xref: /linux/Documentation/ABI/testing/sysfs-driver-w1_therm (revision e2c94d6f572079511945e64537eb1218643f2e68)

What:		/sys/bus/w1/devices/.../alarms
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(RW) read or write TH and TL (Temperature High an Low) alarms.
		Values shall be space separated and in the device range
		(typical -55 degC to 125 degC), if not values will be trimmed
		to device min/max capabilities. Values are integer as they are
		stored in a 8bit register in the device. Lowest value is
		automatically put to TL. Once set, alarms could be search at
		master level, refer to Documentation/w1/w1_generic.rst for
		detailed information
Users:		any user space application which wants to communicate with
		w1_term device


What:		/sys/bus/w1/devices/.../eeprom
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(WO) writing that file will either trigger a save of the
		device data to its embedded EEPROM, either restore data
		embedded in device EEPROM. Be aware that devices support
		limited EEPROM writing cycles (typical 50k)
			* 'save': save device RAM to EEPROM
			* 'restore': restore EEPROM data in device RAM
Users:		any user space application which wants to communicate with
		w1_term device


What:		/sys/bus/w1/devices/.../ext_power
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(RO) return the power status by asking the device
			* '0': device parasite powered
			* '1': device externally powered
			* '-xx': xx is kernel error when reading power status
Users:		any user space application which wants to communicate with
		w1_term device


What:		/sys/bus/w1/devices/.../resolution
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(RW) get or set the device resolution (on supported devices,
		if not, this entry is not present). Note that the resolution
		will be changed only in device RAM, so it will be cleared when
		power is lost. Trigger a 'save' to EEPROM command to keep
		values after power-on. Read or write are :
			* '9..12': device resolution in bit
			or resolution to set in bit
			* '-xx': xx is kernel error when reading the resolution
			* Anything else: do nothing
Users:		any user space application which wants to communicate with
		w1_term device


What:		/sys/bus/w1/devices/.../temperature
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(RO) return the temperature in 1/1000 degC.
		Note that the conversion duration depend on the resolution (if
		device support this feature). It takes 94ms in 9bits
		resolution, 750ms for 12bits.
Users:		any user space application which wants to communicate with
		w1_term device


What:		/sys/bus/w1/devices/.../w1_slave
Date:		May 2020
Contact:	Akira Shimahara <akira215corp@gmail.com>
Description:
		(RW) return the temperature in 1/1000 degC.
		*read*: return 2 lines with the hexa output data sent on the
		bus, return the CRC check and temperature in 1/1000 degC
		*write* :
			* '0' : save the 2 or 3 bytes to the device EEPROM
			(i.e. TH, TL and config register)
			* '9..12' : set the device resolution in RAM
			(if supported)
			* Anything else: do nothing
		refer to Documentation/w1/slaves/w1_therm.rst for detailed
		information.
Users:		any user space application which wants to communicate with
		w1_term device