On 29/06/16 13:08, Linus Walleij wrote:
> IS_ERR_OR_NULL() should never be used with regulators because
> a NULL pointer may be a perfectly valid dummy regulator
>
> We should always succeed to fetch and enable a regulator, but
> it may be a dummy. That is fine, so bail out for any real
> errors or probe deferrals
>
> Include the error code in the warning print so we know what
> kind of problem we're dealing with (for example it is nice to
> see if it is a probe deferral).
>
> As we will bail out of probe if the regulator is erroneous,
> just issue regulator_disable() on the poweroff path: it will
> succeed.
>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Lars-Peter Clausen Lars-Peter Clausen <lars@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Applied to the togreg branch of iio.git - initially pushed out
as testing for the autobuilders to play with it.
Thanks,
Jonathan
> ---
> ChangeLog v2->v3:
> - Fix the unrelated chunk removing the Vid regulator that
> the next patch adds. Was basing development on a bad tree
> and not looking close enough.
> ChangeLog v1->v2:
> - No changes
> ---
> drivers/iio/magnetometer/ak8975.c | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
> index 57d3654d7caf..7f51adba7bad 100644
> --- a/drivers/iio/magnetometer/ak8975.c
> +++ b/drivers/iio/magnetometer/ak8975.c
> @@ -389,17 +389,16 @@ static int ak8975_power_on(struct i2c_client *client)
> int ret;
>
> data->vdd = devm_regulator_get(&client->dev, "vdd");
> - if (IS_ERR_OR_NULL(data->vdd)) {
> + if (IS_ERR(data->vdd)) {
> ret = PTR_ERR(data->vdd);
> - if (ret == -ENODEV)
> - ret = 0;
> } else {
> ret = regulator_enable(data->vdd);
> }
> -
> - if (ret)
> - dev_err(&client->dev, "failed to enable Vdd supply: %d\n", ret);
> - return ret;
> + if (ret) {
> + dev_warn(&client->dev,
> + "Failed to enable specified Vdd supply\n");
> + return ret;
> + }
> }
>
> /* Disable attached power regulator if any. */
> @@ -408,8 +407,7 @@ static void ak8975_power_off(const struct i2c_client *client)
> const struct iio_dev *indio_dev = i2c_get_clientdata(client);
> const struct ak8975_data *data = iio_priv(indio_dev);
>
> - if (!IS_ERR_OR_NULL(data->vdd))
> - regulator_disable(data->vdd);
> + regulator_disable(data->vdd);
> }
>
> /*
>
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