drivers/iio/light/cm32181.c

   1 /*
   2  * Copyright (C) 2013 Capella Microsystems Inc.
   3  * Author: Kevin Tsai <ktsai@capellamicro.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2, as published
   7  * by the Free Software Foundation.
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/err.h>
  12 #include <linux/i2c.h>
  13 #include <linux/mutex.h>
  14 #include <linux/module.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/regulator/consumer.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/sysfs.h>
  19 #include <linux/iio/events.h>
  20 #include <linux/init.h>
  21
  22 /* Registers Address */
  23 #define CM32181_REG_ADDR_CMD            0x00
  24 #define CM32181_REG_ADDR_ALS            0x04
  25 #define CM32181_REG_ADDR_STATUS         0x06
  26 #define CM32181_REG_ADDR_ID             0x07
  27
  28 /* Number of Configurable Registers */
  29 #define CM32181_CONF_REG_NUM            0x01
  30
  31 /* CMD register */
  32 #define CM32181_CMD_ALS_ENABLE          0x00
  33 #define CM32181_CMD_ALS_DISABLE         0x01
  34 #define CM32181_CMD_ALS_INT_EN          0x02
  35
  36 #define CM32181_CMD_ALS_IT_SHIFT        6
  37 #define CM32181_CMD_ALS_IT_MASK         (0x0F << CM32181_CMD_ALS_IT_SHIFT)
  38 #define CM32181_CMD_ALS_IT_DEFAULT      (0x00 << CM32181_CMD_ALS_IT_SHIFT)
  39
  40 #define CM32181_CMD_ALS_SM_SHIFT        11
  41 #define CM32181_CMD_ALS_SM_MASK         (0x03 << CM32181_CMD_ALS_SM_SHIFT)
  42 #define CM32181_CMD_ALS_SM_DEFAULT      (0x01 << CM32181_CMD_ALS_SM_SHIFT)
  43
  44 #define CM32181_MLUX_PER_BIT            5       /* ALS_SM=01 IT=800ms */
  45 #define CM32181_MLUX_PER_BIT_BASE_IT    800000  /* Based on IT=800ms */
  46 #define CM32181_CALIBSCALE_DEFAULT      1000
  47 #define CM32181_CALIBSCALE_RESOLUTION   1000
  48 #define MLUX_PER_LUX                    1000
  49
  50 static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
  51         CM32181_REG_ADDR_CMD,
  52 };
  53
  54 static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
  55 static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
  56         800000};
  57
  58 struct cm32181_chip {
  59         struct i2c_client *client;
  60         struct mutex lock;
  61         u16 conf_regs[CM32181_CONF_REG_NUM];
  62         int calibscale;
  63 };
  64
  65 /**
  66  * cm32181_reg_init() - Initialize CM32181 registers
  67  * @cm32181:    pointer of struct cm32181.
  68  *
  69  * Initialize CM32181 ambient light sensor register to default values.
  70  *
  71  * Return: 0 for success; otherwise for error code.
  72  */
  73 static int cm32181_reg_init(struct cm32181_chip *cm32181)
  74 {
  75         struct i2c_client *client = cm32181->client;
  76         int i;
  77         s32 ret;
  78
  79         ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
  80         if (ret < 0)
  81                 return ret;
  82
  83         /* check device ID */
  84         if ((ret & 0xFF) != 0x81)
  85                 return -ENODEV;
  86
  87         /* Default Values */
  88         cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
  89                         CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
  90         cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
  91
  92         /* Initialize registers*/
  93         for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
  94                 ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
  95                         cm32181->conf_regs[i]);
  96                 if (ret < 0)
  97                         return ret;
  98         }
  99
 100         return 0;
 101 }
 102
 103 /**
 104  *  cm32181_read_als_it() - Get sensor integration time (ms)
 105  *  @cm32181:   pointer of struct cm32181
 106  *  @val2:      pointer of int to load the als_it value.
 107  *
 108  *  Report the current integartion time by millisecond.
