linux/drivers/input/touchscreen/tsc200x-core.c
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   1/*
   2 * TSC2004/TSC2005 touchscreen driver core
   3 *
   4 * Copyright (C) 2006-2010 Nokia Corporation
   5 * Copyright (C) 2015 QWERTY Embedded Design
   6 * Copyright (C) 2015 EMAC Inc.
   7 *
   8 * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
   9 * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19 * GNU General Public License for more details.
  20 */
  21
  22#include <linux/kernel.h>
  23#include <linux/module.h>
  24#include <linux/input.h>
  25#include <linux/input/touchscreen.h>
  26#include <linux/interrupt.h>
  27#include <linux/delay.h>
  28#include <linux/pm.h>
  29#include <linux/of.h>
  30#include <linux/regulator/consumer.h>
  31#include <linux/regmap.h>
  32#include <linux/gpio/consumer.h>
  33#include "tsc200x-core.h"
  34
  35/*
  36 * The touchscreen interface operates as follows:
  37 *
  38 * 1) Pen is pressed against the touchscreen.
  39 * 2) TSC200X performs AD conversion.
  40 * 3) After the conversion is done TSC200X drives DAV line down.
  41 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
  42 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
  43 *    values.
  44 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
  45 *    tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
  46 * 7) When the penup timer expires, there have not been touch or DAV interrupts
  47 *    during the last 40ms which means the pen has been lifted.
  48 *
  49 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
  50 * after a configurable period (in ms) of activity. If esd_timeout is 0, the
  51 * watchdog is disabled.
  52 */
  53
  54static const struct regmap_range tsc200x_writable_ranges[] = {
  55        regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
  56};
  57
  58static const struct regmap_access_table tsc200x_writable_table = {
  59        .yes_ranges = tsc200x_writable_ranges,
  60        .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
  61};
  62
  63const struct regmap_config tsc200x_regmap_config = {
  64        .reg_bits = 8,
  65        .val_bits = 16,
  66        .reg_stride = 0x08,
  67        .max_register = 0x78,
  68        .read_flag_mask = TSC200X_REG_READ,
  69        .write_flag_mask = TSC200X_REG_PND0,
  70        .wr_table = &tsc200x_writable_table,
  71        .use_single_rw = true,
  72};
  73EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
  74
  75struct tsc200x_data {
  76        u16 x;
  77        u16 y;
  78        u16 z1;
  79        u16 z2;
  80} __packed;
  81#define TSC200X_DATA_REGS 4
  82
  83struct tsc200x {
  84        struct device           *dev;
  85        struct regmap           *regmap;
  86        __u16                   bustype;
  87
  88        struct input_dev        *idev;
  89        char                    phys[32];
  90
  91        struct mutex            mutex;
  92
  93        /* raw copy of previous x,y,z */
  94        int                     in_x;
  95        int                     in_y;
  96        int                     in_z1;
  97        int                     in_z2;
  98
  99        spinlock_t              lock;
 100        struct timer_list       penup_timer;
 101
 102        unsigned int            esd_timeout;
 103        struct delayed_work     esd_work;
 104        unsigned long           last_valid_interrupt;
 105
 106        unsigned int            x_plate_ohm;
 107
 108        bool                    opened;
 109        bool                    suspended;
 110
 111        bool                    pen_down;
 112
 113        struct regulator        *vio;
 114
 115        struct gpio_desc        *reset_gpio;
 116        int                     (*tsc200x_cmd)(struct device *dev, u8 cmd);
 117        int                     irq;
 118};
 119
 120static void tsc200x_update_pen_state(struct tsc200x *ts,
 121                                     int x, int y, int pressure)
 122{
 123        if (pressure) {
 124                input_report_abs(ts->idev, ABS_X, x);
 125                input_report_abs(ts->idev, ABS_Y, y);
 126                input_report_abs(ts->idev, ABS_PRESSURE, pressure);
 127                if (!ts->pen_down) {
 128                        input_report_key(ts->idev, BTN_TOUCH, !!pressure);
 129                        ts->pen_down = true;
 130                }
 131        } else {
 132                input_report_abs(ts->idev, ABS_PRESSURE, 0);
 133                if (ts->pen_down) {
 134                        input_report_key(ts->idev, BTN_TOUCH, 0);
 135                        ts->pen_down = false;
 136                }
 137        }
 138        input_sync(ts->idev);
 139        dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
 140                pressure);
 141}
 142
 143static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
 144{
 145        struct tsc200x *ts = _ts;
 146        unsigned long flags;
 147        unsigned int pressure;
 148        struct tsc200x_data tsdata;
 149        int error;
 150
 151        /* read the coordinates */
 152        error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
 153                                 TSC200X_DATA_REGS);
 154        if (unlikely(error))
 155                goto out;
 156
 157        /* validate position */
 158        if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
 159                goto out;
 160
 161        /* Skip reading if the pressure components are out of range */
 162        if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
 163                goto out;
 164        if (unlikely(tsdata.z1 >= tsdata.z2))
 165                goto out;
 166
 167       /*
 168        * Skip point if this is a pen down with the exact same values as
 169        * the value before pen-up - that implies SPI fed us stale data
 170        */
 171        if (!ts->pen_down &&
 172            ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
 173            ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
 174                goto out;
 175        }
 176
 177        /*
 178         * At this point we are happy we have a valid and useful reading.
