--- /dev/null
+// 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");
projects / platform / kernel / linux-starfive.git / commitdiff