On Tue, 2021-07-27 at 17:49 -0700, Guenter Roeck wrote:

On 7/27/21 3:58 PM, Zev Weiss wrote:

quoted

On Mon, Jul 12, 2021 at 05:04:46PM CDT, Iwona Winiarska wrote:

quoted

From: Jae Hyun Yoo <redacted>

Add documentation for peci-cputemp driver that provides DTS thermal
readings for CPU packages and CPU cores and peci-dimmtemp driver that
provides DTS thermal readings for DIMMs.

Signed-off-by: Jae Hyun Yoo <redacted>
Co-developed-by: Iwona Winiarska <iwona.winiarska@intel.com>
Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
Reviewed-by: Pierre-Louis Bossart <redacted>
---
Documentation/hwmon/index.rst         |  2 +
Documentation/hwmon/peci-cputemp.rst  | 93 +++++++++++++++++++++++++++
Documentation/hwmon/peci-dimmtemp.rst | 58 +++++++++++++++++
MAINTAINERS                           |  2 +
4 files changed, 155 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 bc01601ea81a..cc76b5b3f791 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst

@@ -154,6 +154,8 @@ 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..d3a218ba810a

--- /dev/null
+++ b/Documentation/hwmon/peci-cputemp.rst

@@ -0,0 +1,93 @@
+.. 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 [off-list ref]
+
+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 DTS temperature of the CPU package.

Would this be a good place to note the slightly counter-intuitive nature
of DTS readings?  i.e. add something along the lines of "The DTS sensor
produces a delta relative to Tjmax, so negative values are normal and
values approaching zero are hot."  (In my experience people who aren't
already familiar with it tend to think something's wrong when a CPU
temperature reading shows -50C.)

All attributes shall follow the ABI, and the driver must translate reported
values to degrees C. If those sensors do not follow the ABI and report something
else, I won't accept the driver.

Guenter

Sure, I believe all attributes already follow the ABI and the reported values
are in millidegree Celsius.

Thanks
-Iwona

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