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hwmon: (aht10) Add support for dht20

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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>
This commit is contained in:
Akhilesh Patil
2025-11-02 15:13:20 +05:30
committed by Guenter Roeck
parent 2ea255d35b
commit 3eaf1b6315
3 changed files with 28 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/hwmon/aht10.rst
View File

@@ -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

6
drivers/hwmon/Kconfig
View File

@@ -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.

19
drivers/hwmon/aht10.c
View File

@@ -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);
@@ -75,6 +78,7 @@ MODULE_DEVICE_TABLE(i2c, aht10_id);
* AHT10/AHT20
* @crc8: crc8 support flag
* @meas_size: measurements data size
* @init_cmd: Initialization command
*/
struct aht10_data {
@@ -85,6 +89,7 @@ struct aht10_data {
int humidity;
bool crc8;
unsigned int meas_size;
u8 init_cmd;
};
/*
@@ -94,13 +99,13 @@ 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;
@@ -336,9 +341,17 @@ 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;
}