[PATCH v4 01/11] dt-bindings: thermal: Add Google GS101 TMU

Tudor Ambarus
2026-04-23T15:23:01Z

Document the Thermal Management Unit (TMU) found on the Google GS101 SoC.

The GS101 TMU utilizes a hybrid control model shared between the
Application Processor (AP) and the ACPM (Alive Clock and Power Manager)
firmware. This hybrid ACPM TMU architecture is also present on other
Samsung Exynos SoCs (e.g., AutoV920, Exynos850).

While the TMU is a standard memory-mapped IP block, on this platform
the AP's direct register access is restricted to the interrupt pending
(INTPEND) registers for event identification. High-level functional
tasks, such as sensor initialization, threshold programming, and
temperature reads, are delegated to the ACPM firmware.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
.../bindings/thermal/google,gs101-tmu-top.yaml | 68 ++++++++++++++++++++++
1 file changed, 68 insertions(+)

diff --git a/Documentation/devicetree/bindings/thermal/google,gs101-tmu-top.yaml b/Documentation/devicetree/bindings/thermal/google,gs101-tmu-top.yaml
new file mode 100644
index 000000000000..d0eb2393d581
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/google,gs101-tmu-top.yaml
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/google,gs101-tmu-top.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos ACPM Thermal Management Unit (TMU)
+
+maintainers:
+ - Tudor Ambarus <tudor.ambarus@linaro.org>
+
+description:
+ The Samsung Exynos ACPM TMU is a thermal sensor block found on Exynos
+ based platforms (such as Google GS101 and Exynos850). It supports
+ both direct register-level access and firmware-mediated management
+ via the ACPM (Alive Clock and Power Manager) firmware.
+
+ On these platforms, the hardware is managed in a hybrid fashion. The
+ Application Processor (AP) maintains direct memory-mapped access
+ exclusively to the interrupt pending registers to identify thermal
+ events. All other functional aspects - including sensor
+ initialization, threshold configuration, and temperature acquisition
+ - are handled by the ACPM firmware. The AP coordinates these
+ operations through the ACPM IPC protocol.
+
+properties:
+ compatible:
+ const: google,gs101-tmu-top
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: APB peripheral clock (PCLK) for TMU register access.
+
+ interrupts:
+ maxItems: 1
+
+ "#thermal-sensor-cells":
+ const: 1
+
+ samsung,acpm-ipc:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description: Phandle to the ACPM IPC node.
+
+required:
+ - compatible
+ - reg
+ - clocks
+ - interrupts
+ - "#thermal-sensor-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+ #include <dt-bindings/clock/google,gs101.h>
+
+ thermal-sensor@100a0000 {
+ compatible = "google,gs101-tmu-top";
+ reg = <0x100a0000 0x800>;
+ clocks = <&cmu_misc CLK_GOUT_MISC_TMU_TOP_PCLK>;
+ interrupts = <GIC_SPI 769 IRQ_TYPE_LEVEL_HIGH 0>;
+ #thermal-sensor-cells = <1>;
+ samsung,acpm-ipc = <&acpm_ipc>;
+ };

--
2.54.0.545.g6539524ca2-goog