linux-imx/Documentation/ABI/testing/sysfs-devices-soc

What: /sys/devices/socX Date: January 2012 contact: Lee Jones lee@kernel.org Description: The /sys/devices/ directory contains a sub-directory for each System-on-Chip (SoC) device on a running platform. Information regarding each SoC can be obtained by reading sysfs files. This functionality is only available if implemented by the platform.

	The directory created for each SoC will also house information
	about devices which are commonly contained in /sys/devices/platform.
	It has been agreed that if an SoC device exists, its supported
	devices would be better suited to appear as children of that SoC.

What: /sys/devices/socX/machine Date: January 2012 contact: Lee Jones lee@kernel.org Description: Read-only attribute common to all SoCs. Contains the SoC machine name (e.g. Ux500).

What: /sys/devices/socX/family Date: January 2012 contact: Lee Jones lee@kernel.org Description: Read-only attribute common to all SoCs. Contains SoC family name (e.g. DB8500).

	On many of ARM based silicon with SMCCC v1.2+ compliant firmware
	this will contain the JEDEC JEP106 manufacturer’s identification
	code. The format is "jep106:XXYY" where XX is identity code and
	YY is continuation code.

	This manufacturer’s identification code is defined by one
	or more eight (8) bit fields, each consisting of seven (7)
	data bits plus one (1) odd parity bit. It is a single field,
	limiting the possible number of vendors to 126. To expand
	the maximum number of identification codes, a continuation
	scheme has been defined.

	The specified mechanism is that an identity code of 0x7F
	represents the "continuation code" and implies the presence
	of an additional identity code field, and this mechanism
	may be extended to multiple continuation codes followed
	by the manufacturer's identity code.

	For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,
	which is code 0x3B on the fifth 'page'. This is shortened
	as JEP106 identity code of 0x3B and a continuation code of
	0x4 to represent the four continuation codes preceding the
	identity code.

What: /sys/devices/socX/serial_number Date: January 2019 contact: Bjorn Andersson bjorn.andersson@linaro.org Description: Read-only attribute supported by most SoCs. Contains the SoC's serial number, if available.

What: /sys/devices/socX/soc_id Date: January 2012 contact: Lee Jones lee@kernel.org Description: Read-only attribute supported by most SoCs. In the case of ST-Ericsson's chips this contains the SoC serial number.

	On many of ARM based silicon with SMCCC v1.2+ compliant firmware
	this will contain the SOC ID appended to the family attribute
	to ensure there is no conflict in this namespace across various
	vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity
	code, YY is continuation code and ZZZZ is the SOC ID.

What: /sys/devices/socX/revision Date: January 2012 contact: Lee Jones lee@kernel.org Description: Read-only attribute supported by most SoCs. Contains the SoC's manufacturing revision number.

What: /sys/devices/socX/process Date: January 2012 contact: Lee Jones lee@kernel.org Description: Read-only attribute supported ST-Ericsson's silicon. Contains the the process by which the silicon chip was manufactured.

What: /sys/bus/soc Date: January 2012 contact: Lee Jones lee@kernel.org Description: The /sys/bus/soc/ directory contains the usual sub-folders expected under most buses. /sys/bus/soc/devices is of particular interest, as it contains a symlink for each SoC device found on the system. Each symlink points back into the aforementioned /sys/devices/socX devices.