[PATCH 5/5] clk: mediatek: Add MediaTek Helio X10 MT6795 clock drivers

[AngeloGioacchino Del Regno]

Il 16/05/22 13:30, Matthias Brugger ha scritto:
> 
> 
> On 13/05/2022 18:50, AngeloGioacchino Del Regno wrote:
>> Add the clock drivers for the entire clock tree of MediaTek Helio X10
>> MT6795, including system clocks (apmixedsys, infracfg, pericfg, topckgen)
>> and multimedia clocks (mmsys, mfg, vdecsys, vencsys).
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> 
> Thanks a lot for taking care of this!
> I just wonder if we couldn't build most of the clock drivers as modules like done 
> for the mt6779. It would help us to keep the kernel image smaller.
> 

Hello Matthias!

You're welcome!
...but I simply couldn't stand at seeing partially working (..or actually, not
really working) SoCs upstream. If something is upstream, it must work, or it
shouldn't be here for real :-)

Regarding your question about the clock drivers as module... I believe we can,
but that'd be only for {vdec,venc}sys and *maybe* MFG (gpu clocks): I don't know
if it'd be worth to do, as these are about... 8 clocks out of... I haven't counted
them, but more than 250, I think?

It *should* be straightforward though, just about giving them a tristate in Kconfig
instead of a bool, but that would still be limited to just those three...

The reason for me excluding clk-mt6795-mm from this choice is that - at least for
me - my development platform is a commercial smartphone, where the only thing that
"saves you" is having some display output... I mean - I *do* have a UART port, but
that's only because I've been able to solder thin wires on 0.2mm pads... you surely
agree on the fact that this isn't a common practice, even across developers.

Besides, if you think that clk-mt6795-mm should indeed be a module by default,
well, that.. is.. possible - I don't see why it shouldn't be... obviously keeping
in mind that this will largely slow down the boot process, which isn't a big issue.

In any case, it is *not* possible to compile as module *any* of the clock drivers
that I have included in the CONFIG_COMMON_CLK_MT6795 (apmixed, infra, peri, topck)
as.. you know.. these are "a bit critical" on older platforms :-)


How would you proceed?

Cheers,
Angelo