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From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Tue, 3 Mar 2020 07:01:09 +0000
Message-ID: <CA+V-a8uAWnw4QNvqROmbv75GOwwyTmvbyeFiOE9HOEuByv6=qQ@mail.gmail.com>
Subject: Re: [PATCH] media: i2c: ov5645: Add virtual_channel module parameter
To:     Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Cc:     Fabio Estevam <festevam@gmail.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        linux-media <linux-media@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Jacopo Mondi <jacopo@jmondi.org>,
        =?UTF-8?Q?Niklas_S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>
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Hi Ezequiel,

Thank you for the review.

On Tue, Mar 3, 2020 at 3:01 AM Ezequiel Garcia
<ezequiel@vanguardiasur.com.ar> wrote:
>
> Adding Niklas and Jacopo,
>
> On Mon, Mar 2, 2020, 12:33 PM Fabio Estevam <festevam@gmail.com> wrote:
> >
> > Hi Prabhakar,
> >
> > On Mon, Mar 2, 2020 at 4:19 AM Lad, Prabhakar
> > <prabhakar.csengg@gmail.com> wrote:
> >
> > > > Should this be a device tree property instead?
> > > I did give a thought about it, but making this as DT property would
> > > make it more stiff.
> >
> > In case a system has two OV5645 and we want to operate each OV5645
> > with a different virtual channel, it will not be possible with the
> > module_param approach.
> >
> > Using a device tree property would make it possible though, so I think
> > it makes more sense to use a device tree property for this.
> >
>
> As often happens, driver parameter is probably the easiest and less
> invasive way to customize a driver, so I can imagine myself carrying
> something like this downstream if needed. Haven't we all?
>
> It's definitely not suitable upstream, as Fabio points out, but
> I don't think a devicetree approach is either.
>
Agreed. I was suggesting maybe v4l2-ctl instead ?

> It seems Niklas and Jacopo have been working on adding
> proper support to route this, via some new ioctls.
>
> https://patchwork.linuxtv.org/patch/55300/
>
> Not sure what's the status of it.
>
something similar needs to be implemented for ov5645 driver.

Cheers,
--Prabhakar

> Hope it helps,
> Ezequiel