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authorKun Yi <kunyi@google.com>2020-12-11 13:54:26 -0800
committerGuenter Roeck <linux@roeck-us.net>2020-12-12 08:34:29 -0800
commit6ec3fcf556fe44542934b778aea1b725b0793418 (patch)
tree1488e0b8280df21a32a9e52ef2f3c7c38fb75949 /Documentation/hwmon/sbtsi_temp.rst
parente7bb1a2ab8c4b1569f5b271fd87ca203b1e673a5 (diff)
hwmon: (sbtsi) Add documentation
Document the SB-TSI sensor interface driver. Signed-off-by: Kun Yi <kunyi@google.com> Link: https://lore.kernel.org/r/20201211215427.3281681-3-kunyi@google.com [groeck: Added SPDX license identifier, same as source] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver sbtsi_temp
+==================
+
+Supported hardware:
+
+ * Sideband interface (SBI) Temperature Sensor Interface (SB-TSI)
+ compliant AMD SoC temperature device.
+
+ Prefix: 'sbtsi_temp'
+
+ Addresses scanned: This driver doesn't support address scanning.
+
+ To instantiate this driver on an AMD CPU with SB-TSI
+ support, the i2c bus number would be the bus connected from the board
+ management controller (BMC) to the CPU. The i2c address is specified in
+ Section 6.3.1 of the SoC register reference: The SB-TSI address is normally
+ 98h for socket 0 and 90h for socket 1, but it could vary based on hardware
+ address select pins.
+
+ Datasheet: The SB-TSI interface and protocol is available as part of
+ the open source SoC register reference at:
+
+ https://www.amd.com/system/files/TechDocs/56255_OSRR.pdf
+
+ The Advanced Platform Management Link (APML) Specification is
+ available at:
+
+ http://developer.amd.com/wordpress/media/2012/10/41918.pdf
+
+Author: Kun Yi <kunyi@google.com>
+
+Description
+-----------
+
+The SBI temperature sensor interface (SB-TSI) is an emulation of the software
+and physical interface of a typical 8-pin remote temperature sensor (RTS) on
+AMD SoCs. It implements one temperature sensor with readings and limit
+registers encode the temperature in increments of 0.125 from 0 to 255.875.
+Limits can be set through the writable thresholds, and if reached will trigger
+corresponding alert signals.