It happens that an ADC will only provide raw or processed
voltage conversion channels. (adc/ab8500-gpadc.c).
On the Samsung GT-I9070 this is used for a light sensor
and current sense amplifier so we need to think of something.
The idea is to allow processed channels and scale them
with 1/1 and then the rescaler can modify the result
on top.
Cc: Peter Rosin <peda@xxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/iio/afe/iio-rescale.c | 31 +++++++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index e42ea2b1707d..ea90034cb257 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -29,6 +29,7 @@ struct rescale {
struct iio_channel *source;
struct iio_chan_spec chan;
struct iio_chan_spec_ext_info *ext_info;
+ bool chan_processed;
s32 numerator;
s32 denominator;
};
@@ -43,10 +44,27 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
- return iio_read_channel_raw(rescale->source, val);
+ if (rescale->chan_processed)
+ /*
+ * When only processed channels are supported, we
+ * read the processed data and scale it by 1/1
+ * augmented with whatever the rescaler has calculated.
+ */
+ return iio_read_channel_processed(rescale->source, val);
+ else
+ return iio_read_channel_raw(rescale->source, val);
case IIO_CHAN_INFO_SCALE:
- ret = iio_read_channel_scale(rescale->source, val, val2);
+ if (rescale->chan_processed) {
+ /*
+ * Processed channels are scaled 1-to-1
+ */
+ ret = IIO_VAL_FRACTIONAL;
+ *val = 1;
+ *val2 = 1;
+ } else {
+ ret = iio_read_channel_scale(rescale->source, val, val2);
+ }
switch (ret) {
case IIO_VAL_FRACTIONAL:
*val *= rescale->numerator;
@@ -132,8 +150,13 @@ static int rescale_configure_channel(struct device *dev,
if (!iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||
!iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) {
- dev_err(dev, "source channel does not support raw/scale\n");
- return -EINVAL;
+ if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) {
+ dev_info(dev, "using processed channel\n");
+ rescale->chan_processed = true;
+ } else {
+ dev_err(dev, "source channel does not support raw+scale or processed data\n");
+ return -EINVAL;
+ }
}
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
--
2.26.2
