linux/drivers/input/keyboard/cap11xx.c
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   1/*
   2 * Input driver for Microchip CAP11xx based capacitive touch sensors
   3 *
   4 * (c) 2014 Daniel Mack <linux@zonque.org>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/interrupt.h>
  14#include <linux/input.h>
  15#include <linux/leds.h>
  16#include <linux/of_irq.h>
  17#include <linux/regmap.h>
  18#include <linux/i2c.h>
  19#include <linux/gpio/consumer.h>
  20
  21#define CAP11XX_REG_MAIN_CONTROL        0x00
  22#define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT     (6)
  23#define CAP11XX_REG_MAIN_CONTROL_GAIN_MASK      (0xc0)
  24#define CAP11XX_REG_MAIN_CONTROL_DLSEEP         BIT(4)
  25#define CAP11XX_REG_GENERAL_STATUS      0x02
  26#define CAP11XX_REG_SENSOR_INPUT        0x03
  27#define CAP11XX_REG_NOISE_FLAG_STATUS   0x0a
  28#define CAP11XX_REG_SENOR_DELTA(X)      (0x10 + (X))
  29#define CAP11XX_REG_SENSITIVITY_CONTROL 0x1f
  30#define CAP11XX_REG_CONFIG              0x20
  31#define CAP11XX_REG_SENSOR_ENABLE       0x21
  32#define CAP11XX_REG_SENSOR_CONFIG       0x22
  33#define CAP11XX_REG_SENSOR_CONFIG2      0x23
  34#define CAP11XX_REG_SAMPLING_CONFIG     0x24
  35#define CAP11XX_REG_CALIBRATION         0x26
  36#define CAP11XX_REG_INT_ENABLE          0x27
  37#define CAP11XX_REG_REPEAT_RATE         0x28
  38#define CAP11XX_REG_MT_CONFIG           0x2a
  39#define CAP11XX_REG_MT_PATTERN_CONFIG   0x2b
  40#define CAP11XX_REG_MT_PATTERN          0x2d
  41#define CAP11XX_REG_RECALIB_CONFIG      0x2f
  42#define CAP11XX_REG_SENSOR_THRESH(X)    (0x30 + (X))
  43#define CAP11XX_REG_SENSOR_NOISE_THRESH 0x38
  44#define CAP11XX_REG_STANDBY_CHANNEL     0x40
  45#define CAP11XX_REG_STANDBY_CONFIG      0x41
  46#define CAP11XX_REG_STANDBY_SENSITIVITY 0x42
  47#define CAP11XX_REG_STANDBY_THRESH      0x43
  48#define CAP11XX_REG_CONFIG2             0x44
  49#define CAP11XX_REG_CONFIG2_ALT_POL     BIT(6)
  50#define CAP11XX_REG_SENSOR_BASE_CNT(X)  (0x50 + (X))
  51#define CAP11XX_REG_LED_POLARITY        0x73
  52#define CAP11XX_REG_LED_OUTPUT_CONTROL  0x74
  53
  54#define CAP11XX_REG_LED_DUTY_CYCLE_1    0x90
  55#define CAP11XX_REG_LED_DUTY_CYCLE_2    0x91
  56#define CAP11XX_REG_LED_DUTY_CYCLE_3    0x92
  57#define CAP11XX_REG_LED_DUTY_CYCLE_4    0x93
  58
  59#define CAP11XX_REG_LED_DUTY_MIN_MASK   (0x0f)
  60#define CAP11XX_REG_LED_DUTY_MIN_MASK_SHIFT     (0)
  61#define CAP11XX_REG_LED_DUTY_MAX_MASK   (0xf0)
  62#define CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT     (4)
  63#define CAP11XX_REG_LED_DUTY_MAX_VALUE  (15)
  64
  65#define CAP11XX_REG_SENSOR_CALIB        (0xb1 + (X))
  66#define CAP11XX_REG_SENSOR_CALIB_LSB1   0xb9
  67#define CAP11XX_REG_SENSOR_CALIB_LSB2   0xba
  68#define CAP11XX_REG_PRODUCT_ID          0xfd
  69#define CAP11XX_REG_MANUFACTURER_ID     0xfe
  70#define CAP11XX_REG_REVISION            0xff
  71
  72#define CAP11XX_MANUFACTURER_ID 0x5d
  73
  74#ifdef CONFIG_LEDS_CLASS
  75struct cap11xx_led {
  76        struct cap11xx_priv *priv;
  77        struct led_classdev cdev;
  78        struct work_struct work;
