linux/drivers/iio/light/bh1750.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light sensor driver
   4 *
   5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   6 *
   7 * Data sheets:
   8 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1710fvc-e.pdf
   9 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1715fvc-e.pdf
  10 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf
  11 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
  12 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1751fvi-e.pdf
  13 *
  14 * 7-bit I2C slave addresses:
  15 *  0x23 (ADDR pin low)
  16 *  0x5C (ADDR pin high)
  17 *
  18 */
  19
  20#include <linux/delay.h>
  21#include <linux/i2c.h>
  22#include <linux/iio/iio.h>
  23#include <linux/iio/sysfs.h>
  24#include <linux/module.h>
  25
  26#define BH1750_POWER_DOWN               0x00
  27#define BH1750_ONE_TIME_H_RES_MODE      0x20 /* auto-mode for BH1721 */
  28#define BH1750_CHANGE_INT_TIME_H_BIT    0x40
  29#define BH1750_CHANGE_INT_TIME_L_BIT    0x60
  30
  31enum {
  32        BH1710,
  33        BH1721,
  34        BH1750,
  35};
  36
  37struct bh1750_chip_info;
  38struct bh1750_data {
  39        struct i2c_client *client;
  40        struct mutex lock;
  41        const struct bh1750_chip_info *chip_info;
  42        u16 mtreg;
  43};
  44
  45struct bh1750_chip_info {
  46        u16 mtreg_min;
  47        u16 mtreg_max;
  48        u16 mtreg_default;
  49        int mtreg_to_usec;
  50        int mtreg_to_scale;
  51
  52        /*
  53         * For BH1710/BH1721 all possible integration time values won't fit
  54         * into one page so displaying is limited to every second one.
  55         * Note, that user can still write proper values which were not
  56         * listed.
  57         */
  58        int inc;
  59
  60        u16 int_time_low_mask;
  61        u16 int_time_high_mask;
  62}
  63
  64static const bh1750_chip_info_tbl[] = {
  65        [BH1710] = { 140, 1022, 300, 400,  250000000, 2, 0x001F, 0x03E0 },
  66        [BH1721] = { 140, 1020, 300, 400,  250000000, 2, 0x0010, 0x03E0 },
  67        [BH1750] = { 31,  254,  69,  1740, 57500000,  1, 0x001F, 0x00E0 },
  68};
  69
  70static int bh1750_change_int_time(struct bh1750_data *data, int usec)
  71{
  72        int ret;
  73        u16 val;
  74        u8 regval;
  75        const struct bh1750_chip_info *chip_info = data->chip_info;
  76
  77        if ((usec % chip_info->mtreg_to_usec) != 0)
  78                return -EINVAL;
  79
  80        val = usec / chip_info->mtreg_to_usec;
  81        if (val < chip_info->mtreg_min || val > chip_info->mtreg_max)
  82                return -EINVAL;
  83
  84        ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
  85        if (ret < 0)
  86                return ret;
  87
  88        regval = (val & chip_info->int_time_high_mask) >> 5;
  89        ret = i2c_smbus_write_byte(data->client,
  90                                   BH1750_CHANGE_INT_TIME_H_BIT | regval);
  91        if (ret < 0)
  92                return ret;
  93
  94        regval = val & chip_info->int_time_low_mask;
  95        ret = i2c_smbus_write_byte(data->client,
  96                                   BH1750_CHANGE_INT_TIME_L_BIT | regval);
  97        if (ret < 0)
  98                return ret;
  99
 100        data->mtreg = val;
 101
 102        return 0;
 103}
 104
 105static int bh1750_read(struct bh1750_data *data, int *val)
 106{
 107        int ret;
 108        __be16 result;
 109        const struct bh1750_chip_info *chip_info = data->chip_info;
 110        unsigned long delay = chip_info->mtreg_to_usec * data->mtreg;
 111
 112        /*
 113         * BH1721 will enter continuous mode on receiving this command.
 114         * Note, that this eliminates need for bh1750_resume().
 115         */
 116        ret = i2c_smbus_write_byte(data->client, BH1750_ONE_TIME_H_RES_MODE);
 117        if (ret < 0)
 118                return ret;
 119
 120        usleep_range(delay + 15000, delay + 40000);
 121
 122        ret = i2c_master_recv(data->client, (char *)&result, 2);
 123        if (ret < 0)
 124                return ret;
 125
 126        *val = be16_to_cpu(result);
 127
 128        return 0;
 129}
 130
 131static int bh1750_read_raw(struct iio_dev *indio_dev,
 132                           struct iio_chan_spec const *chan,
 133                           int *val, int *val2, long mask)
 134{
 135        int ret, tmp;
 136        struct bh1750_data *data = iio_priv(indio_dev);
 137        const struct bh1750_chip_info *chip_info = data->chip_info;
 138
 139        switch (mask) {
 140        case IIO_CHAN_INFO_RAW:
 141                switch (chan->type) {
 142                case IIO_LIGHT:
 143                        mutex_lock(&data->lock);
 144                        ret = bh1750_read(data, val);
 145                        mutex_unlock(&data->lock);
 146                        if (ret < 0)
 147                                return ret;
 148
 149                        return IIO_VAL_INT;
 150                default:
 151                        return -EINVAL;
 152                }
 153        case IIO_CHAN_INFO_SCALE:
 154                tmp = chip_info->mtreg_to_scale / data->mtreg;
 155                *val = tmp / 1000000;
 156                *val2 = tmp % 1000000;
 157                return IIO_VAL_INT_PLUS_MICRO;
 158        case IIO_CHAN_INFO_INT_TIME:
 159                *val = 0;
 160                *val2 = chip_info->mtreg_to_usec * data->mtreg;
 161                return IIO_VAL_INT_PLUS_MICRO;
 162        default:
 163                return -EINVAL;
 164        }
 165}
 166
 167static int bh1750_write_raw(struct iio_dev *indio_dev,
