[PATCH] of/irq: Handle explicit interrupt parent

[Geert Uytterhoeven]

If an interrupt controller is used as a proxy, it may have an
"interrupt-parent" property, but lack "interrupts" and
"interrupts-extended" properties.  In that case, the "interrupt-parent"
property in the interrupt controller node is ignored, causing the
interrupt controller to fail to probe, and leading to system boot
failures or crashes.

Fix this by also considering an explicit "interrupt-parent" property in
the interrupt controller node itself.

Fixes: 1b1f04d8271e7ba7 ("of/irq: Ignore interrupt parent for nodes without interrupts")
Reported-by: Marek Szyprowski <m.szyprowski at samsung.com>
Closes: https://lore.kernel.org/20251118115037.1866871-1-m.szyprowski@samsung.com
Reported-by: Mark Brown <broonie at kernel.org>
Closes: https://lore.kernel.org/b037f67a-b241-4689-9914-57ff578c1454@sirena.org.uk
Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
 drivers/of/irq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index a68272db9879bedf..f374d8b212b8669c 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -685,6 +685,8 @@ void __init of_irq_init(const struct of_device_id *matches)
 		desc->interrupt_parent = of_parse_phandle(np, "interrupts-extended", 0);
 		if (!desc->interrupt_parent && of_property_present(np, "interrupts"))
 			desc->interrupt_parent = of_irq_find_parent(np);
+		else if (!desc->interrupt_parent)
+			desc->interrupt_parent = of_parse_phandle(np, "interrupt-parent", 0);
 		if (desc->interrupt_parent == np) {
 			of_node_put(desc->interrupt_parent);
 			desc->interrupt_parent = NULL;
-- 
2.43.0