drivers/input/touchscreen/tsc200x-core.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * TSC2004/TSC2005 touchscreen driver core
   4  *
   5  * Copyright (C) 2006-2010 Nokia Corporation
   6  * Copyright (C) 2015 QWERTY Embedded Design
   7  * Copyright (C) 2015 EMAC Inc.
   8  *
   9  * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
  10  * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/input.h>
  16 #include <linux/input/touchscreen.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/delay.h>
  19 #include <linux/pm.h>
  20 #include <linux/of.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/regmap.h>
  23 #include <linux/gpio/consumer.h>
  24 #include "tsc200x-core.h"
  25
  26 /*
  27  * The touchscreen interface operates as follows:
  28  *
  29  * 1) Pen is pressed against the touchscreen.
  30  * 2) TSC200X performs AD conversion.
  31  * 3) After the conversion is done TSC200X drives DAV line down.
  32  * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
  33  * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
  34  *    values.
  35  * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
  36  *    tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
  37  * 7) When the penup timer expires, there have not been touch or DAV interrupts
  38  *    during the last 40ms which means the pen has been lifted.
  39  *
  40  * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
  41  * after a configurable period (in ms) of activity. If esd_timeout is 0, the
  42  * watchdog is disabled.
  43  */
  44
  45 static const struct regmap_range tsc200x_writable_ranges[] = {
  46         regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
  47 };
  48
  49 static const struct regmap_access_table tsc200x_writable_table = {
  50         .yes_ranges = tsc200x_writable_ranges,
  51         .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
  52 };
  53
  54 const struct regmap_config tsc200x_regmap_config = {
  55         .reg_bits = 8,
  56         .val_bits = 16,
  57         .reg_stride = 0x08,
  58         .max_register = 0x78,
  59         .read_flag_mask = TSC200X_REG_READ,
  60         .write_flag_mask = TSC200X_REG_PND0,
  61         .wr_table = &tsc200x_writable_table,
  62         .use_single_read = true,
  63         .use_single_write = true,
  64 };
  65 EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
  66
  67 struct tsc200x_data {
  68         u16 x;
  69         u16 y;
  70         u16 z1;
  71         u16 z2;
  72 } __packed;
  73 #define TSC200X_DATA_REGS 4
  74
  75 struct tsc200x {
  76         struct device           *dev;
  77         struct regmap           *regmap;
  78         __u16                   bustype;
  79
  80         struct input_dev        *idev;
  81         char                    phys[32];
  82
  83         struct mutex            mutex;
  84
  85         /* raw copy of previous x,y,z */
  86         int                     in_x;
  87         int                     in_y;
  88         int                     in_z1;
  89         int                     in_z2;
  90
  91         struct touchscreen_properties prop;
  92
  93         spinlock_t              lock;
  94         struct timer_list       penup_timer;
  95
  96         unsigned int            esd_timeout;
  97         struct delayed_work     esd_work;
  98         unsigned long           last_valid_interrupt;
  99
 100         unsigned int            x_plate_ohm;
 101
 102         bool                    opened;
 103         bool                    suspended;
 104
 105         bool                    pen_down;
 106
 107         struct regulator        *vio;
 108
 109         struct gpio_desc        *reset_gpio;
 110         int                     (*tsc200x_cmd)(struct device *dev, u8 cmd);
 111         int                     irq;
 112 };
 113
 114 static void tsc200x_update_pen_state(struct tsc200x *ts,
 115                                      int x, int y, int pressure)
 116 {
 117         if (pressure) {
 118                 touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
 119                 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
 120                 if (!ts->pen_down) {
 121                         input_report_key(ts->idev, BTN_TOUCH, !!pressure);
 122                         ts->pen_down = true;
 123                 }
 124         } else {
 125                 input_report_abs(ts->idev, ABS_PRESSURE, 0);
 126                 if (ts->pen_down) {
 127                         input_report_key(ts->idev, BTN_TOUCH, 0);
 128                         ts->pen_down = false;
 129                 }
 130         }
 131         input_sync(ts->idev);
 132         dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
 133                 pressure);
 134 }
 135
 136 static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
 137 {
 138         struct tsc200x *ts = _ts;
 139         unsigned long flags;
 140         unsigned int pressure;
 141         struct tsc200x_data tsdata;
 142         int error;
 143
 144         /* read the coordinates */
 145         error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
 146                                  TSC200X_DATA_REGS);
 147         if (unlikely(error))
 148                 goto out;
 149
 150         /* validate position */
 151         if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
 152                 goto out;
 153
 154         /* Skip reading if the pressure components are out of range */
 155         if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
 156                 goto out;
 157         if (unlikely(tsdata.z1 >= tsdata.z2))
 158                 goto out;
 159
 160        /*
 161         * Skip point if this is a pen down with the exact same values as
 162         * the value before pen-up - that implies SPI fed us stale data
 163         */
 164         if (!ts->pen_down &&
 165             ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
 166             ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
 167                 goto out;
 168         }
 169
 170         /*
 171          * At this point we are happy we have a valid and useful reading.
