linux-kernel - Re: [PATCH] iio: adc: ad7192: Correct reference voltage

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Date:   Sun, 24 Sep 2023 15:50:32 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     alisadariana@...il.com
Cc:     Alisa-Dariana Roman <alisa.roman@...log.com>,
        stable@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>,
        Michael Hennerich <Michael.Hennerich@...log.com>,
        Alexandru Tachici <alexandru.tachici@...log.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: adc: ad7192: Correct reference voltage

On Sun, 24 Sep 2023 01:58:27 +0300
alisadariana@...il.com wrote:

> From: Alisa-Dariana Roman <alisadariana@...il.com>
> 
> The avdd and the reference voltage are two different sources but the
> reference voltage was assigned according to the avdd supply.
> 
> Add vref regulator structure and set the reference voltage according to
> the vref supply from the devicetree.
> 
> In case vref supply is missing, reference voltage is set according to
> the avdd supply for compatibility with old devicetrees.
> 
> Fixes: b581f748cce0 ("staging: iio: adc: ad7192: move out of staging")
> Signed-off-by: Alisa-Dariana Roman <alisa.roman@...log.com>
> Cc: stable@...r.kernel.org

Looks good but I'd prefer dev_err_probe() for the error messages.
Obviously that wasn't true for the existing one but as we are touching the
code good to clean it up.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/ad7192.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index 69d1103b9508..c414fed60dd3 100644
> --- a/drivers/iio/adc/ad7192.c
> +++ b/drivers/iio/adc/ad7192.c
> @@ -177,6 +177,7 @@ struct ad7192_chip_info {
>  struct ad7192_state {
>  	const struct ad7192_chip_info	*chip_info;
>  	struct regulator		*avdd;
> +	struct regulator		*vref;
>  	struct clk			*mclk;
>  	u16				int_vref_mv;
>  	u32				fclk;
> @@ -1008,10 +1009,32 @@ static int ad7192_probe(struct spi_device *spi)
>  	if (ret)
>  		return dev_err_probe(&spi->dev, ret, "Failed to enable specified DVdd supply\n");
>  
> -	ret = regulator_get_voltage(st->avdd);
> -	if (ret < 0) {
> -		dev_err(&spi->dev, "Device tree error, reference voltage undefined\n");
> -		return ret;
> +	st->vref = devm_regulator_get_optional(&spi->dev, "vref");
> +	if (IS_ERR(st->vref)) {
> +		if (PTR_ERR(st->vref) != -ENODEV)
> +			return PTR_ERR(st->vref);
> +
> +		ret = regulator_get_voltage(st->avdd);
> +		if (ret < 0) {
> +			dev_err(&spi->dev, "Device tree error, AVdd voltage undefined\n");
dev_err_probe()

> +			return ret;
> +		}
> +	} else {
> +		ret = regulator_enable(st->vref);
> +		if (ret) {
> +			dev_err(&spi->dev, "Failed to enable specified Vref supply\n");
dev_err_probe()
> +			return ret;
> +		}
> +
> +		ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, st->vref);
> +		if (ret)
> +			return ret;
> +
> +		ret = regulator_get_voltage(st->vref);
> +		if (ret < 0) {
> +			dev_err(&spi->dev, "Device tree error, Vref voltage undefined\n");
dev_err_probe()

> +			return ret;
> +		}
>  	}
>  	st->int_vref_mv = ret / 1000;
>