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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: Florian Boor <florian.boor@kernelconcepts.de>
Link: https://lore.kernel.org/r/20210930104249.2924336-1-florian.boor@kernelconcepts.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Florian Boor 2021-09-30 12:42:48 +02:00 committed by Jonathan Cameron
parent 2021ef0609
commit 6b104e7895
1 changed files with 51 additions and 17 deletions
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68
drivers/iio/adc/ad799x.c
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@ -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:
ret = regulator_get_voltage(st->vref);
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)) {
ret = PTR_ERR(st->vref);
goto error_disable_reg;
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");
}
}
ret = regulator_enable(st->vref);
if (ret)
goto error_disable_reg;
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;
@ -845,7 +872,8 @@ static int ad799x_probe(struct i2c_client *client,
error_cleanup_ring:
iio_triggered_buffer_cleanup(indio_dev);
error_disable_vref:
regulator_disable(st->vref);
if (st->vref)
regulator_disable(st->vref);
error_disable_reg:
regulator_disable(st->reg);
@ -860,7 +888,8 @@ static int ad799x_remove(struct i2c_client *client)
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
regulator_disable(st->vref);
if (st->vref)
regulator_disable(st->vref);
regulator_disable(st->reg);
kfree(st->rx_buf);
@ -872,7 +901,8 @@ 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);
regulator_disable(st->vref);
if (st->vref)
regulator_disable(st->vref);
regulator_disable(st->reg);
return 0;
@ -889,17 +919,21 @@ static int __maybe_unused ad799x_resume(struct device *dev)
dev_err(dev, "Unable to enable vcc regulator\n");
return ret;
}
ret = regulator_enable(st->vref);
if (ret) {
regulator_disable(st->reg);
dev_err(dev, "Unable to enable vref 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) {
regulator_disable(st->vref);
if (st->vref)
regulator_disable(st->vref);
regulator_disable(st->reg);
return ret;
}