drivers/iio/light/cm32181.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2013 Capella Microsystems Inc.
   4  * Author: Kevin Tsai <ktsai@capellamicro.com>
   5  */
   6
   7 #include <linux/acpi.h>
   8 #include <linux/delay.h>
   9 #include <linux/err.h>
  10 #include <linux/i2c.h>
  11 #include <linux/mutex.h>
  12 #include <linux/module.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/iio/iio.h>
  17 #include <linux/iio/sysfs.h>
  18 #include <linux/iio/events.h>
  19 #include <linux/init.h>
  20
  21 /* Registers Address */
  22 #define CM32181_REG_ADDR_CMD            0x00
  23 #define CM32181_REG_ADDR_WH             0x01
  24 #define CM32181_REG_ADDR_WL             0x02
  25 #define CM32181_REG_ADDR_TEST           0x03
  26 #define CM32181_REG_ADDR_ALS            0x04
  27 #define CM32181_REG_ADDR_STATUS         0x06
  28 #define CM32181_REG_ADDR_ID             0x07
  29
  30 /* Number of Configurable Registers */
  31 #define CM32181_CONF_REG_NUM            4
  32
  33 /* CMD register */
  34 #define CM32181_CMD_ALS_DISABLE         BIT(0)
  35 #define CM32181_CMD_ALS_INT_EN          BIT(1)
  36 #define CM32181_CMD_ALS_THRES_WINDOW    BIT(2)
  37
  38 #define CM32181_CMD_ALS_PERS_SHIFT      4
  39 #define CM32181_CMD_ALS_PERS_MASK       (0x03 << CM32181_CMD_ALS_PERS_SHIFT)
  40 #define CM32181_CMD_ALS_PERS_DEFAULT    (0x01 << CM32181_CMD_ALS_PERS_SHIFT)
  41
  42 #define CM32181_CMD_ALS_IT_SHIFT        6
  43 #define CM32181_CMD_ALS_IT_MASK         (0x0F << CM32181_CMD_ALS_IT_SHIFT)
  44 #define CM32181_CMD_ALS_IT_DEFAULT      (0x00 << CM32181_CMD_ALS_IT_SHIFT)
  45
  46 #define CM32181_CMD_ALS_SM_SHIFT        11
  47 #define CM32181_CMD_ALS_SM_MASK         (0x03 << CM32181_CMD_ALS_SM_SHIFT)
  48 #define CM32181_CMD_ALS_SM_DEFAULT      (0x01 << CM32181_CMD_ALS_SM_SHIFT)
  49
  50 #define CM32181_LUX_PER_BIT             500     /* ALS_SM=01 IT=800ms */
  51 #define CM32181_LUX_PER_BIT_RESOLUTION  100000
  52 #define CM32181_LUX_PER_BIT_BASE_IT     800000  /* Based on IT=800ms */
  53 #define CM32181_CALIBSCALE_DEFAULT      100000
  54 #define CM32181_CALIBSCALE_RESOLUTION   100000
  55
  56 #define SMBUS_ALERT_RESPONSE_ADDRESS    0x0c
  57
  58 /* CPM0 Index 0: device-id (3218 or 32181), 1: Unknown, 2: init_regs_bitmap */
  59 #define CPM0_REGS_BITMAP                2
  60 #define CPM0_HEADER_SIZE                3
  61
  62 /* CPM1 Index 0: lux_per_bit, 1: calibscale, 2: resolution (100000) */
  63 #define CPM1_LUX_PER_BIT                0
  64 #define CPM1_CALIBSCALE                 1
  65 #define CPM1_SIZE                       3
  66
  67 /* CM3218 Family */
  68 static const int cm3218_als_it_bits[] = { 0, 1, 2, 3 };
  69 static const int cm3218_als_it_values[] = { 100000, 200000, 400000, 800000 };
  70
  71 /* CM32181 Family */
  72 static const int cm32181_als_it_bits[] = { 12, 8, 0, 1, 2, 3 };
  73 static const int cm32181_als_it_values[] = {
  74         25000, 50000, 100000, 200000, 400000, 800000
  75 };
  76
  77 struct cm32181_chip {
  78         struct i2c_client *client;
  79         struct device *dev;
  80         struct mutex lock;
  81         u16 conf_regs[CM32181_CONF_REG_NUM];
  82         unsigned long init_regs_bitmap;
  83         int calibscale;
  84         int lux_per_bit;
  85         int lux_per_bit_base_it;
  86         int num_als_it;
  87         const int *als_it_bits;
  88         const int *als_it_values;
  89 };
  90
  91 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2);
  92
  93 #ifdef CONFIG_ACPI
  94 /**
  95  * cm32181_acpi_get_cpm() - Get CPM object from ACPI
  96  * @dev:        pointer of struct device.
