xref: /kernel/linux/linux-6.6/Documentation/ABI/testing/sysfs-devices-platform-ACPI-TAD (revision 62306a36)

		ACPI Time and Alarm (TAD) device attributes.

What:		/sys/bus/platform/devices/ACPI000E:00/caps
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RO) Hexadecimal bitmask of the TAD attributes are reported by
		the platform firmware (see ACPI 6.2, section 9.18.2):

		======= ======================================================
		BIT(0): AC wakeup implemented if set
		BIT(1): DC wakeup implemented if set
		BIT(2): Get/set real time features implemented if set
		BIT(3): Real time accuracy in milliseconds if set
		BIT(4): Correct status reported for wakeups from S4/S5 if set
		BIT(5): The AC timer wakes up from S4 if set
		BIT(6): The AC timer wakes up from S5 if set
		BIT(7): The DC timer wakes up from S4 if set
		BIT(8): The DC timer wakes up from S5 if set
		======= ======================================================

		The other bits are reserved.

What:		/sys/bus/platform/devices/ACPI000E:00/ac_alarm
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RW) The AC alarm timer value.

		Reads return the current AC alarm timer value in seconds or
		"disabled", if the AC alarm is not set to wake up the system.

		Write a new AC alarm timer value in seconds or "disabled" to it
		to set the AC alarm timer or to disable it, respectively.

		If the AC alarm timer is set through this attribute and it
		expires, it will immediately wake up the system from the S3
		sleep state (and from S4/S5 too if supported) until its status
		is explicitly cleared via the ac_status attribute.

What:		/sys/bus/platform/devices/ACPI000E:00/ac_policy
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RW) The AC alarm expired timer wake policy (see ACPI 6.2,
		Section 9.18 for details).

		Reads return the current expired timer wake delay for the AC
		alarm timer or "never", if the policy is to discard AC timer
		wakeups if the system is on DC power.

		Write a new expired timer wake delay for the AC alarm timer in
		seconds or "never" to it to set the expired timer wake delay for
		the AC alarm timer or to set its expired wake policy to discard
		wakeups if the system is on DC power, respectively.

What:		/sys/bus/platform/devices/ACPI000E:00/ac_status
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RW) The AC alarm status.

		Reads return a hexadecimal bitmask representing the AC alarm
		timer status with the following meaning of bits (see ACPI 6.2,
		Section 9.18.5):

		======= ======================================================
		Bit(0): The timer has expired if set.
		Bit(1): The timer has woken up the system from a sleep state
		        (S3 or S4/S5 if supported) if set.
		======= ======================================================

		The other bits are reserved.

		Reads also cause the AC alarm timer status to be reset.

		Another way to reset the status of the AC alarm timer is to
		write (the number) 0 to this file.

		If the status return value indicates that the timer has expired,
		it will immediately wake up the system from the S3 sleep state
		(and from S4/S5 too if supported) until its status is explicitly
		cleared through this attribute.

What:		/sys/bus/platform/devices/ACPI000E:00/dc_alarm
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RW,optional) The DC alarm timer value.

		This attribute is only present if the TAD supports a separate
		DC timer.

		It is analogous to the ac_alarm attribute.

What:		/sys/bus/platform/devices/ACPI000E:00/dc_policy
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description:
		(RW,optional) The DC alarm expired timer wake policy.

		This attribute is only present if the TAD supports a separate
		DC timer.

		It is analogous to the ac_policy attribute.

What:		/sys/bus/platform/devices/ACPI000E:00/dc_status
Date:		March 2018
Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Description:
		(RW,optional) The DC alarm status.

		This attribute is only present if the TAD supports a separate
		DC timer.

		It is analogous to the ac_status attribute.