[PATCH v4] iio: gyro: mpu3050: fix runtime PM leak when enabling trigger fails

[Biren Pandya <birenpandya@gmail.com>]

mpu3050_drdy_trigger_set_state() calls pm_runtime_get_sync() when the
trigger is enabled, but several error paths in the enable branch return
directly without dropping the usage counter again. pm_runtime_get_sync()
increments the usage counter, so every failed enable leaks a runtime PM
reference and the device can no longer autosuspend. The driver state flag
hw_irq_trigger is also left set after a failed enable.

Jump to a common error label that drops the reference and clears
hw_irq_trigger, mirroring the disable path. The success path deliberately
keeps the reference, as the device must stay resumed while the trigger is
active.

Signed-off-by: Biren Pandya <birenpandya@gmail.com>
---
Changes in v4:
- Reverted stray change converting `mpu3050_read_mem()` kernel-doc to a regular comment.
- Dropped AI assistance tag from the commit message.
Changes in v3:
- Changed to a unified error label instead of individual drops.
Changes in v2:
- Fixed a missed PM release in the first error branch.

 drivers/iio/gyro/mpu3050-core.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/gyro/mpu3050-core.c b/drivers/iio/gyro/mpu3050-core.c
index d84e04e4b4314..783be9a786df0 100644
--- a/drivers/iio/gyro/mpu3050-core.c
+++ b/drivers/iio/gyro/mpu3050-core.c
@@ -994,14 +994,14 @@ static int mpu3050_drdy_trigger_set_state(struct iio_trigger *trig,
 		/* Disable all things in the FIFO */
 		ret = regmap_write(mpu3050->map, MPU3050_FIFO_EN, 0);
 		if (ret)
-			return ret;
+			goto err_power_down;
 
 		/* 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_power_down;
 
 		mpu3050->pending_fifo_footer = false;
 
@@ -1013,12 +1013,12 @@ static int mpu3050_drdy_trigger_set_state(struct iio_trigger *trig,
 				   MPU3050_FIFO_EN_GYRO_ZOUT |
 				   MPU3050_FIFO_EN_FOOTER);
 		if (ret)
-			return ret;
+			goto err_power_down;
 
 		/* Configure the sample engine */
 		ret = mpu3050_start_sampling(mpu3050);
 		if (ret)
-			return ret;
+			goto err_power_down;
 
 		/* Clear IRQ flag */
 		ret = regmap_read(mpu3050->map, MPU3050_INT_STATUS, &val);
@@ -1037,10 +1037,16 @@ static int mpu3050_drdy_trigger_set_state(struct iio_trigger *trig,
 
 		ret = regmap_write(mpu3050->map, MPU3050_INT_CFG, val);
 		if (ret)
-			return ret;
+			goto err_power_down;
 	}
 
 	return 0;
+
+err_power_down:
+	pm_runtime_put_autosuspend(mpu3050->dev);
+	mpu3050->hw_irq_trigger = false;
+
+	return ret;
 }
 
 static const struct iio_trigger_ops mpu3050_trigger_ops = {
-- 
2.50.1 (Apple Git-155)