  97  * @obj_name:   pointer of ACPI object name.
  98  * @values:     pointer of array for return elements.
  99  * @count:      maximum size of return array.
 100  *
 101  * Convert ACPI CPM table to array.
 102  *
 103  * Return: -ENODEV for fail.  Otherwise is number of elements.
 104  */
 105 static int cm32181_acpi_get_cpm(struct device *dev, char *obj_name,
 106                                 u64 *values, int count)
 107 {
 108         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 109         union acpi_object *cpm, *elem;
 110         acpi_handle handle;
 111         acpi_status status;
 112         int i;
 113
 114         handle = ACPI_HANDLE(dev);
 115         if (!handle)
 116                 return -ENODEV;
 117
 118         status = acpi_evaluate_object(handle, obj_name, NULL, &buffer);
 119         if (ACPI_FAILURE(status)) {
 120                 dev_err(dev, "object %s not found\n", obj_name);
 121                 return -ENODEV;
 122         }
 123
 124         cpm = buffer.pointer;
 125         if (cpm->package.count > count)
 126                 dev_warn(dev, "%s table contains %u values, only using first %d values\n",
 127                          obj_name, cpm->package.count, count);
 128
 129         count = min_t(int, cpm->package.count, count);
 130         for (i = 0; i < count; i++) {
 131                 elem = &(cpm->package.elements[i]);
 132                 values[i] = elem->integer.value;
 133         }
 134
 135         kfree(buffer.pointer);
 136
 137         return count;
 138 }
 139
 140 static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181)
 141 {
 142         u64 vals[CPM0_HEADER_SIZE + CM32181_CONF_REG_NUM];
 143         struct device *dev = cm32181->dev;
 144         int i, count;
 145
 146         count = cm32181_acpi_get_cpm(dev, "CPM0", vals, ARRAY_SIZE(vals));
 147         if (count <= CPM0_HEADER_SIZE)
 148                 return;
 149
 150         count -= CPM0_HEADER_SIZE;
 151
 152         cm32181->init_regs_bitmap = vals[CPM0_REGS_BITMAP];
 153         cm32181->init_regs_bitmap &= GENMASK(count - 1, 0);
 154         for_each_set_bit(i, &cm32181->init_regs_bitmap, count)
 155                 cm32181->conf_regs[i] = vals[CPM0_HEADER_SIZE + i];
 156
 157         count = cm32181_acpi_get_cpm(dev, "CPM1", vals, ARRAY_SIZE(vals));
 158         if (count != CPM1_SIZE)
 159                 return;
 160
 161         cm32181->lux_per_bit = vals[CPM1_LUX_PER_BIT];
 162
 163         /* Check for uncalibrated devices */
 164         if (vals[CPM1_CALIBSCALE] == CM32181_CALIBSCALE_DEFAULT)
 165                 return;
 166
 167         cm32181->calibscale = vals[CPM1_CALIBSCALE];
 168         /* CPM1 lux_per_bit is for the current it value */
 169         cm32181_read_als_it(cm32181, &cm32181->lux_per_bit_base_it);
 170 }
 171 #else
 172 static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181)
 173 {
 174 }
 175 #endif /* CONFIG_ACPI */
 176
 177 /**
 178  * cm32181_reg_init() - Initialize CM32181 registers
 179  * @cm32181:    pointer of struct cm32181.
 180  *
 181  * Initialize CM32181 ambient light sensor register to default values.
 182  *
 183  * Return: 0 for success; otherwise for error code.
