From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Peter Senna Tschudin <peter.senna@collabora.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: Wed, 18 Jan 2017 23:10:58 +0200 [thread overview]
Message-ID: <2088084.GDlN6tZSQv@avalon> (raw)
In-Reply-To: <20170116083711.GA18775@collabora.com>
Hi Peter,
On Monday 16 Jan 2017 09:37:11 Peter Senna Tschudin wrote:
> On Tue, Jan 10, 2017 at 11:04:58PM +0200, Laurent Pinchart wrote:
> > 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.
Which firmware are you talking about ? Firmware running on the bridges, or
somewhere else ?
> 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?
You didn't, we did :-) I've been telling for quite some time now that we must
decouple bridges from connectors, and this is another example of why we have
such a need. Bridges should expose additional functions needed to implement
connector operations, and the connector should be instantiated by the display
driver with the help of bridge operations. You could then create a connector
that relies on one bridge to read the EDID and on the other bridge to handle
HPD.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2017-01-18 21:10 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
2017-01-18 21:10 ` Laurent Pinchart [this message]
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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