[PATCH] iio: gyro: bmg160: reject duplicate event disable

[Jiale Yao]

The IIO core does not filter duplicate writes to the event enable
attribute. bmg160_write_event_config() already ignores repeated enable
requests, but a repeated disable request still calls
bmg160_set_power_state(data, false), dropping a runtime PM reference
that was not acquired for this request. This can underflow the runtime
PM usage count and trigger a "Runtime PM usage count underflow" warning.

Return early when the requested state already matches ev_enable_state.

Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
---
 drivers/iio/gyro/bmg160_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c
index d611341a0e2a..0b5621455216 100644
--- a/drivers/iio/gyro/bmg160_core.c
+++ b/drivers/iio/gyro/bmg160_core.c
@@ -761,7 +761,7 @@ static int bmg160_write_event_config(struct iio_dev *indio_dev,
 	struct bmg160_data *data = iio_priv(indio_dev);
 	int ret;
 
-	if (state && data->ev_enable_state)
+	if (state == data->ev_enable_state)
 		return 0;
 
 	mutex_lock(&data->mutex);
-- 
2.34.1