 184  */
 185 static int cm32181_reg_init(struct cm32181_chip *cm32181)
 186 {
 187         struct i2c_client *client = cm32181->client;
 188         int i;
 189         s32 ret;
 190
 191         ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
 192         if (ret < 0)
 193                 return ret;
 194
 195         /* check device ID */
 196         switch (ret & 0xFF) {
 197         case 0x18: /* CM3218 */
 198                 cm32181->num_als_it = ARRAY_SIZE(cm3218_als_it_bits);
 199                 cm32181->als_it_bits = cm3218_als_it_bits;
 200                 cm32181->als_it_values = cm3218_als_it_values;
 201                 break;
 202         case 0x81: /* CM32181 */
 203         case 0x82: /* CM32182, fully compat. with CM32181 */
 204                 cm32181->num_als_it = ARRAY_SIZE(cm32181_als_it_bits);
 205                 cm32181->als_it_bits = cm32181_als_it_bits;
 206                 cm32181->als_it_values = cm32181_als_it_values;
 207                 break;
 208         default:
 209                 return -ENODEV;
 210         }
 211
 212         /* Default Values */
 213         cm32181->conf_regs[CM32181_REG_ADDR_CMD] =
 214                         CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
 215         cm32181->init_regs_bitmap = BIT(CM32181_REG_ADDR_CMD);
 216         cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
 217         cm32181->lux_per_bit = CM32181_LUX_PER_BIT;
 218         cm32181->lux_per_bit_base_it = CM32181_LUX_PER_BIT_BASE_IT;
 219
 220         if (ACPI_HANDLE(cm32181->dev))
 221                 cm32181_acpi_parse_cpm_tables(cm32181);
 222
 223         /* Initialize registers*/
 224         for_each_set_bit(i, &cm32181->init_regs_bitmap, CM32181_CONF_REG_NUM) {
 225                 ret = i2c_smbus_write_word_data(client, i,
 226                                                 cm32181->conf_regs[i]);
 227                 if (ret < 0)
 228                         return ret;
 229         }
 230
 231         return 0;
 232 }
 233
 234 /**
 235  *  cm32181_read_als_it() - Get sensor integration time (ms)
 236  *  @cm32181:   pointer of struct cm32181
 237  *  @val2:      pointer of int to load the als_it value.
 238  *
 239  *  Report the current integration time in milliseconds.
 240  *
 241  *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 242  */
 243 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
 244 {
 245         u16 als_it;
 246         int i;
 247
 248         als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
 249         als_it &= CM32181_CMD_ALS_IT_MASK;
 250         als_it >>= CM32181_CMD_ALS_IT_SHIFT;
 251         for (i = 0; i < cm32181->num_als_it; i++) {
 252                 if (als_it == cm32181->als_it_bits[i]) {
 253                         *val2 = cm32181->als_it_values[i];
 254                         return IIO_VAL_INT_PLUS_MICRO;
 255                 }
 256         }
 257
 258         return -EINVAL;
 259 }
 260
 261 /**
 262  * cm32181_write_als_it() - Write sensor integration time
 263  * @cm32181:    pointer of struct cm32181.
 264  * @val:        integration time by millisecond.
 265  *
 266  * Convert integration time (ms) to sensor value.
 267  *
 268  * Return: i2c_smbus_write_word_data command return value.
 269  */
 270 static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
 271 {
 272         struct i2c_client *client = cm32181->client;
 273         u16 als_it;
 274         int ret, i, n;
 275
 276         n = cm32181->num_als_it;
 277         for (i = 0; i < n; i++)
 278                 if (val <= cm32181->als_it_values[i])
 279                         break;
 280         if (i >= n)
 281                 i = n - 1;
 282
 283         als_it = cm32181->als_it_bits[i];
 284         als_it <<= CM32181_CMD_ALS_IT_SHIFT;
 285
 286         mutex_lock(&cm32181->lock);
 287         cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
 288                 ~CM32181_CMD_ALS_IT_MASK;
 289         cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
 290                 als_it;
 291         ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
 292                         cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
 293         mutex_unlock(&cm32181->lock);
 294
 295         return ret;
 296 }
 297
 298 /**
 299  * cm32181_get_lux() - report current lux value
 300  * @cm32181:    pointer of struct cm32181.
