[PATCH 6.12 169/265] hwmon: (aht10) Add support for dht20

Greg Kroah-Hartman
2026-03-12T20:22:44Z

From: Akhilesh Patil <akhilesh@ee.iitb.ac.in>

[ Upstream commit 3eaf1b631506e8de2cb37c278d5bc042521e82c1 ]

Add support for dht20 temperature and humidity sensor from Aosong.
Modify aht10 driver to handle different init command for dht20 sensor by
adding init_cmd entry in the driver data. dht20 sensor is compatible with
aht10 hwmon driver with this change.

Tested on TI am62x SK board with dht20 sensor connected at i2c-2 port.

Signed-off-by: Akhilesh Patil <akhilesh@ee.iitb.ac.in>
Link: https://lore.kernel.org/r/2025112-94320-906858@bhairav-test.ee.iitb.ac.in
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Stable-dep-of: b7497b5a99f5 ("hwmon: (aht10) Fix initialization commands for AHT20")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/hwmon/aht10.rst | 10 +++++++++-
drivers/hwmon/Kconfig | 6 +++---
drivers/hwmon/aht10.c | 19 ++++++++++++++++---
3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/Documentation/hwmon/aht10.rst b/Documentation/hwmon/aht10.rst
index 213644b4ecba6..7903b6434326d 100644
--- a/Documentation/hwmon/aht10.rst
+++ b/Documentation/hwmon/aht10.rst
@@ -20,6 +20,14 @@ Supported chips:

English: http://www.aosong.com/userfiles/files/media/Data%20Sheet%20AHT20.pdf

+ * Aosong DHT20
+
+ Prefix: 'dht20'
+
+ Addresses scanned: None
+
+ Datasheet: https://www.digikey.co.nz/en/htmldatasheets/production/9184855/0/0/1/101020932
+
Author: Johannes Cornelis Draaijer <jcdra1@gmail.com>

@@ -33,7 +41,7 @@ The address of this i2c device may only be 0x38
Special Features
----------------

-AHT20 has additional CRC8 support which is sent as the last byte of the sensor
+AHT20, DHT20 has additional CRC8 support which is sent as the last byte of the sensor
values.

Usage Notes
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 58480a3f4683f..19622dd6ec93a 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -245,12 +245,12 @@ config SENSORS_ADT7475
will be called adt7475.

config SENSORS_AHT10
- tristate "Aosong AHT10, AHT20"
+ tristate "Aosong AHT10, AHT20, DHT20"
depends on I2C
select CRC8
help
- If you say yes here, you get support for the Aosong AHT10 and AHT20
- temperature and humidity sensors
+ If you say yes here, you get support for the Aosong AHT10, AHT20 and
+ DHT20 temperature and humidity sensors

This driver can also be built as a module. If so, the module
will be called aht10.
diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
index 312ef3e987540..231aba885beaa 100644
--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -37,6 +37,8 @@
#define AHT10_CMD_MEAS 0b10101100
#define AHT10_CMD_RST 0b10111010

+#define DHT20_CMD_INIT 0x71
+
/*
* Flags in the answer byte/command
*/
@@ -48,11 +50,12 @@

#define AHT10_MAX_POLL_INTERVAL_LEN 30

-enum aht10_variant { aht10, aht20 };
+enum aht10_variant { aht10, aht20, dht20};

static const struct i2c_device_id aht10_id[] = {
{ "aht10", aht10 },
{ "aht20", aht20 },
+ { "dht20", dht20 },
{ },
};
MODULE_DEVICE_TABLE(i2c, aht10_id);
@@ -77,6 +80,7 @@ MODULE_DEVICE_TABLE(i2c, aht10_id);
* AHT10/AHT20
* @crc8: crc8 support flag
* @meas_size: measurements data size
+ * @init_cmd: Initialization command
*/

struct aht10_data {
@@ -92,6 +96,7 @@ struct aht10_data {
int humidity;
bool crc8;
unsigned int meas_size;
+ u8 init_cmd;
};

/**
@@ -101,13 +106,13 @@ struct aht10_data {
*/
static int aht10_init(struct aht10_data *data)
{
- const u8 cmd_init[] = {AHT10_CMD_INIT, AHT10_CAL_ENABLED | AHT10_MODE_CYC,
+ const u8 cmd_init[] = {data->init_cmd, AHT10_CAL_ENABLED | AHT10_MODE_CYC,
0x00};
int res;
u8 status;
struct i2c_client *client = data->client;

- res = i2c_master_send(client, cmd_init, 3);
+ res = i2c_master_send(client, cmd_init, sizeof(cmd_init));
if (res < 0)
return res;

@@ -352,9 +357,17 @@ static int aht10_probe(struct i2c_client *client)
data->meas_size = AHT20_MEAS_SIZE;
data->crc8 = true;
crc8_populate_msb(crc8_table, AHT20_CRC8_POLY);
+ data->init_cmd = AHT10_CMD_INIT;
+ break;
+ case dht20:
+ data->meas_size = AHT20_MEAS_SIZE;
+ data->crc8 = true;
+ crc8_populate_msb(crc8_table, AHT20_CRC8_POLY);
+ data->init_cmd = DHT20_CMD_INIT;
break;
default:
data->meas_size = AHT10_MEAS_SIZE;
+ data->init_cmd = AHT10_CMD_INIT;
break;
}

--
2.51.0