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