Commit 6b104e78 authored by Florian Boor's avatar Florian Boor Committed by Jonathan Cameron
Browse files

iio: adc: ad799x: Implement selecting external reference voltage input on... 


iio: adc: ad799x: Implement selecting external reference voltage input on AD7991, AD7995 and AD7999.

Make use of the AD7991_REF_SEL bit and support using the external
reference voltage if 'vref-supply' is present. Use VCC voltage supply
as reference if no extra reference is supplied.

Signed-off-by: default avatarFlorian Boor <florian.boor@kernelconcepts.de>
Link: https://lore.kernel.org/r/20210930104249.2924336-1-florian.boor@kernelconcepts.de


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 2021ef06

drivers/iio/adc/ad799x.c

+51 −17
Original line number Diff line number Diff line
@@ -299,7 +299,11 @@ static int ad799x_read_raw(struct iio_dev *indio_dev, 
			GENMASK(chan->scan_type.realbits - 1, 0);

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		if (st->vref)

			ret = regulator_get_voltage(st->vref);

		else

			ret = regulator_get_voltage(st->reg);



		if (ret < 0)

			return ret;

		*val = ret / 1000;
@@ -770,6 +774,7 @@ static int ad799x_probe(struct i2c_client *client, 
				   const struct i2c_device_id *id)

{

	int ret;

	int extra_config = 0;

	struct ad799x_state *st;

	struct iio_dev *indio_dev;

	const struct ad799x_chip_info *chip_info =
@@ -797,14 +802,36 @@ static int ad799x_probe(struct i2c_client *client, 
	ret = regulator_enable(st->reg);

	if (ret)

		return ret;

	st->vref = devm_regulator_get(&client->dev, "vref");



	/* check if an external reference is supplied */

	st->vref = devm_regulator_get_optional(&client->dev, "vref");



	if (IS_ERR(st->vref)) {

		if (PTR_ERR(st->vref) == -ENODEV) {

			st->vref = NULL;

			dev_info(&client->dev, "Using VCC reference voltage\n");

		} else {

			ret = PTR_ERR(st->vref);

			goto error_disable_reg;

		}

	}



	if (st->vref) {

		/*

		 * Use external reference voltage if supported by hardware.

		 * This is optional if voltage / regulator present, use VCC otherwise.

		 */

		if ((st->id == ad7991) || (st->id == ad7995) || (st->id == ad7999)) {

			dev_info(&client->dev, "Using external reference voltage\n");

			extra_config |= AD7991_REF_SEL;

			ret = regulator_enable(st->vref);

			if (ret)

				goto error_disable_reg;

		} else {

			st->vref = NULL;

			dev_warn(&client->dev, "Supplied reference not supported\n");

		}

	}



	st->client = client;
@@ -815,7 +842,7 @@ static int ad799x_probe(struct i2c_client *client, 
	indio_dev->channels = st->chip_config->channel;

	indio_dev->num_channels = chip_info->num_channels;



	ret = ad799x_update_config(st, st->chip_config->default_config);

	ret = ad799x_update_config(st, st->chip_config->default_config | extra_config);

	if (ret)

		goto error_disable_vref;
@@ -845,6 +872,7 @@ static int ad799x_probe(struct i2c_client *client, 
error_cleanup_ring:

	iio_triggered_buffer_cleanup(indio_dev);

error_disable_vref:

	if (st->vref)

		regulator_disable(st->vref);

error_disable_reg:

	regulator_disable(st->reg);
@@ -860,6 +888,7 @@ static int ad799x_remove(struct i2c_client *client) 
	iio_device_unregister(indio_dev);



	iio_triggered_buffer_cleanup(indio_dev);

	if (st->vref)

		regulator_disable(st->vref);

	regulator_disable(st->reg);

	kfree(st->rx_buf);
@@ -872,6 +901,7 @@ static int __maybe_unused ad799x_suspend(struct device *dev) 
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));

	struct ad799x_state *st = iio_priv(indio_dev);



	if (st->vref)

		regulator_disable(st->vref);

	regulator_disable(st->reg);
@@ -889,16 +919,20 @@ static int __maybe_unused ad799x_resume(struct device *dev) 
		dev_err(dev, "Unable to enable vcc regulator\n");

		return ret;

	}



	if (st->vref) {

		ret = regulator_enable(st->vref);

		if (ret) {

			regulator_disable(st->reg);

			dev_err(dev, "Unable to enable vref regulator\n");

			return ret;

		}

	}



	/* resync config */

	ret = ad799x_update_config(st, st->config);

	if (ret) {

		if (st->vref)

			regulator_disable(st->vref);

		regulator_disable(st->reg);

		return ret;