[PATCH v2] iio: flow: slf3s: disable regulator if measurement restart fails

["Li Youhong" <dayou5941@163.com>]

From: Li Youhong <liyouhong@kylinos.cn>

slf3s_resume() enables the vdd regulator and then starts continuous
measurement. If slf3s_start_meas() fails, resume returns an error
while leaving the regulator enabled.

After a failed resume the device stays suspended until another resume
attempt. That later resume will call regulator_enable() again. Without
a matching disable on the failed path, the regulator enable count is
skewed and the supply can remain on even after a successful suspend.

Disable vdd when slf3s_start_meas() fails so the enable/disable pairing
stays balanced across resume retries.

Fixes: d240b0b8a1ce ("iio: flow: add Sensirion SLF3S liquid flow sensor driver")
Signed-off-by: Li Youhong <liyouhong@kylinos.cn>
---
v2:
- Expand the commit message to explain resume-retry regulator refcounting
  v1 Link: https://lore.kernel.org/all/20260901025010.356735-1-dayou5941@163.com/

 drivers/iio/flow/slf3s.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/flow/slf3s.c b/drivers/iio/flow/slf3s.c
index dfa7c1409045..9b63ceb3768a 100644
--- a/drivers/iio/flow/slf3s.c
+++ b/drivers/iio/flow/slf3s.c
@@ -487,7 +487,11 @@ static int slf3s_resume(struct device *dev)
 
 	fsleep(SLF3S_POWER_UP_DELAY_US);
 
-	return slf3s_start_meas(sf, sf->medium);
+	ret = slf3s_start_meas(sf, sf->medium);
+	if (ret)
+		regulator_disable(sf->vdd);
+
+	return ret;
 }
 
 static DEFINE_SIMPLE_DEV_PM_OPS(slf3s_pm_ops, slf3s_suspend, slf3s_resume);
-- 
2.25.1