1 files changed, 473 insertions, 0 deletions
diff --git a/drivers/iio/humidity/hdc3020.c b/drivers/iio/humidity/hdc3020.c
new file mode 100644
index 0000000000..ed70415512
--- /dev/null
+++ b/drivers/iio/humidity/hdc3020.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * hdc3020.c - Support for the TI HDC3020,HDC3021 and HDC3022
+ * temperature + relative humidity sensors
+ *
+ * Copyright (C) 2023
+ *
+ * Datasheet: https://www.ti.com/lit/ds/symlink/hdc3020.pdf
+ */
+
+#include <linux/bitops.h>
+#include <linux/cleanup.h>
+#include <linux/crc8.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#include <asm/unaligned.h>
+
+#include <linux/iio/iio.h>
+
+#define HDC3020_HEATER_CMD_MSB		0x30 /* shared by all heater commands */
+#define HDC3020_HEATER_ENABLE		0x6D
+#define HDC3020_HEATER_DISABLE		0x66
+#define HDC3020_HEATER_CONFIG		0x6E
+
+#define HDC3020_READ_RETRY_TIMES	10
+#define HDC3020_BUSY_DELAY_MS		10
+
+#define HDC3020_CRC8_POLYNOMIAL		0x31
+
+static const u8 HDC3020_S_AUTO_10HZ_MOD0[2] = { 0x27, 0x37 };
+
+static const u8 HDC3020_EXIT_AUTO[2] = { 0x30, 0x93 };
+
+static const u8 HDC3020_R_T_RH_AUTO[2] = { 0xE0, 0x00 };
+static const u8 HDC3020_R_T_LOW_AUTO[2] = { 0xE0, 0x02 };
+static const u8 HDC3020_R_T_HIGH_AUTO[2] = { 0xE0, 0x03 };
+static const u8 HDC3020_R_RH_LOW_AUTO[2] = { 0xE0, 0x04 };
+static const u8 HDC3020_R_RH_HIGH_AUTO[2] = { 0xE0, 0x05 };
+
+struct hdc3020_data {
+	struct i2c_client *client;
+	/*
+	 * Ensure that the sensor configuration (currently only heater is
+	 * supported) will not be changed during the process of reading
+	 * sensor data (this driver will try HDC3020_READ_RETRY_TIMES times
+	 * if the device does not respond).
+	 */
+	struct mutex lock;
+};
+
+static const int hdc3020_heater_vals[] = {0, 1, 0x3FFF};
+
+static const struct iio_chan_spec hdc3020_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_PEAK) |
+		BIT(IIO_CHAN_INFO_TROUGH) | BIT(IIO_CHAN_INFO_OFFSET),
+	},
+	{
+		.type = IIO_HUMIDITYRELATIVE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_PEAK) |
+		BIT(IIO_CHAN_INFO_TROUGH),
+	},
+	{
+		/*
+		 * For setting the internal heater, which can be switched on to
+		 * prevent or remove any condensation that may develop when the
+		 * ambient environment approaches its dew point temperature.
+		 */
+		.type = IIO_CURRENT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW),
+		.output = 1,
+	},
+};
+
+DECLARE_CRC8_TABLE(hdc3020_crc8_table);
+
+static int hdc3020_write_bytes(struct hdc3020_data *data, const u8 *buf, u8 len)
+{
+	struct i2c_client *client = data->client;
+	struct i2c_msg msg;
+	int ret, cnt;
+
+	msg.addr = client->addr;
+	msg.flags = 0;
+	msg.buf = (char *)buf;
+	msg.len = len;
+
+	/*
+	 * During the measurement process, HDC3020 will not return data.
+	 * So wait for a while and try again
+	 */
+	for (cnt = 0; cnt < HDC3020_READ_RETRY_TIMES; cnt++) {
+		ret = i2c_transfer(client->adapter, &msg, 1);
+		if (ret == 1)
+			return 0;
+
+		mdelay(HDC3020_BUSY_DELAY_MS);
+	}
+	dev_err(&client->dev, "Could not write sensor command\n");
+
+	return -ETIMEDOUT;
+}
+
+static int hdc3020_read_bytes(struct hdc3020_data *data, const u8 *buf,
+			      void *val, int len)
+{
+	int ret, cnt;
+	struct i2c_client *client = data->client;
+	struct i2c_msg msg[2] = {
+		[0] = {
+			.addr = client->addr,
+			.flags = 0,
+			.buf = (char *)buf,
+			.len = 2,
+		},
+		[1] = {
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.buf = val,
+			.len = len,
+		},
+	};
+
+	/*
+	 * During the measurement process, HDC3020 will not return data.
