kernel/drivers/iio/light/cm3232.c

   1 /*
   2  * CM3232 Ambient Light Sensor
   3  *
   4  * Copyright (C) 2014-2015 Capella Microsystems Inc.
   5  * Author: Kevin Tsai <ktsai@capellamicro.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2, as published
   9  * by the Free Software Foundation.
  10  *
  11  * IIO driver for CM3232 (7-bit I2C slave address 0x10).
  12  */
  13
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/iio/iio.h>
  17 #include <linux/iio/sysfs.h>
  18 #include <linux/init.h>
  19
  20 /* Registers Address */
  21 #define CM3232_REG_ADDR_CMD             0x00
  22 #define CM3232_REG_ADDR_ALS             0x50
  23 #define CM3232_REG_ADDR_ID              0x53
  24
  25 #define CM3232_CMD_ALS_DISABLE          BIT(0)
  26
  27 #define CM3232_CMD_ALS_IT_SHIFT         2
  28 #define CM3232_CMD_ALS_IT_MASK          (BIT(2) | BIT(3) | BIT(4))
  29 #define CM3232_CMD_ALS_IT_DEFAULT       (0x01 << CM3232_CMD_ALS_IT_SHIFT)
  30
  31 #define CM3232_CMD_ALS_RESET            BIT(6)
  32
  33 #define CM3232_CMD_DEFAULT              CM3232_CMD_ALS_IT_DEFAULT
  34
  35 #define CM3232_HW_ID                    0x32
  36 #define CM3232_CALIBSCALE_DEFAULT       100000
  37 #define CM3232_CALIBSCALE_RESOLUTION    100000
  38 #define CM3232_MLUX_PER_LUX             1000
  39
  40 #define CM3232_MLUX_PER_BIT_DEFAULT     64
  41 #define CM3232_MLUX_PER_BIT_BASE_IT     100000
  42
  43 static const struct {
  44         int val;
  45         int val2;
  46         u8 it;
  47 } cm3232_als_it_scales[] = {
  48         {0, 100000, 0}, /* 0.100000 */
  49         {0, 200000, 1}, /* 0.200000 */
  50         {0, 400000, 2}, /* 0.400000 */
  51         {0, 800000, 3}, /* 0.800000 */
  52         {1, 600000, 4}, /* 1.600000 */
  53         {3, 200000, 5}, /* 3.200000 */
  54 };
  55
  56 struct cm3232_als_info {
  57         u8 regs_cmd_default;
  58         u8 hw_id;
  59         int calibscale;
  60         int mlux_per_bit;
  61         int mlux_per_bit_base_it;
  62 };
  63
  64 static struct cm3232_als_info cm3232_als_info_default = {
  65         .regs_cmd_default = CM3232_CMD_DEFAULT,
  66         .hw_id = CM3232_HW_ID,
  67         .calibscale = CM3232_CALIBSCALE_DEFAULT,
  68         .mlux_per_bit = CM3232_MLUX_PER_BIT_DEFAULT,
  69         .mlux_per_bit_base_it = CM3232_MLUX_PER_BIT_BASE_IT,
  70 };
  71
  72 struct cm3232_chip {
  73         struct i2c_client *client;
  74         struct cm3232_als_info *als_info;
  75         u8 regs_cmd;
  76         u16 regs_als;
  77 };
  78
  79 /**
  80  * cm3232_reg_init() - Initialize CM3232
  81  * @chip:       pointer of struct cm3232_chip.
  82  *
  83  * Check and initialize CM3232 ambient light sensor.
  84  *
  85  * Return: 0 for success; otherwise for error code.
