drivers/staging/greybus/Documentation/sysfs-bus-greybus

What:		/sys/bus/greybus/device/endo-0xXXXX
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The "root" endo for the Greybus device tree. XXX is
		replaced with the numeric value of the endo layout
		scheme as documented in the ARA Module Developer Kit.

What:		/sys/bus/greybus/device/endo-0xXXXX/Endo/id
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The Endo ID, which is a 2-byte hexadecimal value
		defined by the the Endo layout scheme, documented in
		the ARA Module Developer Kit.

What:		/sys/bus/greybus/device/endo-0xXXXX/Endo/ap_intf_id
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The AP interface ID, a small non-zero integer which
		defines the position of the AP module on the Endo.
		The interface positions are defined in the ARA
		Module Developer Kit.

What:		/sys/bus/greybus/device/endo-0xXXXX/SVC/serial_number
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The serial number of the SVC device

What:		/sys/bus/greybus/device/endo-0xXXXX/SVC/version
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The version number of the firmware in the SVC device.

What:		/sys/bus/greybus/device/endo-0xXXXX/.../epm
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The EPM (Electropermanent Magnet) control file for
		the specific module slot the file is present in.
		Writing 1 to it turns it on, writing 0 to it turns it
		off.  Reading the value returns if it is on or off.

What:		/sys/bus/greybus/device/endo-0xXXXX/.../power_control
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The power control file for the specific module slot that
		the file is present in.  Writing 1 to it turns power on
		to the module, writing 0 to it turns power off to the
		module.  Reading the value returns if it is on or off.

What:		/sys/bus/greybus/device/endo-0xXXXX/.../present
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The "is a module present in the slot" file for the
		specific module slot that the file is present in.
		This is read-only, 1 means a module is present, 0 means
		no module is present.

What:		/sys/bus/greybus/device/.../product
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		Product ID of a Greybus interface block.

What:		/sys/bus/greybus/device/.../product_string
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		Product ID string of a Greybus interface block.

What:		/sys/bus/greybus/device/.../unique_id
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		Unique ID of a Greybus interface block.

What:		/sys/bus/greybus/device/.../vendor
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		Vendor ID of a Greybus interface block.

What:		/sys/bus/greybus/device/.../vendor_string
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		Vendor ID string of a Greybus interface block.

What:		/sys/bus/greybus/device/.../state
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The current state of a Greybus connection.

		It will be one of the following values:
		0 - invalid
		1 - disabled
		2 - enabled
		3 - error
		4 - destroying

What:		/sys/bus/greybus/device/.../protocol_id
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The protocol ID of a Greybus connection.

What:		/sys/bus/greybus/device/.../device_id
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		The device ID of a Greybus bundle.

What:		/sys/bus/greybus/device/.../state
Date:		October 2015
KernelVersion:	4.XX
Contact:	Greg Kroah-Hartman <greg@kroah.com>
Description:
		A bundle has a state that is managed by the userspace
		Endo process.  This file allows that Endo to signal
		other Android HALs that the state of the bundle has
		changed to a specific value.  When written to, any
		process watching the file will be woken up, and the new
		value can be read. It's a "poor-man's IPC", yes, but
		simplifies the Android userspace code immensely.