1x00_ts_driver = {
 428        .add            = ucb1x00_ts_add,
 429        .remove         = ucb1x00_ts_remove,
 430};
 431
 432static int __init ucb1x00_ts_init(void)
 433{
 434        return ucb1x00_register_driver(&ucb1x00_ts_driver);
 435}
 436
 437static void __exit ucb1x00_ts_exit(void)
 438{
 439        ucb1x00_unregister_driver(&ucb1x00_ts_driver);
 440}
 441
 442module_param(adcsync, int, 0444);
 443module_init(ucb1x00_ts_init);
 444module_exit(ucb1x00_ts_exit);
 445
 446MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 447MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
 448MODULE_LICENSE("GPL");
 449
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