[PATCH 2/2] coresight: tnoc: Fix clock refcount imbalance on platform remove

[Jie Gan]

coresight_get_enable_clocks() enables the programming clock through
devm_clk_get_optional_enabled(), which also registers a devm action to
call clk_disable_unprepare() when the driver detaches.

After probe, pm_runtime_put() allows the device to suspend and the
runtime suspend callback disables the same clock. During remove the
device is left runtime suspended, so pm_runtime_disable() freezes it
with the clock already disabled. The devm cleanup that runs afterwards
calls clk_disable_unprepare() a second time, underflowing the clock
enable refcount.

Resume the device with pm_runtime_get_sync() before pm_runtime_disable()
so the clock is enabled again and balances the devm-managed disable.

Fixes: 5799dee92dc2 ("coresight-tnoc: add platform driver to support Interconnect TNOC")
Signed-off-by: Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>
---
 drivers/hwtracing/coresight/coresight-tnoc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hwtracing/coresight/coresight-tnoc.c b/drivers/hwtracing/coresight/coresight-tnoc.c
index 9e8de4323d28..a4ac0eb02248 100644
--- a/drivers/hwtracing/coresight/coresight-tnoc.c
+++ b/drivers/hwtracing/coresight/coresight-tnoc.c
@@ -300,6 +300,7 @@ static void itnoc_remove(struct platform_device *pdev)
 	struct trace_noc_drvdata *drvdata = platform_get_drvdata(pdev);
 
 	coresight_unregister(drvdata->csdev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 

-- 
2.34.1