  79        u32 reg;
  80        enum led_brightness new_brightness;
  81};
  82#endif
  83
  84struct cap11xx_priv {
  85        struct regmap *regmap;
  86        struct input_dev *idev;
  87
  88        struct cap11xx_led *leds;
  89        int num_leds;
  90
  91        /* config */
  92        u32 keycodes[];
  93};
  94
  95struct cap11xx_hw_model {
  96        u8 product_id;
  97        unsigned int num_channels;
  98        unsigned int num_leds;
  99};
 100
 101enum {
 102        CAP1106,
 103        CAP1126,
 104        CAP1188,
 105};
 106
 107static const struct cap11xx_hw_model cap11xx_devices[] = {
 108        [CAP1106] = { .product_id = 0x55, .num_channels = 6, .num_leds = 0 },
 109        [CAP1126] = { .product_id = 0x53, .num_channels = 6, .num_leds = 2 },
 110        [CAP1188] = { .product_id = 0x50, .num_channels = 8, .num_leds = 8 },
 111};
 112
 113static const struct reg_default cap11xx_reg_defaults[] = {
 114        { CAP11XX_REG_MAIN_CONTROL,             0x00 },
 115        { CAP11XX_REG_GENERAL_STATUS,           0x00 },
 116        { CAP11XX_REG_SENSOR_INPUT,             0x00 },
 117        { CAP11XX_REG_NOISE_FLAG_STATUS,        0x00 },
 118        { CAP11XX_REG_SENSITIVITY_CONTROL,      0x2f },
 119        { CAP11XX_REG_CONFIG,                   0x20 },
 120        { CAP11XX_REG_SENSOR_ENABLE,            0x3f },
 121        { CAP11XX_REG_SENSOR_CONFIG,            0xa4 },
 122        { CAP11XX_REG_SENSOR_CONFIG2,           0x07 },
 123        { CAP11XX_REG_SAMPLING_CONFIG,          0x39 },
 124        { CAP11XX_REG_CALIBRATION,              0x00 },
 125        { CAP11XX_REG_INT_ENABLE,               0x3f },
 126        { CAP11XX_REG_REPEAT_RATE,              0x3f },
 127        { CAP11XX_REG_MT_CONFIG,                0x80 },
 128        { CAP11XX_REG_MT_PATTERN_CONFIG,        0x00 },
 129        { CAP11XX_REG_MT_PATTERN,               0x3f },
 130        { CAP11XX_REG_RECALIB_CONFIG,           0x8a },
 131        { CAP11XX_REG_SENSOR_THRESH(0),         0x40 },
 132        { CAP11XX_REG_SENSOR_THRESH(1),         0x40 },
 133        { CAP11XX_REG_SENSOR_THRESH(2),         0x40 },
 134        { CAP11XX_REG_SENSOR_THRESH(3),         0x40 },
 135        { CAP11XX_REG_SENSOR_THRESH(4),         0x40 },
 136        { CAP11XX_REG_SENSOR_THRESH(5),         0x40 },
 137        { CAP11XX_REG_SENSOR_NOISE_THRESH,      0x01 },
 138        { CAP11XX_REG_STANDBY_CHANNEL,          0x00 },
 139        { CAP11XX_REG_STANDBY_CONFIG,           0x39 },
 140        { CAP11XX_REG_STANDBY_SENSITIVITY,      0x02 },
 141        { CAP11XX_REG_STANDBY_THRESH,           0x40 },
 142        { CAP11XX_REG_CONFIG2,                  0x40 },
 143        { CAP11XX_REG_LED_POLARITY,             0x00 },
 144        { CAP11XX_REG_SENSOR_CALIB_LSB1,        0x00 },
 145        { CAP11XX_REG_SENSOR_CALIB_LSB2,        0x00 },
 146};
 147
 148static bool cap11xx_volatile_reg(struct device *dev, unsigned int reg)
 149{
 150        switch (reg) {
 151        case CAP11XX_REG_MAIN_CONTROL:
 152        case CAP11XX_REG_SENSOR_INPUT:
 153        case CAP11XX_REG_SENOR_DELTA(0):
