Re: [PATCH v4 0/5] Add Qualcomm JPEG V4L2 encoder for SM8250

[Vladimir Zapolskiy]

On 7/6/26 15:11, Bryan O'Donoghue wrote:
> On 06/07/2026 13:00, Vladimir Zapolskiy wrote:
> > > There is no "master" device in this block of devices - save perhaps for
> > > the CSID mux / wrappers on some of these parts.
> > >
> > > We have shared resources like camera noc, system noc and external clocks.
> > >
> > > Please include power-domains and interconnects.
> >
> > Why? The common power domain and interconnects have already been
> > described as resources of the parent CAMSS device, there is no need
> > to duplicate descriptions in every child device tree node of CAMSS.
>
> CSID, IFE etc are not parents of the JPEG encoder.
>
> The idea is to make all of these peers, eventually. Not particular block
> owns the TITAN_TOP_GDSC - the entire CAMSS block is a collapsible block.

The statement provides the same information as before, e.g. it's found here:

https://lore.kernel.org/linux-media/fbc018f5-c025-4747-85f2-53b45b0f0496@xxxxxxx/

    There's no functional linkage between CAMSS/IFE and JPEG - they are
    peers within the CAMSS power-island.

Thus "the CAMSS power-island" exists, and it got its hardware description
as the CAMSS top device tree node, and TITAN_TOP_GDSC power domain is
a natural resource of all devices on "CAMSS power-island", including the
ones got their description inline CAMSS device tree node or children nodes.

There is a difference between 1 point of resource description and N points
of resource descriptions, the latter one is more complex and error prone,
therefore I belive it shall be disregarded in favour of the former option.

--
Best wishes,
Vladimir