On 23/09/2020 23:00, Rob Herring wrote:
On Wed, Sep 23, 2020 at 11:15 AM Tomi Valkeinen tomi.valkeinen@ti.com wrote:
Hi Rob,
On 23/09/2020 19:17, Rob Herring wrote:
- No eDP. There's really no "eDP connector", as it's always a custom made connection between the DP and the DP panel. So possibly there is no need for edp-connector binding, but even if there is, I don't want to guess what it could look like, and could it be part of the dp-connector binding.
I don't think that's true. Do an image search for 'edp pinout'. AFAICT, there's 2 lane 30 pin and 4 lane 40 pin. One image says 'Table 5-3 in eDP v1.2'. Of course, I'm sure there's custom ones too. From a binding perspective, we probably don't care about the differences, but just need to be able to describe HPD, backlight power, enable, and pwm, and LCD power.
That's true. The eDP spec lists 4 different standard pinouts (how strictly those are followed, I have no idea). But it does not define a connector or a cable. And afaik eDP is defined to be not user-detachable.
Yes, but HPD is still used (or sometimes broken). We could just put that all in panel nodes, but IIRC the last time this came up the issue was handling devices with different panels stuffed by the manufacturer. An eDP connector binding would be one way to handle that as it is somewhat standardized while panel connections aren't at all.
HPD in DisplayPort, and especially in eDP, is not strictly speaking "cable inserted or removed", but rather signaling that the monitor/panel is ready (e.g. after powering it up), or there has been a link issue, or there has been a major change in settings, or signaling DP interrupt, etc. And HPD (and EDID and some other things) are optional with eDP.
I don't think those rule out an edp-connector, but just things to consider.
Tomi