mirror_ubuntu-kernels/drivers/hwmon/hs3001.c

243 lines
5.7 KiB
C

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