irqdomain: Add bus token DOMAIN_BUS_WAKEUP

A single controller can handle normal interrupts and wake-up interrupts
independently, with a different numbering space. It is thus crucial to
allow the driver for such a controller discriminate between the two.

A simple way to do so is to tag the wake-up irqdomain with a "bus token"
that indicates the wake-up domain. This slightly abuses the notion of
bus, but also radically simplifies the design of such a driver. Between
two evils, we choose the least damaging.

Suggested-by: Stephen Boyd <[email protected]>
Signed-off-by: Lina Iyer <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Stephen Boyd <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Lina Iyer

include/linux/irqdomain.h

@@ -83,6 +83,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_IPI,
 	DOMAIN_BUS_FSL_MC_MSI,
 	DOMAIN_BUS_TI_SCI_INTA_MSI,
+	DOMAIN_BUS_WAKEUP,
 };
 
 /**