iio: magnetometer: ak8974: Fix runtime PM imbalance on error

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@zju.edu.cn>
Fixes: 7c94a8b2ee8c ("iio: magn: add a driver for AK8974")
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index 810fdfd37c88b0275129d24934e01c95ecddc821..041c9007bfbe61b27a2bd0d3326a48c0c1e1291e 100644 (file)
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -862,19 +862,21 @@ 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);
@@ -884,14 +886,9 @@ 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;
        switch (ak8974->variant) {
        case AK8974_WHOAMI_VALUE_AMI306:
@@ -957,6 +954,11 @@ no_irq:
                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:
@@ -965,7 +967,6 @@ disable_pm:
        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;