iio:ad5064: Initialize register cache correctly

Initialize the register cache to the proper mid-scale value based on the
resolution of the device.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/iio/dac/ad5064.c b/drivers/iio/dac/ad5064.c
index f724a54bf334..74f2d52795f6 100644
--- a/drivers/iio/dac/ad5064.c
+++ b/drivers/iio/dac/ad5064.c
@@ -438,6 +438,7 @@ static int ad5064_probe(struct device *dev, enum ad5064_type type,
 {
         struct iio_dev *indio_dev;
         struct ad5064_state *st;
+        unsigned int midscale;
         unsigned int i;
         int ret;
 
@@ -474,11 +475,6 @@ static int ad5064_probe(struct device *dev, enum ad5064_type type,
                         goto error_free_reg;
         }
 
-        for (i = 0; i < st->chip_info->num_channels; ++i) {
-                st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
-                st->dac_cache[i] = 0x8000;
-        }
-
         indio_dev->dev.parent = dev;
         indio_dev->name = name;
         indio_dev->info = &ad5064_info;
@@ -486,6 +482,13 @@ static int ad5064_probe(struct device *dev, enum ad5064_type type,
         indio_dev->channels = st->chip_info->channels;
         indio_dev->num_channels = st->chip_info->num_channels;
 
+        midscale = (1 << indio_dev->channels[0].scan_type.realbits) /  2;
+
+        for (i = 0; i < st->chip_info->num_channels; ++i) {
+                st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
+                st->dac_cache[i] = midscale;
+        }
+
         ret = iio_device_register(indio_dev);
         if (ret)
                 goto error_disable_reg;