[PATCH] pmdomain: fix early domain registration

[Johan Hovold <johan@kernel.org>]

A recent change switching to a dynamically allocated root device broke
platforms like rcar-sysc that registers PM domains before the PM domain
bus itself has been registered (cf. commit c5ae5a0c6112 ("pmdomain:
renesas: rcar-sysc: Add genpd OF provider at postcore_initcall")).

Defer the assignment of the parent root device until the domain is
registered with driver core to avoid it being left unset.

Fixes: a96e40f4afdc ("pmdomain: core: switch to dynamic root device")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/CAMuHMdUHabMGJyJ7e7yp7DLC+JJc9k6NK9p4anj2wRKNuwZUng@mail.gmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/pmdomain/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 3f265b57158a..19eaee1819c8 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -2323,7 +2323,6 @@ static int genpd_alloc_data(struct generic_pm_domain *genpd)
 	device_initialize(&genpd->dev);
 	genpd->dev.release = genpd_provider_release;
 	genpd->dev.bus = &genpd_provider_bus_type;
-	genpd->dev.parent = genpd_provider_bus;
 
 	if (!genpd_is_dev_name_fw(genpd)) {
 		dev_set_name(&genpd->dev, "%s", genpd->name);
@@ -2688,6 +2687,7 @@ int of_genpd_add_provider_simple(struct device_node *np,
 	if (!genpd_present(genpd))
 		return -EINVAL;
 
+	genpd->dev.parent = genpd_provider_bus;
 	genpd->dev.of_node = np;
 
 	fwnode = of_fwnode_handle(np);
@@ -2782,6 +2782,7 @@ int of_genpd_add_provider_onecell(struct device_node *np,
 		if (!genpd_present(genpd))
 			goto error;
 
+		genpd->dev.parent = genpd_provider_bus;
 		genpd->dev.of_node = np;
 
 		if (sync_state && !genpd_is_no_sync_state(genpd)) {
-- 
2.53.0