[PATCH] soundwire: qcom: wait for the interrupt thread before gating the clock

[Oleg Keri <okerixx@gmail.com>]

A broadcast write returns as soon as the interrupt thread signals
SPECIAL_CMD_ID_FINISHED, while the thread still has to clear and re-read
the interrupt status. swrm_runtime_suspend() gates hclk right after the
ClockStopNow broadcast, so those accesses race against the clock being
removed; on x1e80100 and glymur hclk is the SoundWire clock itself. The
next clock-stop exit then fails at random: bus clash, parity errors
reported by the peripherals or AUTO_ENUM_FAILED, each leaving one side of
the speakers detached until reboot.

Wait for the interrupt thread to finish before gating the clock.

Fixes: 74e79da9fd46 ("soundwire: qcom: add runtime pm support")
Signed-off-by: Oleg Keri <okerixx@gmail.com>
---
 drivers/soundwire/qcom.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 6e0c5fb10efa..76f940f4eb31 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -1887,6 +1887,7 @@ static int __maybe_unused swrm_runtime_suspend(struct device *dev)
 		}
 	}
 
+	synchronize_irq(ctrl->irq);
 	clk_disable_unprepare(ctrl->hclk);
 
 	usleep_range(300, 305);
-- 
2.55.0