 154        case CAP11XX_REG_SENOR_DELTA(1):
 155        case CAP11XX_REG_SENOR_DELTA(2):
 156        case CAP11XX_REG_SENOR_DELTA(3):
 157        case CAP11XX_REG_SENOR_DELTA(4):
 158        case CAP11XX_REG_SENOR_DELTA(5):
 159        case CAP11XX_REG_PRODUCT_ID:
 160        case CAP11XX_REG_MANUFACTURER_ID:
 161        case CAP11XX_REG_REVISION:
 162                return true;
 163        }
 164
 165        return false;
 166}
 167
 168static const struct regmap_config cap11xx_regmap_config = {
 169        .reg_bits = 8,
 170        .val_bits = 8,
 171
 172        .max_register = CAP11XX_REG_REVISION,
 173        .reg_defaults = cap11xx_reg_defaults,
 174
 175        .num_reg_defaults = ARRAY_SIZE(cap11xx_reg_defaults),
 176        .cache_type = REGCACHE_RBTREE,
 177        .volatile_reg = cap11xx_volatile_reg,
 178};
 179
 180static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
 181{
 182        struct cap11xx_priv *priv = data;
 183        unsigned int status;
 184        int ret, i;
 185
 186        /*
 187         * Deassert interrupt. This needs to be done before reading the status
 188         * registers, which will not carry valid values otherwise.
 189         */
 190        ret = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL, 1, 0);
 191        if (ret < 0)
 192                goto out;
 193
 194        ret = regmap_read(priv->regmap, CAP11XX_REG_SENSOR_INPUT, &status);
 195        if (ret < 0)
 196                goto out;
 197
 198        for (i = 0; i < priv->idev->keycodemax; i++)
 199                input_report_key(priv->idev, priv->keycodes[i],
 200                                 status & (1 << i));
 201
 202        input_sync(priv->idev);
 203
 204out:
 205        return IRQ_HANDLED;
 206}
 207
 208static int cap11xx_set_sleep(struct cap11xx_priv *priv, bool sleep)
 209{
 210        /*
 211         * DLSEEP mode will turn off all LEDS, prevent this
 212         */
 213        if (IS_ENABLED(CONFIG_LEDS_CLASS) && priv->num_leds)
 214                return 0;
 215
 216        return regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
 217                                  CAP11XX_REG_MAIN_CONTROL_DLSEEP,
 218                                  sleep ? CAP11XX_REG_MAIN_CONTROL_DLSEEP : 0);
 219}
 220
 221static int cap11xx_input_open(struct input_dev *idev)
 222{
 223        struct cap11xx_priv *priv = input_get_drvdata(idev);
 224
 225        return cap11xx_set_sleep(priv, false);
 226}
 227
 228static void cap11xx_input_close(struct input_dev *idev)
 229{
 230        struct cap11xx_priv *priv = input_get_drvdata(idev);
 231
 232        cap11xx_set_sleep(priv, true);
 233}
 234
 235#ifdef CONFIG_LEDS_CLASS
 236static void cap11xx_led_work(struct work_struct *work)
 237{
 238        struct cap11xx_led *led = container_of(work, struct cap11xx_led, work);
 239        struct cap11xx_priv *priv = led->priv;
 240        int value = led->new_brightness;
 241
 242        /*
 243         * All LEDs share the same duty cycle as this is a HW limitation.
 244         * Brightness levels per LED are either 0 (OFF) and 1 (ON).
