Re: [PATCH v3 2/4] dt-bindings: media: qcom: Add JPEG encoder binding

[Vladimir Zapolskiy]

On 6/30/26 16:19, Bryan O'Donoghue wrote:
> On 29/06/2026 14:38, Vladimir Zapolskiy wrote:
> > > +                interconnects =
> > > +                    <&gem_noc MASTER_AMPSS_M0 0 &config_noc SLAVE_CAMERA_CFG 0>,
> > > +                    <&mmss_noc MASTER_CAMNOC_HF 0 &mc_virt SLAVE_EBI_CH0 0>,
> > > +                    <&mmss_noc MASTER_CAMNOC_SF 0 &mc_virt SLAVE_EBI_CH0 0>,
> > > +                    <&mmss_noc MASTER_CAMNOC_ICP 0 &mc_virt SLAVE_EBI_CH0 0>;
> > > +                interconnect-names = "cpu-cfg",
> > > +                                     "hf-mnoc",
> > > +                                     "sf-mnoc",
> > > +                                     "icp-mnoc";
> > Since the proper option for describing this hardware is to have it as
> > a child device tree node of CAMSS device tree node, which should serve
> > or be percepted as a bus, it makes no sense to repeat and moreover rename
> > bus/parent's resources, here is the list:
> >
> > * "hf_axi", "sf_axi", "core_ahb", "cpas_ahb" and "cnoc_axi" clocks,
> > * Titan GDSC power domain and all four interconnects.
> >
> > Only "jpeg" clock and iommus are left specific to the hardware description
> > of this IP under CAMSS, right? Thus, it should be reflected like this in
> > the dt description as well, and the complexity of shared resource management
> > has to be done in the driver, which might be tedious unfortunately, but
> > certainly doable.
>
> JPEG should be able to vote for its individual NoC / CamNoC dependencies
> / requirements.

There is no individual interconnects, JPEG interconnects are equal to
bus/parent CAMSS ones.

> Both GDSCs and interconnects should be described in the sub-node.

Why to do it in each child, if GDSCs and interconnects are CAMSS bus/domain
specific? There is no acceptable explanation so far.

> There's no functional linkage between CAMSS/IFE and JPEG - they are
> peers within the CAMSS power-island. Over time we will migrate to

I do not refer to any "functional linkage".

> individual nodes for IFE CSID and these too will appear inside of the
> CAMSS "bus" -> JPEG etc should describe their nocs and power-domains
> individually.
>
> camss@X{
> 	camnoc@{}
> 	csid@{
> 		interconnects = <gem_noc>, <cam_noc>;
> 	};
> 	jpeg@ {
> 		interconnects = <gem_noc>, <cam_noc>;
> 	};
> 	ife@ {
> 		interconnects = <gem_noc>, <cam_noc>;
> 	};
> };

It makes sense only if the lists of interconnects are different, this
is not the case.

--
Best wishes,
Vladimir