On 28/02/14 14:57, Sebastian Hesselbarth wrote: > Out of curiosity, will there be DT nodes for pull-up resistors soon, > too? ;) If they don't work automatically, yes, we need DT nodes and drivers for them. > Honestly, TPD12S015 is a level shifter, there is nothing in it that > would justify a DT node nor a driver. TPD requires a power. Who turns that on? It also has two GPIOs, LS_OE and CT_CP_HPD, which need to be controlled based on what the user wants and the state of the HPD line. Who controls those? > Above you already note, that connector nodes should offer HPD in the > future, but I guess the binding should represent that now already. I think it can be added when somebody uses it. I don't see why that would cause trouble later to those that don't use it. > I will be a DT stub anyway, the corresponding video sink driver will > have to look it up. I'm not sure what you mean with that. Yes, it's not the most complex DT nodes out there. > Looking through the bindings for DVI and HDMI, I guess HPD gpio is > better kept in those nodes. From the relevant (DT) properties DVI and > HDMI connectors are in no way different. Well, I think the HPD gpio should be where it's most logical to have it. I mean, you could have a setup where you have the SoC HDMI encoder and and the HDMI connector, and the HPD pin goes directly to the HDMI encoder, which has HW support for it. In that case, the HDMI encoder node should contain the HPD, and the HDMI encoder should handle it. Or, your HDMI encoder could not have any kind of support for HPD. In that case you could have the HDMI connector driver handle the hotplug event. You could of course make the HDMI encoder driver handle the HPD gpio, but I usually try to have the driver handle the hardware device in question. In OMAP's case, we have the TPD chip between the HDMI encoder and the connector, and the logical place to handle HPD GPIO in that case is the TPD driver, as that's where the HPD is connected to and the TPD needs to be configured according to the state of the HPD. Tomi
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