+	 * So wait for a while and try again
+	 */
+	for (cnt = 0; cnt < HDC3020_READ_RETRY_TIMES; cnt++) {
+		ret = i2c_transfer(client->adapter, msg, 2);
+		if (ret == 2)
+			return 0;
+
+		mdelay(HDC3020_BUSY_DELAY_MS);
+	}
+	dev_err(&client->dev, "Could not read sensor data\n");
+
+	return -ETIMEDOUT;
+}
+
+static int hdc3020_read_measurement(struct hdc3020_data *data,
+				    enum iio_chan_type type, int *val)
+{
+	u8 crc, buf[6];
+	int ret;
+
+	ret = hdc3020_read_bytes(data, HDC3020_R_T_RH_AUTO, buf, 6);
+	if (ret < 0)
+		return ret;
+
+	/* CRC check of the temperature measurement */
+	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
+	if (crc != buf[2])
+		return -EINVAL;
+
+	/* CRC check of the relative humidity measurement */
+	crc = crc8(hdc3020_crc8_table, buf + 3, 2, CRC8_INIT_VALUE);
+	if (crc != buf[5])
+		return -EINVAL;
+
+	if (type == IIO_TEMP)
+		*val = get_unaligned_be16(buf);
+	else if (type == IIO_HUMIDITYRELATIVE)
+		*val = get_unaligned_be16(&buf[3]);
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * After exiting the automatic measurement mode or resetting, the peak
+ * value will be reset to the default value
+ * This method is used to get the highest temp measured during automatic
+ * measurement
+ */
+static int hdc3020_read_high_peak_t(struct hdc3020_data *data, int *val)
+{
+	u8 crc, buf[3];
+	int ret;
+
+	ret = hdc3020_read_bytes(data, HDC3020_R_T_HIGH_AUTO, buf, 3);
+	if (ret < 0)
+		return ret;
+
+	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
+	if (crc != buf[2])
+		return -EINVAL;
+
+	*val = get_unaligned_be16(buf);
+
+	return 0;
+}
+
+/*
+ * This method is used to get the lowest temp measured during automatic
+ * measurement
+ */
+static int hdc3020_read_low_peak_t(struct hdc3020_data *data, int *val)
+{
+	u8 crc, buf[3];
+	int ret;
+
+	ret = hdc3020_read_bytes(data, HDC3020_R_T_LOW_AUTO, buf, 3);
+	if (ret < 0)
+		return ret;
+
+	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
+	if (crc != buf[2])
+		return -EINVAL;
+
+	*val = get_unaligned_be16(buf);
+
+	return 0;
+}
+
+/*
+ * This method is used to get the highest humidity measured during automatic
+ * measurement
+ */
+static int hdc3020_read_high_peak_rh(struct hdc3020_data *data, int *val)
+{
+	u8 crc, buf[3];
+	int ret;
+
+	ret = hdc3020_read_bytes(data, HDC3020_R_RH_HIGH_AUTO, buf, 3);
+	if (ret < 0)
+		return ret;
+
+	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
+	if (crc != buf[2])
+		return -EINVAL;
+
+	*val = get_unaligned_be16(buf);
+
+	return 0;
+}
+
+/*
+ * This method is used to get the lowest humidity measured during automatic
+ * measurement
+ */
+static int hdc3020_read_low_peak_rh(struct hdc3020_data *data, int *val)
+{
+	u8 crc, buf[3];
+	int ret;
+
+	ret = hdc3020_read_bytes(data, HDC3020_R_RH_LOW_AUTO, buf, 3);
+	if (ret < 0)
+		return ret;
+
+	crc = crc8(hdc3020_crc8_table, buf, 2, CRC8_INIT_VALUE);
+	if (crc != buf[2])
+		return -EINVAL;
+
+	*val = get_unaligned_be16(buf);
+
+	return 0;
+}
+
+static int hdc3020_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct hdc3020_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (chan->type != IIO_TEMP && chan->type != IIO_HUMIDITYRELATIVE)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: {
+		guard(mutex)(&data->lock);
+		ret = hdc3020_read_measurement(data, chan->type, val);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	}
+	case IIO_CHAN_INFO_PEAK: {
+		guard(mutex)(&data->lock);
+		if (chan->type == IIO_TEMP) {
+			ret = hdc3020_read_high_peak_t(data, val);
+			if (ret < 0)
+				return ret;
+		} else {
+			ret = hdc3020_read_high_peak_rh(data, val);
+			if (ret < 0)
+				return ret;
+		}
+		return IIO_VAL_INT;
+	}
+	case IIO_CHAN_INFO_TROUGH: {
+		guard(mutex)(&data->lock);
+		if (chan->type == IIO_TEMP) {
