Re: [PATCH v8 1/5] dt-bindings: thermal: Add Google GS101 TMU

[Peter Griffin]

On Wed, 3 Jun 2026 at 14:00, Tudor Ambarus <tudor.ambarus@xxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxx>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
> ---

Reviewed-by: Peter Griffin <peter.griffin@xxxxxxxxxx>

>  .../bindings/thermal/google,gs101-tmu-top.yaml     | 69 ++++++++++++++++++++++
>  1 file changed, 69 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..75560ebca48d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/thermal/google,gs101-tmu-top.yaml
> @@ -0,0 +1,69 @@
> +# 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@xxxxxxxxxx>
> +
> +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"
> +  - samsung,acpm-ipc
> +
> +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>;
> +    };
>
> --
> 2.54.0.1013.g208068f2d8-goog
>