Re: [PATCH] arm64: dts: imx95: remove CLK_GPUAPB

[Rain Yang <jiyu.yang@oss.nxp.com>]

On Wed, Dec 31, 2025 at 03:11:21PM +0100, Marek Vasut wrote:
>On 12/31/25 4:19 AM, Rain Yang wrote:
>> From: Rain Yang <jiyu.yang@nxp.com>
>> 
>> Dropping CLK_GPUAPB simplifies OPP handling and avoids unnecessary
>> complexity.
>> 
>> Fixes: 67934f248e64 ("arm64: dts: imx95: Describe Mali G310 GPU")
>> Signed-off-by: Rain Yang <jiyu.yang@nxp.com>
>> ---
>>   arch/arm64/boot/dts/freescale/imx95.dtsi | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/arch/arm64/boot/dts/freescale/imx95.dtsi b/arch/arm64/boot/dts/freescale/imx95.dtsi
>> index 88bde59e61b2..ab446aa6f73c 100644
>> --- a/arch/arm64/boot/dts/freescale/imx95.dtsi
>> +++ b/arch/arm64/boot/dts/freescale/imx95.dtsi
>> @@ -2164,8 +2164,8 @@ netc_emdio: mdio@0,0 {
>>   		gpu: gpu@4d900000 {
>>   			compatible = "nxp,imx95-mali", "arm,mali-valhall-csf";
>>   			reg = <0 0x4d900000 0 0x480000>;
>> -			clocks = <&scmi_clk IMX95_CLK_GPU_CGC>, <&scmi_clk IMX95_CLK_GPUAPB>;
>> -			clock-names = "core", "coregroup";
>> +			clocks = <&scmi_clk IMX95_CLK_GPU_CGC>;
>> +			clock-names = "core";
>
>I don't think this is correct, SM can disable the GPUAPB clock from the SM
>monitor:
>
>>$ clock.w gpuapb off
>
>Linux has to make sure the GPUAPB clock are enabled to access the GPU
>register, hence the clock have to be described in DT.
Hi Marek,

CLK_GPU and CLK_GPUAPB can only be controlled internally by the SM, not by Linux.
CLK_GPUAPB always runs at a fixed frequency, does not require dynamic adjustment,
and is practically always on.
Additionally, CLK_GPUAPB's frequency is absent from all OPP entries. Removing it
could simplify OPP handling logic and reduce unnecessary complexity.