 168                            struct iio_chan_spec const *chan,
 169                            int val, int val2, long mask)
 170{
 171        int ret;
 172        struct bh1750_data *data = iio_priv(indio_dev);
 173
 174        switch (mask) {
 175        case IIO_CHAN_INFO_INT_TIME:
 176                if (val != 0)
 177                        return -EINVAL;
 178
 179                mutex_lock(&data->lock);
 180                ret = bh1750_change_int_time(data, val2);
 181                mutex_unlock(&data->lock);
 182                return ret;
 183        default:
 184                return -EINVAL;
 185        }
 186}
 187
 188static ssize_t bh1750_show_int_time_available(struct device *dev,
 189                struct device_attribute *attr, char *buf)
 190{
 191        int i;
 192        size_t len = 0;
 193        struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev));
 194        const struct bh1750_chip_info *chip_info = data->chip_info;
 195
 196        for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += chip_info->inc)
 197                len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ",
 198                                 chip_info->mtreg_to_usec * i);
 199
 200        buf[len - 1] = '\n';
 201
 202        return len;
 203}
 204
 205static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available);
 206
 207static struct attribute *bh1750_attributes[] = {
 208        &iio_dev_attr_integration_time_available.dev_attr.attr,
 209        NULL,
 210};
 211
 212static const struct attribute_group bh1750_attribute_group = {
 213        .attrs = bh1750_attributes,
 214};
 215
 216static const struct iio_info bh1750_info = {
 217        .attrs = &bh1750_attribute_group,
 218        .read_raw = bh1750_read_raw,
 219        .write_raw = bh1750_write_raw,
 220};
 221
 222static const struct iio_chan_spec bh1750_channels[] = {
 223        {
 224                .type = IIO_LIGHT,
 225                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 226                                      BIT(IIO_CHAN_INFO_SCALE) |
 227                                      BIT(IIO_CHAN_INFO_INT_TIME)
 228        }
 229};
 230
 231static int bh1750_probe(struct i2c_client *client,
 232                        const struct i2c_device_id *id)
 233{
 234        int ret, usec;
 235        struct bh1750_data *data;
 236        struct iio_dev *indio_dev;
 237
 238        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 239                                I2C_FUNC_SMBUS_WRITE_BYTE))
 240                return -EOPNOTSUPP;
 241
 242        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 243        if (!indio_dev)
 244                return -ENOMEM;
 245
 246        data = iio_priv(indio_dev);
 247        i2c_set_clientdata(client, indio_dev);
 248        data->client = client;
 249        data->chip_info = &bh1750_chip_info_tbl[id->driver_data];
 250
 251        usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default;
 252        ret = bh1750_change_int_time(data, usec);
 253        if (ret < 0)
 254                return ret;
 255
 256        mutex_init(&data->lock);
 257        indio_dev->dev.parent = &client->dev;
 258        indio_dev->info = &bh1750_info;
 259        indio_dev->name = id->name;
 260        indio_dev->channels = bh1750_channels;
 261        indio_dev->num_channels = ARRAY_SIZE(bh1750_channels);
 262        indio_dev->modes = INDIO_DIRECT_MODE;
 263
 264        return iio_device_register(indio_dev);
 265}
 266
 267static int bh1750_remove(struct i2c_client *client)
 268{
 269        struct iio_dev *indio_dev = i2c_get_clientdata(client);
 270        struct bh1750_data *data = iio_priv(indio_dev);
 271
 272        iio_device_unregister(indio_dev);
 273
 274        mutex_lock(&data->lock);
 275        i2c_smbus_write_byte(client, BH1750_POWER_DOWN);
 276        mutex_unlock(&data->lock);
 277
 278        return 0;
 279}
 280
 281static int __maybe_unused bh1750_suspend(struct device *dev)
 282{
 283        int ret;
 284        struct bh1750_data *data =
 285                iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 286
 287        /*
 288         * This is mainly for BH1721 which doesn't enter power down
 289         * mode automatically.
 290         */
 291        mutex_lock(&data->lock);
 292        ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN);
 293        mutex_unlock(&data->lock);
 294
 295        return ret;
 296}
 297
 298static SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL);
 299
 300static const struct i2c_device_id bh1750_id[] = {
 301        { "bh1710", BH1710 },
 302        { "bh1715", BH1750 },
 303        { "bh1721", BH1721 },
 304        { "bh1750", BH1750 },
 305        { "bh1751", BH1750 },
 306        { }
 307};
 308MODULE_DEVICE_TABLE(i2c, bh1750_id);
 309
 310static const struct of_device_id bh1750_of_match[] = {
 311        { .compatible = "rohm,bh1710", },
 312        { .compatible = "rohm,bh1715", },
 313        { .compatible = "rohm,bh1721", },
 314        { .compatible = "rohm,bh1750", },
 315        { .compatible = "rohm,bh1751", },
 316        { }
 317};
 318MODULE_DEVICE_TABLE(of, bh1750_of_match);
 319
 320static struct i2c_driver bh1750_driver = {
 321        .driver = {
 322                .name = "bh1750",
 323                .of_match_table = bh1750_of_match,
 324                .pm = &bh1750_pm_ops,
 325        },
 326        .probe = bh1750_probe,
 327        .remove = bh1750_remove,
 328        .id_table = bh1750_id,
 329
 330};
 331module_i2c_driver(bh1750_driver);
 332
 333MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 334MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver");
 335MODULE_LICENSE("GPL v2");
 336