On Wed, Jan 7, 2015 at 9:51 AM, Marc Zyngier [off-list ref] wrote:

There is a number of cases where a kernel subsystem may want to
introspect the state of an interrupt at the irqchip level:

- When a peripheral is shared between virtual machines,
  its interrupt state becomes part of the guest's state,
  and must be switched accordingly. KVM on arm/arm64 requires
  this for its guest-visible timer
- Some GPIO controllers seem to require peeking into the
  interrupt controller they are connected to to report
  their internal state

This seem to be a pattern that is common enough for the core code
to try and support this without too many horrible hacks. Introduce
a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state)
to retrieve the bits that can be of interest to another subsystem:
pending, active, and masked.

- irq_get_irqchip_state returns the state of the interrupt according
  to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE,
  IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL.
- irq_set_irqchip_state similarly sets the state of the interrupt.

Reviewed-by: Bjorn Andersson <redacted>
Tested-by: Bjorn Andersson <redacted>
Signed-off-by: Marc Zyngier <redacted>

Any update on the status of this?

I would like to be able to move ahead with the pinctrl driver for the
Qualcomm PM8921 pmic, that depends on this being in place.

Regards,
Bjorn