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authorFlorian Boor <florian.boor@kernelconcepts.de>2021-09-30 12:42:48 +0200
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2021-10-19 09:30:43 +0200
commit6b104e7895ab16b9b7f466c5f2ca282b87f661e8 (patch)
tree7158a0cf1dd5997c93572a82c2e907c541c3bfaf /drivers/iio/adc/ad799x.c
parentiio: adc: max1027: fix error code in max1027_wait_eoc() (diff)
downloadlinux-6b104e7895ab16b9b7f466c5f2ca282b87f661e8.tar.xz
linux-6b104e7895ab16b9b7f466c5f2ca282b87f661e8.zip
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>
Diffstat (limited to 'drivers/iio/adc/ad799x.c')
-rw-r--r--drivers/iio/adc/ad799x.c68
1 files changed, 51 insertions, 17 deletions
diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
index 18bf8386d50a..220228c375d3 100644
--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -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;
}