[PATCH v4 12/13] docs: hwmon: Document PECI drivers

From: Iwona Winiarska
Date: Tue Nov 23 2021 - 09:13:29 EST

From: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>

Add documentation for peci-cputemp driver that provides DTS thermal
readings for CPU packages and CPU cores, and peci-dimmtemp driver that
provides Temperature Sensor on DIMM readings.

Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
Co-developed-by: Iwona Winiarska <iwona.winiarska@xxxxxxxxx>
Signed-off-by: Iwona Winiarska <iwona.winiarska@xxxxxxxxx>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
Documentation/hwmon/index.rst | 2 +
Documentation/hwmon/peci-cputemp.rst | 90 +++++++++++++++++++++++++++
Documentation/hwmon/peci-dimmtemp.rst | 57 +++++++++++++++++
MAINTAINERS | 2 +
4 files changed, 151 insertions(+)
create mode 100644 Documentation/hwmon/peci-cputemp.rst
create mode 100644 Documentation/hwmon/peci-dimmtemp.rst

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 7046bf1870d9..6ebd73a55c26 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -156,6 +156,8 @@ Hardware Monitoring Kernel Drivers
pcf8591
pim4328
pm6764tr
+ peci-cputemp
+ peci-dimmtemp
pmbus
powr1220
pxe1610
diff --git a/Documentation/hwmon/peci-cputemp.rst b/Documentation/hwmon/peci-cputemp.rst
new file mode 100644
index 000000000000..fe0422248dc5
--- /dev/null
+++ b/Documentation/hwmon/peci-cputemp.rst
@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver peci-cputemp
+==========================
+
+Supported chips:
+ One of Intel server CPUs listed below which is connected to a PECI bus.
+ * Intel Xeon E5/E7 v3 server processors
+ Intel Xeon E5-14xx v3 family
+ Intel Xeon E5-24xx v3 family
+ Intel Xeon E5-16xx v3 family
+ Intel Xeon E5-26xx v3 family
+ Intel Xeon E5-46xx v3 family
+ Intel Xeon E7-48xx v3 family
+ Intel Xeon E7-88xx v3 family
+ * Intel Xeon E5/E7 v4 server processors
+ Intel Xeon E5-16xx v4 family
+ Intel Xeon E5-26xx v4 family
+ Intel Xeon E5-46xx v4 family
+ Intel Xeon E7-48xx v4 family
+ Intel Xeon E7-88xx v4 family
+ * Intel Xeon Scalable server processors
+ Intel Xeon D family
+ Intel Xeon Bronze family
+ Intel Xeon Silver family
+ Intel Xeon Gold family
+ Intel Xeon Platinum family
+
+ Datasheet: Available from http://www.intel.com/design/literature.htm
+
+Author: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
+
+Description
+-----------
+
+This driver implements a generic PECI hwmon feature which provides Digital
+Thermal Sensor (DTS) thermal readings of the CPU package and CPU cores that are
+accessible via the processor PECI interface.
+
+All temperature values are given in millidegree Celsius and will be measurable
+only when the target CPU is powered on.
+
+Sysfs interface
+-------------------
+
+======================= =======================================================
+temp1_label "Die"
+temp1_input Provides current die temperature of the CPU package.
+temp1_max Provides thermal control temperature of the CPU package
+ which is also known as Tcontrol.
+temp1_crit Provides shutdown temperature of the CPU package which
+ is also known as the maximum processor junction
+ temperature, Tjmax or Tprochot.
+temp1_crit_hyst Provides the hysteresis value from Tcontrol to Tjmax of
+ the CPU package.
+
+temp2_label "DTS"
+temp2_input Provides current temperature of the CPU package scaled
+ to match DTS thermal profile.
+temp2_max Provides thermal control temperature of the CPU package
+ which is also known as Tcontrol.
+temp2_crit Provides shutdown temperature of the CPU package which
+ is also known as the maximum processor junction