 301  *
 302  * Convert sensor raw data to lux.  It depends on integration
 303  * time and calibscale variable.
 304  *
 305  * Return: Positive value is lux, otherwise is error code.
 306  */
 307 static int cm32181_get_lux(struct cm32181_chip *cm32181)
 308 {
 309         struct i2c_client *client = cm32181->client;
 310         int ret;
 311         int als_it;
 312         u64 lux;
 313
 314         ret = cm32181_read_als_it(cm32181, &als_it);
 315         if (ret < 0)
 316                 return -EINVAL;
 317
 318         lux = cm32181->lux_per_bit;
 319         lux *= cm32181->lux_per_bit_base_it;
 320         lux = div_u64(lux, als_it);
 321
 322         ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
 323         if (ret < 0)
 324                 return ret;
 325
 326         lux *= ret;
 327         lux *= cm32181->calibscale;
 328         lux = div_u64(lux, CM32181_CALIBSCALE_RESOLUTION);
 329         lux = div_u64(lux, CM32181_LUX_PER_BIT_RESOLUTION);
 330
 331         if (lux > 0xFFFF)
 332                 lux = 0xFFFF;
 333
 334         return lux;
 335 }
 336
 337 static int cm32181_read_raw(struct iio_dev *indio_dev,
 338                             struct iio_chan_spec const *chan,
 339                             int *val, int *val2, long mask)
 340 {
 341         struct cm32181_chip *cm32181 = iio_priv(indio_dev);
 342         int ret;
 343
 344         switch (mask) {
 345         case IIO_CHAN_INFO_PROCESSED:
 346                 ret = cm32181_get_lux(cm32181);
 347                 if (ret < 0)
 348                         return ret;
 349                 *val = ret;
 350                 return IIO_VAL_INT;
 351         case IIO_CHAN_INFO_CALIBSCALE:
 352                 *val = cm32181->calibscale;
 353                 return IIO_VAL_INT;
 354         case IIO_CHAN_INFO_INT_TIME:
 355                 *val = 0;
 356                 ret = cm32181_read_als_it(cm32181, val2);
 357                 return ret;
 358         }
 359
 360         return -EINVAL;
 361 }
 362
 363 static int cm32181_write_raw(struct iio_dev *indio_dev,
 364                              struct iio_chan_spec const *chan,
 365                              int val, int val2, long mask)
 366 {
 367         struct cm32181_chip *cm32181 = iio_priv(indio_dev);
 368         int ret;
 369
 370         switch (mask) {
 371         case IIO_CHAN_INFO_CALIBSCALE:
 372                 cm32181->calibscale = val;
 373                 return val;
 374         case IIO_CHAN_INFO_INT_TIME:
 375                 ret = cm32181_write_als_it(cm32181, val2);
 376                 return ret;
 377         }
 378
 379         return -EINVAL;
 380 }
 381
 382 /**
 383  * cm32181_get_it_available() - Get available ALS IT value
 384  * @dev:        pointer of struct device.
 385  * @attr:       pointer of struct device_attribute.
 386  * @buf:        pointer of return string buffer.
 387  *
 388  * Display the available integration time values by millisecond.
 389  *
 390  * Return: string length.