 109  *
 110  *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 111  */
 112 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
 113 {
 114         u16 als_it;
 115         int i;
 116
 117         als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
 118         als_it &= CM32181_CMD_ALS_IT_MASK;
 119         als_it >>= CM32181_CMD_ALS_IT_SHIFT;
 120         for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
 121                 if (als_it == als_it_bits[i]) {
 122                         *val2 = als_it_value[i];
 123                         return IIO_VAL_INT_PLUS_MICRO;
 124                 }
 125         }
 126
 127         return -EINVAL;
 128 }
 129
 130 /**
 131  * cm32181_write_als_it() - Write sensor integration time
 132  * @cm32181:    pointer of struct cm32181.
 133  * @val:        integration time by millisecond.
 134  *
 135  * Convert integration time (ms) to sensor value.
 136  *
 137  * Return: i2c_smbus_write_word_data command return value.
 138  */
 139 static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
 140 {
 141         struct i2c_client *client = cm32181->client;
 142         u16 als_it;
 143         int ret, i, n;
 144
 145         n = ARRAY_SIZE(als_it_value);
 146         for (i = 0; i < n; i++)
 147                 if (val <= als_it_value[i])
 148                         break;
 149         if (i >= n)
 150                 i = n - 1;
 151
 152         als_it = als_it_bits[i];
 153         als_it <<= CM32181_CMD_ALS_IT_SHIFT;
 154
 155         mutex_lock(&cm32181->lock);
 156         cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
 157                 ~CM32181_CMD_ALS_IT_MASK;
 158         cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
 159                 als_it;
 160         ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
 161                         cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
 162         mutex_unlock(&cm32181->lock);
 163
 164         return ret;
 165 }
 166
 167 /**
 168  * cm32181_get_lux() - report current lux value
 169  * @cm32181:    pointer of struct cm32181.
 170  *
 171  * Convert sensor raw data to lux.  It depends on integration
 172  * time and calibscale variable.
 173  *
 174  * Return: Positive value is lux, otherwise is error code.
 175  */
 176 static int cm32181_get_lux(struct cm32181_chip *cm32181)
 177 {
 178         struct i2c_client *client = cm32181->client;
 179         int ret;
 180         int als_it;
 181         unsigned long lux;
 182
 183         ret = cm32181_read_als_it(cm32181, &als_it);
 184         if (ret < 0)
 185                 return -EINVAL;
 186
 187         lux = CM32181_MLUX_PER_BIT;
 188         lux *= CM32181_MLUX_PER_BIT_BASE_IT;
 189         lux /= als_it;
 190
 191         ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
 192         if (ret < 0)
 193                 return ret;
 194
 195         lux *= ret;
 196         lux *= cm32181->calibscale;
 197         lux /= CM32181_CALIBSCALE_RESOLUTION;
 198         lux /= MLUX_PER_LUX;
 199
 200         if (lux > 0xFFFF)
 201                 lux = 0xFFFF;
 202
 203         return lux;
 204 }
 205
 206 static int cm32181_read_raw(struct iio_dev *indio_dev,
 207                             struct iio_chan_spec const *chan,
 208                             int *val, int *val2, long mask)
 209 {
 210         struct cm32181_chip *cm32181 = iio_priv(indio_dev);
 211         int ret;
 212
 213         switch (mask) {
 214         case IIO_CHAN_INFO_PROCESSED:
 215                 ret = cm32181_get_lux(cm32181);
 216                 if (ret < 0)
 217                         return ret;
 218                 *val = ret;
 219                 return IIO_VAL_INT;
 220         case IIO_CHAN_INFO_CALIBSCALE:
 221                 *val = cm32181->calibscale;
 222                 return IIO_VAL_INT;
 223         case IIO_CHAN_INFO_INT_TIME:
 224                 *val = 0;
 225                 ret = cm32181_read_als_it(cm32181, val2);
 226                 return ret;
 227         }
 228
 229         return -EINVAL;
 230 }
 231
 232 static int cm32181_write_raw(struct iio_dev *indio_dev,
 233                              struct iio_chan_spec const *chan,
 234                              int val, int val2, long mask)
 235 {
 236         struct cm32181_chip *cm32181 = iio_priv(indio_dev);
 237         int ret;
 238
 239         switch (mask) {
 240         case IIO_CHAN_INFO_CALIBSCALE:
 241                 cm32181->calibscale = val;
 242                 return val;
 243         case IIO_CHAN_INFO_INT_TIME:
 244                 ret = cm32181_write_als_it(cm32181, val2);
 245                 return ret;
 246         }
 247
 248         return -EINVAL;
 249 }
 250
 251 /**
 252  * cm32181_get_it_available() - Get available ALS IT value
 253  * @dev:        pointer of struct device.
