[PATCH] iio: dac: ti-dac5571: make vref regulator optional

[Marcus Folkesson]

The `vref` regulator is declared as optional in the device-tree binding,
but the driver does require it.

Go for the device-tree binding and make the `vref` regulator optional.

Signed-off-by: Marcus Folkesson <marcus.folkes...@gmail.com>
---
 drivers/iio/dac/ti-dac5571.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/dac/ti-dac5571.c b/drivers/iio/dac/ti-dac5571.c
index f6dcd8bce2b0..bf21cc312096 100644
--- a/drivers/iio/dac/ti-dac5571.c
+++ b/drivers/iio/dac/ti-dac5571.c
@@ -251,6 +251,9 @@ static int dac5571_read_raw(struct iio_dev *indio_dev,
                return IIO_VAL_INT;
 
        case IIO_CHAN_INFO_SCALE:
+               if (!data->vref)
+                       return -EOPNOTSUPP;
+
                ret = regulator_get_voltage(data->vref);
                if (ret < 0)
                        return ret;
@@ -335,13 +338,21 @@ static int dac5571_probe(struct i2c_client *client,
        indio_dev->num_channels = spec->num_channels;
        data->spec = spec;
 
-       data->vref = devm_regulator_get(dev, "vref");
-       if (IS_ERR(data->vref))
-               return PTR_ERR(data->vref);
+       data->vref = devm_regulator_get_optional(dev, "vref");
+       if (IS_ERR(data->vref)) {
+               if (PTR_ERR(data->vref) == -ENODEV) {
+                       data->vref = NULL;
+               } else {
+                       dev_err(dev, "failed to get regulator (%ld)\n",
+                                       PTR_ERR(data->vref));
+                       return PTR_ERR(data->vref);
+               }
 
-       ret = regulator_enable(data->vref);
-       if (ret < 0)
-               return ret;
+       } else {
+               ret = regulator_enable(data->vref);
+               if (ret)
+                       return ret;
+       }
 
        mutex_init(&data->lock);
 
@@ -373,7 +384,9 @@ static int dac5571_probe(struct i2c_client *client,
        return 0;
 
  err:
-       regulator_disable(data->vref);
+       if (data->vref)
+               regulator_disable(data->vref);
+
        return ret;
 }
 
@@ -383,7 +396,8 @@ static int dac5571_remove(struct i2c_client *i2c)
        struct dac5571_data *data = iio_priv(indio_dev);
 
        iio_device_unregister(indio_dev);
-       regulator_disable(data->vref);
+       if (data->vref)
+               regulator_disable(data->vref);
 
        return 0;
 }
-- 
2.18.0