On Wed, Jan 18, 2023 at 3:11 AM Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote: > > Do not create device link for clock controllers. Some of the clocks > provided to the device via OF can be the clocks that are just parents to > the clocks provided by this clock controller. Clock subsystem already > has support for handling missing clock parents correctly (clock > orphans). Later when the parent clock is registered, clocks get > populated properly. > > An example of the system where this matters is the SDM8450 MTP board > (see arch/arm64/boot/dts/qcom/sdm845-mtp.dts). Here the dispcc uses > clocks provided by dsi0_phy and dsi1_phy device tree nodes. However the > dispcc itself provides clocks to both PHYs, to the PHY parent device, > etc. With just dsi0_phy in place devlink is able to break the > dependency, but with two PHYs, dispcc doesn't get probed at all, thus > breaking display support. > > Cc: Bjorn Andersson <andersson@xxxxxxxxxx> > Cc: Stephen Boyd <sboyd@xxxxxxxxxx> > Cc: Saravana Kannan <saravanak@xxxxxxxxxx> > Cc: Abel Vesa <abel.vesa@xxxxxxxxxx> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> > --- > > This patch has been posted a year ago in January 2022 ([1]). Since that time > Saravana failed to produce patches to assist in debugging the issue > ([2]) or to fix the issue ([3]). The issue we observe has been described > by Abel at ([4]). As we work on adding support for Dual DSI > configurations, the issue becomes more and more important, since binding > the whole display subsystem fails. That's ample time to fix this, so I intend to apply this. But I'll give it a few days for comments. Rob
