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

Message ID 1463066372-13115-3-git-send-email-jonathanh@nvidia.com
State Superseded, archived
Delegated to: Jon Hunter
Headers show

Commit Message

Jon Hunter May 12, 2016, 3:19 p.m. UTC
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@nvidia.com>
---
 kernel/irq/manage.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Marc Zyngier June 4, 2016, 9:41 a.m. UTC | #1
On Thu, 12 May 2016 16:19:25 +0100
Jon Hunter <jonathanh@nvidia.com> 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@nvidia.com>

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

	M.
diff mbox

Patch

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index ef0bc02c3a70..eaedeb74b49d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1117,6 +1117,13 @@  __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 	new->irq = irq;
 
 	/*
+	 * If the trigger type is not specified by the caller,
+	 * then use the default for this interrupt.
+	 */
+	if (!(new->flags & IRQF_TRIGGER_MASK))
+		new->flags |= irqd_get_trigger_type(&desc->irq_data);
+
+	/*
 	 * Check whether the interrupt nests into another interrupt
 	 * thread.
 	 */