Re: [PATCH v2 4/7] thermal: samsung: Add support for GS101 TMU

Alexey Klimov
2026-03-01T03:33:26Z

On Mon Jan 19, 2026 at 12:08 PM GMT, Tudor Ambarus wrote:
> Add the thermal driver for the Google GS101 SoC.

Is this driver for GS101 platforms only or for all Exynos-based
platforms where we have deal with thermal unit via ACPM?

> The GS101 TMU utilizes a hybrid management model shared between the
> Application Processor (AP) and the ACPM (Alive Clock and Power Manager)
> firmware. The driver maintains direct memory-mapped access to the TMU
> interrupt pending registers to identify thermal events, while delegating
> functional tasks - such as sensor initialization, threshold configuration,
> and temperature acquisition - to the ACPM firmware via the ACPM IPC
> protocol.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
> ---
> drivers/thermal/samsung/Kconfig | 16 +
> drivers/thermal/samsung/Makefile | 2 +
> drivers/thermal/samsung/acpm-tmu.c | 643 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 661 insertions(+)
>
> diff --git a/drivers/thermal/samsung/Kconfig b/drivers/thermal/samsung/Kconfig
> index f4eff5a41a84ce02b12abb85d6a0f8818031d0dc..5679dfa85f4079c7d40317ac231bd6a1af93c7e7 100644
> --- a/drivers/thermal/samsung/Kconfig
> +++ b/drivers/thermal/samsung/Kconfig
> @@ -9,3 +9,19 @@ config EXYNOS_THERMAL
> the TMU, reports temperature and handles cooling action if defined.
> This driver uses the Exynos core thermal APIs and TMU configuration
> data from the supported SoCs.
> +
> +config EXYNOS_ACPM_THERMAL
> + tristate "Exynos ACPM thermal management unit driver"
> + depends on THERMAL_OF
> + depends on EXYNOS_ACPM_PROTOCOL || (COMPILE_TEST && !EXYNOS_ACPM_PROTOCOL)
> + help
> + Support for the Thermal Management Unit (TMU) on Google GS101 SoC.
> +
> + The TMU on GS101 is managed through a hybrid architecture. This driver
> + handles direct register access for thermal interrupt status monitoring
> + and communicates with the Alive Clock and Power Manager (ACPM)
> + firmware via the ACPM IPC protocol for functional sensor control and
> + configuration.
> +
> + Select this if you want to monitor device temperature and enable
> + thermal mitigation on GS101 based devices.

I don't understand this. What this driver actually supports/implements?
Dealing with TMU over ACPM firmware is not exclusive to Google GS101 SoC,
some other Exynos-based systems has this as well. However, it names
the config option EXYNOS_ACPM_THERMAL but a lot of other things say that
it is only for GS101, isn't it?
Does it implement the generic layer dealing with TMU via ACPM (hence the name)
and adds specific things to support gs101?

Should it be something like this (feel free to correct):
Support for the Thermal Management Unit (TMU) exported via ACPM.

This driver handles direct register access for thermal interrupt
status monitoring and communicates with the Alive Clock and Power
Manager (ACPM) firmware via the ACPM IPC protocol for functional
sensor control and configuration.

Select this if you want to monitor device temperature and enable
thermal mitigation on Exynos-based devices that implement dealing
with TMU via ACPM, for instance, GS101-based devices.

?

[...]
Best regards,
Alexey