pmdomain: samsung: Fix splash-screen handover by enforcing a sync_state

It's has been reported that some Samsung platforms fails to boot with
genpd's new sync_state support.

Typically the problem exists for platforms where bootloaders are turning on
the splash-screen and handing it over to be managed by the kernel. However,
at this point, it's not clear how to correctly solve the problem.

Although, to make the platforms boot again, let's add a temporary hack in
the samsung power-domain provider driver, which enforces a sync_state that
allows the power-domains to be reset before consumer devices starts to be
attached.

Reported-by: Marek Szyprowski <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Acked-by: Krzysztof Kozlowski <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

drivers/pmdomain/samsung/exynos-pm-domains.c

@@ -147,6 +147,15 @@ static int exynos_pd_probe(struct platform_device *pdev)
 				parent.np, child.np);
 	}
 
+	/*
+	 * Some Samsung platforms with bootloaders turning on the splash-screen
+	 * and handing it over to the kernel, requires the power-domains to be
+	 * reset during boot. As a temporary hack to manage this, let's enforce
+	 * a sync_state.
+	 */
+	if (!ret)
+		of_genpd_sync_state(np);
+
 	pm_runtime_enable(dev);
 	return ret;
 }