 245         */
 246        regmap_update_bits(priv->regmap, CAP11XX_REG_LED_OUTPUT_CONTROL,
 247                                BIT(led->reg), value ? BIT(led->reg) : 0);
 248}
 249
 250static void cap11xx_led_set(struct led_classdev *cdev,
 251                           enum led_brightness value)
 252{
 253        struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
 254
 255        if (led->new_brightness == value)
 256                return;
 257
 258        led->new_brightness = value;
 259        schedule_work(&led->work);
 260}
 261
 262static int cap11xx_init_leds(struct device *dev,
 263                             struct cap11xx_priv *priv, int num_leds)
 264{
 265        struct device_node *node = dev->of_node, *child;
 266        struct cap11xx_led *led;
 267        int cnt = of_get_child_count(node);
 268        int error;
 269
 270        if (!num_leds || !cnt)
 271                return 0;
 272
 273        if (cnt > num_leds)
 274                return -EINVAL;
 275
 276        led = devm_kcalloc(dev, cnt, sizeof(struct cap11xx_led), GFP_KERNEL);
 277        if (!led)
 278                return -ENOMEM;
 279
 280        priv->leds = led;
 281
 282        error = regmap_update_bits(priv->regmap,
 283                                CAP11XX_REG_LED_OUTPUT_CONTROL, 0xff, 0);
 284        if (error)
 285                return error;
 286
 287        error = regmap_update_bits(priv->regmap, CAP11XX_REG_LED_DUTY_CYCLE_4,
 288                                CAP11XX_REG_LED_DUTY_MAX_MASK,
 289                                CAP11XX_REG_LED_DUTY_MAX_VALUE <<
 290                                CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT);
 291        if (error)
 292                return error;
 293
 294        for_each_child_of_node(node, child) {
 295                u32 reg;
 296
 297                led->cdev.name =
 298                        of_get_property(child, "label", NULL) ? : child->name;
 299                led->cdev.default_trigger =
 300                        of_get_property(child, "linux,default-trigger", NULL);
 301                led->cdev.flags = 0;
 302                led->cdev.brightness_set = cap11xx_led_set;
 303                led->cdev.max_brightness = 1;
 304                led->cdev.brightness = LED_OFF;
 305
 306                error = of_property_read_u32(child, "reg", &reg);
 307                if (error != 0 || reg >= num_leds) {
 308                        of_node_put(child);
 309                        return -EINVAL;
 310                }
 311
 312                led->reg = reg;
 313                led->priv = priv;
 314
 315                INIT_WORK(&led->work, cap11xx_led_work);
 316
 317                error = devm_led_classdev_register(dev, &led->cdev);
 318                if (error) {
 319                        of_node_put(child);
 320                        return error;
 321                }
 322
 323                priv->num_leds++;
 324                led++;
 325        }
 326
 327        return 0;
 328}
 329#else
 330static int cap11xx_init_leds(struct device *dev,
 331                             struct cap11xx_priv *priv, int num_leds)
 332{
 333        return 0;
 334}
 335#endif
 336
 337static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
 338                             const struct i2c_device_id *id)
 339{
 340        struct device *dev = &i2c_client->dev;
 341        struct cap11xx_priv *priv;
 342        struct device_node *node;
 343        const struct cap11xx_hw_model *cap;
 344        int i, error, irq, gain = 0;
 345        unsigned int val, rev;
 346        u32 gain32;
 347
 348        if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
 349                dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
 350                return -EINVAL;
 351        }
 352
 353        cap = &cap11xx_devices[id->driver_data];
 354        if (!cap || !cap->num_channels) {
 355                dev_err(dev, "Invalid device configuration\n");
 356                return -EINVAL;
 357        }
 358
 359        priv = devm_kzalloc(dev,
 360                            sizeof(*priv) +
 361                                cap->num_channels * sizeof(priv->keycodes[0]),
 362                            GFP_KERNEL);
 363        if (!priv)
 364                return -ENOMEM;
 365
 366        priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
 367        if (IS_ERR(priv->regmap))
 368                return PTR_ERR(priv->regmap);
 369
 370        error = regmap_read(priv->regmap, CAP11XX_REG_PRODUCT_ID, &val);
 371        if (error)
 372                return error;
 373
 374        if (val != cap->product_id) {
 375                dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
 376                        val, cap->product_id);
 377                return -ENXIO;
 378        }
 379
 380        error = regmap_read(priv->regmap, CAP11XX_REG_MANUFACTURER_ID, &val);
 381        if (error)
 382                return error;
 383
 384        if (val != CAP11XX_MANUFACTURER_ID) {
