[PATCH v2] of/irq: Ignore interrupt parent for nodes without interrupts

[Rob Herring (Arm)]

On Fri, 14 Nov 2025 11:47:54 +0100, Geert Uytterhoeven wrote:
> The Devicetree Specification states:
> 
>     The root of the interrupt tree is determined when traversal of the
>     interrupt tree reaches an interrupt controller node without an
>     interrupts property and thus no explicit interrupt parent.
> 
> However, of_irq_init() gratuitously assumes that a node without
> interrupts has an actual interrupt parent if it finds an
> interrupt-parent property higher up in the device tree.  Hence when such
> a property is present (e.g. in the root node), the root interrupt
> controller may not be detected as such, causing a panic:
> 
>     OF: of_irq_init: children remain, but no parents
>     Kernel panic - not syncing: No interrupt controller found.
> 
> Commit e91033621d56e055 ("of/irq: Use interrupts-extended to find
> parent") already fixed a first part, by checking for the presence of an
> interrupts-extended property.  Fix the second part by only calling
> of_irq_find_parent() when an interrupts property is present.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
> ---
> v2:
>   - Split off from series "[PATCH/RFC 0/2] of/irq: Fix root interrupt
>     controller handling"[1] to relax dependencies,
>   - Drop RFC.
> 
> [1] https://lore.kernel.org/all/cover.1759485668.git.geert+renesas@glider.be
> ---
>  drivers/of/irq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Applied, thanks!