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authorAntoni Pokusinski <apokusinski01@gmail.com>2024-09-30 22:53:47 +0200
committerGuenter Roeck <linux@roeck-us.net>2024-11-10 14:48:07 -0800
commit0eed6fc3d2b9eef8074dc799176e0c1e78a3cc3f (patch)
tree502ba950b64eaef8ed8495d73c997cefc4f7e5ca /Documentation/hwmon
parent83cca55a63344f0d43102badc0e77e715180153f (diff)
hwmon: (sht4x): add heater support
Add support for manipulating the internal heater of sht4x devices. Enabling the heater removes condensed water from the sensor surface which disturbs the relative humidity measurements. The heater can operate at three heating levels (20, 110 or 200 milliwatts). Also, two heating durations may be selected (0.1 or 1s). Once the heating time elapses the heater is automatically switched off. Changes since v3: * struct sht4x_data: add heating_complete timestamp * struct sht4x_data: add data_pending flag * heater_enable_store: return -EINVAL if input != 1 * heater_enable_store: check for data->heating_complete and update it * heater_enable_store: set data_pending flag after heating request * sht4x_read_values: msleep if heating in progress * sht4x_read_values: dont send measurement request if data_pending * heater_enable attr: make it RW * Documentation: update info about heater_enable attr Changes since v2: * heater_enable_store: remove unnecessary if * Documentation: remove incorrect info about turning off the heater * be more specific in the patch description Changes since v1: * explain the use case of the new attributes set * heater_enable attr: make it write-only * heater_enable_store: define cmd as u8 instead of u8* * heater_enable_store: remove unreachable data path * heater_enable_store: remove unnecessary lock * heater_enable_store: call i2c_master_send only if status==true * define attributes as DEVICE_ATTR_* instead of SENSOR_DEVICE_ATTR_* Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com> Message-ID: <20240930205346.2147-1-apokusinski01@gmail.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'Documentation/hwmon')
-rw-r--r--Documentation/hwmon/sht4x.rst14
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/hwmon/sht4x.rst b/Documentation/hwmon/sht4x.rst
index daf21e763425..ba094ad0e281 100644
--- a/Documentation/hwmon/sht4x.rst
+++ b/Documentation/hwmon/sht4x.rst
@@ -42,4 +42,18 @@ humidity1_input Measured humidity in %H
update_interval The minimum interval for polling the sensor,
in milliseconds. Writable. Must be at least
2000.
+heater_power The requested heater power, in milliwatts.
+ Available values: 20, 110, 200 (default: 200).
+heater_time The requested operating time of the heater,
+ in milliseconds.
+ Available values: 100, 1000 (default 1000).
+heater_enable Enable the heater with the selected power
+ and for the selected time in order to remove
+ condensed water from the sensor surface. The
+ heater cannot be manually turned off once
+ enabled (it will automatically turn off
+ after completing its operation).
+
+ - 0: turned off (read-only value)
+ - 1: turn on
=============== ============================================