drivers/input/touchscreen/bu21029_ts.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Rohm BU21029 touchscreen controller driver
   4  *
   5  * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH
   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
  12 #include <linux/delay.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/i2c.h>
  15 #include <linux/input.h>
  16 #include <linux/input/touchscreen.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/irq.h>
  19 #include <linux/module.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <linux/timer.h>
  22
  23 /*
  24  * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only)
  25  * +--------+--------+--------+--------+--------+--------+--------+--------+
  26  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  27  * +--------+--------+--------+--------+--------+--------+--------+--------+
  28  * |                                 HW_IDH                                |
  29  * +--------+--------+--------+--------+--------+--------+--------+--------+
  30  * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only)
  31  * +--------+--------+--------+--------+--------+--------+--------+--------+
  32  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  33  * +--------+--------+--------+--------+--------+--------+--------+--------+
  34  * |                                 HW_IDL                                |
  35  * +--------+--------+--------+--------+--------+--------+--------+--------+
  36  * HW_IDH: high 8bits of IC's ID
  37  * HW_IDL: low  8bits of IC's ID
  38  */
  39 #define BU21029_HWID_REG        (0x0E << 3)
  40 #define SUPPORTED_HWID          0x0229
  41
  42 /*
  43  * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20)
  44  * +--------+--------+--------+--------+--------+--------+--------+--------+
  45  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  46  * +--------+--------+--------+--------+--------+--------+--------+--------+
  47  * |   0    |   0    |  CALIB |  INTRM |   0    |   0    |   0    |   0    |
  48  * +--------+--------+--------+--------+--------+--------+--------+--------+
  49  * CALIB: 0 = not to use calibration result (*)
  50  *        1 = use calibration result
  51  * INTRM: 0 = INT output depend on "pen down" (*)
  52  *        1 = INT output always "0"
  53  */
  54 #define BU21029_CFR0_REG        (0x00 << 3)
  55 #define CFR0_VALUE              0x00
  56
  57 /*
  58  * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6)
  59  * +--------+--------+--------+--------+--------+--------+--------+--------+
  60  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  61  * +--------+--------+--------+--------+--------+--------+--------+--------+
  62  * |  MAV   |         AVE[2:0]         |   0    |         SMPL[2:0]        |
  63  * +--------+--------+--------+--------+--------+--------+--------+--------+
  64  * MAV:  0 = median average filter off
  65  *       1 = median average filter on (*)
  66  * AVE:  AVE+1 = number of average samples for MAV,
  67  *               if AVE>SMPL, then AVE=SMPL (=3)
  68  * SMPL: SMPL+1 = number of conversion samples for MAV (=7)
  69  */
  70 #define BU21029_CFR1_REG        (0x01 << 3)
  71 #define CFR1_VALUE              0xA6
  72
  73 /*
  74  * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04)
  75  * +--------+--------+--------+--------+--------+--------+--------+--------+
  76  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  77  * +--------+--------+--------+--------+--------+--------+--------+--------+
  78  * |          INTVL_TIME[3:0]          |          TIME_ST_ADC[3:0]         |
  79  * +--------+--------+--------+--------+--------+--------+--------+--------+
  80  * INTVL_TIME: waiting time between completion of conversion
  81  *             and start of next conversion, only usable in
  82  *             autoscan mode (=20.480ms)
  83  * TIME_ST_ADC: waiting time between application of voltage
  84  *              to panel and start of A/D conversion (=100us)
  85  */
  86 #define BU21029_CFR2_REG        (0x02 << 3)
  87 #define CFR2_VALUE              0xC9
  88
  89 /*
  90  * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72)
  91  * +--------+--------+--------+--------+--------+--------+--------+--------+
  92  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
  93  * +--------+--------+--------+--------+--------+--------+--------+--------+
  94  * |  RM8   | STRETCH|  PU90K |  DUAL  |           PIDAC_OFS[3:0]          |
  95  * +--------+--------+--------+--------+--------+--------+--------+--------+
  96  * RM8: 0 = coordinate resolution is 12bit (*)
