root/drivers/iio/humidity/hdc2010.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * hdc2010.c - Support for the TI HDC2010 and HDC2080
 * temperature + relative humidity sensors
 *
 * Copyright (C) 2020 Norphonic AS
 * Author: Eugene Zaikonnikov <ez@norphonic.com>
 *
 * Datasheet: https://www.ti.com/product/HDC2010/datasheet
 * Datasheet: https://www.ti.com/product/HDC2080/datasheet
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/bitops.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define HDC2010_REG_TEMP_LOW                    0x00
#define HDC2010_REG_TEMP_HIGH                   0x01
#define HDC2010_REG_HUMIDITY_LOW                0x02
#define HDC2010_REG_HUMIDITY_HIGH               0x03
#define HDC2010_REG_INTERRUPT_DRDY              0x04
#define HDC2010_REG_TEMP_MAX                    0x05
#define HDC2010_REG_HUMIDITY_MAX                0x06
#define HDC2010_REG_INTERRUPT_EN                0x07
#define HDC2010_REG_TEMP_OFFSET_ADJ             0x08
#define HDC2010_REG_HUMIDITY_OFFSET_ADJ         0x09
#define HDC2010_REG_TEMP_THR_L                  0x0a
#define HDC2010_REG_TEMP_THR_H                  0x0b
#define HDC2010_REG_RH_THR_L                    0x0c
#define HDC2010_REG_RH_THR_H                    0x0d
#define HDC2010_REG_RESET_DRDY_INT_CONF         0x0e
#define HDC2010_REG_MEASUREMENT_CONF            0x0f

#define HDC2010_MEAS_CONF                       GENMASK(2, 1)
#define HDC2010_MEAS_TRIG                       BIT(0)
#define HDC2010_HEATER_EN                       BIT(3)
#define HDC2010_AMM                             GENMASK(6, 4)

struct hdc2010_data {
        struct i2c_client *client;
        struct mutex lock;
        u8 measurement_config;
        u8 interrupt_config;
        u8 drdy_config;
};

enum hdc2010_addr_groups {
        HDC2010_GROUP_TEMP = 0,
        HDC2010_GROUP_HUMIDITY,
};

struct hdc2010_reg_record {
        unsigned long primary;
        unsigned long peak;
};

static const struct hdc2010_reg_record hdc2010_reg_translation[] = {
        [HDC2010_GROUP_TEMP] = {
                .primary = HDC2010_REG_TEMP_LOW,
                .peak = HDC2010_REG_TEMP_MAX,
        },
        [HDC2010_GROUP_HUMIDITY] = {
                .primary = HDC2010_REG_HUMIDITY_LOW,
                .peak = HDC2010_REG_HUMIDITY_MAX,
        },
};

static IIO_CONST_ATTR(out_current_heater_raw_available, "0 1");

static struct attribute *hdc2010_attributes[] = {
        &iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
        NULL
};

static const struct attribute_group hdc2010_attribute_group = {
        .attrs = hdc2010_attributes,
};

static const struct iio_chan_spec hdc2010_channels[] = {
        {
                .type = IIO_TEMP,
                .address = HDC2010_GROUP_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_PEAK) |
                        BIT(IIO_CHAN_INFO_OFFSET) |
                        BIT(IIO_CHAN_INFO_SCALE),
        },
        {
                .type = IIO_HUMIDITYRELATIVE,
                .address = HDC2010_GROUP_HUMIDITY,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_PEAK) |
                        BIT(IIO_CHAN_INFO_SCALE),
        },
        {
                .type = IIO_CURRENT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .extend_name = "heater",
                .output = 1,
        },
};

static int hdc2010_update_drdy_config(struct hdc2010_data *data,
                                             char mask, char val)
{
        u8 tmp = (~mask & data->drdy_config) | val;
        int ret;

        ret = i2c_smbus_write_byte_data(data->client,
                                        HDC2010_REG_RESET_DRDY_INT_CONF, tmp);
        if (ret)
                return ret;

        data->drdy_config = tmp;

        return 0;
}

static int hdc2010_get_prim_measurement_word(struct hdc2010_data *data,
                                             struct iio_chan_spec const *chan)
{
        struct i2c_client *client = data->client;
        s32 ret;

        ret = i2c_smbus_read_word_data(client,
                        hdc2010_reg_translation[chan->address].primary);

        if (ret < 0)
                dev_err(&client->dev, "Could not read sensor measurement word\n");

        return ret;
}

static int hdc2010_get_peak_measurement_byte(struct hdc2010_data *data,
                                             struct iio_chan_spec const *chan)
{
        struct i2c_client *client = data->client;
        s32 ret;

        ret = i2c_smbus_read_byte_data(client,
                        hdc2010_reg_translation[chan->address].peak);

        if (ret < 0)
                dev_err(&client->dev, "Could not read sensor measurement byte\n");

        return ret;
}

static int hdc2010_get_heater_status(struct hdc2010_data *data)
{
        return !!(data->drdy_config & HDC2010_HEATER_EN);
}

static int hdc2010_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int *val,
                            int *val2, long mask)
{
        struct hdc2010_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW: {
                int ret;

                if (chan->type == IIO_CURRENT) {
                        *val = hdc2010_get_heater_status(data);
                        return IIO_VAL_INT;
                }
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                mutex_lock(&data->lock);
                ret = hdc2010_get_prim_measurement_word(data, chan);
                mutex_unlock(&data->lock);
                iio_device_release_direct(indio_dev);
                if (ret < 0)
                        return ret;
                *val = ret;
                return IIO_VAL_INT;
        }
        case IIO_CHAN_INFO_PEAK: {
                int ret;

