eb0e90a820
The Surface Aggregator EC provides varying functionality, depending on the Surface device. To manage this functionality, we use dedicated client devices for each subsystem or virtual device of the EC. While some of these clients are described as standard devices in ACPI and the corresponding client drivers can be implemented as platform drivers in the kernel (making use of the controller API already present), many devices, especially on newer Surface models, cannot be found there. To simplify management of these devices, we introduce a new bus and client device type for the Surface Aggregator subsystem. The new device type takes care of managing the controller reference, essentially guaranteeing its validity for as long as the client device exists, thus alleviating the need to manually establish device links for that purpose in the client driver (as has to be done with the platform devices). Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com> Reviewed-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20201221183959.1186143-7-luzmaximilian@gmail.com Signed-off-by: Hans de Goede <hdegoede@redhat.com>
69 lines
3.1 KiB
Plaintext
69 lines
3.1 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0+
|
|
# Copyright (C) 2019-2020 Maximilian Luz <luzmaximilian@gmail.com>
|
|
|
|
menuconfig SURFACE_AGGREGATOR
|
|
tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers"
|
|
depends on SERIAL_DEV_BUS
|
|
select CRC_CCITT
|
|
help
|
|
The Surface System Aggregator Module (Surface SAM or SSAM) is an
|
|
embedded controller (EC) found on 5th- and later-generation Microsoft
|
|
Surface devices (i.e. Surface Pro 5, Surface Book 2, Surface Laptop,
|
|
and newer, with exception of Surface Go series devices).
|
|
|
|
Depending on the device in question, this EC provides varying
|
|
functionality, including:
|
|
- EC access from ACPI via Surface ACPI Notify (5th- and 6th-generation)
|
|
- battery status information (all devices)
|
|
- thermal sensor access (all devices)
|
|
- performance mode / cooling mode control (all devices)
|
|
- clipboard detachment system control (Surface Book 2 and 3)
|
|
- HID / keyboard input (Surface Laptops, Surface Book 3)
|
|
|
|
This option controls whether the Surface SAM subsystem core will be
|
|
built. This includes a driver for the Surface Serial Hub (SSH), which
|
|
is the device responsible for the communication with the EC, and a
|
|
basic kernel interface exposing the EC functionality to other client
|
|
drivers, i.e. allowing them to make requests to the EC and receive
|
|
events from it. Selecting this option alone will not provide any
|
|
client drivers and therefore no functionality beyond the in-kernel
|
|
interface. Said functionality is the responsibility of the respective
|
|
client drivers.
|
|
|
|
Note: While 4th-generation Surface devices also make use of a SAM EC,
|
|
due to a difference in the communication interface of the controller,
|
|
only 5th and later generations are currently supported. Specifically,
|
|
devices using SAM-over-SSH are supported, whereas devices using
|
|
SAM-over-HID, which is used on the 4th generation, are currently not
|
|
supported.
|
|
|
|
Choose m if you want to build the SAM subsystem core and SSH driver as
|
|
module, y if you want to build it into the kernel and n if you don't
|
|
want it at all.
|
|
|
|
config SURFACE_AGGREGATOR_BUS
|
|
bool "Surface System Aggregator Module Bus"
|
|
depends on SURFACE_AGGREGATOR
|
|
default y
|
|
help
|
|
Expands the Surface System Aggregator Module (SSAM) core driver by
|
|
providing a dedicated bus and client-device type.
|
|
|
|
This bus and device type are intended to provide and simplify support
|
|
for non-platform and non-ACPI SSAM devices, i.e. SSAM devices that are
|
|
not auto-detectable via the conventional means (e.g. ACPI).
|
|
|
|
config SURFACE_AGGREGATOR_ERROR_INJECTION
|
|
bool "Surface System Aggregator Module Error Injection Capabilities"
|
|
depends on SURFACE_AGGREGATOR
|
|
depends on FUNCTION_ERROR_INJECTION
|
|
help
|
|
Provides error-injection capabilities for the Surface System
|
|
Aggregator Module subsystem and Surface Serial Hub driver.
|
|
|
|
Specifically, exports error injection hooks to be used with the
|
|
kernel's function error injection capabilities to simulate underlying
|
|
transport and communication problems, such as invalid data sent to or
|
|
received from the EC, dropped data, and communication timeouts.
|
|
Intended for development and debugging.
|