linux-kernel - Re: [PATCH v5 08/14] iio: adc: ad7768-1: add regulator to control VCM output

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <bbdbf4ff-662e-459b-a31f-bc58e738a51f@baylibre.com>
Date: Fri, 11 Apr 2025 16:44:55 -0500
From: David Lechner <dlechner@...libre.com>
To: Jonathan Santos <Jonathan.Santos@...log.com>, linux-iio@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-gpio@...r.kernel.org
Cc: lars@...afoo.de, Michael.Hennerich@...log.com,
 marcelo.schmitt@...log.com, jic23@...nel.org, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org, marcelo.schmitt1@...il.com,
 linus.walleij@...aro.org, brgl@...ev.pl, lgirdwood@...il.com,
 broonie@...nel.org, jonath4nns@...il.com
Subject: Re: [PATCH v5 08/14] iio: adc: ad7768-1: add regulator to control VCM
 output

On 4/11/25 10:57 AM, Jonathan Santos wrote:
> The VCM output voltage can be used as a common-mode voltage within the
> amplifier preconditioning circuits external to the AD7768-1.
> 
> This change allows the user to configure VCM output using the regulator
> framework.
> 
> Acked-by: Marcelo Schmitt <marcelo.schmitt@...log.com>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@...log.com>
> ---

...

> +static int ad7768_vcm_is_enabled(struct regulator_dev *rdev)
> +{
> +	struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret, val;
> +
> +	if (!indio_dev)
> +		return -EINVAL;
> +
> +	if (!iio_device_claim_direct(indio_dev))
> +		return -EBUSY;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);

If we put iio_device_release_direct(indio_dev); here, we can avoid
the goto.

> +	if (ret)
> +		goto err_release;
> +
> +	ret = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) != AD7768_VCM_OFF;
> +err_release:
> +	iio_device_release_direct(indio_dev);
> +
> +	return ret;
> +}
> +
> +static int ad7768_set_voltage_sel(struct regulator_dev *rdev,
> +				  unsigned int selector)
> +{
> +	unsigned int regval = AD7768_REG_ANALOG2_VCM(selector + 1);
> +	struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (!indio_dev)
> +		return -EINVAL;
> +
> +	if (!iio_device_claim_direct(indio_dev))
> +		return -EBUSY;
> +
> +	ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
> +				 AD7768_REG_ANALOG2_VCM_MSK, regval);
> +	iio_device_release_direct(indio_dev);
> +	st->vcm_output_sel = selector;

Do we still want to make this assignment if there is an error?

> +
> +	return ret;
> +}
> +
> +static int ad7768_get_voltage_sel(struct regulator_dev *rdev)
> +{
> +	struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret, val;
> +
> +	if (!indio_dev)
> +		return -EINVAL;
> +
> +	if (!iio_device_claim_direct(indio_dev))
> +		return -EBUSY;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
> +	if (ret)
> +		goto err_release;

Can rearrange to avoid goto here too.

> +
> +	val = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val);
> +	ret = clamp(val, 1, (int)rdev->desc->n_voltages) - 1;
> +err_release:
> +	iio_device_release_direct(indio_dev);
> +
> +	return ret;
> +}
> +

...

> +static int ad7768_register_regulators(struct device *dev, struct ad7768_state *st,
> +				      struct iio_dev *indio_dev)
> +{
> +	struct regulator_config config = {
> +		.dev = dev,
> +		.driver_data = indio_dev,
> +	};
> +	int ret;
> +
> +	/* Disable the regulator before registering it */
> +	ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
> +				 AD7768_REG_ANALOG2_VCM_MSK, AD7768_VCM_OFF);
> +	if (ret)
> +		return -EINVAL;

Why not return ret; ?

> +
> +	st->vcm_rdev = devm_regulator_register(dev, &vcm_desc, &config);
> +	if (IS_ERR(st->vcm_rdev))
> +		return dev_err_probe(dev, PTR_ERR(st->vcm_rdev),
> +				     "failed to register VCM regulator\n");
> +
> +	return 0;
> +}
> +