 179         * Remember it for later comparisons. We may now begin downsampling.
 180         */
 181        ts->in_x = tsdata.x;
 182        ts->in_y = tsdata.y;
 183        ts->in_z1 = tsdata.z1;
 184        ts->in_z2 = tsdata.z2;
 185
 186        /* Compute touch pressure resistance using equation #1 */
 187        pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
 188        pressure = pressure * ts->x_plate_ohm / 4096;
 189        if (unlikely(pressure > MAX_12BIT))
 190                goto out;
 191
 192        spin_lock_irqsave(&ts->lock, flags);
 193
 194        tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
 195        mod_timer(&ts->penup_timer,
 196                  jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
 197
 198        spin_unlock_irqrestore(&ts->lock, flags);
 199
 200        ts->last_valid_interrupt = jiffies;
 201out:
 202        return IRQ_HANDLED;
 203}
 204
 205static void tsc200x_penup_timer(unsigned long data)
 206{
 207        struct tsc200x *ts = (struct tsc200x *)data;
 208        unsigned long flags;
 209
 210        spin_lock_irqsave(&ts->lock, flags);
 211        tsc200x_update_pen_state(ts, 0, 0, 0);
 212        spin_unlock_irqrestore(&ts->lock, flags);
 213}
 214
 215static void tsc200x_start_scan(struct tsc200x *ts)
 216{
 217        regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
 218        regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
 219        regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
 220        ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
 221}
 222
 223static void tsc200x_stop_scan(struct tsc200x *ts)
 224{
 225        ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
 226}
 227
 228static void tsc200x_reset(struct tsc200x *ts)
 229{
 230        if (ts->reset_gpio) {
 231                gpiod_set_value_cansleep(ts->reset_gpio, 1);
 232                usleep_range(100, 500); /* only 10us required */
 233                gpiod_set_value_cansleep(ts->reset_gpio, 0);
 234        }
 235}
 236
 237/* must be called with ts->mutex held */
 238static void __tsc200x_disable(struct tsc200x *ts)
 239{
 240        tsc200x_stop_scan(ts);
 241
 242        disable_irq(ts->irq);
 243        del_timer_sync(&ts->penup_timer);
 244
 245        cancel_delayed_work_sync(&ts->esd_work);
 246
 247        enable_irq(ts->irq);
 248}
 249
 250/* must be called with ts->mutex held */
 251static void __tsc200x_enable(struct tsc200x *ts)
 252{
 253        tsc200x_start_scan(ts);
 254
 255        if (ts->esd_timeout && ts->reset_gpio) {
 256                ts->last_valid_interrupt = jiffies;
 257                schedule_delayed_work(&ts->esd_work,
 258                                round_jiffies_relative(
 259                                        msecs_to_jiffies(ts->esd_timeout)));
 260        }
 261}
 262
 263static ssize_t tsc200x_selftest_show(struct device *dev,
 264                                     struct device_attribute *attr,
 265                                     char *buf)
 266{
 267        struct tsc200x *ts = dev_get_drvdata(dev);
 268        unsigned int temp_high;
 269        unsigned int temp_high_orig;
 270        unsigned int temp_high_test;
 271        bool success = true;
 272        int error;
 273
 274        mutex_lock(&ts->mutex);
 275
 276        /*
 277         * Test TSC200X communications via temp high register.
