linux-wandboard

MLK-16705-1 soc: imx: pm-domains: add wakeup unit irqchip to manage wakeup source

For a resource enabled as wakeup source, its power needs to
be kept on during suspend, this is required by SCFW to support
wakeup ability for a resource.

This patch adds a virtual wakeup unit to support this function,
wakeup unit is registered as a irqchip being a child of GIC,
if a resource can be enabled as a wakeup source, needs to pass
its irq number in device tree power domain node using
"wakeup-irq = <x>" format, as power domain driver needs to map
the irq number to resource ID, also needs to assign its interrupt
parent to wakeup unit instead of GIC. During suspend, when power
domain driver intends to power off a resource, it will skip power
off operation if the resource is enabled as wakeup source.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Bai Ping <ping.bai@nxp.com>