 172          * Remember it for later comparisons. We may now begin downsampling.
 173          */
 174         ts->in_x = tsdata.x;
 175         ts->in_y = tsdata.y;
 176         ts->in_z1 = tsdata.z1;
 177         ts->in_z2 = tsdata.z2;
 178
 179         /* Compute touch pressure resistance using equation #1 */
 180         pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
 181         pressure = pressure * ts->x_plate_ohm / 4096;
 182         if (unlikely(pressure > MAX_12BIT))
 183                 goto out;
 184
 185         spin_lock_irqsave(&ts->lock, flags);
 186
 187         tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
 188         mod_timer(&ts->penup_timer,
 189                   jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
 190
 191         spin_unlock_irqrestore(&ts->lock, flags);
 192
 193         ts->last_valid_interrupt = jiffies;
 194 out:
 195         return IRQ_HANDLED;
 196 }
 197
 198 static void tsc200x_penup_timer(struct timer_list *t)
 199 {
 200         struct tsc200x *ts = from_timer(ts, t, penup_timer);
 201         unsigned long flags;
 202
 203         spin_lock_irqsave(&ts->lock, flags);
 204         tsc200x_update_pen_state(ts, 0, 0, 0);
 205         spin_unlock_irqrestore(&ts->lock, flags);
 206 }
 207
 208 static void tsc200x_start_scan(struct tsc200x *ts)
 209 {
 210         regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
 211         regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
 212         regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
 213         ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
 214 }
 215
 216 static void tsc200x_stop_scan(struct tsc200x *ts)
 217 {
 218         ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
 219 }
 220
 221 static void tsc200x_reset(struct tsc200x *ts)
 222 {
 223         if (ts->reset_gpio) {
 224                 gpiod_set_value_cansleep(ts->reset_gpio, 1);
 225                 usleep_range(100, 500); /* only 10us required */
 226                 gpiod_set_value_cansleep(ts->reset_gpio, 0);
 227         }
 228 }
 229
 230 /* must be called with ts->mutex held */
 231 static void __tsc200x_disable(struct tsc200x *ts)
 232 {
 233         tsc200x_stop_scan(ts);
 234
 235         disable_irq(ts->irq);
 236         del_timer_sync(&ts->penup_timer);
 237
 238         cancel_delayed_work_sync(&ts->esd_work);
 239
 240         enable_irq(ts->irq);
 241 }
 242
 243 /* must be called with ts->mutex held */
 244 static void __tsc200x_enable(struct tsc200x *ts)
 245 {
 246         tsc200x_start_scan(ts);
 247
 248         if (ts->esd_timeout && ts->reset_gpio) {
 249                 ts->last_valid_interrupt = jiffies;
 250                 schedule_delayed_work(&ts->esd_work,
 251                                 round_jiffies_relative(
 252                                         msecs_to_jiffies(ts->esd_timeout)));
 253         }
 254 }
 255
 256 static ssize_t tsc200x_selftest_show(struct device *dev,
 257                                      struct device_attribute *attr,
 258                                      char *buf)
 259 {
 260         struct tsc200x *ts = dev_get_drvdata(dev);
 261         unsigned int temp_high;
 262         unsigned int temp_high_orig;
 263         unsigned int temp_high_test;
 264         bool success = true;
 265         int error;
 266
 267         mutex_lock(&ts->mutex);
 268
 269         /*
 270          * Test TSC200X communications via temp high register.
