From: Peter Senna Tschudin <peter.senna@collabora.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org,
Peter Senna Tschudin <peter.senna@collabora.co.uk>,
Rob Herring <robh@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Peter Senna Tschudin <peter.senna@gmail.com>,
Takashi Iwai <tiwai@suse.com>, Yakir Yang <ykk@rock-chips.com>,
Jiri Slaby <jslaby@suse.cz>,
Martyn Welch <martyn.welch@collabora.co.uk>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Russell King <linux@armlinux.org.uk>,
Javier Martinez Canillas <javier@dowhile0.org>,
Thierry Reding <treding@nvidia.com>,
Guenter Roeck <linux@roeck-us.net>,
martin.donnelly@ge.com,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
enric.balletbo@collabora.com,
Russell King <rmk+kernel@armlinux.org.uk>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org " <linux-kernel@vger.kernel.org>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
Kumar Gala <galak@codeaurora.org>,
Fabio Estevam <fabio.estevam@nxp.com>,
Andrew Morton <akpm@linux-foundation.org>,
Shawn Guo <shawnguo@kernel.org>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH V7 1/4] Documentation/devicetree/bindings: b850v3_lvds_dp
Date: Mon, 16 Jan 2017 09:37:11 +0100 [thread overview]
Message-ID: <20170116083711.GA18775@collabora.com> (raw)
In-Reply-To: <6276161.johxDync2u@avalon>
On Tue, Jan 10, 2017 at 11:04:58PM +0200, Laurent Pinchart wrote:
> Hi Peter,
Laurent!
>
> On Saturday 07 Jan 2017 01:29:52 Peter Senna Tschudin wrote:
> > On 04 January, 2017 21:39 CET, Rob Herring wrote:
> > > On Tue, Jan 3, 2017 at 5:34 PM, Peter Senna Tschudin wrote:
> > >> On 03 January, 2017 23:51 CET, Rob Herring <robh@kernel.org> wrote:
> > >>> On Sun, Jan 01, 2017 at 09:24:29PM +0100, Peter Senna Tschudin wrote:
> > >>>> Devicetree bindings documentation for the GE B850v3 LVDS/DP++
> > >>>> display bridge.
> > >>>>
> > >>>> Cc: Martyn Welch <martyn.welch@collabora.co.uk>
> > >>>> Cc: Martin Donnelly <martin.donnelly@ge.com>
> > >>>> Cc: Javier Martinez Canillas <javier@dowhile0.org>
> > >>>> Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > >>>> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> > >>>> Cc: Rob Herring <robh@kernel.org>
> > >>>> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> > >>>> Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
> > >>>> ---
> > >>>> There was an Acked-by from Rob Herring <robh@kernel.org> for V6, but
> > >>>> I changed the bindings to use i2c_new_secondary_device() so I
> > >>>> removed it from the commit message.
> > >>>>
> > >>>> .../devicetree/bindings/ge/b850v3-lvds-dp.txt | 39 ++++++++++++++
> > >>> Generally, bindings are not organized by vendor. Put in
> > >>> bindings/display/bridge/... instead.
> > >>
> > >> Will change that.
> > >>
> > >>>> 1 file changed, 39 insertions(+)
> > >>>> create mode 100644
> > >>>> Documentation/devicetree/bindings/ge/b850v3-lvds-dp.txt
> > >>>>
> > >>>> diff --git a/Documentation/devicetree/bindings/ge/b850v3-lvds-dp.txt
> > >>>> b/Documentation/devicetree/bindings/ge/b850v3-lvds-dp.txt new file
> > >>>> mode 100644
> > >>>> index 0000000..1bc6ebf
> > >>>> --- /dev/null
> > >>>> +++ b/Documentation/devicetree/bindings/ge/b850v3-lvds-dp.txt
> > >>>> @@ -0,0 +1,39 @@
> > >>>> +Driver for GE B850v3 LVDS/DP++ display bridge
> > >>>> +
> > >>>> +Required properties:
> > >>>> + - compatible : should be "ge,b850v3-lvds-dp".
