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. Currently the qcom/sdm845-mtp board is already broken and I've just posted a patch adding Dual DSI variant for the qcom/sdm845-db845c board ([5]). [1] https://lore.kernel.org/lkml/20211125183622.597177-1-dmitry.baryshkov@xxxxxxxxxx/ [2] https://lore.kernel.org/lkml/CAA8EJpqELXvRMPWJdTLCURjwkcMxyPDPj1tVZPkdOT_JVQb4-w@xxxxxxxxxxxxxx/ [3] https://lore.kernel.org/all/CAGETcx8F0wP+RA0KpjOJeZfc=DVG-MbM_=SkRHD4UhD2ReL7Kw@xxxxxxxxxxxxxx/ [4] https://lore.kernel.org/all/YrsdLQrOtg1qdaoE@xxxxxxxxxx/ [5] https://lore.kernel.org/all/20230118082048.2198715-1-dmitry.baryshkov@xxxxxxxxxx/ --- drivers/of/property.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/of/property.c b/drivers/of/property.c index 134cfc980b70..d323bf26a613 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1297,7 +1297,6 @@ struct supplier_bindings { bool node_not_dev; }; -DEFINE_SIMPLE_PROP(clocks, "clocks", "#clock-cells") DEFINE_SIMPLE_PROP(interconnects, "interconnects", "#interconnect-cells") DEFINE_SIMPLE_PROP(iommus, "iommus", "#iommu-cells") DEFINE_SIMPLE_PROP(mboxes, "mboxes", "#mbox-cells") @@ -1327,6 +1326,21 @@ DEFINE_SIMPLE_PROP(backlight, "backlight", NULL) DEFINE_SUFFIX_PROP(regulators, "-supply", NULL) DEFINE_SUFFIX_PROP(gpio, "-gpio", "#gpio-cells") +static struct device_node *parse_clocks(struct device_node *np, + const char *prop_name, int index) +{ + /* + * Do not create clock-related device links for clocks controllers, + * clock orphans will handle missing clock parents automatically. + */ + if (!strcmp(prop_name, "clocks") && + of_find_property(np, "#clock-cells", NULL)) + return NULL; + + return parse_prop_cells(np, prop_name, index, "clocks", + "#clock-cells"); +} + static struct device_node *parse_gpios(struct device_node *np, const char *prop_name, int index) { -- 2.39.0
