Re: [PATCH RFC 4/7] iio: addac: ad74115: Use devm_regulator_get_enable_get_voltage()

Jonathan Cameron
2024-03-28T13:58:27Z

On Wed, 27 Mar 2024 18:18:53 -0500
David Lechner <dlechner@baylibre.com> wrote:

> We can reduce boilerplate code by using
> devm_regulator_get_enable_get_voltage().
There is a change in behaviour in this one. I'd like some
explanation in the patch title for why it is always safe to get
the voltage of avdd_mv when previously it wasn't.

There seems to me to be a corner case where a DTS is not providing
the entry because it's always powered on so we get a stub regulator
but that doesn't matter because we aren't in DIN_THRESHOLD_MOD_AVDD.
After this change that dts is broken as now we read the voltage
whatever.

You could use the optional form and then fail the probe if
in a mode where the value will be used?

>
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---
> drivers/iio/addac/ad74115.c | 28 +++-------------------------
> 1 file changed, 3 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/iio/addac/ad74115.c b/drivers/iio/addac/ad74115.c
> index e6bc5eb3788d..01073d7de6aa 100644
> --- a/drivers/iio/addac/ad74115.c
> +++ b/drivers/iio/addac/ad74115.c
> @@ -199,7 +199,6 @@ struct ad74115_state {
> struct spi_device *spi;
> struct regmap *regmap;
> struct iio_trigger *trig;
> - struct regulator *avdd;
>
> /*
> * Synchronize consecutive operations when doing a one-shot
> @@ -1672,14 +1671,6 @@ static int ad74115_setup(struct iio_dev *indio_dev)
> if (ret)
> return ret;
>
> - if (val == AD74115_DIN_THRESHOLD_MODE_AVDD) {
> - ret = regulator_get_voltage(st->avdd);
> - if (ret < 0)
> - return ret;
> -
> - st->avdd_mv = ret / 1000;
> - }
> -
> st->din_threshold_mode = val;
>
> ret = ad74115_apply_fw_prop(st, &ad74115_dac_bipolar_fw_prop, &val);
> @@ -1788,11 +1779,6 @@ static int ad74115_reset(struct ad74115_state *st)
> return 0;
> }
>
> -static void ad74115_regulator_disable(void *data)
> -{
> - regulator_disable(data);
> -}
> -
> static int ad74115_setup_trigger(struct iio_dev *indio_dev)
> {
> struct ad74115_state *st = iio_priv(indio_dev);
> @@ -1855,19 +1841,11 @@ static int ad74115_probe(struct spi_device *spi)
> indio_dev->modes = INDIO_DIRECT_MODE;
> indio_dev->info = &ad74115_info;
>
> - st->avdd = devm_regulator_get(dev, "avdd");
> - if (IS_ERR(st->avdd))
> - return PTR_ERR(st->avdd);
> -
> - ret = regulator_enable(st->avdd);
> - if (ret) {
> - dev_err(dev, "Failed to enable avdd regulator\n");
> + ret = devm_regulator_get_enable_get_voltage(dev, "avdd");
> + if (ret < 0)
> return ret;
> - }
>
> - ret = devm_add_action_or_reset(dev, ad74115_regulator_disable, st->avdd);
> - if (ret)
> - return ret;
> + st->avdd_mv = ret / 1000;
>
> ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulator_names),
> regulator_names);
>