On Tue, May 28, 2024 at 01:39:52PM GMT, Arnaud Vrac wrote: > On 28/05/2024 11:17, Maxime Ripard wrote: > > On Tue, May 28, 2024 at 10:05:50AM GMT, Arnaud Vrac wrote: > > > On 28/05/2024 09:43, Maxime Ripard wrote: > > > > Hi, > > > > > > > > On Mon, May 27, 2024 at 06:03:56PM GMT, Marc Gonzalez wrote: > > > > > From: Arnaud Vrac <avrac@xxxxxxxxxx> > > > > > > > > > > The TI TDP158 is an AC-Coupled HDMI signal to TMDS Redriver supporting > > > > > DVI 1.0 and HDMI 1.4b and 2.0b output signals. > > > > > > > > > > Since it's an I2C-programmable bridge, it could have a proper driver, > > > > > but the default settings work fine, thus simple bridge is sufficient. > > > > > > > > No it doesn't. That bridge supports HDMI 2.0 which means you'll need to > > > > change the TMDS clock ratio when programming a TMDS character rate > > > > higher than 340MHz. And you'll need hotplug support to deal with it > > > > properly too. > > > > > > > > So sorry, you need a real driver there. > > > > > > Hello, this is an HDMI redriver, which simply cleans up the HDMI > > > signal, so no programming is needed to support HDMI 2.0. > > > > I mean, if I'm to trust the datasheet, it is more complicated than that. > > It snoops the DDC bus so it can update the TMDS clock ratio bit if it's > > sent on its input side, but that wouldn't happen with DP for example. > > > > That's a use case we can't test and will never use as a device > integrator, unfortunately. > > To support our simple HDMI redriver use case, would it be ok to write > a driver just handling power up with documented bindings with the chip > default settings ? Someone with an actual need for more specific > setups could then implement the additional code needed to support > that. The bindings could be extended without breaking compatibility. Sure, that's what I meant. We need to make sure the binding is extensible enough / take all the possibilities into account, but the driver can definitely be minimal. Maxime
Attachment:
signature.asc
Description: PGP signature
