linux-stable/Documentation/ABI/testing/sysfs-class-power-surface
Maximilian Luz 167f77f7d0 power: supply: Add battery driver for Surface Aggregator Module
On newer Microsoft Surface models (specifically 7th-generation, i.e.
Surface Pro 7, Surface Book 3, Surface Laptop 3, and Surface Laptop Go),
battery and AC status/information is no longer handled via standard ACPI
devices, but instead directly via the Surface System Aggregator Module
(SSAM), i.e. the embedded controller on those devices.

While on previous generation models, battery status is also handled via
SSAM, an ACPI shim was present to translate the standard ACPI battery
interface to SSAM requests. The SSAM interface itself, which is modeled
closely after the ACPI interface, has not changed.

This commit introduces a new SSAM client device driver to support
battery status/information via the aforementioned interface on said
Surface models. It is in parts based on the standard ACPI battery
driver.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2021-04-08 14:30:28 +02:00

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What: /sys/class/power_supply/<supply_name>/alarm
Date: April 2021
KernelVersion: 5.13
Contact: Maximilian Luz <luzmaximilian@gmail.com>
Description:
Battery trip point. When the remaining battery capacity crosses this
value in either direction, the system will be notified and if
necessary woken.
Set to zero to clear/disable.
Access: Read, Write
Valid values: In micro-Wh or micro-Ah, depending on the power unit
of the battery