 278         */
 279        __tsc200x_disable(ts);
 280
 281        error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
 282        if (error) {
 283                dev_warn(dev, "selftest failed: read error %d\n", error);
 284                success = false;
 285                goto out;
 286        }
 287
 288        temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
 289
 290        error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
 291        if (error) {
 292                dev_warn(dev, "selftest failed: write error %d\n", error);
 293                success = false;
 294                goto out;
 295        }
 296
 297        error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 298        if (error) {
 299                dev_warn(dev, "selftest failed: read error %d after write\n",
 300                         error);
 301                success = false;
 302                goto out;
 303        }
 304
 305        if (temp_high != temp_high_test) {
 306                dev_warn(dev, "selftest failed: %d != %d\n",
 307                         temp_high, temp_high_test);
 308                success = false;
 309        }
 310
 311        /* hardware reset */
 312        tsc200x_reset(ts);
 313
 314        if (!success)
 315                goto out;
 316
 317        /* test that the reset really happened */
 318        error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 319        if (error) {
 320                dev_warn(dev, "selftest failed: read error %d after reset\n",
 321                         error);
 322                success = false;
 323                goto out;
 324        }
 325
 326        if (temp_high != temp_high_orig) {
 327                dev_warn(dev, "selftest failed after reset: %d != %d\n",
 328                         temp_high, temp_high_orig);
 329                success = false;
 330        }
 331
 332out:
 333        __tsc200x_enable(ts);
 334        mutex_unlock(&ts->mutex);
 335
 336        return sprintf(buf, "%d\n", success);
 337}
 338
 339static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
 340
 341static struct attribute *tsc200x_attrs[] = {
 342        &dev_attr_selftest.attr,
 343        NULL
 344};
 345
 346static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
 347                                      struct attribute *attr, int n)
 348{
 349        struct device *dev = container_of(kobj, struct device, kobj);
 350        struct tsc200x *ts = dev_get_drvdata(dev);
 351        umode_t mode = attr->mode;
 352
 353        if (attr == &dev_attr_selftest.attr) {
 354                if (!ts->reset_gpio)
 355                        mode = 0;
 356        }
 357
 358        return mode;
 359}
 360
 361static const struct attribute_group tsc200x_attr_group = {
 362        .is_visible     = tsc200x_attr_is_visible,
 363        .attrs          = tsc200x_attrs,
 364};
 365
 366static void tsc200x_esd_work(struct work_struct *work)
 367{
 368        struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
 369        int error;
 370        unsigned int r;
 371
 372        if (!mutex_trylock(&ts->mutex)) {
 373                /*
 374                 * If the mutex is taken, it means that disable or enable is in
 375                 * progress. In that case just reschedule the work. If the work
 376                 * is not needed, it will be canceled by disable.
 377                 */
 378                goto reschedule;
 379        }
 380
 381        if (time_is_after_jiffies(ts->last_valid_interrupt +
 382                                  msecs_to_jiffies(ts->esd_timeout)))
 383                goto out;
 384
 385        /* We should be able to read register without disabling interrupts. */
 386        error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
 387        if (!error &&
 388            !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
 389                goto out;
 390        }
 391
 392        /*
 393         * If we could not read our known value from configuration register 0
 394         * then we should reset the controller as if from power-up and start
 395         * scanning again.
 396         */
 397        dev_info(ts->dev, "TSC200X not responding - resetting\n");
 398
 399        disable_irq(ts->irq);
 400        del_timer_sync(&ts->penup_timer);
 401
 402        tsc200x_update_pen_state(ts, 0, 0, 0);
 403
 404        tsc200x_reset(ts);
 405
 406        enable_irq(ts->irq);
 407        tsc200x_start_scan(ts);
 408
 409out:
 410        mutex_unlock(&ts->mutex);
 411reschedule:
 412        /* re-arm the watchdog */
 413        schedule_delayed_work(&ts->esd_work,
 414                              round_jiffies_relative(
 415                                        msecs_to_jiffies(ts->esd_timeout)));
 416}
 417
 418static int tsc200x_open(struct input_dev *input)
 419{
 420        struct tsc200x *ts = input_get_drvdata(input);
 421
 422        mutex_lock(&ts->mutex);
 423
 424        if (!ts->suspended)
 425                __tsc200x_enable(ts);
 426
 427        ts->opened = true;
 428
 429        mutex_unlock(&ts->mutex);
 430
 431        return 0;
 432}
 433
 434static void tsc200x_close(struct input_dev *input)
 435{
 436        struct tsc200x *ts = input_get_drvdata(input);
 437
 438        mutex_lock(&ts->mutex);
 439
 440        if (!ts->suspended)
 441                __tsc200x_disable(ts);
 442
 443        ts->opened = false;
 444
 445        mutex_unlock(&ts->mutex);
 446}
 447
 448int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
 449                  struct regmap *regmap,
 450                  int (*tsc200x_cmd)(struct device *dev, u8 cmd))
 451{
 452        struct tsc200x *ts;
 453        struct input_dev *input_dev;
 454        u32 x_plate_ohm;
 455        u32 esd_timeout;
 456        int error;
 457
 458        if (irq <= 0) {
 459                dev_err(dev, "no irq\n");
 460                return -ENODEV;
 461        }
 462
 463        if (IS_ERR(regmap))