 271          */
 272         __tsc200x_disable(ts);
 273
 274         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
 275         if (error) {
 276                 dev_warn(dev, "selftest failed: read error %d\n", error);
 277                 success = false;
 278                 goto out;
 279         }
 280
 281         temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
 282
 283         error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
 284         if (error) {
 285                 dev_warn(dev, "selftest failed: write error %d\n", error);
 286                 success = false;
 287                 goto out;
 288         }
 289
 290         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 291         if (error) {
 292                 dev_warn(dev, "selftest failed: read error %d after write\n",
 293                          error);
 294                 success = false;
 295                 goto out;
 296         }
 297
 298         if (temp_high != temp_high_test) {
 299                 dev_warn(dev, "selftest failed: %d != %d\n",
 300                          temp_high, temp_high_test);
 301                 success = false;
 302         }
 303
 304         /* hardware reset */
 305         tsc200x_reset(ts);
 306
 307         if (!success)
 308                 goto out;
 309
 310         /* test that the reset really happened */
 311         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 312         if (error) {
 313                 dev_warn(dev, "selftest failed: read error %d after reset\n",
 314                          error);
 315                 success = false;
 316                 goto out;
 317         }
 318
 319         if (temp_high != temp_high_orig) {
 320                 dev_warn(dev, "selftest failed after reset: %d != %d\n",
 321                          temp_high, temp_high_orig);
 322                 success = false;
 323         }
 324
 325 out:
 326         __tsc200x_enable(ts);
 327         mutex_unlock(&ts->mutex);
 328
 329         return sprintf(buf, "%d\n", success);
 330 }
 331
 332 static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
 333
 334 static struct attribute *tsc200x_attrs[] = {
 335         &dev_attr_selftest.attr,
 336         NULL
 337 };
 338
 339 static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
 340                                       struct attribute *attr, int n)
 341 {
 342         struct device *dev = kobj_to_dev(kobj);
 343         struct tsc200x *ts = dev_get_drvdata(dev);
 344         umode_t mode = attr->mode;
 345
 346         if (attr == &dev_attr_selftest.attr) {
 347                 if (!ts->reset_gpio)
 348                         mode = 0;
 349         }
 350
 351         return mode;
 352 }
 353
 354 static const struct attribute_group tsc200x_attr_group = {
 355         .is_visible     = tsc200x_attr_is_visible,
 356         .attrs          = tsc200x_attrs,
 357 };
 358
 359 const struct attribute_group *tsc200x_groups[] = {
 360         &tsc200x_attr_group,
 361         NULL
 362 };
 363 EXPORT_SYMBOL_GPL(tsc200x_groups);
 364
 365 static void tsc200x_esd_work(struct work_struct *work)
 366 {
 367         struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
 368         int error;
 369         unsigned int r;
 370
 371         if (!mutex_trylock(&ts->mutex)) {
 372                 /*
 373                  * If the mutex is taken, it means that disable or enable is in
 374                  * progress. In that case just reschedule the work. If the work
 375                  * is not needed, it will be canceled by disable.
 376                  */
 377                 goto reschedule;
 378         }
 379
 380         if (time_is_after_jiffies(ts->last_valid_interrupt +
 381                                   msecs_to_jiffies(ts->esd_timeout)))
 382                 goto out;
 383
 384         /* We should be able to read register without disabling interrupts. */
 385         error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
 386         if (!error &&
 387             !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
 388                 goto out;
 389         }
 390
 391         /*
 392          * If we could not read our known value from configuration register 0
 393          * then we should reset the controller as if from power-up and start
 394          * scanning again.
 395          */
 396         dev_info(ts->dev, "TSC200X not responding - resetting\n");
 397
 398         disable_irq(ts->irq);
 399         del_timer_sync(&ts->penup_timer);
 400
 401         tsc200x_update_pen_state(ts, 0, 0, 0);
 402
 403         tsc200x_reset(ts);
 404
 405         enable_irq(ts->irq);
 406         tsc200x_start_scan(ts);
 407
 408 out:
 409         mutex_unlock(&ts->mutex);
 410 reschedule:
 411         /* re-arm the watchdog */
 412         schedule_delayed_work(&ts->esd_work,
 413                               round_jiffies_relative(
 414                                         msecs_to_jiffies(ts->esd_timeout)));
 415 }
 416
 417 static int tsc200x_open(struct input_dev *input)
 418 {
 419         struct tsc200x *ts = input_get_drvdata(input);
 420
 421         mutex_lock(&ts->mutex);
 422
 423         if (!ts->suspended)
 424                 __tsc200x_enable(ts);
 425
 426         ts->opened = true;
 427
 428         mutex_unlock(&ts->mutex);
 429
 430         return 0;
 431 }
 432
 433 static void tsc200x_close(struct input_dev *input)
 434 {
 435         struct tsc200x *ts = input_get_drvdata(input);
 436
 437         mutex_lock(&ts->mutex);
 438
 439         if (!ts->suspended)
 440                 __tsc200x_disable(ts);
 441
 442         ts->opened = false;
 443
 444         mutex_unlock(&ts->mutex);
 445 }
 446
 447 int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
 448                   struct regmap *regmap,
 449                   int (*tsc200x_cmd)(struct device *dev, u8 cmd))