 391  */
 392 static ssize_t cm32181_get_it_available(struct device *dev,
 393                         struct device_attribute *attr, char *buf)
 394 {
 395         struct cm32181_chip *cm32181 = iio_priv(dev_to_iio_dev(dev));
 396         int i, n, len;
 397
 398         n = cm32181->num_als_it;
 399         for (i = 0, len = 0; i < n; i++)
 400                 len += sprintf(buf + len, "0.%06u ", cm32181->als_it_values[i]);
 401         return len + sprintf(buf + len, "\n");
 402 }
 403
 404 static const struct iio_chan_spec cm32181_channels[] = {
 405         {
 406                 .type = IIO_LIGHT,
 407                 .info_mask_separate =
 408                         BIT(IIO_CHAN_INFO_PROCESSED) |
 409                         BIT(IIO_CHAN_INFO_CALIBSCALE) |
 410                         BIT(IIO_CHAN_INFO_INT_TIME),
 411         }
 412 };
 413
 414 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
 415                         S_IRUGO, cm32181_get_it_available, NULL, 0);
 416
 417 static struct attribute *cm32181_attributes[] = {
 418         &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
 419         NULL,
 420 };
 421
 422 static const struct attribute_group cm32181_attribute_group = {
 423         .attrs = cm32181_attributes
 424 };
 425
 426 static const struct iio_info cm32181_info = {
 427         .read_raw               = &cm32181_read_raw,
 428         .write_raw              = &cm32181_write_raw,
 429         .attrs                  = &cm32181_attribute_group,
 430 };
 431
 432 static int cm32181_probe(struct i2c_client *client)
 433 {
 434         struct device *dev = &client->dev;
 435         struct cm32181_chip *cm32181;
 436         struct iio_dev *indio_dev;
 437         int ret;
 438
 439         indio_dev = devm_iio_device_alloc(dev, sizeof(*cm32181));
 440         if (!indio_dev)
 441                 return -ENOMEM;
 442
 443         /*
 444          * Some ACPI systems list 2 I2C resources for the CM3218 sensor, the
 445          * SMBus Alert Response Address (ARA, 0x0c) and the actual I2C address.
 446          * Detect this and take the following step to deal with it:
 447          * 1. When a SMBus Alert capable sensor has an Alert asserted, it will
 448          *    not respond on its actual I2C address. Read a byte from the ARA
 449          *    to clear any pending Alerts.
 450          * 2. Create a "dummy" client for the actual I2C address and
 451          *    use that client to communicate with the sensor.
 452          */
 453         if (ACPI_HANDLE(dev) && client->addr == SMBUS_ALERT_RESPONSE_ADDRESS) {
 454                 struct i2c_board_info board_info = { .type = "dummy" };
 455
 456                 i2c_smbus_read_byte(client);
 457
 458                 client = i2c_acpi_new_device(dev, 1, &board_info);
 459                 if (IS_ERR(client))
 460                         return PTR_ERR(client);
 461         }
 462
 463         cm32181 = iio_priv(indio_dev);
 464         cm32181->client = client;
 465         cm32181->dev = dev;
 466
 467         mutex_init(&cm32181->lock);
 468         indio_dev->channels = cm32181_channels;
 469         indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
 470         indio_dev->info = &cm32181_info;
 471         indio_dev->name = dev_name(dev);
 472         indio_dev->modes = INDIO_DIRECT_MODE;
 473
 474         ret = cm32181_reg_init(cm32181);
 475         if (ret) {
 476                 dev_err(dev, "%s: register init failed\n", __func__);
 477                 return ret;
 478         }
 479
 480         ret = devm_iio_device_register(dev, indio_dev);
 481         if (ret) {
 482                 dev_err(dev, "%s: regist device failed\n", __func__);
 483                 return ret;
 484         }
 485
 486         return 0;
 487 }
 488
 489 static const struct of_device_id cm32181_of_match[] = {
 490         { .compatible = "capella,cm3218" },
 491         { .compatible = "capella,cm32181" },
 492         { }
 493 };
 494 MODULE_DEVICE_TABLE(of, cm32181_of_match);
 495
 496 #ifdef CONFIG_ACPI
 497 static const struct acpi_device_id cm32181_acpi_match[] = {
 498         { "CPLM3218", 0 },
 499         { }
 500 };
 501 MODULE_DEVICE_TABLE(acpi, cm32181_acpi_match);
 502 #endif
 503
 504 static struct i2c_driver cm32181_driver = {
 505         .driver = {
 506                 .name   = "cm32181",
 507                 .acpi_match_table = ACPI_PTR(cm32181_acpi_match),
 508                 .of_match_table = cm32181_of_match,
 509         },
 510         .probe_new      = cm32181_probe,
 511 };
 512
 513 module_i2c_driver(cm32181_driver);
 514
 515 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
 516 MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
 517 MODULE_LICENSE("GPL");