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_rw = true,
  72 };
  73 EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
  74
  75 struct tsc200x_data {
  76         u16 x;
  77         u16 y;
  78         u16 z1;
  79         u16 z2;
  80 } __packed;
  81 #define TSC200X_DATA_REGS 4
  82
  83 struct 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
 120 static 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
 143 static 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;
 201 out:
 202         return IRQ_HANDLED;
 203 }
 204
 205 static 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
 215 static 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
 223 static void tsc200x_stop_scan(struct tsc200x *ts)
 224 {
 225         ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
 226 }
 227
 228 static 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 */
 238 static 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 */
 251 static 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
 263 static 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
 332 out:
 333         __tsc200x_enable(ts);
 334         mutex_unlock(&ts->mutex);
 335
 336         return sprintf(buf, "%d\n", success);
 337 }
 338
 339 static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
 340
 341 static struct attribute *tsc200x_attrs[] = {
 342         &dev_attr_selftest.attr,
 343         NULL
 344 };
 345
 346 static 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
 361 static const struct attribute_group tsc200x_attr_group = {
 362         .is_visible     = tsc200x_attr_is_visible,
 363         .attrs          = tsc200x_attrs,
 364 };
 365
 366 static 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
 409 out:
 410         mutex_unlock(&ts->mutex);
 411 reschedule:
 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
 418 static 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
 434 static 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
 448 int 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
 580 err_remove_sysfs:
 581         sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
 582 disable_regulator:
 583         regulator_disable(ts->vio);
 584         return error;
 585 }
 586 EXPORT_SYMBOL_GPL(tsc200x_probe);
 587
 588 int 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 }
 598 EXPORT_SYMBOL_GPL(tsc200x_remove);
 599
 600 static 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
 616 static 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
 632 SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
 633 EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
 634
 635 MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
 636 MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
 637 MODULE_LICENSE("GPL");