 254  * @attr:       pointer of struct device_attribute.
 255  * @buf:        pointer of return string buffer.
 256  *
 257  * Display the available integration time values by millisecond.
 258  *
 259  * Return: string length.
 260  */
 261 static ssize_t cm32181_get_it_available(struct device *dev,
 262                         struct device_attribute *attr, char *buf)
 263 {
 264         int i, n, len;
 265
 266         n = ARRAY_SIZE(als_it_value);
 267         for (i = 0, len = 0; i < n; i++)
 268                 len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
 269         return len + sprintf(buf + len, "\n");
 270 }
 271
 272 static const struct iio_chan_spec cm32181_channels[] = {
 273         {
 274                 .type = IIO_LIGHT,
 275                 .info_mask_separate =
 276                         BIT(IIO_CHAN_INFO_PROCESSED) |
 277                         BIT(IIO_CHAN_INFO_CALIBSCALE) |
 278                         BIT(IIO_CHAN_INFO_INT_TIME),
 279         }
 280 };
 281
 282 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
 283                         S_IRUGO, cm32181_get_it_available, NULL, 0);
 284
 285 static struct attribute *cm32181_attributes[] = {
 286         &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
 287         NULL,
 288 };
 289
 290 static const struct attribute_group cm32181_attribute_group = {
 291         .attrs = cm32181_attributes
 292 };
 293
 294 static const struct iio_info cm32181_info = {
 295         .driver_module          = THIS_MODULE,
 296         .read_raw               = &cm32181_read_raw,
 297         .write_raw              = &cm32181_write_raw,
 298         .attrs                  = &cm32181_attribute_group,
 299 };
 300
 301 static int cm32181_probe(struct i2c_client *client,
 302                         const struct i2c_device_id *id)
 303 {
 304         struct cm32181_chip *cm32181;
 305         struct iio_dev *indio_dev;
 306         int ret;
 307
 308         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
 309         if (!indio_dev) {
 310                 dev_err(&client->dev, "devm_iio_device_alloc failed\n");
 311                 return -ENOMEM;
 312         }
 313
 314         cm32181 = iio_priv(indio_dev);
 315         i2c_set_clientdata(client, indio_dev);
 316         cm32181->client = client;
 317
 318         mutex_init(&cm32181->lock);
 319         indio_dev->dev.parent = &client->dev;
 320         indio_dev->channels = cm32181_channels;
 321         indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
 322         indio_dev->info = &cm32181_info;
 323         indio_dev->name = id->name;
 324         indio_dev->modes = INDIO_DIRECT_MODE;
 325
 326         ret = cm32181_reg_init(cm32181);
 327         if (ret) {
 328                 dev_err(&client->dev,
 329                         "%s: register init failed\n",
 330                         __func__);
 331                 return ret;
 332         }
 333
 334         ret = devm_iio_device_register(&client->dev, indio_dev);
 335         if (ret) {
 336                 dev_err(&client->dev,
 337                         "%s: regist device failed\n",
 338                         __func__);
 339                 return ret;
 340         }
 341
 342         return 0;
 343 }
 344
 345 static const struct i2c_device_id cm32181_id[] = {
 346         { "cm32181", 0 },
 347         { }
 348 };
 349
 350 MODULE_DEVICE_TABLE(i2c, cm32181_id);
 351
 352 static const struct of_device_id cm32181_of_match[] = {
 353         { .compatible = "capella,cm32181" },
 354         { }
 355 };
 356
 357 static struct i2c_driver cm32181_driver = {
 358         .driver = {
 359                 .name   = "cm32181",
 360                 .of_match_table = of_match_ptr(cm32181_of_match),
 361                 .owner  = THIS_MODULE,
 362         },
 363         .id_table       = cm32181_id,
 364         .probe          = cm32181_probe,
 365 };
 366
 367 module_i2c_driver(cm32181_driver);
 368
 369 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
 370 MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
 371 MODULE_LICENSE("GPL");