diff options
Diffstat (limited to 'drivers/hwmon/hs3001.c')
| -rw-r--r-- | drivers/hwmon/hs3001.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/hwmon/hs3001.c b/drivers/hwmon/hs3001.c new file mode 100644 index 000000000000..ac574e46d069 --- /dev/null +++ b/drivers/hwmon/hs3001.c @@ -0,0 +1,242 @@ +// 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"); |