Re: [PATCH] dt-bindings: thermal: Use signed integers for coefficients
From: Daniel Lezcano
Date: Thu Nov 05 2026 - 10:43:30 EST
Hi Lukasz,
On 11/5/26 11:45, Lukasz Luba wrote:
Hi Daniel,Thanks for the review
On 11/3/26 21:43, Daniel Lezcano wrote:
The coefficients property describes the coefficients of a linear
equation used to derive a thermal zone temperature. Both the slope
and the constant offset can be negative, and the thermal core stores
them as signed integers.
Existing Device Trees already rely on signed values. OMAP4460 uses
an offset of -9301, while OMAP5 uses offsets of -1791 and -2992.
Broadcom platforms also use negative slopes. Declaring the property
as uint32-array does not represent these values correctly.
This looks like a good argument which was missed back then (that
the negative values are possible).
Change the property type to int32-array so schema validation decodes
the cells as signed 32-bit integers, matching their intended meaning
and the thermal implementation. The cell width and binary encoding
remain unchanged, preserving compatibility with existing Device
Trees.
Fixes: 1202a442a31f ("dt-bindings: thermal: Add yaml bindings for thermal zones")
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/thermal/thermal-zones.yaml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/thermal/thermal- zones.yaml b/Documentation/devicetree/bindings/thermal/thermal-zones.yaml
index 999ad40a20d5..72e419124f98 100644
--- a/Documentation/devicetree/bindings/thermal/thermal-zones.yaml
+++ b/Documentation/devicetree/bindings/thermal/thermal-zones.yaml
@@ -101,7 +101,7 @@ patternProperties:
thermal zone.
coefficients:
- $ref: /schemas/types.yaml#/definitions/uint32-array
+ $ref: /schemas/types.yaml#/definitions/int32-array
description:
An array of integers containing the coefficients of a linear equation
that binds all the sensors listed in this thermal zone.
Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx>