linux-kernel - Re: [PATCH 1/8] media: dt-bindings: qcom-kaanapali-iris: Add kaanapali video codec binding

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Message-ID: <sf2ujxfthvpwfp5ksqfww6qh5zfygf5lubylfrvtc5lwxakkz3@7gqxhbdafwvi>
Date: Thu, 25 Sep 2025 23:33:20 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Vikash Garodia <vikash.garodia@....qualcomm.com>
Cc: Dikshita Agarwal <dikshita.agarwal@....qualcomm.com>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Bryan O'Donoghue <bod@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>, linux-arm-msm@...r.kernel.org,
        linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Vishnu Reddy <quic_bvisredd@...cinc.com>
Subject: Re: [PATCH 1/8] media: dt-bindings: qcom-kaanapali-iris: Add
 kaanapali video codec binding

On Fri, Sep 26, 2025 at 01:15:15AM +0530, Vikash Garodia wrote:
> 
> On 9/26/2025 1:08 AM, Dmitry Baryshkov wrote:
> > On Fri, Sep 26, 2025 at 01:01:29AM +0530, Vikash Garodia wrote:
> >>
> >> On 9/26/2025 12:55 AM, Dmitry Baryshkov wrote:
> >>> On Thu, Sep 25, 2025 at 04:44:39AM +0530, Vikash Garodia wrote:
> >>>> Kaanapali SOC brings in the new generation of video IP i.e iris4. When
> >>>> compared to previous generation, iris3x, it has,
> >>>> - separate power domains for stream and pixel processing hardware blocks
> >>>>   (bse and vpp).
> >>>> - additional power domain for apv codec.
> >>>> - power domains for individual pipes (VPPx).
> >>>> - different clocks and reset lines.
> >>>>
> >>>> There are variants of this hardware, where only a single VPP pipe would
> >>>> be functional (VPP0), and APV may not be present. In such case, the
> >>>> hardware can be enabled without those 2 related power doamins, and
> >>>> corresponding clocks. This explains the min entries for power domains
> >>>> and clocks.
> >>>> Iommus include all the different stream-ids which can be possibly
> >>>> generated by vpu4 video hardware in both secure and non secure
> >>>> execution mode.
> >>>>
> >>>> This patch depends on following patches
> >>>> https://lore.kernel.org/all/20250924-knp-interconnect-v1-1-4c822a72141c@oss.qualcomm.com/
> >>>> https://lore.kernel.org/all/20250924-knp-clk-v1-3-29b02b818782@oss.qualcomm.com/
> >>>>
> >>>> Signed-off-by: Vikash Garodia <vikash.garodia@....qualcomm.com>
> >>>> ---
> >>>>  .../bindings/media/qcom,kaanapali-iris.yaml        | 236 +++++++++++++++++++++
> >>>>  1 file changed, 236 insertions(+)
> >>>>
> >>>> diff --git a/Documentation/devicetree/bindings/media/qcom,kaanapali-iris.yaml b/Documentation/devicetree/bindings/media/qcom,kaanapali-iris.yaml
> >>>> new file mode 100644
> >>>> index 0000000000000000000000000000000000000000..f3528d514fe29771227bee5f156962fedb1ea9cd
> >>>> --- /dev/null
> >>>> +++ b/Documentation/devicetree/bindings/media/qcom,kaanapali-iris.yaml
> >>>> @@ -0,0 +1,236 @@
> >>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>>> +%YAML 1.2
> >>>> +---
> >>>> +$id: http://devicetree.org/schemas/media/qcom,kaanapali-iris.yaml#
> >>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>>> +
> >>>> +title: Qualcomm kaanapali iris video encode and decode accelerators
> >>>> +
> >>>> +maintainers:
> >>>> +  - Vikash Garodia <vikash.garodia@....qualcomm.com>
> >>>> +  - Dikshita Agarwal <dikshita.agarwal@....qualcomm.com>
> >>>> +
> >>>> +description:
> >>>> +  The iris video processing unit is a video encode and decode accelerator
> >>>> +  present on Qualcomm platforms.
> >>>> +
> >>>> +properties:
> >>>> +  compatible:
> >>>> +    const: qcom,kaanapali-iris
> >>>> +
> >>>> +  reg:
> >>>> +    maxItems: 1
> >>>> +
> >>>> +  interrupts:
> >>>> +    maxItems: 1
> >>>> +
> >>>> +  power-domains:
> >>>> +    minItems: 5
> >>>> +    maxItems: 7
> >>>
> >>> You are sending bindings for a single device on a single platform. How
> >>> comes that it has min != max?
> >>
> >> I was planning to reuse this binding for the variant SOCs of kaanapali/vpu4. If
> >> we do not have min interface, then for those variants, we have to either have
> >> separate bindings or add if/else conditions(?). Introducing min now can make it
> >> easily usable for upcoming vpu4 variants.
> > 
> > No, it makes it harder to follow the changes. This platform has
> > this-and-that requirements. Then you add another platform and it's clear
> > that the changes are for that platform. Now you have mixed two different
> > patches into a single one.
> 
> you are suggesting to add new schema when the new variant comes in ?

No, I'm suggesting extending the schema when the new variant comes in
instead.

> there is
> also a possibility that this hardware(kaanapali) can be used without those
> optional power domains as well. Let say, someone does not want apv codec, in
> such case, that pd becomes optional.

That's totally a software construct - not enabling unused domains. Here
you are describing, you know, the hardware. And in the hardware the IP
core has a fixed number of connected clocks and power domains.


-- 
With best wishes
Dmitry