  86  */
  87 static int cm3232_reg_init(struct cm3232_chip *chip)
  88 {
  89         struct i2c_client *client = chip->client;
  90         s32 ret;
  91
  92         chip->als_info = &cm3232_als_info_default;
  93
  94         /* Identify device */
  95         ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID);
  96         if (ret < 0) {
  97                 dev_err(&chip->client->dev, "Error reading addr_id\n");
  98                 return ret;
  99         }
 100
 101         if ((ret & 0xFF) != chip->als_info->hw_id)
 102                 return -ENODEV;
 103
 104         /* Disable and reset device */
 105         chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET;
 106         ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 107                                         chip->regs_cmd);
 108         if (ret < 0) {
 109                 dev_err(&chip->client->dev, "Error writing reg_cmd\n");
 110                 return ret;
 111         }
 112
 113         /* Register default value */
 114         chip->regs_cmd = chip->als_info->regs_cmd_default;
 115
 116         /* Configure register */
 117         ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 118                                         chip->regs_cmd);
 119         if (ret < 0)
 120                 dev_err(&chip->client->dev, "Error writing reg_cmd\n");
 121
 122         return 0;
 123 }
 124
 125 /**
 126  *  cm3232_read_als_it() - Get sensor integration time
 127  *  @chip:      pointer of struct cm3232_chip
 128  *  @val:       pointer of int to load the integration (sec).
 129  *  @val2:      pointer of int to load the integration time (microsecond).
 130  *
 131  *  Report the current integration time.
 132  *
 133  *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 134  */
 135 static int cm3232_read_als_it(struct cm3232_chip *chip, int *val, int *val2)
 136 {
 137         u16 als_it;
 138         int i;
 139
 140         als_it = chip->regs_cmd;
 141         als_it &= CM3232_CMD_ALS_IT_MASK;
 142         als_it >>= CM3232_CMD_ALS_IT_SHIFT;
 143         for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
 144                 if (als_it == cm3232_als_it_scales[i].it) {
 145                         *val = cm3232_als_it_scales[i].val;
 146                         *val2 = cm3232_als_it_scales[i].val2;
 147                         return IIO_VAL_INT_PLUS_MICRO;
 148                 }
 149         }
 150
 151         return -EINVAL;
 152 }
 153
 154 /**
 155  * cm3232_write_als_it() - Write sensor integration time
 156  * @chip:       pointer of struct cm3232_chip.
 157  * @val:        integration time in second.
 158  * @val2:       integration time in microsecond.
 159  *
 160  * Convert integration time to sensor value.
 161  *
 162  * Return: i2c_smbus_write_byte_data command return value.
 163  */
 164 static int cm3232_write_als_it(struct cm3232_chip *chip, int val, int val2)
 165 {
 166         struct i2c_client *client = chip->client;
 167         u16 als_it, cmd;
 168         int i;
 169         s32 ret;
 170
 171         for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
 172                 if (val == cm3232_als_it_scales[i].val &&
 173                         val2 == cm3232_als_it_scales[i].val2) {
 174
 175                         als_it = cm3232_als_it_scales[i].it;
 176                         als_it <<= CM3232_CMD_ALS_IT_SHIFT;
 177
 178                         cmd = chip->regs_cmd & ~CM3232_CMD_ALS_IT_MASK;
 179                         cmd |= als_it;
 180                         ret = i2c_smbus_write_byte_data(client,
 181                                                         CM3232_REG_ADDR_CMD,
 182                                                         cmd);
 183                         if (ret < 0)
 184                                 return ret;
 185                         chip->regs_cmd = cmd;
 186                         return 0;
 187                 }
 188         }
 189         return -EINVAL;
 190 }
 191
 192 /**
 193  * cm3232_get_lux() - report current lux value
 194  * @chip:       pointer of struct cm3232_chip.
 195  *
 196  * Convert sensor data to lux.  It depends on integration
 197  * time and calibscale variable.
 198  *
 199  * Return: Zero or positive value is lux, otherwise error code.
