Hi Francesco, On Sat, Sep 03, 2022 at 02:47:43PM +0200, Francesco Dolcini wrote: > On Sat, Sep 03, 2022 at 03:24:51AM +0300, Laurent Pinchart wrote: > > 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. Sure, and so do mainline requirements :-) > > 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). If those "SoM family" peripherals are on the carrier board, what's the issue with describing them in the carrier board .dtsi ? And if they're on an add-on board (such as, if I understand correctly, the DSI to HDMI encoder for the Dahlia carrier board), what's the issue with describing them in an overlay ? > Of course, we keep these stuff disabled by default, so apart for some small size > increase I do not see a real issue. It's the same issue as adding any DT node for peripherals that do not exist, I fail to see a compelling reason to do so here, given that this seems to be easy to handle in the carrier board .dtsi or in overlays. Maybe I'm missing something ? > [1] https://docs.toradex.com/110977-verdin_imx8m_plus_v1.1_datasheet.pdf -- Regards, Laurent Pinchart
