243 lines
5.7 KiB
C
243 lines
5.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* This is a non-complete driver implementation for the
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* HS3001 humidity and temperature sensor and compatibles. It does not include
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* the configuration possibilities, where it needs to be set to 'programming mode'
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* during power-up.
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*
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*
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* Copyright (C) 2023 SYS TEC electronic AG
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* Author: Andre Werner <andre.werner@systec-electronic.com>
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*/
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#include <linux/bitfield.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/hwmon.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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/* Measurement times */
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#define HS3001_WAKEUP_TIME 100 /* us */
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#define HS3001_8BIT_RESOLUTION 550 /* us */
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#define HS3001_10BIT_RESOLUTION 1310 /* us */
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#define HS3001_12BIT_RESOLUTION 4500 /* us */
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#define HS3001_14BIT_RESOLUTION 16900 /* us */
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#define HS3001_RESPONSE_LENGTH 4
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#define HS3001_FIXPOINT_ARITH 1000U
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#define HS3001_MASK_HUMIDITY_0X3FFF GENMASK(13, 0)
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#define HS3001_MASK_STATUS_0XC0 GENMASK(7, 6)
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/* Definitions for Status Bits of A/D Data */
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#define HS3001_DATA_VALID 0x00 /* Valid Data */
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#define HS3001_DATA_STALE 0x01 /* Stale Data */
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struct hs3001_data {
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struct i2c_client *client;
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struct mutex i2c_lock; /* lock for sending i2c commands */
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u32 wait_time; /* in us */
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int temperature; /* in milli degree */
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u32 humidity; /* in milli % */
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};
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static int hs3001_extract_temperature(u16 raw)
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{
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/* fixpoint arithmetic 1 digit */
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u32 temp = (raw >> 2) * HS3001_FIXPOINT_ARITH * 165;
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temp /= (1 << 14) - 1;
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return (int)temp - 40 * HS3001_FIXPOINT_ARITH;
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}
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static u32 hs3001_extract_humidity(u16 raw)
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{
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u32 hum = (raw & HS3001_MASK_HUMIDITY_0X3FFF) * HS3001_FIXPOINT_ARITH * 100;
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return hum / (1 << 14) - 1;
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}
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static int hs3001_data_fetch_command(struct i2c_client *client,
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struct hs3001_data *data)
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{
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int ret;
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u8 buf[HS3001_RESPONSE_LENGTH];
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u8 hs3001_status;
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ret = i2c_master_recv(client, buf, HS3001_RESPONSE_LENGTH);
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if (ret != HS3001_RESPONSE_LENGTH) {
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ret = ret < 0 ? ret : -EIO;
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dev_dbg(&client->dev,
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"Error in i2c communication. Error code: %d.\n", ret);
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return ret;
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}
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hs3001_status = FIELD_GET(HS3001_MASK_STATUS_0XC0, buf[0]);
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if (hs3001_status == HS3001_DATA_STALE) {
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dev_dbg(&client->dev, "Sensor busy.\n");
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return -EBUSY;
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}
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if (hs3001_status != HS3001_DATA_VALID) {
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dev_dbg(&client->dev, "Data invalid.\n");
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return -EIO;
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}
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data->humidity =
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hs3001_extract_humidity(be16_to_cpup((__be16 *)&buf[0]));
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data->temperature =
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hs3001_extract_temperature(be16_to_cpup((__be16 *)&buf[2]));
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return 0;
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}
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static umode_t hs3001_is_visible(const void *data, enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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/* Both, humidity and temperature can only be read. */
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return 0444;
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}
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static int hs3001_read(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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struct hs3001_data *data = dev_get_drvdata(dev);
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struct i2c_client *client = data->client;
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int ret;
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mutex_lock(&data->i2c_lock);
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ret = i2c_master_send(client, NULL, 0);
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if (ret < 0) {
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mutex_unlock(&data->i2c_lock);
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return ret;
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}
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/*
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* Sensor needs some time to process measurement depending on
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* resolution (ref. datasheet)
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*/
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fsleep(data->wait_time);
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ret = hs3001_data_fetch_command(client, data);
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mutex_unlock(&data->i2c_lock);
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if (ret < 0)
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return ret;
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switch (type) {
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case hwmon_temp:
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switch (attr) {
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case hwmon_temp_input:
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*val = data->temperature;
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break;
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default:
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return -EINVAL;
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}
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break;
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case hwmon_humidity:
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switch (attr) {
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case hwmon_humidity_input:
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*val = data->humidity;
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break;
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default:
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return -EINVAL;
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}
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static const struct hwmon_channel_info *hs3001_info[] = {
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HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
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HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT),
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NULL
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};
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static const struct hwmon_ops hs3001_hwmon_ops = {
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.is_visible = hs3001_is_visible,
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.read = hs3001_read,
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};
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static const struct hwmon_chip_info hs3001_chip_info = {
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.ops = &hs3001_hwmon_ops,
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.info = hs3001_info,
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};
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/* device ID table */
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static const struct i2c_device_id hs3001_ids[] = {
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{ "hs3001", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, hs3001_ids);
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static const struct of_device_id hs3001_of_match[] = {
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{.compatible = "renesas,hs3001"},
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{ },
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};
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MODULE_DEVICE_TABLE(of, hs3001_of_match);
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static int hs3001_probe(struct i2c_client *client)
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{
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struct hs3001_data *data;
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struct device *hwmon_dev;
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struct device *dev = &client->dev;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -EOPNOTSUPP;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->client = client;
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/*
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* Measurement time = wake-up time + measurement time temperature
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* + measurement time humidity. This is currently static, because
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* enabling programming mode is not supported, yet.
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*/
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data->wait_time = (HS3001_WAKEUP_TIME + HS3001_14BIT_RESOLUTION +
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HS3001_14BIT_RESOLUTION);
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mutex_init(&data->i2c_lock);
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hwmon_dev = devm_hwmon_device_register_with_info(dev,
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client->name,
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data,
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&hs3001_chip_info,
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NULL);
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if (IS_ERR(hwmon_dev))
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return dev_err_probe(dev, PTR_ERR(hwmon_dev),
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"Unable to register hwmon device.\n");
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return 0;
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}
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static struct i2c_driver hs3001_i2c_driver = {
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.driver = {
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.name = "hs3001",
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.of_match_table = hs3001_of_match,
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},
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.probe = hs3001_probe,
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.id_table = hs3001_ids,
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};
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module_i2c_driver(hs3001_i2c_driver);
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MODULE_AUTHOR("Andre Werner <andre.werner@systec-electronic.com>");
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MODULE_DESCRIPTION("HS3001 humidity and temperature sensor base driver");
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MODULE_LICENSE("GPL");
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