  97  *      1 = coordinate resolution is 8bit
  98  * STRETCH: 0 = SCL_STRETCH function off
  99  *          1 = SCL_STRETCH function on (*)
 100  * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*)
 101  *        1 = internal pull-up resistance for touch detection is ~90kohms
 102  * DUAL: 0 = dual touch detection off (*)
 103  *       1 = dual touch detection on
 104  * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary
 105  *            to change this from initial value
 106  */
 107 #define BU21029_CFR3_REG        (0x0B << 3)
 108 #define CFR3_VALUE              0x42
 109
 110 /*
 111  * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00)
 112  * +--------+--------+--------+--------+--------+--------+--------+--------+
 113  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 114  * +--------+--------+--------+--------+--------+--------+--------+--------+
 115  * |   0    |         PVDD[2:0]        |   0    |         AVDD[2:0]        |
 116  * +--------+--------+--------+--------+--------+--------+--------+--------+
 117  * PVDD: output voltage of panel output regulator (=2.000V)
 118  * AVDD: output voltage of analog circuit regulator (=2.000V)
 119  */
 120 #define BU21029_LDO_REG         (0x0C << 3)
 121 #define LDO_VALUE               0x77
 122
 123 /*
 124  * Serial Interface Command Byte 1 (CID=1)
 125  * +--------+--------+--------+--------+--------+--------+--------+--------+
 126  * |   D7   |   D6   |   D5   |   D4   |   D3   |   D2   |   D1   |   D0   |
 127  * +--------+--------+--------+--------+--------+--------+--------+--------+
 128  * |   1    |                 CF                |  CMSK  |  PDM   |  STP   |
 129  * +--------+--------+--------+--------+--------+--------+--------+--------+
 130  * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan)
 131  * CMSK: 0 = executes convert function (*)
 132  *       1 = reads the convert result
 133  * PDM: 0 = power down after convert function stops (*)
 134  *      1 = keep power on after convert function stops
 135  * STP: 1 = abort current conversion and power down, set to "0" automatically
 136  */
 137 #define BU21029_AUTOSCAN        0x80
 138
 139 /*
 140  * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and
 141  * conversion time), where tConv4 is calculated by formula:
 142  * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3
 143  * see figure 8 in datasheet p15 for details of each field.
 144  */
 145 #define PEN_UP_TIMEOUT_MS       50
 146
 147 #define STOP_DELAY_MIN_US       50
 148 #define STOP_DELAY_MAX_US       1000
 149 #define START_DELAY_MS          2
 150 #define BUF_LEN                 8
 151 #define SCALE_12BIT             (1 << 12)
 152 #define MAX_12BIT               ((1 << 12) - 1)
 153 #define DRIVER_NAME             "bu21029"
 154
 155 struct bu21029_ts_data {
 156         struct i2c_client               *client;
 157         struct input_dev                *in_dev;
 158         struct timer_list               timer;
 159         struct regulator                *vdd;
 160         struct gpio_desc                *reset_gpios;
 161         u32                             x_plate_ohms;
 162         struct touchscreen_properties   prop;
 163 };
 164
 165 static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf)
 166 {
 167         u16 x, y, z1, z2;
 168         u32 rz;
 169         s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE);
 170
 171         /*
 172          * compose upper 8 and lower 4 bits into a 12bit value:
 173          * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 174          * |            ByteH              |            ByteL              |
 175          * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 176          * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00|
 177          * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 178          * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 |
 179          * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 180          */
 181         x  = (buf[0] << 4) | (buf[1] >> 4);
 182         y  = (buf[2] << 4) | (buf[3] >> 4);
 183         z1 = (buf[4] << 4) | (buf[5] >> 4);
 184         z2 = (buf[6] << 4) | (buf[7] >> 4);
 185
 186         if (z1 && z2) {
 187                 /*
 188                  * calculate Rz (pressure resistance value) by equation:
 189                  * Rz = Rx * (x/Q) * ((z2/z1) - 1), where
 190                  * Rx is x-plate resistance,
 191                  * Q  is the touch screen resolution (8bit = 256, 12bit = 4096)
 192                  * x, z1, z2 are the measured positions.
