linux-kernel - Re: [PATCH 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI D-PHY driver

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: <3b760685-97db-46e3-80a3-7fad69ad31cd@oss.qualcomm.com>
Date: Tue, 15 Jul 2025 11:01:32 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Vinod Koul
 <vkoul@...nel.org>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc: Bryan O'Donoghue <bod@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-phy@...ts.infradead.org, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI D-PHY driver

On 7/15/25 8:35 AM, Vladimir Zapolskiy wrote:
> On 7/15/25 03:13, Bryan O'Donoghue wrote:
>> On 14/07/2025 16:30, Vladimir Zapolskiy wrote:
>>>>
>>>> I think that is genuinely something we should handle in camss-csid.c
>>>> maybe with some meta-data inside of the ports/endpoints..
>>>>
>>>
>>> This is a CSIPHY property, a CSIPHY hardware configuration and a wiring
>>> of sensors to a CSIPHY. Where is the relation to CSID here? There is no.
>>
>> All the PHY really needs to know is the # of lanes in aggregate, which
>> physical lanes to map to which logical lanes and the pixel clock.
>>
>> We should add additional support to the Kernel's D-PHY API parameters
>> mechanism to support that physical-to-logical mapping but, that's not
>> required for this series or for any currently know upstream user of CAMSS.
>>
>>> Please share at least a device tree node description, which supports
>>> a connection of two sensors to a single CSIPHY, like it shall be done
>>> expectedly.
>> &camss {
>>       port@0 {
>>           csiphy0_lanes01_ep: endpoint0 {
>>               data-lanes = <0 1>;
>>               remote-endpoint = <&sensor0_ep>;
>>           };
>>
>>           csiphy0_lanes23_ep: endpoint0 {
>>               data-lanes = <2 3>;
>>               remote-endpoint = <&sensor1_ep>;
>>           };
>>        };
>> };
> 
> Don't you understand that this is broken?.. That's no good.
> 
> Please listen and reread the messages given to you above, your proposed
> "solution" does not support by design a valid hardware setup of two
> sensors connected to the same CSIPHY.
> 
> I would propose to stop force pushing an uncorrectable dt scheme, it
> makes no sense.

If all you're asking for is an ability to grab an of_graph reference
from the camss (v4l2) driver, you can simply do something along the
lines of of_graph_get_remote_port(phy->dev->of_node)

Konrad