Re: [PATCH] arm64: dts: imx95: Use GPU_CGC as core clock for GPU

[Marek Vasut <marek.vasut@mailbox.org>]

On 12/3/25 10:28 AM, Rain Yang wrote:

Hello Rain,

>>> Thanks for integrating this downstream patch.
>>
>> Which downstream patch do you refer to ?
>>
>>> Please note that CLK_GPUAPB and CLK_GPU are
>>> always-on, so the commit message should be amended accordingly.
>>
>> The GPU clock do not seem to be always-on, neither do the GPUAPB . It seems
>> the SM can turn those clock off perfectly well.
>>
>>> Additionally, the IMX95_CLK_GPUAPB handle shall be removed, as there is no valid OPP entry
>>> in the frequency table, this also helps minimize differences between downstream and upstream,
>>> reducing maintenance effort.
>>
>> Downstream kernel forks are not relevant to this discussion, upstream your
>> content and then you won't have to spend maintenance effort on downstream
>> stuff.
> 
> This patch [1] was the reference point.

Sigh ... I was not aware of that one.

Maybe next time, it would be good to upstream these changes directly ?

> For the Linux working environment,
> CLK_GPU and CLK_GPUAPB are always-on, while CLK_GPU_CGC can be gated off.
> 
> Regarding the IMX95_CLK_GPUAPB handle, my suggestion was based on the absence
> of its frequency in any OPP entry within the frequency table. Removing it
> could simplify the OPP handling logic and reduce unnecessary complexity.

If the clock can be disabled by SM, Linux has to make sure they are NOT 
disabled, so they must be described in DT, right ?

> [1] https://github.com/nxp-imx/linux-imx/commit/695f2bdc57b869ca5189313e4b5fa7eb5a12f622


-- 
Best regards,
Marek Vasut