On Thu, Aug 30, 2018 at 4:10 AM John Garry [off-list ref] wrote:

In commit c58caaab3bf8 ("serial: 8250: of: Defer probe on missing IRQ"), a
check was added for the UART driver being probed prior to the parent IRQ
controller.

Unfortunately this breaks certain boards which have no interrupt support,
like Huawei D03.

Indeed, the 8250 DT bindings state that interrupts should be supported -
not must.

To fix, switch from irq_of_parse_and_map() to of_irq_get(), which
does relay whether the IRQ host controller domain is not ready, i.e.
defer probe, instead of assuming it.

Good, one less user of irq_of_parse_and_map().

Reviewed-by: Rob Herring <robh@kernel.org>