 385                dev_err(dev, "Manufacturer ID: Got 0x%02x, expected 0x%02x\n",
 386                        val, CAP11XX_MANUFACTURER_ID);
 387                return -ENXIO;
 388        }
 389
 390        error = regmap_read(priv->regmap, CAP11XX_REG_REVISION, &rev);
 391        if (error < 0)
 392                return error;
 393
 394        dev_info(dev, "CAP11XX detected, revision 0x%02x\n", rev);
 395        i2c_set_clientdata(i2c_client, priv);
 396        node = dev->of_node;
 397
 398        if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
 399                if (is_power_of_2(gain32) && gain32 <= 8)
 400                        gain = ilog2(gain32);
 401                else
 402                        dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
 403        }
 404
 405        if (of_property_read_bool(node, "microchip,irq-active-high")) {
 406                error = regmap_update_bits(priv->regmap, CAP11XX_REG_CONFIG2,
 407                                           CAP11XX_REG_CONFIG2_ALT_POL, 0);
 408                if (error)
 409                        return error;
 410        }
 411
 412        /* Provide some useful defaults */
 413        for (i = 0; i < cap->num_channels; i++)
 414                priv->keycodes[i] = KEY_A + i;
 415
 416        of_property_read_u32_array(node, "linux,keycodes",
 417                                   priv->keycodes, cap->num_channels);
 418
 419        error = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
 420                                   CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
 421                                   gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
 422        if (error)
 423                return error;
 424
 425        /* Disable autorepeat. The Linux input system has its own handling. */
 426        error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
 427        if (error)
 428                return error;
 429
 430        priv->idev = devm_input_allocate_device(dev);
 431        if (!priv->idev)
 432                return -ENOMEM;
 433
 434        priv->idev->name = "CAP11XX capacitive touch sensor";
 435        priv->idev->id.bustype = BUS_I2C;
 436        priv->idev->evbit[0] = BIT_MASK(EV_KEY);
 437
 438        if (of_property_read_bool(node, "autorepeat"))
 439                __set_bit(EV_REP, priv->idev->evbit);
 440
 441        for (i = 0; i < cap->num_channels; i++)
 442                __set_bit(priv->keycodes[i], priv->idev->keybit);
 443
 444        __clear_bit(KEY_RESERVED, priv->idev->keybit);
 445
 446        priv->idev->keycode = priv->keycodes;
 447        priv->idev->keycodesize = sizeof(priv->keycodes[0]);
 448        priv->idev->keycodemax = cap->num_channels;
 449
 450        priv->idev->id.vendor = CAP11XX_MANUFACTURER_ID;
 451        priv->idev->id.product = cap->product_id;
 452        priv->idev->id.version = rev;
 453
 454        priv->idev->open = cap11xx_input_open;
 455        priv->idev->close = cap11xx_input_close;
 456
 457        error = cap11xx_init_leds(dev, priv, cap->num_leds);
 458        if (error)
 459                return error;
 460
 461        input_set_drvdata(priv->idev, priv);
 462
 463        /*
 464         * Put the device in deep sleep mode for now.
 465         * ->open() will bring it back once the it is actually needed.
 466         */
 467        cap11xx_set_sleep(priv, true);
 468
 469        error = input_register_device(priv->idev);
 470        if (error)
 471                return error;
 472
 473        irq = irq_of_parse_and_map(node, 0);
 474        if (!irq) {
 475                dev_err(dev, "Unable to parse or map IRQ\n");
 476                return -ENXIO;
 477        }
 478
 479        error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
 480                                          IRQF_ONESHOT, dev_name(dev), priv);
 481        if (error)
 482                return error;
 483
 484        return 0;
 485}
 486
 487static const struct of_device_id cap11xx_dt_ids[] = {
 488        { .compatible = "microchip,cap1106", },
 489        { .compatible = "microchip,cap1126", },
 490        { .compatible = "microchip,cap1188", },
 491        {}
 492};
 493MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);
 494
 495static const struct i2c_device_id cap11xx_i2c_ids[] = {
 496        { "cap1106", CAP1106 },
 497        { "cap1126", CAP1126 },
 498        { "cap1188", CAP1188 },
 499        {}
 500};
 501MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);
 502
 503static struct i2c_driver cap11xx_i2c_driver = {
 504        .driver = {
 505                .name   = "cap11xx",
 506                .of_match_table = cap11xx_dt_ids,
 507        },
 508        .id_table       = cap11xx_i2c_ids,
 509        .probe          = cap11xx_i2c_probe,
 510};
 511
 512module_i2c_driver(cap11xx_i2c_driver);
 513
 514MODULE_DESCRIPTION("Microchip CAP11XX driver");
 515MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
 516MODULE_LICENSE("GPL v2");
 517