[PATCH 3/3] clk: qcom: gdsc: tear down per-domain genpds in gdsc_unregister()

[Herman van Hazendonk <github.com@herrie.org>]

gdsc_unregister() removes the OF provider entry and tears down the
parent/subdomain wiring, but never calls pm_genpd_remove() on the
individual generic_pm_domain structures registered by gdsc_init():

	void gdsc_unregister(struct gdsc_desc *desc)
	{
		struct device *dev = desc->dev;
		size_t num = desc->num;

		gdsc_pm_subdomain_remove(desc, num);
		of_genpd_del_provider(dev->of_node);
	}

That leaves dangling entries on the global gpd_list. After a provider
unbind/rebind cycle (deferred-probe replay during early boot, real
module unload of a clk driver that owns GDSCs, or an OF-overlay tear-
down) the next gdsc_init() will end up trying to re-register a name
that is still in the list and pm_genpd_init() returns -EEXIST.

While we are here, flip the order so the consumer-facing OF provider
entry is the first thing removed -- otherwise a fresh
of_genpd_get_from_provider() call racing with the teardown could
attach to a domain that is mid-removal.

Iterate the scs[] array and pm_genpd_remove() each registered domain
after the subdomain links are torn down. The regulators stay devm-
managed (devm_regulator_get_optional() in gdsc_register()), so the
release happens automatically when the underlying device is unbound;
just the genpd accounting needs to be undone explicitly.

Signed-off-by: Herman van Hazendonk <github.com@herrie.org>
---
 drivers/clk/qcom/gdsc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index a80a489763ed..71826ccbd9bd 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -645,10 +645,18 @@ int gdsc_register(struct gdsc_desc *desc,
 void gdsc_unregister(struct gdsc_desc *desc)
 {
 	struct device *dev = desc->dev;
+	struct gdsc **scs = desc->scs;
 	size_t num = desc->num;
+	int i;
 
-	gdsc_pm_subdomain_remove(desc, num);
 	of_genpd_del_provider(dev->of_node);
+	gdsc_pm_subdomain_remove(desc, num);
+
+	for (i = 0; i < num; i++) {
+		if (!scs[i])
+			continue;
+		pm_genpd_remove(&scs[i]->pd);
+	}
 }
 
 /*
-- 
2.43.0