> > >>>
> > >>> Isn't '-lvds-dp' redundant? The part# should be enough.
> > >>
> > >> b850v3 is the name of the product, this is why the proposed name. What
> > >> about, b850v3-dp2 dp2 indicating the second DP output?
> > >
> > > Humm, b850v3 is the board name? This node should be the name of the bridge
> > > chip.
> >
> > From the cover letter:
> >
> > -- // --
> > There are two physical bridges on the video signal pipeline: a STDP4028(LVDS
> > to DP) and a STDP2690(DP to DP++). The hardware and firmware made it
> > complicated for this binding to comprise two device tree nodes, as the
> > design goal is to configure both bridges based on the LVDS signal, which
> > leave the driver powerless to control the video processing pipeline. The
> > two bridges behaves as a single bridge, and the driver is only needed for
> > telling the host about EDID / HPD, and for giving the host powers to ack
> > interrupts. The video signal pipeline is as follows:
> >
> > Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
> > -- // --
>
> You forgot to prefix your patch series with [HACK] ;-)
>
> How about fixing the issues that make the two DT nodes solution difficult ?
> What are they ?
The Firmware and the hardware design. Both bridges, with stock firmware,
are fully capable of providig EDID information and handling interrupts.
But on this specific design, with this specific firmware, I need to read
EDID from one bridge, and handle interrupts on the other. Back when I
was starting the development I could not come up with a proper way to
split EDID and interrupts between two bridges in a way that would result
in a fully functional connector. Did I miss something?
>
> --
> Regards,
>
> Laurent Pinchart
>
next prev parent reply other threads:[~2017-01-16 8:37 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-01 20:24 [PATCH V7 0/4] Add driver for GE B850v3 LVDS/DP++ Bridge Peter Senna Tschudin
2017-01-01 20:24 ` [PATCH V7 1/4] Documentation/devicetree/bindings: b850v3_lvds_dp Peter Senna Tschudin
2017-01-03 22:51 ` Rob Herring
2017-01-03 23:34 ` Peter Senna Tschudin
2017-01-04 20:39 ` Rob Herring
2017-01-07 1:29 ` Peter Senna Tschudin
2017-01-10 21:04 ` Laurent Pinchart
2017-01-16 8:37 ` Peter Senna Tschudin [this message]
2017-01-18 21:10 ` Laurent Pinchart
2017-01-19 8:12 ` Peter Senna Tschudin
2017-01-19 8:17 ` Laurent Pinchart
2017-01-19 9:25 ` Peter Senna Tschudin
2017-01-19 11:49 ` Laurent Pinchart
2017-01-10 21:06 ` Laurent Pinchart
2017-01-01 20:24 ` [PATCH V7 2/4] MAINTAINERS: Add entry for GE B850v3 LVDS/DP++ Bridge Peter Senna Tschudin
2017-01-01 20:24 ` [PATCH V7 3/4] drm/bridge: Add driver " Peter Senna Tschudin
2017-01-02 11:26 ` Peter Senna Tschudin
2017-01-05 7:48 ` Archit Taneja
2017-01-28 14:16 ` Peter Senna Tschudin
2017-01-30 17:05 ` Jani Nikula
2017-02-01 9:44 ` Archit Taneja
2017-02-01 10:58 ` Peter Senna Tschudin
2017-02-01 11:35 ` Daniel Vetter
2017-02-01 12:21 ` Peter Senna Tschudin
2017-02-02 9:56 ` Archit Taneja
2017-02-02 1:46 ` Emil Velikov
2017-02-02 11:53 ` Peter Senna Tschudin
2017-02-02 12:37 ` Emil Velikov
2017-02-03 8:00 ` Daniel Vetter
2017-02-03 12:25 ` Emil Velikov
2017-02-06 8:45 ` Daniel Vetter
2017-01-01 20:24 ` [PATCH V7 4/4] dts/imx6q-b850v3: Use " Peter Senna Tschudin
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