 193                  */
 194                 rz  = z2 - z1;
 195                 rz *= x;
 196                 rz *= bu21029->x_plate_ohms;
 197                 rz /= z1;
 198                 rz  = DIV_ROUND_CLOSEST(rz, SCALE_12BIT);
 199                 if (rz <= max_pressure) {
 200                         touchscreen_report_pos(bu21029->in_dev, &bu21029->prop,
 201                                                x, y, false);
 202                         input_report_abs(bu21029->in_dev, ABS_PRESSURE,
 203                                          max_pressure - rz);
 204                         input_report_key(bu21029->in_dev, BTN_TOUCH, 1);
 205                         input_sync(bu21029->in_dev);
 206                 }
 207         }
 208 }
 209
 210 static void bu21029_touch_release(struct timer_list *t)
 211 {
 212         struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer);
 213
 214         input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0);
 215         input_report_key(bu21029->in_dev, BTN_TOUCH, 0);
 216         input_sync(bu21029->in_dev);
 217 }
 218
 219 static irqreturn_t bu21029_touch_soft_irq(int irq, void *data)
 220 {
 221         struct bu21029_ts_data *bu21029 = data;
 222         u8 buf[BUF_LEN];
 223         int error;
 224
 225         /*
 226          * Read touch data and deassert interrupt (will assert again after
 227          * INTVL_TIME + tConv4 for continuous touch)
 228          */
 229         error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN,
 230                                               sizeof(buf), buf);
 231         if (error < 0)
 232                 goto out;
 233
 234         bu21029_touch_report(bu21029, buf);
 235
 236         /* reset timer for pen up detection */
 237         mod_timer(&bu21029->timer,
 238                   jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS));
 239
 240 out:
 241         return IRQ_HANDLED;
 242 }
 243
 244 static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029)
 245 {
 246         if (bu21029->reset_gpios) {
 247                 gpiod_set_value_cansleep(bu21029->reset_gpios, 1);
 248                 usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US);
 249         }
 250 }
 251
 252 static int bu21029_start_chip(struct input_dev *dev)
 253 {
 254         struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
 255         struct i2c_client *i2c = bu21029->client;
 256         struct {
 257                 u8 reg;
 258                 u8 value;
 259         } init_table[] = {
 260                 {BU21029_CFR0_REG, CFR0_VALUE},
 261                 {BU21029_CFR1_REG, CFR1_VALUE},
 262                 {BU21029_CFR2_REG, CFR2_VALUE},
 263                 {BU21029_CFR3_REG, CFR3_VALUE},
 264                 {BU21029_LDO_REG,  LDO_VALUE}
 265         };
 266         int error, i;
 267         __be16 hwid;
 268
 269         error = regulator_enable(bu21029->vdd);
 270         if (error) {
 271                 dev_err(&i2c->dev, "failed to power up chip: %d", error);
 272                 return error;
 273         }
 274
 275         /* take chip out of reset */
 276         if (bu21029->reset_gpios) {
 277                 gpiod_set_value_cansleep(bu21029->reset_gpios, 0);
 278                 msleep(START_DELAY_MS);
 279         }
 280
 281         error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG,
 282                                               sizeof(hwid), (u8 *)&hwid);
 283         if (error < 0) {
 284                 dev_err(&i2c->dev, "failed to read HW ID\n");
 285                 goto err_out;
 286         }
 287
 288         if (be16_to_cpu(hwid) != SUPPORTED_HWID) {
 289                 dev_err(&i2c->dev,
 290                         "unsupported HW ID 0x%x\n", be16_to_cpu(hwid));
 291                 error = -ENODEV;
 292                 goto err_out;
 293         }
 294
 295         for (i = 0; i < ARRAY_SIZE(init_table); ++i) {
 296                 error = i2c_smbus_write_byte_data(i2c,
 297                                                   init_table[i].reg,
 298                                                   init_table[i].value);
 299                 if (error < 0) {
 300                         dev_err(&i2c->dev,
 301                                 "failed to write %#02x to register %#02x: %d\n",
 302                                 init_table[i].value, init_table[i].reg,
 303                                 error);
 304                         goto err_out;
 305                 }
 306         }
 307
 308         error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN);
 309         if (error < 0) {
 310                 dev_err(&i2c->dev, "failed to start autoscan\n");
 311                 goto err_out;
 312         }
 313
 314         enable_irq(bu21029->client->irq);
 315         return 0;
 316
 317 err_out:
 318         bu21029_put_chip_in_reset(bu21029);
 319         regulator_disable(bu21029->vdd);
 320         return error;
 321 }
 322
 323 static void bu21029_stop_chip(struct input_dev *dev)
 324 {
 325         struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
 326
 327         disable_irq(bu21029->client->irq);
 328         del_timer_sync(&bu21029->timer);
 329
 330         bu21029_put_chip_in_reset(bu21029);
 331         regulator_disable(bu21029->vdd);
 332 }
 333
 334 static int bu21029_probe(struct i2c_client *client,
 335                          const struct i2c_device_id *id)
 336 {
 337         struct bu21029_ts_data *bu21029;
 338         struct input_dev *in_dev;
 339         int error;
 340
 341         if (!i2c_check_functionality(client->adapter,
 342                                      I2C_FUNC_SMBUS_WRITE_BYTE |
