[PATCH 00/10] media: Add support for Raspberry Pi 4 ISP

[Stefan Wahren]

Hi Jai,

Am 22.01.26 um 07:31 schrieb Jai Luthra:
> Hi Stefan,
>
> Quoting Stefan Wahren (2026-01-22 00:06:23)
>> Hi Jai,
>>
>> Am 13.01.26 um 10:05 schrieb Jai Luthra:
>>> Hi,
>>>
>>> This series adds support for the ISP used in Raspberry Pi 4 (and earlier
>>> variants) by adding the bcm2835-isp V4L2 driver.
>> could you please point me to the upstream patch, which enables VCHIQ
>> support for Raspberry Pi 4?
> The VCHIQ driver currently in upstream is working fine in my testing with
> the ISP on Raspberry Pi 4.
This is good :-)
>
> arch/arm/boot/dts/broadcom/bcm2711-rpi.dts inherits the vchiq device tree
> node from bcm2835-rpi.dts, which uses the "brcm,bcm2835-vchiq" compatible.
Yes, I remember this wasn't intended in the first place, which resulted 
in situation that somethings on Raspberry Pi 4 didn't work (don't 
remember exactly), but fixing wasn't really possible because the DTB 
files has already been shipped and we didn't want to cause a regression 
by excluding Raspberry Pi 4 afterwards.
>
>> AFAIR only Raspberry Pi 0 - 3 were officially supported.
>>
> Ah my bad. Do you know which peripheral requires the changes to VCHIQ and
> DMA to function properly on Pi 4?
>
> I saw the downstream tree defines new bcm2711-* compatibles for the DMA
> engine and VCHIQ, mostly for 36-bit address support. I had those patches in
> my tree at some point while debugging, but dropped them as the issue was
> found in the firmware clock management.
>
> If 36-bit addresses are indeed required for some ISP feature I didn't
> notice, I can add those patches back before posting the next revision.
This isn't trivial, because AFAIK the DMA driver needs to be extended 
before. Dave Stevenson send the last patches regarding this topic.

I currently don't have the time to review the series in depth, but I'm 
fine without 36-bit support as ISP works on Raspberry Pi 4.

But I've a small request for this series. Could you please drop the 
suggesting passages that Raspberry 4 is officially supported?
You can still leave, the statement that it has been successfully tested 
on Raspberry 4.

Best regards