                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                mutex_lock(&data->lock);
                ret = hdc2010_get_peak_measurement_byte(data, chan);
                mutex_unlock(&data->lock);
                iio_device_release_direct(indio_dev);
                if (ret < 0)
                        return ret;
                /* Scaling up the value so we can use same offset as RAW */
                *val = ret * 256;
                return IIO_VAL_INT;
        }
        case IIO_CHAN_INFO_SCALE:
                *val2 = 65536;
                if (chan->type == IIO_TEMP)
                        *val = 165000;
                else
                        *val = 100000;
                return IIO_VAL_FRACTIONAL;
        case IIO_CHAN_INFO_OFFSET:
                *val = -15887;
                *val2 = 515151;
                return IIO_VAL_INT_PLUS_MICRO;
        default:
                return -EINVAL;
        }
}

static int hdc2010_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct hdc2010_data *data = iio_priv(indio_dev);
        int new, ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (chan->type != IIO_CURRENT || val2 != 0)
                        return -EINVAL;

                switch (val) {
                case 1:
                        new = HDC2010_HEATER_EN;
                        break;
                case 0:
                        new = 0;
                        break;
                default:
                        return -EINVAL;
                }

                mutex_lock(&data->lock);
                ret = hdc2010_update_drdy_config(data, HDC2010_HEATER_EN, new);
                mutex_unlock(&data->lock);
                return ret;
        default:
                return -EINVAL;
        }
}

static const struct iio_info hdc2010_info = {
        .read_raw = hdc2010_read_raw,
        .write_raw = hdc2010_write_raw,
        .attrs = &hdc2010_attribute_group,
};

static int hdc2010_probe(struct i2c_client *client)
{
        struct iio_dev *indio_dev;
        struct hdc2010_data *data;
        u8 tmp;
        int ret;

        if (!i2c_check_functionality(client->adapter,
            I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
                return -EOPNOTSUPP;

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
        if (!indio_dev)
                return -ENOMEM;

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->client = client;
        mutex_init(&data->lock);

        /*
         * As DEVICE ID register does not differentiate between
         * HDC2010 and HDC2080, we have the name hardcoded
         */
        indio_dev->name = "hdc2010";
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &hdc2010_info;

        indio_dev->channels = hdc2010_channels;
        indio_dev->num_channels = ARRAY_SIZE(hdc2010_channels);

        /* Enable Automatic Measurement Mode at 5Hz */
        ret = hdc2010_update_drdy_config(data, HDC2010_AMM, HDC2010_AMM);
        if (ret)
                return ret;

        /*
         * We enable both temp and humidity measurement.
         * However the measurement won't start even in AMM until triggered.
         */
        tmp = (data->measurement_config & ~HDC2010_MEAS_CONF) |
                HDC2010_MEAS_TRIG;

        ret = i2c_smbus_write_byte_data(client, HDC2010_REG_MEASUREMENT_CONF, tmp);
        if (ret) {
                dev_warn(&client->dev, "Unable to set up measurement\n");
                if (hdc2010_update_drdy_config(data, HDC2010_AMM, 0))
                        dev_warn(&client->dev, "Unable to restore default AMM\n");
                return ret;
        }

        data->measurement_config = tmp;

        return iio_device_register(indio_dev);
}

static void hdc2010_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct hdc2010_data *data = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        /* Disable Automatic Measurement Mode */
        if (hdc2010_update_drdy_config(data, HDC2010_AMM, 0))
                dev_warn(&client->dev, "Unable to restore default AMM\n");
}

static const struct i2c_device_id hdc2010_id[] = {
        { "hdc2010" },
        { "hdc2080" },
        { }
};
MODULE_DEVICE_TABLE(i2c, hdc2010_id);

static const struct of_device_id hdc2010_dt_ids[] = {
        { .compatible = "ti,hdc2010" },
        { .compatible = "ti,hdc2080" },
        { }
};
MODULE_DEVICE_TABLE(of, hdc2010_dt_ids);

static struct i2c_driver hdc2010_driver = {
        .driver = {
                .name   = "hdc2010",
                .of_match_table = hdc2010_dt_ids,
        },
        .probe = hdc2010_probe,
        .remove = hdc2010_remove,
        .id_table = hdc2010_id,
};
module_i2c_driver(hdc2010_driver);

MODULE_AUTHOR("Eugene Zaikonnikov <ez@norphonic.com>");
MODULE_DESCRIPTION("TI HDC2010 humidity and temperature sensor driver");
MODULE_LICENSE("GPL");