Re: [PATCH] iio: dac: ad7303: use regulator get optional to check for ext supply

From: Jonathan Cameron
Date: Sat Nov 16 2019 - 11:18:07 EST


On Wed, 13 Nov 2019 10:33:03 +0200
Alexandru Tachici <alexandru.tachici@xxxxxxxxxx> wrote:

> Previously, the code was using the of_read_property_bool() to check if
> an external regulator was provided. However, this is redundant, as it's
> more simple/direct to just ask the regulator is provided, via a
> `devm_regulator_get_optional()` call.
>
> Signed-off-by: Alexandru Tachici <alexandru.tachici@xxxxxxxxxx>

Hi.
I agree in principle but I don't think devm_regulator_get_optional
returns NULL when a regulator isn't supplied.

Thanks,

Jonathan

> ---
> drivers/iio/dac/ad7303.c | 23 +++++------------------
> 1 file changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
> index 14bbac6bee98..e0c5fed4475c 100644
> --- a/drivers/iio/dac/ad7303.c
> +++ b/drivers/iio/dac/ad7303.c
> @@ -12,7 +12,6 @@
> #include <linux/slab.h>
> #include <linux/sysfs.h>
> #include <linux/regulator/consumer.h>
> -#include <linux/of.h>
>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> @@ -202,7 +201,6 @@ static int ad7303_probe(struct spi_device *spi)
> const struct spi_device_id *id = spi_get_device_id(spi);
> struct iio_dev *indio_dev;
> struct ad7303_state *st;
> - bool ext_ref;
> int ret;
>
> indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> @@ -224,24 +222,13 @@ static int ad7303_probe(struct spi_device *spi)
> if (ret)
> return ret;
>
> - if (spi->dev.of_node) {
> - ext_ref = of_property_read_bool(spi->dev.of_node,
> - "REF-supply");
> - } else {
> - struct ad7303_platform_data *pdata = spi->dev.platform_data;
> - if (pdata && pdata->use_external_ref)
> - ext_ref = true;
> - else
> - ext_ref = false;
> + st->vref_reg = devm_regulator_get_optional(&spi->dev, "REF");
> + if (IS_ERR(st->vref_reg)) {
> + ret = PTR_ERR(st->vref_reg);

devm_regulator_get_optional returns a ptr encoding -ENODEV if the
regulator is not supplied. That isn't an error here so needs to be
handled differently from other error codes.

> + goto err_disable_vdd_reg;
> }
>
> - if (ext_ref) {
> - st->vref_reg = devm_regulator_get(&spi->dev, "REF");
> - if (IS_ERR(st->vref_reg)) {
> - ret = PTR_ERR(st->vref_reg);
> - goto err_disable_vdd_reg;
> - }
> -
> + if (st->vref_reg) {
> ret = regulator_enable(st->vref_reg);
> if (ret)
> goto err_disable_vdd_reg;