1# SPDX-License-Identifier: GPL-2.0+ 2# Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com> 3 4menuconfig SURFACE_AGGREGATOR 5 tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers" 6 depends on SERIAL_DEV_BUS 7 select CRC_CCITT 8 help 9 The Surface System Aggregator Module (Surface SAM or SSAM) is an 10 embedded controller (EC) found on 5th- and later-generation Microsoft 11 Surface devices (i.e. Surface Pro 5, Surface Book 2, Surface Laptop, 12 and newer, with exception of Surface Go series devices). 13 14 Depending on the device in question, this EC provides varying 15 functionality, including: 16 - EC access from ACPI via Surface ACPI Notify (5th- and 6th-generation) 17 - battery status information (all devices) 18 - thermal sensor access (all devices) 19 - performance mode / cooling mode control (all devices) 20 - clipboard detachment system control (Surface Book 2 and 3) 21 - HID / keyboard input (Surface Laptops, Surface Book 3) 22 23 This option controls whether the Surface SAM subsystem core will be 24 built. This includes a driver for the Surface Serial Hub (SSH), which 25 is the device responsible for the communication with the EC, and a 26 basic kernel interface exposing the EC functionality to other client 27 drivers, i.e. allowing them to make requests to the EC and receive 28 events from it. Selecting this option alone will not provide any 29 client drivers and therefore no functionality beyond the in-kernel 30 interface. Said functionality is the responsibility of the respective 31 client drivers. 32 33 Note: While 4th-generation Surface devices also make use of a SAM EC, 34 due to a difference in the communication interface of the controller, 35 only 5th and later generations are currently supported. Specifically, 36 devices using SAM-over-SSH are supported, whereas devices using 37 SAM-over-HID, which is used on the 4th generation, are currently not 38 supported. 39 40 Choose m if you want to build the SAM subsystem core and SSH driver as 41 module, y if you want to build it into the kernel and n if you don't 42 want it at all. 43 44config SURFACE_AGGREGATOR_BUS 45 bool "Surface System Aggregator Module Bus" 46 depends on SURFACE_AGGREGATOR 47 default y 48 help 49 Expands the Surface System Aggregator Module (SSAM) core driver by 50 providing a dedicated bus and client-device type. 51 52 This bus and device type are intended to provide and simplify support 53 for non-platform and non-ACPI SSAM devices, i.e. SSAM devices that are 54 not auto-detectable via the conventional means (e.g. ACPI). 55 56config SURFACE_AGGREGATOR_ERROR_INJECTION 57 bool "Surface System Aggregator Module Error Injection Capabilities" 58 depends on SURFACE_AGGREGATOR 59 depends on FUNCTION_ERROR_INJECTION 60 help 61 Provides error-injection capabilities for the Surface System 62 Aggregator Module subsystem and Surface Serial Hub driver. 63 64 Specifically, exports error injection hooks to be used with the 65 kernel's function error injection capabilities to simulate underlying 66 transport and communication problems, such as invalid data sent to or 67 received from the EC, dropped data, and communication timeouts. 68 Intended for development and debugging. 69