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Date:   Wed, 4 Jan 2023 15:55:53 +0200
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc:     linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Wolfram Sang <wsa@kernel.org>,
        Luca Ceresoli <luca.ceresoli@bootlin.com>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        Matti Vaittinen <Matti.Vaittinen@fi.rohmeurope.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Peter Rosin <peda@axentia.se>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Michael Tretter <m.tretter@pengutronix.de>,
        Shawn Tu <shawnx.tu@intel.com>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mike Pagano <mpagano@gentoo.org>,
        Krzysztof =?utf-8?Q?Ha=C5=82asa?= <khalasa@piap.pl>,
        Marek Vasut <marex@denx.de>
Subject: Re: [PATCH v5 7/8] media: i2c: add DS90UB913 driver
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Hi Tomi,

On Mon, Dec 26, 2022 at 09:25:34PM +0200, Tomi Valkeinen wrote:
> On 26/12/2022 18:56, Laurent Pinchart wrote:
> > On Wed, Dec 14, 2022 at 08:36:47AM +0200, Tomi Valkeinen wrote:
> >> On 14/12/2022 08:29, Tomi Valkeinen wrote:
> >>
> >>>> wondering if the struct device of the DS90UB913 could be passed instead
> >>>> of the port, to avoid passing the port throught
> >>>> ds90ub9xx_platform_data.
> >>>
> >>> Interesting thought. That would limit the number of remote i2c busses to
> >>> one, though. Not a problem for FPD-Link, but I wonder if that's assuming
> >>> too much for the future users. Then again, this is an in-kernel API so
> >>> we could extend it later if needed. So I'll try this out and see if I
> >>> hit any issues.
> >>
> >> Right, so the issue with this one would be that it would prevent a
> >> single device uses. E.g. a single chip which acts as an ATR (similar to
> >> i2c-mux chips), i.e. it contains both the main and the remote i2c busses.
> > 
> > I don't think I understand this, sorry.
> 
> What you are suggesting above means that we'd have a separate device for 
> each port of the ATR. Which is fine in our current case, as the i2c 
> master busses are behind separate remote devices.
> 
> But if you consider a case similar to i2c-mux, where we have a single 
> chip with the slave bus and, say, 4 master busses. We would probably 
> have only a single device for that.

Hmmm... Yes you're right, it won't work in that case. Maybe we could
have two functions, the existing i2c_atr_add_adapter(), and another one
that wraps it ? It would be nice if we could get rid of the platform
data for the UB913 and UB953 drivers.

-- 
Regards,

Laurent Pinchart