 464                return PTR_ERR(regmap);
 465
 466        if (!tsc200x_cmd) {
 467                dev_err(dev, "no cmd function\n");
 468                return -ENODEV;
 469        }
 470
 471        ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 472        if (!ts)
 473                return -ENOMEM;
 474
 475        input_dev = devm_input_allocate_device(dev);
 476        if (!input_dev)
 477                return -ENOMEM;
 478
 479        ts->irq = irq;
 480        ts->dev = dev;
 481        ts->idev = input_dev;
 482        ts->regmap = regmap;
 483        ts->tsc200x_cmd = tsc200x_cmd;
 484
 485        error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
 486        ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
 487
 488        error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
 489                                         &esd_timeout);
 490        ts->esd_timeout = error ? 0 : esd_timeout;
 491
 492        ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 493        if (IS_ERR(ts->reset_gpio)) {
 494                error = PTR_ERR(ts->reset_gpio);
 495                dev_err(dev, "error acquiring reset gpio: %d\n", error);
 496                return error;
 497        }
 498
 499        ts->vio = devm_regulator_get(dev, "vio");
 500        if (IS_ERR(ts->vio)) {
 501                error = PTR_ERR(ts->vio);
 502                dev_err(dev, "error acquiring vio regulator: %d", error);
 503                return error;
 504        }
 505
 506        mutex_init(&ts->mutex);
 507
 508        spin_lock_init(&ts->lock);
 509        setup_timer(&ts->penup_timer, tsc200x_penup_timer, (unsigned long)ts);
 510
 511        INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
 512
 513        snprintf(ts->phys, sizeof(ts->phys),
 514                 "%s/input-ts", dev_name(dev));
 515
 516        if (tsc_id->product == 2004) {
 517                input_dev->name = "TSC200X touchscreen";
 518        } else {
 519                input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
 520                                                 "TSC%04d touchscreen",
 521                                                 tsc_id->product);
 522                if (!input_dev->name)
 523                        return -ENOMEM;
 524        }
 525
 526        input_dev->phys = ts->phys;
 527        input_dev->id = *tsc_id;
 528
 529        input_dev->open = tsc200x_open;
 530        input_dev->close = tsc200x_close;
 531
 532        input_set_drvdata(input_dev, ts);
 533
 534        __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
 535        input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 536
 537        input_set_abs_params(input_dev, ABS_X,
 538                             0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
 539        input_set_abs_params(input_dev, ABS_Y,
 540                             0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
 541        input_set_abs_params(input_dev, ABS_PRESSURE,
 542                             0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
 543
 544        touchscreen_parse_properties(input_dev, false, NULL);
 545
 546        /* Ensure the touchscreen is off */
 547        tsc200x_stop_scan(ts);
 548
 549        error = devm_request_threaded_irq(dev, irq, NULL,
 550                                          tsc200x_irq_thread,
 551                                          IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 552                                          "tsc200x", ts);
 553        if (error) {
 554                dev_err(dev, "Failed to request irq, err: %d\n", error);
 555                return error;
 556        }
 557
 558        error = regulator_enable(ts->vio);
 559        if (error)
 560                return error;
 561
 562        dev_set_drvdata(dev, ts);
 563        error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
 564        if (error) {
 565                dev_err(dev,
 566                        "Failed to create sysfs attributes, err: %d\n", error);
 567                goto disable_regulator;
 568        }
 569
 570        error = input_register_device(ts->idev);
 571        if (error) {
 572                dev_err(dev,
 573                        "Failed to register input device, err: %d\n", error);
 574                goto err_remove_sysfs;
 575        }
 576
 577        irq_set_irq_wake(irq, 1);
 578        return 0;
 579
 580err_remove_sysfs:
 581        sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
 582disable_regulator:
 583        regulator_disable(ts->vio);
 584        return error;
 585}
 586EXPORT_SYMBOL_GPL(tsc200x_probe);
 587
 588int tsc200x_remove(struct device *dev)
 589{
 590        struct tsc200x *ts = dev_get_drvdata(dev);
 591
 592        sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
 593
 594        regulator_disable(ts->vio);
 595
 596        return 0;
 597}
 598EXPORT_SYMBOL_GPL(tsc200x_remove);
 599
 600static int __maybe_unused tsc200x_suspend(struct device *dev)
 601{
 602        struct tsc200x *ts = dev_get_drvdata(dev);
 603
 604        mutex_lock(&ts->mutex);
 605
 606        if (!ts->suspended && ts->opened)
 607                __tsc200x_disable(ts);
 608
 609        ts->suspended = true;
 610
 611        mutex_unlock(&ts->mutex);
 612
 613        return 0;
 614}
 615
 616static int __maybe_unused tsc200x_resume(struct device *dev)
 617{
 618        struct tsc200x *ts = dev_get_drvdata(dev);
 619
 620        mutex_lock(&ts->mutex);
 621
 622        if (ts->suspended && ts->opened)
 623                __tsc200x_enable(ts);
 624
 625        ts->suspended = false;
 626
 627        mutex_unlock(&ts->mutex);
 628
 629        return 0;
 630}
 631
 632SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
 633EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
 634
 635MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
 636MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
 637MODULE_LICENSE("GPL");
 638