linux/drivers/platform/surface/Kconfig
Maximilian Luz fc622b3d36 platform/surface: Set up Surface Aggregator device registry
The Surface System Aggregator Module (SSAM) subsystem provides various
functionalities, which are separated by spreading them across multiple
devices and corresponding drivers. Parts of that functionality / some of
those devices, however, can (as far as we currently know) not be
auto-detected by conventional means. While older (specifically 5th- and
6th-)generation models do advertise most of their functionality via
standard platform devices in ACPI, newer generations do not.

As we are currently also not aware of any feasible way to query said
functionalities dynamically, this poses a problem. There is, however, a
device in ACPI that seems to be used by Windows for identifying
different Surface models: The Windows Surface Integration Device (WSID).
This device seems to have a HID corresponding to the overall set of
functionalities SSAM provides for the associated model.

This commit introduces a registry providing non-detectable device
information via software nodes. In addition, a SSAM platform hub driver
is introduced, which takes care of creating and managing the SSAM
devices specified in this registry. This approach allows for a
hierarchical setup akin to ACPI and is easily extendable, e.g. via
firmware node properties.

Note that this commit only provides the basis for the platform hub and
registry, and does not add any content to it. The registry will be
expanded in subsequent commits.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210212115439.1525216-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2021-03-06 10:23:26 +01:00

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# SPDX-License-Identifier: GPL-2.0-only
#
# Microsoft Surface Platform-Specific Drivers
#
menuconfig SURFACE_PLATFORMS
bool "Microsoft Surface Platform-Specific Device Drivers"
depends on ACPI
default y
help
Say Y here to get to see options for platform-specific device drivers
for Microsoft Surface devices. This option alone does not add any
kernel code.
If you say N, all options in this submenu will be skipped and disabled.
if SURFACE_PLATFORMS
config SURFACE3_WMI
tristate "Surface 3 WMI Driver"
depends on ACPI_WMI
depends on DMI
depends on INPUT
depends on SPI
help
Say Y here if you have a Surface 3.
To compile this driver as a module, choose M here: the module will
be called surface3-wmi.
config SURFACE_3_BUTTON
tristate "Power/home/volume buttons driver for Microsoft Surface 3 tablet"
depends on KEYBOARD_GPIO && I2C
help
This driver handles the power/home/volume buttons on the Microsoft Surface 3 tablet.
config SURFACE_3_POWER_OPREGION
tristate "Surface 3 battery platform operation region support"
depends on I2C
help
This driver provides support for ACPI operation
region of the Surface 3 battery platform driver.
config SURFACE_ACPI_NOTIFY
tristate "Surface ACPI Notify Driver"
depends on SURFACE_AGGREGATOR
help
Surface ACPI Notify (SAN) driver for Microsoft Surface devices.
This driver provides support for the ACPI interface (called SAN) of
the Surface System Aggregator Module (SSAM) EC. This interface is used
on 5th- and 6th-generation Microsoft Surface devices (including
Surface Pro 5 and 6, Surface Book 2, Surface Laptops 1 and 2, and in
reduced functionality on the Surface Laptop 3) to execute SSAM
requests directly from ACPI code, as well as receive SSAM events and
turn them into ACPI notifications. It essentially acts as a
translation layer between the SSAM controller and ACPI.
Specifically, this driver may be needed for battery status reporting,
thermal sensor access, and real-time clock information, depending on
the Surface device in question.
config SURFACE_AGGREGATOR_CDEV
tristate "Surface System Aggregator Module User-Space Interface"
depends on SURFACE_AGGREGATOR
help
Provides a misc-device interface to the Surface System Aggregator
Module (SSAM) controller.
This option provides a module (called surface_aggregator_cdev), that,
when loaded, will add a client device (and its respective driver) to
the SSAM controller. Said client device manages a misc-device
interface (/dev/surface/aggregator), which can be used by user-space
tools to directly communicate with the SSAM EC by sending requests and
receiving the corresponding responses.
The provided interface is intended for debugging and development only,
and should not be used otherwise.
config SURFACE_AGGREGATOR_REGISTRY
tristate "Surface System Aggregator Module Device Registry"
depends on SURFACE_AGGREGATOR
depends on SURFACE_AGGREGATOR_BUS
help
Device-registry and device-hubs for Surface System Aggregator Module
(SSAM) devices.
Provides a module and driver which act as a device-registry for SSAM
client devices that cannot be detected automatically, e.g. via ACPI.
Such devices are instead provided via this registry and attached via
device hubs, also provided in this module.
Devices provided via this registry are:
- Platform profile (performance-/cooling-mode) device (5th- and later
generations).
- Battery/AC devices (7th-generation).
- HID input devices (7th-generation).
Select M (recommended) or Y here if you want support for the above
mentioned devices on the corresponding Surface models. Without this
module, the respective devices will not be instantiated and thus any
functionality provided by them will be missing, even when drivers for
these devices are present. In other words, this module only provides
the respective client devices. Drivers for these devices still need to
be selected via the other options.
config SURFACE_GPE
tristate "Surface GPE/Lid Support Driver"
depends on DMI
help
This driver marks the GPEs related to the ACPI lid device found on
Microsoft Surface devices as wakeup sources and prepares them
accordingly. It is required on those devices to allow wake-ups from
suspend by opening the lid.
config SURFACE_HOTPLUG
tristate "Surface Hot-Plug Driver"
depends on GPIOLIB
help
Driver for out-of-band hot-plug event signaling on Microsoft Surface
devices with hot-pluggable PCIe cards.
This driver is used on Surface Book (2 and 3) devices with a
hot-pluggable discrete GPU (dGPU). When not in use, the dGPU on those
devices can enter D3cold, which prevents in-band (standard) PCIe
hot-plug signaling. Thus, without this driver, detaching the base
containing the dGPU will not correctly update the state of the
corresponding PCIe device if it is in D3cold. This driver adds support
for out-of-band hot-plug notifications, ensuring that the device state
is properly updated even when the device in question is in D3cold.
Select M or Y here, if you want to (fully) support hot-plugging of
dGPU devices on the Surface Book 2 and/or 3 during D3cold.
config SURFACE_PRO3_BUTTON
tristate "Power/home/volume buttons driver for Microsoft Surface Pro 3/4 tablet"
depends on INPUT
help
This driver handles the power/home/volume buttons on the Microsoft Surface Pro 3/4 tablet.
source "drivers/platform/surface/aggregator/Kconfig"
endif # SURFACE_PLATFORMS