Documentation: hwmon: coretemp: Update supported CPUs and TjMax values

Update the coretemp documentation to reflect current driver capabilities:

- Extend the supported CPU model list to include Atom processors from
  Bonnell through Jasper Lake, maintaining the original format with
  model numbers and adding X86_FEATURE_DTHERM as the actual detection
  mechanism. Added models: 0x37 (Bay Trail), 0x4a (Merrifield),
  0x4c (Cherry Trail), 0x5a (Moorefield), 0x5c (Apollo Lake),
  0x7a (Gemini Lake), 0x96 (Elkhart Lake), 0x9c (Jasper Lake)

- Update the description to note that per-package temperature sensing
  is available on Sandy Bridge and all newer processors

- Clarify that TjMax is read from MSR_IA32_TEMPERATURE_TARGET on modern
  CPUs (Nehalem and newer)

- Add TjMax values for newer Atom processor families to Appendix A:
  - 22nm Silvermont/Bay Trail: E38xx at 110C, Z37xx at 90C
  - 22nm Silvermont/Moorefield: Z35xx at 90C
  - 14nm Airmont/Cherry Trail: Z8xxx at 90C
  - 14nm Goldmont/Apollo Lake: 105C
  - 14nm Goldmont Plus/Gemini Lake: 105C
  - 10nm Tremont/Elkhart Lake: 105C
  - 10nm Tremont/Jasper Lake: 105C

TjMax values obtained from Intel ARK and official datasheets:
- E3845: https://www.intel.com/content/www/us/en/products/sku/78475/intel-atom-processor-e3845-2m-cache-1-91-ghz/specifications.html
- Z3600/Z3700: https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z36xxx-z37xxx-datasheet-vol-1.pdf

Signed-off-by: Laveesh Bansal <laveeshb@laveeshbansal.com>
Link: https://lore.kernel.org/r/20260106155426.547872-2-laveeshb@laveeshbansal.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/Documentation/hwmon/coretemp.rst b/Documentation/hwmon/coretemp.rst
index c609329e3bc459d4c7815a49ef48eac617848a35..7a5fbb37b0f33c352429eb8df55bf655c833990d 100644 (file)
--- a/Documentation/hwmon/coretemp.rst
+++ b/Documentation/hwmon/coretemp.rst
@@ -2,17 +2,21 @@ Kernel driver coretemp
 ======================
 
 Supported chips:
-  * All Intel Core family
+  * All Intel Core family and Atom processors with Digital Thermal Sensor (DTS)
 
     Prefix: 'coretemp'
 
-    CPUID: family 0x6, models
+    CPUID: family 0x6, models with X86_FEATURE_DTHERM, including:
 
                            - 0xe (Pentium M DC), 0xf (Core 2 DC 65nm),
                            - 0x16 (Core 2 SC 65nm), 0x17 (Penryn 45nm),
                            - 0x1a (Nehalem), 0x1c (Atom), 0x1e (Lynnfield),
                            - 0x26 (Tunnel Creek Atom), 0x27 (Medfield Atom),
-                           - 0x36 (Cedar Trail Atom)
+                           - 0x36 (Cedar Trail Atom), 0x37 (Bay Trail Atom),
+                           - 0x4a (Merrifield Atom), 0x4c (Cherry Trail Atom),
+                           - 0x5a (Moorefield Atom), 0x5c (Apollo Lake Atom),
+                           - 0x7a (Gemini Lake Atom),
+                           - 0x96 (Elkhart Lake Atom), 0x9c (Jasper Lake Atom)
 
     Datasheet:
 
@@ -28,9 +32,9 @@ Description
 
 This driver permits reading the DTS (Digital Temperature Sensor) embedded
 inside Intel CPUs. This driver can read both the per-core and per-package
-temperature using the appropriate sensors. The per-package sensor is new;
-as of now, it is present only in the SandyBridge platform. The driver will
-show the temperature of all cores inside a package under a single device
+temperature using the appropriate sensors. The per-package sensor is
+available on Sandy Bridge and all newer processors. The driver will show
+the temperature of all cores inside a package under a single device
 directory inside hwmon.
 
 Temperature is measured in degrees Celsius and measurement resolution is
@@ -56,10 +60,11 @@ tempX_label   Contains string "Core X", where X is processor
                  where Y is the package number.
 ================= ========================================================
 
-On CPU models which support it, TjMax is read from a model-specific register.
-On other models, it is set to an arbitrary value based on weak heuristics.
-If these heuristics don't work for you, you can pass the correct TjMax value
-as a module parameter (tjmax).
+On modern CPUs (Nehalem and newer), TjMax is read from the
+MSR_IA32_TEMPERATURE_TARGET register. On older models without this MSR,
+TjMax is determined using lookup tables or heuristics. If these don't work
+for your CPU, you can pass the correct TjMax value as a module parameter
+(tjmax).
 
 Appendix A. Known TjMax lists (TBD):
 Some information comes from ark.intel.com
@@ -100,6 +105,40 @@ Process            Processor                                       TjMax(C)
                D2700/2550/2500                                 100
                N2850/2800/2650/2600                            100
 
+22nm           Atom Processors (Silvermont/Bay Trail)
+               E3845/3827/3826/3825/3815/3805                  110
+               Z3795/3775/3770/3740/3736/3735/3680             90
+
+22nm           Atom Processors (Silvermont/Moorefield)
+               Z3580/3570/3560/3530                            90
+
+14nm           Atom Processors (Airmont/Cherry Trail)
+               x5-Z8550/Z8500/Z8350/Z8330/Z8300                90
+               x7-Z8750/Z8700                                  90
+
+14nm           Atom Processors (Goldmont/Apollo Lake)
+               x5-E3940/E3930                                  105
+               x7-E3950                                        105
+
+14nm           Celeron/Pentium Processors
+               (Goldmont/Apollo Lake)
+               J3455/J3355                                     105
+               N3450/N3350                                     105
+               N4200                                           105
+
+14nm           Celeron/Pentium Processors
+               (Goldmont Plus/Gemini Lake)
+               J4105/J4005                                     105
+               N4100/N4000                                     105
+               N5000                                           105
+
+10nm           Atom Processors (Tremont/Elkhart Lake)
+               x6000E                                          105
+
+10nm           Celeron/Pentium Processors
+               (Tremont/Jasper Lake)
+               N4500/N5100/N6000 series                        105
+
 45nm           Xeon Processors 5400 Quad-Core
                X5492, X5482, X5472, X5470, X5460, X5450        85
                E5472, E5462, E5450/40/30/20/10/05              85