[PATCH] [v2] iio: magnetometer: ak8974: Fix runtime PM imbalance on error

From: Dinghao Liu
Date: Tue May 26 2020 - 06:48:05 EST


When devm_regmap_init_i2c() returns an error code, a pairing
runtime PM usage counter decrement is needed to keep the
counter balanced. For error paths after ak8974_set_power(),
ak8974_detect() and ak8974_reset(), things are the same.

However, When iio_triggered_buffer_setup() returns an error
code, there will be two PM usgae counter decrements.

Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
---

Changelog:

v2: - Change 3 goto targets from "power_off" to
"disabel_pm". Remove unused lable "power_off".
Move 3 PM runtime related calls to the end of
the function.
---
drivers/iio/magnetometer/ak8974.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index d32996702110..c48c67d4b371 100644
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -764,19 +764,21 @@ static int ak8974_probe(struct i2c_client *i2c,
ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
if (IS_ERR(ak8974->map)) {
dev_err(&i2c->dev, "failed to allocate register map\n");
+ pm_runtime_put_noidle(&i2c->dev);
+ pm_runtime_disable(&i2c->dev);
return PTR_ERR(ak8974->map);
}

ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
if (ret) {
dev_err(&i2c->dev, "could not power on\n");
- goto power_off;
+ goto disable_pm;
}

ret = ak8974_detect(ak8974);
if (ret) {
dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
- goto power_off;
+ goto disable_pm;
}

ret = ak8974_selftest(ak8974);
@@ -786,14 +788,9 @@ static int ak8974_probe(struct i2c_client *i2c,
ret = ak8974_reset(ak8974);
if (ret) {
dev_err(&i2c->dev, "AK8974 reset failed\n");
- goto power_off;
+ goto disable_pm;
}

- pm_runtime_set_autosuspend_delay(&i2c->dev,
- AK8974_AUTOSUSPEND_DELAY);
- pm_runtime_use_autosuspend(&i2c->dev);
- pm_runtime_put(&i2c->dev);
-
indio_dev->dev.parent = &i2c->dev;
indio_dev->channels = ak8974_channels;
indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
@@ -846,6 +843,11 @@ static int ak8974_probe(struct i2c_client *i2c,
goto cleanup_buffer;
}

+ pm_runtime_set_autosuspend_delay(&i2c->dev,
+ AK8974_AUTOSUSPEND_DELAY);
+ pm_runtime_use_autosuspend(&i2c->dev);
+ pm_runtime_put(&i2c->dev);
+
return 0;

cleanup_buffer:
@@ -854,7 +856,6 @@ static int ak8974_probe(struct i2c_client *i2c,
pm_runtime_put_noidle(&i2c->dev);
pm_runtime_disable(&i2c->dev);
ak8974_set_power(ak8974, AK8974_PWR_OFF);
-power_off:
regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);

return ret;
--
2.17.1