[PATCH 08/21] soundwire: qcom: Disable runtime PM and avoid clock underflow in qcom_swrm_remove()

[Lee Jones]

When the controller is runtime-suspended, swrm_runtime_suspend() has
already disabled ctrl->hclk.  If the device is unbound in that state,
qcom_swrm_remove() omits pm_runtime_disable() and unconditionally calls
clk_disable_unprepare(), triggering a clock enable count underflow and
leaving runtime PM enabled.

Resume the device before removing the bus master, disable runtime PM,
and only disable ctrl->hclk if the device is not runtime-suspended.

Fixes: 74e79da9fd46 ("soundwire: qcom: add runtime pm support")
Closes: https://sashiko.dev/#/bug/linux-e26e04cd-3dec-4a3d-94e6-f45403c4bb57
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
---
 drivers/soundwire/qcom.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 205011234030..246bc063b850 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -1791,8 +1791,13 @@ static void qcom_swrm_remove(struct platform_device *pdev)
 {
 	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(&pdev->dev);
 
+	pm_runtime_get_sync(&pdev->dev);
 	sdw_bus_master_delete(&ctrl->bus);
-	clk_disable_unprepare(ctrl->hclk);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		clk_disable_unprepare(ctrl->hclk);
+	pm_runtime_set_suspended(&pdev->dev);
 }
 
 static int __maybe_unused swrm_runtime_resume(struct device *dev)
-- 
2.56.0.317.g454f8302e1-goog