 343                                      I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 344                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 345                 dev_err(&client->dev,
 346                         "i2c functionality support is not sufficient\n");
 347                 return -EIO;
 348         }
 349
 350         bu21029 = devm_kzalloc(&client->dev, sizeof(*bu21029), GFP_KERNEL);
 351         if (!bu21029)
 352                 return -ENOMEM;
 353
 354         error = device_property_read_u32(&client->dev, "rohm,x-plate-ohms",
 355                                          &bu21029->x_plate_ohms);
 356         if (error) {
 357                 dev_err(&client->dev,
 358                         "invalid 'x-plate-ohms' supplied: %d\n", error);
 359                 return error;
 360         }
 361
 362         bu21029->vdd = devm_regulator_get(&client->dev, "vdd");
 363         if (IS_ERR(bu21029->vdd)) {
 364                 error = PTR_ERR(bu21029->vdd);
 365                 if (error != -EPROBE_DEFER)
 366                         dev_err(&client->dev,
 367                                 "failed to acquire 'vdd' supply: %d\n", error);
 368                 return error;
 369         }
 370
 371         bu21029->reset_gpios = devm_gpiod_get_optional(&client->dev,
 372                                                        "reset", GPIOD_OUT_HIGH);
 373         if (IS_ERR(bu21029->reset_gpios)) {
 374                 error = PTR_ERR(bu21029->reset_gpios);
 375                 if (error != -EPROBE_DEFER)
 376                         dev_err(&client->dev,
 377                                 "failed to acquire 'reset' gpio: %d\n", error);
 378                 return error;
 379         }
 380
 381         in_dev = devm_input_allocate_device(&client->dev);
 382         if (!in_dev) {
 383                 dev_err(&client->dev, "unable to allocate input device\n");
 384                 return -ENOMEM;
 385         }
 386
 387         bu21029->client = client;
 388         bu21029->in_dev = in_dev;
 389         timer_setup(&bu21029->timer, bu21029_touch_release, 0);
 390
 391         in_dev->name            = DRIVER_NAME;
 392         in_dev->id.bustype      = BUS_I2C;
 393         in_dev->open            = bu21029_start_chip;
 394         in_dev->close           = bu21029_stop_chip;
 395
 396         input_set_capability(in_dev, EV_KEY, BTN_TOUCH);
 397         input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 398         input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 399         input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 400         touchscreen_parse_properties(in_dev, false, &bu21029->prop);
 401
 402         input_set_drvdata(in_dev, bu21029);
 403
 404         irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
 405         error = devm_request_threaded_irq(&client->dev, client->irq,
 406                                           NULL, bu21029_touch_soft_irq,
 407                                           IRQF_ONESHOT, DRIVER_NAME, bu21029);
 408         if (error) {
 409                 dev_err(&client->dev,
 410                         "unable to request touch irq: %d\n", error);
 411                 return error;
 412         }
 413
 414         error = input_register_device(in_dev);
 415         if (error) {
 416                 dev_err(&client->dev,
 417                         "unable to register input device: %d\n", error);
 418                 return error;
 419         }
 420
 421         i2c_set_clientdata(client, bu21029);
 422
 423         return 0;
 424 }
 425
 426 static int __maybe_unused bu21029_suspend(struct device *dev)
 427 {
 428         struct i2c_client *i2c = to_i2c_client(dev);
 429         struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
 430
 431         if (!device_may_wakeup(dev)) {
 432                 mutex_lock(&bu21029->in_dev->mutex);
 433                 if (bu21029->in_dev->users)
 434                         bu21029_stop_chip(bu21029->in_dev);
 435                 mutex_unlock(&bu21029->in_dev->mutex);
 436         }
 437
 438         return 0;
 439 }
 440
 441 static int __maybe_unused bu21029_resume(struct device *dev)
 442 {
 443         struct i2c_client *i2c = to_i2c_client(dev);
 444         struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
 445
 446         if (!device_may_wakeup(dev)) {
 447                 mutex_lock(&bu21029->in_dev->mutex);
 448                 if (bu21029->in_dev->users)
 449                         bu21029_start_chip(bu21029->in_dev);
 450                 mutex_unlock(&bu21029->in_dev->mutex);
 451         }
 452
 453         return 0;
 454 }
 455 static SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume);
 456
 457 static const struct i2c_device_id bu21029_ids[] = {
 458         { DRIVER_NAME, 0 },
 459         { /* sentinel */ }
 460 };
 461 MODULE_DEVICE_TABLE(i2c, bu21029_ids);
 462
 463 #ifdef CONFIG_OF
 464 static const struct of_device_id bu21029_of_ids[] = {
 465         { .compatible = "rohm,bu21029" },
 466         { /* sentinel */ }
 467 };
 468 MODULE_DEVICE_TABLE(of, bu21029_of_ids);
 469 #endif
 470
 471 static struct i2c_driver bu21029_driver = {
 472         .driver = {
 473                 .name           = DRIVER_NAME,
 474                 .of_match_table = of_match_ptr(bu21029_of_ids),
 475                 .pm             = &bu21029_pm_ops,
 476         },
 477         .id_table       = bu21029_ids,
 478         .probe          = bu21029_probe,
 479 };
 480 module_i2c_driver(bu21029_driver);
 481
 482 MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>");
 483 MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
 484 MODULE_LICENSE("GPL v2");