 450 {
 451         struct tsc200x *ts;
 452         struct input_dev *input_dev;
 453         u32 x_plate_ohm;
 454         u32 esd_timeout;
 455         int error;
 456
 457         if (irq <= 0) {
 458                 dev_err(dev, "no irq\n");
 459                 return -ENODEV;
 460         }
 461
 462         if (IS_ERR(regmap))
 463                 return PTR_ERR(regmap);
 464
 465         if (!tsc200x_cmd) {
 466                 dev_err(dev, "no cmd function\n");
 467                 return -ENODEV;
 468         }
 469
 470         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 471         if (!ts)
 472                 return -ENOMEM;
 473
 474         input_dev = devm_input_allocate_device(dev);
 475         if (!input_dev)
 476                 return -ENOMEM;
 477
 478         ts->irq = irq;
 479         ts->dev = dev;
 480         ts->idev = input_dev;
 481         ts->regmap = regmap;
 482         ts->tsc200x_cmd = tsc200x_cmd;
 483
 484         error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
 485         ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
 486
 487         error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
 488                                          &esd_timeout);
 489         ts->esd_timeout = error ? 0 : esd_timeout;
 490
 491         ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 492         if (IS_ERR(ts->reset_gpio)) {
 493                 error = PTR_ERR(ts->reset_gpio);
 494                 dev_err(dev, "error acquiring reset gpio: %d\n", error);
 495                 return error;
 496         }
 497
 498         ts->vio = devm_regulator_get(dev, "vio");
 499         if (IS_ERR(ts->vio)) {
 500                 error = PTR_ERR(ts->vio);
 501                 dev_err(dev, "error acquiring vio regulator: %d", error);
 502                 return error;
 503         }
 504
 505         mutex_init(&ts->mutex);
 506
 507         spin_lock_init(&ts->lock);
 508         timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
 509
 510         INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
 511
 512         snprintf(ts->phys, sizeof(ts->phys),
 513                  "%s/input-ts", dev_name(dev));
 514
 515         if (tsc_id->product == 2004) {
 516                 input_dev->name = "TSC200X touchscreen";
 517         } else {
 518                 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
 519                                                  "TSC%04d touchscreen",
 520                                                  tsc_id->product);
 521                 if (!input_dev->name)
 522                         return -ENOMEM;
 523         }
 524
 525         input_dev->phys = ts->phys;
 526         input_dev->id = *tsc_id;
 527
 528         input_dev->open = tsc200x_open;
 529         input_dev->close = tsc200x_close;
 530
 531         input_set_drvdata(input_dev, ts);
 532
 533         __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
 534         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 535
 536         input_set_abs_params(input_dev, ABS_X,
 537                              0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
 538         input_set_abs_params(input_dev, ABS_Y,
 539                              0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
 540         input_set_abs_params(input_dev, ABS_PRESSURE,
 541                              0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
 542
 543         touchscreen_parse_properties(input_dev, false, &ts->prop);
 544
 545         /* Ensure the touchscreen is off */
 546         tsc200x_stop_scan(ts);
 547
 548         error = devm_request_threaded_irq(dev, irq, NULL,
 549                                           tsc200x_irq_thread,
 550                                           IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 551                                           "tsc200x", ts);
 552         if (error) {
 553                 dev_err(dev, "Failed to request irq, err: %d\n", error);
 554                 return error;
 555         }
 556
 557         error = regulator_enable(ts->vio);
 558         if (error)
 559                 return error;
 560
 561         dev_set_drvdata(dev, ts);
 562
 563         error = input_register_device(ts->idev);
 564         if (error) {
 565                 dev_err(dev,
 566                         "Failed to register input device, err: %d\n", error);
 567                 goto disable_regulator;
 568         }
 569
 570         irq_set_irq_wake(irq, 1);
 571         return 0;
 572
 573 disable_regulator:
 574         regulator_disable(ts->vio);
 575         return error;
 576 }
 577 EXPORT_SYMBOL_GPL(tsc200x_probe);
 578
 579 void tsc200x_remove(struct device *dev)
 580 {
 581         struct tsc200x *ts = dev_get_drvdata(dev);
 582
 583         regulator_disable(ts->vio);
 584 }
 585 EXPORT_SYMBOL_GPL(tsc200x_remove);
 586
 587 static int tsc200x_suspend(struct device *dev)
 588 {
 589         struct tsc200x *ts = dev_get_drvdata(dev);
 590
 591         mutex_lock(&ts->mutex);
 592
 593         if (!ts->suspended && ts->opened)
 594                 __tsc200x_disable(ts);
 595
 596         ts->suspended = true;
 597
 598         mutex_unlock(&ts->mutex);
 599
 600         return 0;
 601 }
 602
 603 static int tsc200x_resume(struct device *dev)
 604 {
 605         struct tsc200x *ts = dev_get_drvdata(dev);
 606
 607         mutex_lock(&ts->mutex);
 608
 609         if (ts->suspended && ts->opened)
 610                 __tsc200x_enable(ts);
 611
 612         ts->suspended = false;
 613
 614         mutex_unlock(&ts->mutex);
 615
 616         return 0;
 617 }
 618
 619 EXPORT_GPL_SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
 620
 621 MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
 622 MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
 623 MODULE_LICENSE("GPL");