From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Date: Fri, 28 Feb 2014 16:34:31 +0000 Subject: Re: [PATCH 4/9] Doc/DT: Add DT binding documentation for HDMI Connector Message-Id: <20140228163431.GV21483@n2100.arm.linux.org.uk> List-Id: References: <1393590016-9361-1-git-send-email-tomi.valkeinen@ti.com> <1393590016-9361-5-git-send-email-tomi.valkeinen@ti.com> <20140228160612.GR21483@n2100.arm.linux.org.uk> <5310B609.1010105@ti.com> In-Reply-To: <5310B609.1010105@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tomi Valkeinen Cc: devicetree@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Andrzej Hajda , Laurent Pinchart , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth On Fri, Feb 28, 2014 at 06:15:05PM +0200, Tomi Valkeinen wrote: > On 28/02/14 18:06, Russell King - ARM Linux wrote: > > >> +hdmi0: connector@1 { > >> + compatible = "hdmi-connector"; > >> + label = "hdmi"; > >> + > >> + hdmi_connector_in: endpoint { > >> + remote-endpoint = <&tpd12s015_out>; > >> + }; > >> +}; > > > > It seems rather weird to have DVI connectors having an optional I2C > > property, but HDMI (which augments DVI) not having that as at least an > > optional property. > > I have added only the properties that I have used. I did think about the > i2c for HDMI also, but thought that I don't use it, and so can't test > it, and so I could well create a bad binding. > > And, as I don't see any issue in adding it later, when someone uses it, > I decided to leave it out. > > > I can quite well see the iMX HDMI support needing an i2c bus here. > > > > Also, HDMI has two connector standards - type A and type B, much like > > the single vs dual link of DVI. Again, DRM exposes this to userspace. > > True, but isn't that just a form factor? No functional differences? But > I agree, we can add the two types here also to the compatible string. HDMI A is 19 pins carrying TMDS channels 0-2. HDMI B is 29 pins carrying TMDS channels 0-5. So, the difference is the same as the single vs dual link on DVI-D/I connectors. There's actually three HDMI connectors: All three connectors carry all required HDMI signals, including a TMDS link. The Type B connector is slightly larger and carries a second TMDS link, which is necessary to support very high resolution displays using dual link. The Type C connector carries the same signals as the Type A but is more compact and intended for mobile applications. So, Type C and Type A are electrically the same. -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it.