[PATCH 0/2] Add AHT20 sensor bindings and fix driver initialization

[PATCH 0/2] Add AHT20 sensor bindings and fix driver initialization

[Hao Yu]

This patch series adds device tree binding documentation for the
Aosong AHT10/AHT20 series sensors and fixes
initialization issues in the driver.

The AHT20 sensor was tested on rk3566_lckfb board with I2C-2 port.
Temperature and humidity readings are now accurate after fixing
the initialization command sequence with aht20.

Patch 1/2: Add device tree binding documentation for AHT10 series
Patch 2/2: Fix driver initialization commands and add DT support


Hao Yu (2):
  dt-bindings: hwmon: add aosong,aht10 family
  hwmon: (aht10) Fix initialization commands and add DT support

 .../bindings/hwmon/aosong,aht10.yaml          | 41 +++++++++++++++++++
 drivers/hwmon/aht10.c                         | 16 +++++++-
 2 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/aosong,aht10.yaml

-- 
2.34.1

[PATCH 1/2] dt-bindings: hwmon: add aosong,aht10 family

[Hao Yu]

Add Aosong AHT10, AHT20, and DHT20 humidity and temperature sensors.

Signed-off-by: Hao Yu <haoyufine@gmail.com>
---
 .../bindings/hwmon/aosong,aht10.yaml          | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/aosong,aht10.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/aosong,aht10.yaml b/Documentation/devicetree/bindings/hwmon/aosong,aht10.yaml
new file mode 100644
index 000000000000..6eb3944ae3da
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/aosong,aht10.yaml
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/aosong,aht10.yaml#
+$schema: http://devicetree.org/meta-schema.yaml#
+
+title: Aosong AHT10/AHT20/DHT20 Temperature and Humidity Sensor
+
+maintainers:
+  - Hao Yu <haoyufine@gmail.com>
+
+description: |
+  The Aosong AHT10, AHT20, and DHT20 are I2C humidity and temperature sensors.
+
+properties:
+  compatible:
+    enum:
+      - aosong,aht10
+      - aosong,aht20
+      - aosong,dht20
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        sensor@38 {
+            compatible = "aosong,aht20";
+            reg = <0x38>;
+        };
+    };
-- 
2.34.1

[PATCH 2/2] hwmon: (aht10) Fix initialization commands and add DT support

[Hao Yu]

Correct AHT20 initialization command sequence and
change DHT20 command format to 0bxxxxx notation.

Tested on rk3566_lckfb board with aht20 sensor connected at i2c-2 port.

Signed-off-by: Hao Yu <haoyufine@gmail.com>
---
 drivers/hwmon/aht10.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
index 007befdba977..c18332cc48ba 100644
--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -37,7 +37,9 @@
 #define AHT10_CMD_MEAS	0b10101100
 #define AHT10_CMD_RST	0b10111010
 
-#define DHT20_CMD_INIT	0x71
+#define AHT20_CMD_INIT 0b10111110
+
+#define DHT20_CMD_INIT	0b01110001
 
 /*
  * Flags in the answer byte/command
@@ -60,6 +62,15 @@ static const struct i2c_device_id aht10_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, aht10_id);
 
+static const struct of_device_id aht10_of_match[] = {
+	{ .compatible = "aosong,aht10", .data = (void *)aht10 },
+	{ .compatible = "aosong,aht20", .data = (void *)aht20 },
+	{ .compatible = "aosong,dht20", .data = (void *)dht20 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, aht10_of_match);
+
 /**
  *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
  *   @client: the i2c client associated with the AHT10/AHT20
@@ -341,7 +352,7 @@ 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;
+		data->init_cmd = AHT20_CMD_INIT;
 		break;
 	case dht20:
 		data->meas_size = AHT20_MEAS_SIZE;
@@ -375,6 +386,7 @@ static int aht10_probe(struct i2c_client *client)
 static struct i2c_driver aht10_driver = {
 	.driver = {
 		.name = "aht10",
+		.of_match_table = aht10_of_match,
 	},
 	.probe      = aht10_probe,
 	.id_table   = aht10_id,
-- 
2.34.1

Re: [PATCH 2/2] hwmon: (aht10) Fix initialization commands and add DT support

[Guenter Roeck]

On 2/22/26 02:58, Hao Yu wrote:
> Correct AHT20 initialization command sequence and
> change DHT20 command format to 0bxxxxx notation.
> 

That needs to explain what is wrong. The current initialization command
is 0b11100001. Changing it to 0b10111110 but does not explain why the old
value is incorrect. Something like "Per AHT20 datasheet, the initialization
command for AHT20 is 0b10111110" plus an explanation that the AHT10
initialization sequence does not work as intended.

