From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Marco Felsch <m.felsch@pengutronix.de>
Cc: hans.verkuil@cisco.com, mchehab@kernel.org, robh+dt@kernel.org,
mark.rutland@arm.com, linux-media@vger.kernel.org,
devicetree@vger.kernel.org, graphics@pengutronix.de
Subject: Re: [PATCH 1/3] media: dt-bindings: add bindings for Toshiba TC358746
Date: Mon, 4 Mar 2019 14:10:05 +0200 [thread overview]
Message-ID: <20190304121004.qlqf2guz2yt7vnvu@paasikivi.fi.intel.com> (raw)
In-Reply-To: <20190301105235.a23jwiwmxejuv2yf@pengutronix.de>
Hi Macro,
On Fri, Mar 01, 2019 at 11:52:35AM +0100, Marco Felsch wrote:
> Hi Sakari,
>
> On 19-02-18 12:03, Sakari Ailus wrote:
> > Hi Marco,
> >
> > My apologies for reviewing this so late. You've received good comments
> > already. I have a few more.
>
> Thanks for your review for the other patches as well =) Sorry for my
> delayed response.
>
> > On Tue, Dec 18, 2018 at 03:12:38PM +0100, Marco Felsch wrote:
> > > Add corresponding dt-bindings for the Toshiba tc358746 device.
> > >
> > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > > ---
> > > .../bindings/media/i2c/toshiba,tc358746.txt | 80 +++++++++++++++++++
> > > 1 file changed, 80 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt
> > > new file mode 100644
> > > index 000000000000..499733df744a
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt
> > > @@ -0,0 +1,80 @@
> > > +* Toshiba TC358746 Parallel to MIPI CSI2-TX or MIPI CSI2-RX to Parallel Bridge
> > > +
> > > +The Toshiba TC358746 is a bridge that converts a Parallel-in stream to MIPI CSI-2 TX
> > > +or a MIPI CSI-2 RX stream into a Parallel-out. It is programmable through I2C.
> >
> > This is interesting. The driver somehow needs to figure out the direction
> > of the data flow if it does not originate from DT. I guess it shouldn't as
> > it's not the property of an individual device, albeit in practice in all
> > hardware I've seen the direction of the pipeline is determinable and this
> > is visible in the kAPI as well. So I'm suggesting no changes due to this in
> > bindings, likely we'll need to address it somehow elsewhere going forward.
>
> What did you mean with "... and this is visible in the kAPI as well"?
> I'm relative new in the linux-media world but I never saw a device which
> supports two directions. Our customer which uses that chip use it
> only in parallel-in/csi-out mode. To be flexible the switching should be
> done by a subdev-ioctl but it is also reasonable to define a default value
> within the DT.
What I meant that the V4L2 sub-device API does not provide any information
on the direction. It is implicit --- MC does, but it does it based on the
links created by the driver.
I agree a DT property would be a good way to tell this, especially now that
there's a related hardware configuration (but which the software cannot
obtain directly).
--
Regards,
Sakari Ailus
sakari.ailus@linux.intel.com
next prev parent reply other threads:[~2019-03-04 12:10 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 14:12 [PATCH 0/3] media: add Toshiba TC358746 Bridge support Marco Felsch
2018-12-18 14:12 ` [PATCH 1/3] media: dt-bindings: add bindings for Toshiba TC358746 Marco Felsch
2018-12-28 23:10 ` Rob Herring
2019-02-13 17:57 ` Jacopo Mondi
2019-03-01 10:26 ` Marco Felsch
2019-03-04 9:38 ` Jacopo Mondi
2019-03-04 16:43 ` Marco Felsch
2019-02-18 10:03 ` Sakari Ailus
2019-03-01 10:52 ` Marco Felsch
2019-03-01 11:07 ` Ian Arkver
2019-03-01 13:01 ` Marco Felsch
2019-03-04 9:41 ` Jacopo Mondi
2019-03-04 12:36 ` Sakari Ailus
2019-03-04 16:55 ` Marco Felsch
2019-03-04 18:17 ` Sakari Ailus
2019-03-05 8:49 ` Jacopo Mondi
2019-03-05 18:14 ` Marco Felsch
2019-04-16 10:45 ` Marco Felsch
2019-04-29 16:44 ` Marco Felsch
2019-03-04 12:10 ` Sakari Ailus [this message]
2018-12-18 14:12 ` [PATCH 2/3] media: tc358746: add Toshiba TC358746 Parallel to CSI-2 bridge driver Marco Felsch
2018-12-19 1:24 ` kbuild test robot
2018-12-20 19:37 ` kbuild test robot
2019-02-18 11:25 ` Sakari Ailus
2018-12-18 14:12 ` [PATCH 3/3] media: tc358746: update MAINTAINERS file Marco Felsch
2019-02-18 11:46 ` Sakari Ailus
2019-03-04 17:31 ` Marco Felsch
2019-03-04 18:18 ` Sakari Ailus
2019-01-23 12:54 ` [PATCH 0/3] media: add Toshiba TC358746 Bridge support Marco Felsch
2019-02-12 16:10 ` Marco Felsch
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