linux-kernel - Re: [PATCH v5 0/4] media: raspberrypi: Support RPi5's CFE

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Message-ID: <ZvUmK3wGvcrytqg-@kekkonen.localdomain>
Date: Thu, 26 Sep 2024 09:15:23 +0000
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: Jacopo Mondi <jacopo.mondi@...asonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Naushir Patuck <naush@...pberrypi.com>, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	Kieran Bingham <kieran.bingham@...asonboard.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Subject: Re: [PATCH v5 0/4] media: raspberrypi: Support RPi5's CFE

Hi Jacopo,

On Thu, Sep 26, 2024 at 11:04:36AM +0200, Jacopo Mondi wrote:
> Hi Tomi
> 
> On Thu, Sep 26, 2024 at 10:13:29AM GMT, Tomi Valkeinen wrote:
> > Hi,
> >
> > On 10/09/2024 11:07, Tomi Valkeinen wrote:
> > > This series adds support to the CFE hardware block on RaspberryPi 5. The
> > > CFE (Camera Front End) contains a CSI-2 receiver and Front End, a small
> > > ISP.
> > >
> > > To run this, you need the basic RPi5 kernel support plus relevant dts
> > > changes to enable the cfe and camera. My work branch with everything
> > > needed to run CFE can be found from:
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux.git rp1-cfe
> > >
> > > A few notes about the patches:
> > >
> > > - The original work was done by RaspberryPi, mostly by Naushir Patuck.
> > > - The second video node only sets V4L2_CAP_META_CAPTURE instead of both
> > >    V4L2_CAP_META_CAPTURE and V4L2_CAP_META_CAPTURE like the other nodes.
> > >    This is a temporary workaround for userspace (libcamera), and
> > >    hopefully can be removed soon.
> > >
> > > I have tested this with:
> > > - A single IMX219 sensor connected to the RPi5's CSI-2 port
> > > - Arducam's UB960 FPD-Link board with four imx219 sensors connected
> > >
> > >   Tomi
> > >
> > > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
> > > ---
> > > Changes in v5:
> > > - Add "depends on PM". The platforms that use CFE will always have PM in
> > >    practice, and it's not worth supporting both the PM and !PM cases as
> > >    it adds complexity to the driver.
> > > - Link to v4: https://lore.kernel.org/r/20240904-rp1-cfe-v4-0-f1b5b3d69c81@ideasonboard.com
> >
> > Is this solution to the PM issue ok for everyone? It feels most sensible to
> > me. Any other comments?
> 
> There was consensus at the media summit that platform drivers are
> allowed to depend on PM.

I'd say you should have generally a good idea these devices aren't found in
systems without runtime PM support and that mostly applies to platform
drivers.

> 
> I'll do the same for my latest PiSP BE series.

Ack.

-- 
Kind regards,

Sakari Ailus