+			ret = hdc3020_read_low_peak_t(data, val);
+			if (ret < 0)
+				return ret;
+		} else {
+			ret = hdc3020_read_low_peak_rh(data, val);
+			if (ret < 0)
+				return ret;
+		}
+		return IIO_VAL_INT;
+	}
+	case IIO_CHAN_INFO_SCALE:
+		*val2 = 65536;
+		if (chan->type == IIO_TEMP)
+			*val = 175;
+		else
+			*val = 100;
+		return IIO_VAL_FRACTIONAL;
+
+	case IIO_CHAN_INFO_OFFSET:
+		if (chan->type != IIO_TEMP)
+			return -EINVAL;
+
+		*val = -16852;
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int hdc3020_read_available(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  const int **vals,
+				  int *type, int *length, long mask)
+{
+	if (mask != IIO_CHAN_INFO_RAW || chan->type != IIO_CURRENT)
+		return -EINVAL;
+
+	*vals = hdc3020_heater_vals;
+	*type = IIO_VAL_INT;
+
+	return IIO_AVAIL_RANGE;
+}
+
+static int hdc3020_update_heater(struct hdc3020_data *data, int val)
+{
+	u8 buf[5];
+	int ret;
+
+	if (val < hdc3020_heater_vals[0] || val > hdc3020_heater_vals[2])
+		return -EINVAL;
+
+	buf[0] = HDC3020_HEATER_CMD_MSB;
+
+	if (!val) {
+		buf[1] = HDC3020_HEATER_DISABLE;
+		return hdc3020_write_bytes(data, buf, 2);
+	}
+
+	buf[1] = HDC3020_HEATER_CONFIG;
+	put_unaligned_be16(val & GENMASK(13, 0), &buf[2]);
+	buf[4] = crc8(hdc3020_crc8_table, buf + 2, 2, CRC8_INIT_VALUE);
+	ret = hdc3020_write_bytes(data, buf, 5);
+	if (ret < 0)
+		return ret;
+
+	buf[1] = HDC3020_HEATER_ENABLE;
+
+	return hdc3020_write_bytes(data, buf, 2);
+}
+
+static int hdc3020_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct hdc3020_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_CURRENT)
+			return -EINVAL;
+
+		guard(mutex)(&data->lock);
+		return hdc3020_update_heater(data, val);
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info hdc3020_info = {
+	.read_raw = hdc3020_read_raw,
+	.write_raw = hdc3020_write_raw,
+	.read_avail = hdc3020_read_available,
+};
+
+static void hdc3020_stop(void *data)
+{
+	hdc3020_write_bytes((struct hdc3020_data *)data, HDC3020_EXIT_AUTO, 2);
+}
+
+static int hdc3020_probe(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev;
+	struct hdc3020_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, 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);
+	data->client = client;
+	mutex_init(&data->lock);
+
+	crc8_populate_msb(hdc3020_crc8_table, HDC3020_CRC8_POLYNOMIAL);
+
+	indio_dev->name = "hdc3020";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &hdc3020_info;
+	indio_dev->channels = hdc3020_channels;
+	indio_dev->num_channels = ARRAY_SIZE(hdc3020_channels);
+
+	ret = hdc3020_write_bytes(data, HDC3020_S_AUTO_10HZ_MOD0, 2);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "Unable to set up measurement\n");
+
+	ret = devm_add_action_or_reset(&data->client->dev, hdc3020_stop, data);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(&data->client->dev, indio_dev);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "Failed to add device");
+
+	return 0;
+}
+
+static const struct i2c_device_id hdc3020_id[] = {
+	{ "hdc3020" },
+	{ "hdc3021" },
+	{ "hdc3022" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, hdc3020_id);
+
+static const struct of_device_id hdc3020_dt_ids[] = {
+	{ .compatible = "ti,hdc3020" },
+	{ .compatible = "ti,hdc3021" },
+	{ .compatible = "ti,hdc3022" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, hdc3020_dt_ids);
+
+static struct i2c_driver hdc3020_driver = {
+	.driver = {
+		.name = "hdc3020",
+		.of_match_table = hdc3020_dt_ids,
+	},
+	.probe = hdc3020_probe,
+	.id_table = hdc3020_id,
+};
+module_i2c_driver(hdc3020_driver);
+
+MODULE_AUTHOR("Javier Carrasco <javier.carrasco.cruz@gmail.com>");
+MODULE_AUTHOR("Li peiyu <579lpy@gmail.com>");
+MODULE_DESCRIPTION("TI HDC3020 humidity and temperature sensor driver");
+MODULE_LICENSE("GPL");