+ temperature, Tjmax or Tprochot.
+temp2_crit_hyst Provides the hysteresis value from Tcontrol to Tjmax of
+ the CPU package.
+
+temp3_label "Tcontrol"
+temp3_input Provides current Tcontrol temperature of the CPU
+ package which is also known as Fan Temperature target.
+ Indicates the relative value from thermal monitor trip
+ temperature at which fans should be engaged.
+temp3_crit Provides Tcontrol critical value of the CPU package
+ which is same to Tjmax.
+
+temp4_label "Tthrottle"
+temp4_input Provides current Tthrottle temperature of the CPU
+ package. Used for throttling temperature. If this value
+ is allowed and lower than Tjmax - the throttle will
+ occur and reported at lower than Tjmax.
+
+temp5_label "Tjmax"
+temp5_input Provides the maximum junction temperature, Tjmax of the
+ CPU package.
+
+temp[6-N]_label Provides string "Core X", where X is resolved core
+ number.
+temp[6-N]_input Provides current temperature of each core.
+
+======================= =======================================================
diff --git a/Documentation/hwmon/peci-dimmtemp.rst b/Documentation/hwmon/peci-dimmtemp.rst
new file mode 100644
index 000000000000..e562aed620de
--- /dev/null
+++ b/Documentation/hwmon/peci-dimmtemp.rst
@@ -0,0 +1,57 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver peci-dimmtemp
+===========================
+
+Supported chips:
+ One of Intel server CPUs listed below which is connected to a PECI bus.
+ * Intel Xeon E5/E7 v3 server processors
+ Intel Xeon E5-14xx v3 family
+ Intel Xeon E5-24xx v3 family
+ Intel Xeon E5-16xx v3 family
+ Intel Xeon E5-26xx v3 family
+ Intel Xeon E5-46xx v3 family
+ Intel Xeon E7-48xx v3 family
+ Intel Xeon E7-88xx v3 family
+ * Intel Xeon E5/E7 v4 server processors
+ Intel Xeon E5-16xx v4 family
+ Intel Xeon E5-26xx v4 family
+ Intel Xeon E5-46xx v4 family
+ Intel Xeon E7-48xx v4 family
+ Intel Xeon E7-88xx v4 family
+ * Intel Xeon Scalable server processors
+ Intel Xeon D family
+ Intel Xeon Bronze family
+ Intel Xeon Silver family
+ Intel Xeon Gold family
+ Intel Xeon Platinum family
+
+ Datasheet: Available from http://www.intel.com/design/literature.htm
+
+Author: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
+
+Description
+-----------
+
+This driver implements a generic PECI hwmon feature which provides
+Temperature sensor on DIMM readings that are accessible via the processor PECI interface.
+
+All temperature values are given in millidegree Celsius and will be measurable
+only when the target CPU is powered on.
+
+Sysfs interface
+-------------------
+
+======================= =======================================================
+
+temp[N]_label Provides string "DIMM CI", where C is DIMM channel and
+ I is DIMM index of the populated DIMM.
+temp[N]_input Provides current temperature of the populated DIMM.
+temp[N]_max Provides thermal control temperature of the DIMM.
+temp[N]_crit Provides shutdown temperature of the DIMM.
+
+======================= =======================================================
+
+Note:
+ DIMM temperature attributes will appear when the client CPU's BIOS
+ completes memory training and testing.
diff --git a/MAINTAINERS b/MAINTAINERS
index af226d613a2c..6266e996dca0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14923,6 +14923,8 @@ PECI HARDWARE MONITORING DRIVERS
M: Iwona Winiarska <iwona.winiarska@xxxxxxxxx>
L: linux-hwmon@xxxxxxxxxxxxxxx
S: Supported
+F: Documentation/hwmon/peci-cputemp.rst
+F: Documentation/hwmon/peci-dimmtemp.rst
F: drivers/hwmon/peci/

PECI SUBSYSTEM
--
2.31.1