> Tested on rk3566_lckfb board with aht20 sensor connected at i2c-2 port.
> 
> Signed-off-by: Hao Yu <haoyufine@gmail.com>

Fixes: d2abcb5cc885 ("hwmon: (aht10) Add support for compatible aht20")

> ---
>   drivers/hwmon/aht10.c | 16 ++++++++++++++--
>   1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
> index 007befdba977..c18332cc48ba 100644
> --- a/drivers/hwmon/aht10.c
> +++ b/drivers/hwmon/aht10.c
> @@ -37,7 +37,9 @@
>   #define AHT10_CMD_MEAS	0b10101100
>   #define AHT10_CMD_RST	0b10111010
>   
> -#define DHT20_CMD_INIT	0x71
> +#define AHT20_CMD_INIT 0b10111110

tab after AHT20_CMD_INIT

Thanks,
Guenter

> +
> +#define DHT20_CMD_INIT	0b01110001
>  
>   /*
>    * Flags in the answer byte/command
> @@ -60,6 +62,15 @@ static const struct i2c_device_id aht10_id[] = {
>   };
>   MODULE_DEVICE_TABLE(i2c, aht10_id);
>   
> +static const struct of_device_id aht10_of_match[] = {
> +	{ .compatible = "aosong,aht10", .data = (void *)aht10 },
> +	{ .compatible = "aosong,aht20", .data = (void *)aht20 },
> +	{ .compatible = "aosong,dht20", .data = (void *)dht20 },
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(of, aht10_of_match);
> +
>   /**
>    *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
>    *   @client: the i2c client associated with the AHT10/AHT20
> @@ -341,7 +352,7 @@ 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;
> +		data->init_cmd = AHT20_CMD_INIT;
>   		break;
>   	case dht20:
>   		data->meas_size = AHT20_MEAS_SIZE;
> @@ -375,6 +386,7 @@ static int aht10_probe(struct i2c_client *client)
>   static struct i2c_driver aht10_driver = {
>   	.driver = {
>   		.name = "aht10",
> +		.of_match_table = aht10_of_match,
>   	},
>   	.probe      = aht10_probe,
>   	.id_table   = aht10_id,

Re: [PATCH 2/2] hwmon: (aht10) Fix initialization commands and add DT support

[Guenter Roeck]

On 2/22/26 02:58, Hao Yu wrote:
> Correct AHT20 initialization command sequence and
> change DHT20 command format to 0bxxxxx notation.
> 
> Tested on rk3566_lckfb board with aht20 sensor connected at i2c-2 port.
> 
> Signed-off-by: Hao Yu <haoyufine@gmail.com>
> ---
>   drivers/hwmon/aht10.c | 16 ++++++++++++++--
>   1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
> index 007befdba977..c18332cc48ba 100644
> --- a/drivers/hwmon/aht10.c
> +++ b/drivers/hwmon/aht10.c
> @@ -37,7 +37,9 @@
>   #define AHT10_CMD_MEAS	0b10101100
>   #define AHT10_CMD_RST	0b10111010
>   
> -#define DHT20_CMD_INIT	0x71
> +#define AHT20_CMD_INIT 0b10111110
> +
> +#define DHT20_CMD_INIT	0b01110001
>   
>   /*
>    * Flags in the answer byte/command
> @@ -60,6 +62,15 @@ static const struct i2c_device_id aht10_id[] = {
>   };
>   MODULE_DEVICE_TABLE(i2c, aht10_id);
>   
> +static const struct of_device_id aht10_of_match[] = {
> +	{ .compatible = "aosong,aht10", .data = (void *)aht10 },
> +	{ .compatible = "aosong,aht20", .data = (void *)aht20 },
> +	{ .compatible = "aosong,dht20", .data = (void *)dht20 },
> +	{}
> +};

Also, adding DT support needs a separate patch. One is a bug fix which needs
to be marked as such for stable backport. Adding DT support is new code.

Thanks,
Guenter

> +
> +MODULE_DEVICE_TABLE(of, aht10_of_match);
> +
>   /**
>    *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
>    *   @client: the i2c client associated with the AHT10/AHT20
> @@ -341,7 +352,7 @@ 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;
> +		data->init_cmd = AHT20_CMD_INIT;
>   		break;
>   	case dht20:
>   		data->meas_size = AHT20_MEAS_SIZE;
> @@ -375,6 +386,7 @@ static int aht10_probe(struct i2c_client *client)
>   static struct i2c_driver aht10_driver = {
>   	.driver = {
>   		.name = "aht10",
> +		.of_match_table = aht10_of_match,
>   	},
>   	.probe      = aht10_probe,
>   	.id_table   = aht10_id,

[PATCH v3 0/2] hwmon: aht10: add Device Tree support

[Hao Yu]

This series adds Device Tree support for Aosong AHT10, AHT20, and DHT20.
Tested on linux_lckfb with AHT20, and the driver works as expected.