 200  */
 201 static int cm3232_get_lux(struct cm3232_chip *chip)
 202 {
 203         struct i2c_client *client = chip->client;
 204         struct cm3232_als_info *als_info = chip->als_info;
 205         int ret;
 206         int val, val2;
 207         int als_it;
 208         u64 lux;
 209
 210         /* Calculate mlux per bit based on als_it */
 211         ret = cm3232_read_als_it(chip, &val, &val2);
 212         if (ret < 0)
 213                 return -EINVAL;
 214         als_it = val * 1000000 + val2;
 215         lux = (__force u64)als_info->mlux_per_bit;
 216         lux *= als_info->mlux_per_bit_base_it;
 217         lux = div_u64(lux, als_it);
 218
 219         ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ALS);
 220         if (ret < 0) {
 221                 dev_err(&client->dev, "Error reading reg_addr_als\n");
 222                 return ret;
 223         }
 224
 225         chip->regs_als = (u16)ret;
 226         lux *= chip->regs_als;
 227         lux *= als_info->calibscale;
 228         lux = div_u64(lux, CM3232_CALIBSCALE_RESOLUTION);
 229         lux = div_u64(lux, CM3232_MLUX_PER_LUX);
 230
 231         if (lux > 0xFFFF)
 232                 lux = 0xFFFF;
 233
 234         return (int)lux;
 235 }
 236
 237 static int cm3232_read_raw(struct iio_dev *indio_dev,
 238                         struct iio_chan_spec const *chan,
 239                         int *val, int *val2, long mask)
 240 {
 241         struct cm3232_chip *chip = iio_priv(indio_dev);
 242         struct cm3232_als_info *als_info = chip->als_info;
 243         int ret;
 244
 245         switch (mask) {
 246         case IIO_CHAN_INFO_PROCESSED:
 247                 ret = cm3232_get_lux(chip);
 248                 if (ret < 0)
 249                         return ret;
 250                 *val = ret;
 251                 return IIO_VAL_INT;
 252         case IIO_CHAN_INFO_CALIBSCALE:
 253                 *val = als_info->calibscale;
 254                 return IIO_VAL_INT;
 255         case IIO_CHAN_INFO_INT_TIME:
 256                 return cm3232_read_als_it(chip, val, val2);
 257         }
 258
 259         return -EINVAL;
 260 }
 261
 262 static int cm3232_write_raw(struct iio_dev *indio_dev,
 263                         struct iio_chan_spec const *chan,
 264                         int val, int val2, long mask)
 265 {
 266         struct cm3232_chip *chip = iio_priv(indio_dev);
 267         struct cm3232_als_info *als_info = chip->als_info;
 268
 269         switch (mask) {
 270         case IIO_CHAN_INFO_CALIBSCALE:
 271                 als_info->calibscale = val;
 272                 return 0;
 273         case IIO_CHAN_INFO_INT_TIME:
 274                 return cm3232_write_als_it(chip, val, val2);
 275         }
 276
 277         return -EINVAL;
 278 }
 279
 280 /**
 281  * cm3232_get_it_available() - Get available ALS IT value
 282  * @dev:        pointer of struct device.
 283  * @attr:       pointer of struct device_attribute.
 284  * @buf:        pointer of return string buffer.
 285  *
 286  * Display the available integration time in second.
 287  *
 288  * Return: string length.
