drivers/input/touchscreen/tsc200x-core.c

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