Changes in v3:
- Move bindings to trivial-devices.yaml per Krzysztof's suggestion.
- Link to v2: https://lore.kernel.org/linux-hwmon/20260222105831.7360-1-haoyufine@gmail.com/

Hao Yu (2):
  dt-bindings: hwmon: add Aosong AHT10/AHT20/DHT20 to trivial devices
  hwmon: (aht10) add device tree ID matching

 Documentation/devicetree/bindings/trivial-devices.yaml |  4 ++++
 drivers/hwmon/aht10.c                                  | 10 ++++++++++
 2 files changed, 14 insertions(+)

-- 
2.34.1

[PATCH v3 1/2] dt-bindings: hwmon: add Aosong AHT10/AHT20/DHT20 to trivial devices

[Hao Yu]

Add Aosong AHT10, AHT20 and DHT20 temperature and humidity sensors
to the trivial-devices documentation. These sensors use a standard
I2C interface and do not require complex binding definitions.

Signed-off-by: Hao Yu <haoyufine@gmail.com>
---
 Documentation/devicetree/bindings/trivial-devices.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index a482aeadcd44..aa924a410fc3 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -59,6 +59,10 @@ properties:
           - adi,lt7182s
             # AMS iAQ-Core VOC Sensor
           - ams,iaq-core
+            # Aosong temperature & humidity sensors with I2C interface
+          - aosong,aht10
+          - aosong,aht20
+          - aosong,dht20
             # Arduino microcontroller interface over SPI on UnoQ board
           - arduino,unoq-mcu
             # Temperature monitoring of Astera Labs PT5161L PCIe retimer
-- 
2.34.1

Re: [PATCH v3 1/2] dt-bindings: hwmon: add Aosong AHT10/AHT20/DHT20 to trivial devices

[Krzysztof Kozlowski]

On 23/02/2026 18:38, Hao Yu wrote:
> Add Aosong AHT10, AHT20 and DHT20 temperature and humidity sensors
> to the trivial-devices documentation. These sensors use a standard
> I2C interface and do not require complex binding definitions.
> 
> Signed-off-by: Hao Yu <haoyufine@gmail.com>
> ---
>  Documentation/devicetree/bindings/trivial-devices.yaml | 4 ++++
>  1 file changed, 4 insertions(+)
> 

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: hwmon: add Aosong AHT10/AHT20/DHT20 to trivial devices

[Guenter Roeck]

On Tue, Feb 24, 2026 at 01:38:52AM +0800, Hao Yu wrote:
> Add Aosong AHT10, AHT20 and DHT20 temperature and humidity sensors
> to the trivial-devices documentation. These sensors use a standard
> I2C interface and do not require complex binding definitions.
> 
> Signed-off-by: Hao Yu <haoyufine@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Applied.

Thanks,
Guenter

[PATCH v3 2/2] hwmon: (aht10) add device tree ID matching

[Hao Yu]

Add of_device_id table to allow the driver to be matched via
Device Tree. This is required for supporting the AHT10/20/DHT20
sensors on platforms using DT.

Signed-off-by: Hao Yu <haoyufine@gmail.com>
---
 drivers/hwmon/aht10.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
index 007befdba977..cd802dad5eca 100644
--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -60,6 +60,15 @@ static const struct i2c_device_id aht10_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, aht10_id);
 
+static const struct of_device_id aht10_of_match[] = {
+	{ .compatible = "aosong,aht10", .data = (void *)aht10 },
+	{ .compatible = "aosong,aht20", .data = (void *)aht20 },
+	{ .compatible = "aosong,dht20", .data = (void *)dht20 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, aht10_of_match);
+
 /**
  *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
  *   @client: the i2c client associated with the AHT10/AHT20
@@ -375,6 +384,7 @@ static int aht10_probe(struct i2c_client *client)
 static struct i2c_driver aht10_driver = {
 	.driver = {
 		.name = "aht10",
+		.of_match_table = aht10_of_match,
 	},
 	.probe      = aht10_probe,
 	.id_table   = aht10_id,
-- 
2.34.1

Re: [PATCH v3 2/2] hwmon: (aht10) add device tree ID matching

[Guenter Roeck]

On Tue, Feb 24, 2026 at 01:38:53AM +0800, Hao Yu wrote:
> Add of_device_id table to allow the driver to be matched via
> Device Tree. This is required for supporting the AHT10/20/DHT20
> sensors on platforms using DT.
> 
> Signed-off-by: Hao Yu <haoyufine@gmail.com>

Applied.

Thanks,
Guenter