Re: [PATCH v3 5/5] iio: dac: ad5504: fix scale via output-range-microvolt

[David Lechner <dlechner@baylibre.com>]

On 5/9/26 9:20 AM, Taha Ed-Dafili wrote:
> The AD5504 full-scale range is hardware-determined by the R_SEL pin,
> not the VCC supply voltage.
> 
> Fix the scaling logic by reading the standard 'output-range-microvolt'
> property from the device tree instead of querying the VCC regulator or
> relying on legacy platform data (pdata).
> 
> As a result of this transition:
> - The 'vcc' regulator is now only enabled, not read.
> - Legacy pdata support is removed, as it is no longer required for
>   fallback voltage calculations.
> - Strict array bounds checking is added for the DT property.
> 
> Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
> ---
>  drivers/iio/dac/ad5504.c | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/dac/ad5504.c b/drivers/iio/dac/ad5504.c
> index 9e95da6e49d6..040f580b8282 100644
> --- a/drivers/iio/dac/ad5504.c
> +++ b/drivers/iio/dac/ad5504.c
> @@ -14,10 +14,12 @@
>  #include <linux/kstrtox.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/module.h>
> +#include <linux/property.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/spi/spi.h>
>  #include <linux/sysfs.h>
>  #include <linux/types.h>
> +#include <linux/units.h>
>  
>  #include <linux/iio/dac/ad5504.h>
>  #include <linux/iio/events.h>
> @@ -274,9 +276,9 @@ static const struct iio_chan_spec ad5504_channels[] = {
>  static int ad5504_probe(struct spi_device *spi)
>  {
>  	struct device *dev = &spi->dev;
> -	const struct ad5504_platform_data *pdata = dev_get_platdata(dev);
>  	struct iio_dev *indio_dev;
>  	struct ad5504_state *st;
> +	u32 range[2];
>  	int ret;
>  
>  	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> @@ -285,16 +287,19 @@ static int ad5504_probe(struct spi_device *spi)
>  
>  	st = iio_priv(indio_dev);
>  
> -	ret = devm_regulator_get_enable_read_voltage(dev, "vcc");
> -	if (ret < 0 && ret != -ENODEV)

I don't think this would ever return -ENODEV, even on ACPI. It will
just get a dummy regulator now.

> +	ret = devm_regulator_get_enable(dev, "vcc");
> +	if (ret && ret != -ENODEV)
>  		return ret;
> -	if (ret == -ENODEV) {
> -		if (pdata->vref_mv)
> -			st->vref_mv = pdata->vref_mv;
> -		else
> -			dev_warn(dev, "reference voltage unspecified\n");
> -	} else {
> -		st->vref_mv = ret / 1000;
> +
> +	st->vref_mv = 60 * MILLI;
> +	ret = device_property_read_u32_array(dev, "output-range-microvolt",
> +					     range, ARRAY_SIZE(range));
> +	if (!ret) {
> +		if (range[0] != 0 || (range[1] != 30 * MICRO && range[1] != 60 * MICRO))
> +			return -EINVAL;
> +
> +		if (range[1] == 30 * MICRO)
> +			st->vref_mv = 30 * MILLI;
>  	}
>  
>  	st->spi = spi;