linux-kernel - Re: [PATCH 1/2] media: dt-bindings: media: camss: Restrict bus-type property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <D6AJ9U23ANWI.1DLHNPU5A6HQ4@fairphone.com>
Date: Fri, 13 Dec 2024 12:24:31 +0100
From: "Luca Weiss" <luca.weiss@...rphone.com>
To: "Vladimir Zapolskiy" <vladimir.zapolskiy@...aro.org>, "Krzysztof
 Kozlowski" <krzk@...nel.org>
Cc: "Robert Foss" <rfoss@...nel.org>, "Todor Tomov" <todor.too@...il.com>,
 "Bryan O'Donoghue" <bryan.odonoghue@...aro.org>, "Mauro Carvalho Chehab"
 <mchehab@...nel.org>, "Rob Herring" <robh@...nel.org>, "Krzysztof
 Kozlowski" <krzk+dt@...nel.org>, "Conor Dooley" <conor+dt@...nel.org>,
 "Barnabas Czeman" <barnabas.czeman@...nlining.org>, "AngeloGioacchino Del
 Regno" <angelogioacchino.delregno@...ainline.org>, "Caleb Connolly"
 <caleb.connolly@...aro.org>, "David Heidelberg" <david@...t.cz>,
 <~postmarketos/upstreaming@...ts.sr.ht>, <phone-devel@...r.kernel.org>,
 <linux-arm-msm@...r.kernel.org>, <linux-media@...r.kernel.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] media: dt-bindings: media: camss: Restrict bus-type
 property

On Fri Dec 13, 2024 at 11:50 AM CET, Vladimir Zapolskiy wrote:
> On 12/13/24 11:34, Krzysztof Kozlowski wrote:
> > On Mon, Dec 09, 2024 at 01:01:05PM +0100, Luca Weiss wrote:
> >> The CSIPHY of Qualcomm SoCs support both D-PHY and C-PHY standards for
> >> CSI-2, but not any others so restrict the bus-type property describing
> >> this to the supported values.
> >>
> >> The only exception here is MSM8916 which only supports D-PHY. C-PHY was
> >> introduced with newer SoCs.
> >>
> >> Do note, that currently the Linux driver only supports D-PHY.
> >>
> >> Signed-off-by: Luca Weiss <luca.weiss@...rphone.com>
> >> ---
> >>   .../bindings/media/qcom,msm8916-camss.yaml         |  8 ++++++
> >>   .../bindings/media/qcom,msm8953-camss.yaml         | 15 +++++++++++
> >>   .../bindings/media/qcom,msm8996-camss.yaml         | 20 +++++++++++++++
> >>   .../bindings/media/qcom,sc8280xp-camss.yaml        | 20 +++++++++++++++
> >>   .../bindings/media/qcom,sdm660-camss.yaml          | 20 +++++++++++++++
> >>   .../bindings/media/qcom,sdm845-camss.yaml          | 20 +++++++++++++++
> >>   .../bindings/media/qcom,sm8250-camss.yaml          | 30 ++++++++++++++++++++++
> >>   7 files changed, 133 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/media/qcom,msm8916-camss.yaml b/Documentation/devicetree/bindings/media/qcom,msm8916-camss.yaml
> >> index 9cc0a968a401836814560c1af3ee84d946500b4f..3de2a3d2b5b761106975aab65ff614b2ef579ef5 100644
> >> --- a/Documentation/devicetree/bindings/media/qcom,msm8916-camss.yaml
> >> +++ b/Documentation/devicetree/bindings/media/qcom,msm8916-camss.yaml
> >> @@ -94,6 +94,10 @@ properties:
> >>                   minItems: 1
> >>                   maxItems: 4
> >>   
> >> +              bus-type:
> >> +                enum:
> >> +                  - 4 # MEDIA_BUS_TYPE_CSI2_DPHY
> >> +
> >>               required:
> >>                 - data-lanes
> >>   
> >> @@ -113,6 +117,10 @@ properties:
> >>                   minItems: 1
> >>                   maxItems: 4
> >>   
> >> +              bus-type:
> >> +                enum:
> >> +                  - 4 # MEDIA_BUS_TYPE_CSI2_DPHY
> >> +
>
> But is it really needed to specify the single supported bus-type?
>
> I believe it is not, at least it's not ever done for other media devices
> like sensors.

Through video-interfaces.yaml 'bus-type' is already allowed but not
restricted to the values that actually make any sense on such hardware,
so in my opinion this makes sense to have here.

>
> Here I would prefer to get a comment from Linux Media and/or DTB experts.

I'm far from either, so happy to get more comments on this!

Regards
Luca

>
> --
> Best wishes,
> Vladimir