[PATCH v2 2/2] iio: gyro: mpu3050: Fix runtime PM refcount leak in trigger enable path

[laixiangwu]

mpu3050_drdy_trigger_enable() calls pm_runtime_get_sync() when
enabling the data ready trigger, but all five error returns in the
enable path return directly without the matching
pm_runtime_put_autosuspend(). The disable path, in contrast, drops
the reference correctly.

As a result, a failed trigger enable leaves the runtime PM usage
counter incremented and the sensor can never runtime suspend. It also
leaves hw_irq_trigger set to true, claiming the hardware IRQ is in
use when it is not.

Use pm_runtime_resume_and_get(), which does not leave the usage
counter incremented when resume fails, and add an error label that
drops the runtime PM reference and clears hw_irq_trigger so that a
failed enable returns with the device in the same state as before
the attempt.

Fixes: 3904b28efb2c ("iio: gyro: Add driver for the MPU-3050 gyroscope")
Signed-off-by: laixiangwu <laixiangwu@xxxxxxxxxxxxxxxxxxxx>
---

Changes in v2:
- Rebase the fix on a new precursor patch that splits the enable and
  disable paths of mpu3050_drdy_trigger_set_state() into separate
  helpers, as suggested by the reviewer, so the error label only
  applies to the enable path.
- Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync(),
  as suggested by the reviewer; it also keeps the usage counter
  balanced when the resume fails, so no manual
  pm_runtime_put_noidle() is needed in the caller.

Link: https://lore.kernel.org/r/20261030084305.1660-1-laixiangwu@xxxxxxxxxxxxxxxxxxxx
 drivers/iio/gyro/mpu3050-core.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/gyro/mpu3050-core.c b/drivers/iio/gyro/mpu3050-core.c
index d966911ab..fc305564d 100644
--- a/drivers/iio/gyro/mpu3050-core.c
+++ b/drivers/iio/gyro/mpu3050-core.c
@@ -957,20 +957,23 @@ static int mpu3050_drdy_trigger_enable(struct mpu3050 *mpu3050)
 	unsigned int val;
 	int ret;
 
-	pm_runtime_get_sync(mpu3050->dev);
+	ret = pm_runtime_resume_and_get(mpu3050->dev);
+	if (ret)
+		return ret;
+
 	mpu3050->hw_irq_trigger = true;
 
 	/* Disable all things in the FIFO */
 	ret = regmap_write(mpu3050->map, MPU3050_FIFO_EN, 0);
 	if (ret)
-		return ret;
+		goto err_put_pm;
 
 	/* Reset and enable the FIFO */
 	ret = regmap_set_bits(mpu3050->map, MPU3050_USR_CTRL,
 			      MPU3050_USR_CTRL_FIFO_EN |
 			      MPU3050_USR_CTRL_FIFO_RST);
 	if (ret)
-		return ret;
+		goto err_put_pm;
 
 	mpu3050->pending_fifo_footer = false;
 
@@ -982,12 +985,12 @@ static int mpu3050_drdy_trigger_enable(struct mpu3050 *mpu3050)
 			   MPU3050_FIFO_EN_GYRO_ZOUT |
 			   MPU3050_FIFO_EN_FOOTER);
 	if (ret)
-		return ret;
+		goto err_put_pm;
 
 	/* Configure the sample engine */
 	ret = mpu3050_start_sampling(mpu3050);
 	if (ret)
-		return ret;
+		goto err_put_pm;
 
 	/* Clear IRQ flag */
 	ret = regmap_read(mpu3050->map, MPU3050_INT_STATUS, &val);
@@ -1006,9 +1009,15 @@ static int mpu3050_drdy_trigger_enable(struct mpu3050 *mpu3050)
 
 	ret = regmap_write(mpu3050->map, MPU3050_INT_CFG, val);
 	if (ret)
-		return ret;
+		goto err_put_pm;
 
 	return 0;
+
+err_put_pm:
+	pm_runtime_put_autosuspend(mpu3050->dev);
+	mpu3050->hw_irq_trigger = false;
+
+	return ret;
 }
 
 /**