Re: [PATCH V4 2/9] genirq: Look-up trigger type if not specified by caller

From: Marc Zyngier
Date: Sat Jun 04 2016 - 05:41:31 EST


On Thu, 12 May 2016 16:19:25 +0100
Jon Hunter <jonathanh@xxxxxxxxxx> wrote:

> For some devices the IRQ trigger type for a device is read from
> firmware, such as device-tree. The IRQ trigger type is typically read
> when the mapping for IRQ is created, which is before the IRQ is
> requested. Hence, the IRQ trigger type is programmed when mapping the
> IRQ and not when requesting the IRQ.
>
> Although this works for most cases, in order to support IRQ chips which
> require runtime power management, which may not be accessible prior
> to requesting the IRQ, it is desirable to look-up the IRQ trigger type
> when it is requested. Therefore, if the IRQ trigger type is not
> specified when __setup_irq() is called, look-up the saved IRQ trigger
> type. This will allow us to defer the programming of the trigger type
> from when the IRQ is mapped to when it is actually requested.
>
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>

Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>

M.
--
Jazz is not dead. It just smells funny.