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

commit 0187294d227dfc42889e1da8f8ce1e44fc25f147 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index 514ec991ad54012bf7ffc87349acb6494754c861..374b1fdd1e4210cd8706b6fa897755598bea088d 100644 (file)
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -675,19 +675,21 @@ 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 AMI305 found\n");
-               goto power_off;
+               goto disable_pm;
        }
 
        ret = ak8974_selftest(ak8974);
@@ -697,14 +699,9 @@ 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);
@@ -757,6 +754,11 @@ 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:
@@ -765,7 +767,6 @@ 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;