drivers/input/keyboard/cap11xx.c

   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
  75 struct 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
  84 struct 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
  95 struct cap11xx_hw_model {
  96         u8 product_id;
  97         unsigned int num_channels;
  98         unsigned int num_leds;
  99 };
 100
 101 enum {
 102         CAP1106,
 103         CAP1126,
 104         CAP1188,
 105 };
 106
 107 static 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
 113 static 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
 148 static 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
 168 static 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
 180 static 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
 204 out:
 205         return IRQ_HANDLED;
 206 }
 207
 208 static 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
 221 static 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
 228 static 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
 236 static 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
 250 static 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
 262 static 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
 330 static int cap11xx_init_leds(struct device *dev,
 331                              struct cap11xx_priv *priv, int num_leds)
 332 {
 333         return 0;
 334 }
 335 #endif
 336
 337 static 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
 487 static const struct of_device_id cap11xx_dt_ids[] = {
 488         { .compatible = "microchip,cap1106", },
 489         { .compatible = "microchip,cap1126", },
 490         { .compatible = "microchip,cap1188", },
 491         {}
 492 };
 493 MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);
 494
 495 static const struct i2c_device_id cap11xx_i2c_ids[] = {
 496         { "cap1106", CAP1106 },
 497         { "cap1126", CAP1126 },
 498         { "cap1188", CAP1188 },
 499         {}
 500 };
 501 MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);
 502
 503 static 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
 512 module_i2c_driver(cap11xx_i2c_driver);
 513
 514 MODULE_DESCRIPTION("Microchip CAP11XX driver");
 515 MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
 516 MODULE_LICENSE("GPL v2");