Re: [PATCH] mfd: tps6586x: Handle interrupts on suspend

From: Thierry Reding
Date: Mon Oct 29 2018 - 05:53:37 EST

On Fri, Oct 19, 2018 at 02:22:53PM +0100, Jon Hunter wrote:
> From: Jonathan Hunter <jonathanh@xxxxxxxxxx>
> The tps6586x driver creates an irqchip that is used by its various child
> devices for managing interrupts. The tps6586x-rtc device is one of its
> children that uses the tps6586x irqchip. When using the tps6586x-rtc as
> a wake-up device from suspend, the following is seen:
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.001 seconds) done.
> OOM killer disabled.
> Freezing remaining freezable tasks ... (elapsed 0.000 seconds) done.
> Disabling non-boot CPUs ...
> Entering suspend state LP1
> Enabling non-boot CPUs ...
> CPU1 is up
> tps6586x 3-0034: failed to read interrupt status
> tps6586x 3-0034: failed to read interrupt status
> The reason why the tps6586x interrupt status cannot be read is because
> the tps6586x interrupt is not masked during suspend and when the
> tps6586x-rtc interrupt occurs, to wake-up the device, the interrupt is
> seen before the i2c controller has been resumed in order to read the
> tps6586x interrupt status.
> The tps6586x-rtc driver sets it's interrupt as a wake-up source during
> suspend, which gets propagated to the parent tps6586x interrupt.
> However, the tps6586x-rtc driver cannot disable it's interrupt during
> suspend otherwise we would never be woken up and so the tps6586x must
> disable it's interrupt instead.
> Prevent the tps6586x interrupt handler from executing on exiting suspend
> before the i2c controller has been resumed by disabling the tps6586x
> interrupt on entering suspend and re-enabling it on resuming from
> suspend.
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
> drivers/mfd/tps6586x.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)

Acked-by: Thierry Reding <treding@xxxxxxxxxx>

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