Re: [PATCH v7 3/3] arm64: dts: imx91: Add thermal-sensor and thermal-zone support

[Alberto Merciai <alb3rt0.m3rciai@gmail.com>]

On Mon, Oct 20, 2025 at 03:00:42PM -0400, Frank Li wrote:
> Add thermal-sensor and thermal-zone support.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> changes in v7
> - new patch
> ---
>  arch/arm64/boot/dts/freescale/imx91.dtsi | 58 ++++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx91.dtsi b/arch/arm64/boot/dts/freescale/imx91.dtsi
> index 4d8300b2a7bca33bd0613db9e79d2fba6b40c052..f075592bfc01f1eb94d2a2bd8eea907cc2aed090 100644
> --- a/arch/arm64/boot/dts/freescale/imx91.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx91.dtsi
> @@ -6,6 +6,54 @@
>  #include "imx91-pinfunc.h"
>  #include "imx91_93_common.dtsi"
>  
> +/{
> +	thermal-zones {
> +		cpu-thermal {
> +			polling-delay-passive = <250>;
> +			polling-delay = <2000>;
> +			thermal-sensors = <&tmu 0>;
> +
> +			trips {
> +				cpu_alert: cpu-alert {
> +					temperature = <80000>;
> +					hysteresis = <2000>;
> +					type = "passive";
> +				};
> +
> +				cpu_crit: cpu-crit {
> +					temperature = <90000>;
> +					hysteresis = <2000>;
> +					type = "critical";
> +				};
> +			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&cpu_alert>;
> +					cooling-device =
> +						<&A55_0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +				};
> +			};
> +		};
> +	};
> +};

Here you define cooling-maps with passive and critical trip points. 

I was trying test that by enabling CONFIG_THERMAL_EMULATION and setting
the emulated temp via 

echo 85000 > /sys/class/thermal/thermal_zone0/emul_temp

By checking with mhz (from lmbench Yocto recipe) command I was expecting that the 91 start
throttling but is not the case, Am I missing something?

Thanks,
Alberto