 289  */
 290 static ssize_t cm3232_get_it_available(struct device *dev,
 291                         struct device_attribute *attr, char *buf)
 292 {
 293         int i, len;
 294
 295         for (i = 0, len = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++)
 296                 len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
 297                         cm3232_als_it_scales[i].val,
 298                         cm3232_als_it_scales[i].val2);
 299         return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
 300 }
 301
 302 static const struct iio_chan_spec cm3232_channels[] = {
 303         {
 304                 .type = IIO_LIGHT,
 305                 .info_mask_separate =
 306                         BIT(IIO_CHAN_INFO_PROCESSED) |
 307                         BIT(IIO_CHAN_INFO_CALIBSCALE) |
 308                         BIT(IIO_CHAN_INFO_INT_TIME),
 309         }
 310 };
 311
 312 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
 313                         S_IRUGO, cm3232_get_it_available, NULL, 0);
 314
 315 static struct attribute *cm3232_attributes[] = {
 316         &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
 317         NULL,
 318 };
 319
 320 static const struct attribute_group cm3232_attribute_group = {
 321         .attrs = cm3232_attributes
 322 };
 323
 324 static const struct iio_info cm3232_info = {
 325         .driver_module          = THIS_MODULE,
 326         .read_raw               = &cm3232_read_raw,
 327         .write_raw              = &cm3232_write_raw,
 328         .attrs                  = &cm3232_attribute_group,
 329 };
 330
 331 static int cm3232_probe(struct i2c_client *client,
 332                         const struct i2c_device_id *id)
 333 {
 334         struct cm3232_chip *chip;
 335         struct iio_dev *indio_dev;
 336         int ret;
 337
 338         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
 339         if (!indio_dev)
 340                 return -ENOMEM;
 341
 342         chip = iio_priv(indio_dev);
 343         i2c_set_clientdata(client, indio_dev);
 344         chip->client = client;
 345
 346         indio_dev->dev.parent = &client->dev;
 347         indio_dev->channels = cm3232_channels;
 348         indio_dev->num_channels = ARRAY_SIZE(cm3232_channels);
 349         indio_dev->info = &cm3232_info;
 350         indio_dev->name = id->name;
 351         indio_dev->modes = INDIO_DIRECT_MODE;
 352
 353         ret = cm3232_reg_init(chip);
 354         if (ret) {
 355                 dev_err(&client->dev,
 356                         "%s: register init failed\n",
 357                         __func__);
 358                 return ret;
 359         }
 360
 361         return iio_device_register(indio_dev);
 362 }
 363
 364 static int cm3232_remove(struct i2c_client *client)
 365 {
 366         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 367
 368         i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 369                 CM3232_CMD_ALS_DISABLE);
 370
 371         iio_device_unregister(indio_dev);
 372
 373         return 0;
 374 }
 375
 376 static const struct i2c_device_id cm3232_id[] = {
 377         {"cm3232", 0},
 378         {}
 379 };
 380
 381 #ifdef CONFIG_PM_SLEEP
 382 static int cm3232_suspend(struct device *dev)
 383 {
 384         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 385         struct cm3232_chip *chip = iio_priv(indio_dev);
 386         struct i2c_client *client = chip->client;
 387         int ret;
 388
 389         chip->regs_cmd |= CM3232_CMD_ALS_DISABLE;
 390         ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 391                                         chip->regs_cmd);
 392
 393         return ret;
 394 }
 395
 396 static int cm3232_resume(struct device *dev)
 397 {
 398         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 399         struct cm3232_chip *chip = iio_priv(indio_dev);
 400         struct i2c_client *client = chip->client;
 401         int ret;
 402
 403         chip->regs_cmd &= ~CM3232_CMD_ALS_DISABLE;
 404         ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
 405                                         chip->regs_cmd | CM3232_CMD_ALS_RESET);
 406
 407         return ret;
 408 }
 409
 410 static const struct dev_pm_ops cm3232_pm_ops = {
 411         SET_SYSTEM_SLEEP_PM_OPS(cm3232_suspend, cm3232_resume)};
 412 #endif
 413
 414 MODULE_DEVICE_TABLE(i2c, cm3232_id);
 415
 416 static const struct of_device_id cm3232_of_match[] = {
 417         {.compatible = "capella,cm3232"},
 418         {}
 419 };
 420
 421 static struct i2c_driver cm3232_driver = {
 422         .driver = {
 423                 .name   = "cm3232",
 424                 .owner  = THIS_MODULE,
 425                 .of_match_table = of_match_ptr(cm3232_of_match),
 426 #ifdef CONFIG_PM_SLEEP
 427                 .pm     = &cm3232_pm_ops,
 428 #endif
 429         },
 430         .id_table       = cm3232_id,
 431         .probe          = cm3232_probe,
 432         .remove         = cm3232_remove,
 433 };
 434
 435 module_i2c_driver(cm3232_driver);
 436
 437 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
 438 MODULE_DESCRIPTION("CM3232 ambient light sensor driver");
 439 MODULE_LICENSE("GPL");