[PATCH] i2c: at91: fix autosuspend cleanup during teardown

[Guangshuo Li]

at91_twi_probe() calls pm_runtime_use_autosuspend(), but neither the
probe error path nor at91_twi_remove() calls the matching
pm_runtime_dont_use_autosuspend() during teardown.

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during teardown, this reference is not dropped.

The documentation for pm_runtime_use_autosuspend() also notes that it
is important to undo it with pm_runtime_dont_use_autosuspend() at
driver exit time, unless runtime PM was initially enabled with
devm_pm_runtime_enable().

Add the missing pm_runtime_dont_use_autosuspend() calls to the probe
error and driver remove paths.

This issue was found by manual code inspection.

Fixes: d64a818859af ("i2c: at91: add support for runtime PM")
Cc: stable at vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
---
 drivers/i2c/busses/i2c-at91-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index b64adef778d4..65b389d07d2f 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -253,6 +253,7 @@ static int at91_twi_probe(struct platform_device *pdev)
 
 	rc = i2c_add_numbered_adapter(&dev->adapter);
 	if (rc) {
+		pm_runtime_dont_use_autosuspend(dev->dev);
 		pm_runtime_disable(dev->dev);
 		pm_runtime_set_suspended(dev->dev);
 
@@ -270,6 +271,7 @@ static void at91_twi_remove(struct platform_device *pdev)
 
 	i2c_del_adapter(&dev->adapter);
 
+	pm_runtime_dont_use_autosuspend(dev->dev);
 	pm_runtime_disable(dev->dev);
 	pm_runtime_set_suspended(dev->dev);
 }
-- 
2.43.0