Re: [linux-sunxi] Re: [PATCH 2/7] dt-bindings: add binding for the Allwinner A64 DE2 bus

From: Jernej Åkrabec
Date: Wed Mar 21 2018 - 13:13:54 EST


Hi all,

Dne sreda, 21. marec 2018 ob 03:18:13 CET je Icenowy Zheng napisal(a):
> ä 2018å3æ21æ GMT+08:00 äå2:46:46, Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
åå:
> >On Sat, Mar 17, 2018 at 01:53:49AM +0800, Icenowy Zheng wrote:
> >> All the sub-blocks of Allwinner A64 DE2 needs the SRAM C on A64 SoC
> >
> >to
> >
> >> be claimed, otherwise the whole DE2 space is inaccessible.
> >>
> >> Add a device tree binding of the DE2 part as a sub-bus.
> >
> >Where did you get the info that it was a bus?
>
> There's no direct evidence, just some guess.
>
> The DE2 is a whole part that is just allocated a memory
> space at the user manual, and the SRAM controls the
> access to all modules in the DE2.
>
> So it might be a bus.
>
> Implement it as a bus is a clear representation on A64.

Since there is already syscon for same mmio region, we migh as well use it
when loading ccu-sun8i-de2 driver on A64.

Other options, like SRAM driver or bus driver, might better represent HW, but
then we would have two DT nodes covering same mmio region, which I think is
not really acceptable.

Any suggestions?

BTW, H6 has same design in this regard.

Best regards,
Jernej