On Sat, Sep 03, 2022 at 03:24:51AM +0300, Laurent Pinchart wrote: > Hi Francesco, > > On Fri, Sep 02, 2022 at 05:57:20PM +0200, Francesco Dolcini wrote: > > Hello Laurent, > > answering here for both patches (1/2 and 2/2). > > > > On Thu, Sep 01, 2022 at 09:07:49PM +0300, Laurent Pinchart wrote: > > > On Thu, Sep 01, 2022 at 05:40:50PM +0200, Max Krummenacher wrote: > > > > From: Max Krummenacher <max.krummenacher@xxxxxxxxxxx> > > > > > > > > Add the hdmi connector present on the dsi to hdmi adapter now > > > > required by the upstream lontium bridge driver. > > > > The dsi to hdmi adapter is enabled in an device tree overlay. > > > > > > Shouldn't the connector also be in the overlay ? There's certainly no > > > physical HDMI connector on the i.MX8MP Verdin SoM :-) > > > > Toradex DTS include and overlay files structure so far has been a little > > bit different and not following the expectation you just stated here, > > you can just check the current *toradex*dts* files and you'll see that there > > is other stuff that is not strictly part of the module. > > > > Copying from a previous email thread on a very similar discussion [0] > > some of the reasons: > > > > - The SoM dtsi representing not only the functionality implemented into > > the SoM, but the whole connector pinout to the carrier makes very easy > > to just include a different som.dtsi in the carrier board dts and just > > switch SoM, for example from a colibri-imx6 to a colibri-imx7. > > That's fine, but I don't see how that's related to the issue at hand. > The DSI to HDMI bridge wouldn't be present on either SoM, would it ? > > > - We avoid code duplication > > > > This is working for us pretty well so far and the majority of the users > > of ours modules rely on this structure, we would prefer not to change that. > > It may work for your current use cases, but it doesn't make it right :-) Most of engineering is about compromise, being consistent with what we did so far and the end-user experience need to be taken into account. > Someone can integrate a Verdin SoM with a carrier board that has no DSI > to HDMI (or LVDS) bridge, there should thus be no such device in the > device tree. The SoM has DSI signals present on its connector, that's > what the SoM .dtsi should expose. Just for the record Verdin i.MX8M Plus do have both HDMI and LVDS on the connector (in addition to DSI) [1], of course we do have also the option to have LVDS or HDMI using an external add-on DSI bridge as this patches are about. Said that it's true that sometime we describe peripherals that are part of the SOM family into the SOM dtsi, this avoid quite a lot of duplications given the amount of carrier board that are available on the market that use just the same building blocks (and this was one of the 2 points I mentioned as a reasoning for our current DTS files structure). Of course, we keep these stuff disabled by default, so apart for some small size increase I do not see a real issue. Francesco [1] https://docs.toradex.com/110977-verdin_imx8m_plus_v1.1_datasheet.pdf
