Add a function to read a processed value from a channel. The function will first
attempt to read the IIO_CHAN_INFO_PROCESSED attribute. If that fails it will
read the IIO_CHAN_INFO_RAW attribute and convert the result from a raw value to
a processed value.
The patch also introduces a function to convert raw value to a processed value
and exports it, in case a user needs or wants to do the conversion by itself.
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
---
Documentation is still missing.
---
drivers/iio/inkern.c | 118 ++++++++++++++++++++++++++++++++++++++++--
include/linux/iio/consumer.h | 4 ++
2 files changed, 118 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index b5afc2f..9bb3391 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -248,6 +248,118 @@ err_unlock:
}
EXPORT_SYMBOL_GPL(iio_read_channel_raw);
+static int iio_read_channel_scale_unlocked(struct iio_channel *chan, int *val,
+ int *val2)
+{
+ return chan->indio_dev->info->read_raw(chan->indio_dev,
+ chan->channel,
+ val, val2,
+ IIO_CHAN_INFO_SCALE);
+}
+
+static int iio_read_channel_offset_unlocked(struct iio_channel *chan, int *val)
+{
+ int val2;
+
+ return chan->indio_dev->info->read_raw(chan->indio_dev,
+ chan->channel,
+ val, &val2,
+ IIO_CHAN_INFO_OFFSET);
+}
+
+/* It may make sense to a add a extra scale attribute here to avoid precession
+ * loss if the user wants a more fine grained value than the IIO default, e.g.
+ * micro instead of milli volt. */
+static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
+ int raw, int *processed)
+{
+ int scale_type, scale_val, scale_val2, offset;
+ s64 raw64 = raw;
+ int ret;
+
+
+ ret = iio_read_channel_offset_unlocked(chan, &offset);
+ if (ret == 0)
+ raw64 += offset;
+
+ scale_type = iio_read_channel_scale_unlocked(chan, &scale_val, &scale_val2);
+ if (scale_type < 0)
+ return scale_type;
+
+ switch (scale_type) {
+ case IIO_VAL_INT:
+ *processed = raw * scale_val;
+ break;
+ case IIO_VAL_INT_PLUS_MICRO:
+ if (scale_val2 < 0)
+ *processed = -raw * scale_val;
+ else
+ *processed = raw * scale_val;
+ *processed += div_s64(raw * (s64)scale_val2, 1000000LL);
+ break;
+ case IIO_VAL_INT_PLUS_NANO:
+ if (scale_val2 < 0)
+ *processed = -raw * scale_val;
+ else
+ *processed = raw * scale_val;
+ *processed += div_s64(raw * (s64)scale_val2, 1000000000LL);
+ break;
+ case IIO_VAL_FRACTIONAL:
+ *processed = div_s64(raw * (s64)scale_val, scale_val2);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+
+int iio_convert_raw_to_processed(struct iio_channel *chan, int raw, int *processed)
+{
+ int ret;
+
+ mutex_lock(&chan->indio_dev->info_exist_lock);
+ if (chan->indio_dev->info == NULL) {
+ ret = -ENODEV;
+ goto err_unlock;
+ }
+
+ ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed);
+
+err_unlock:
+ mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
+
+int iio_read_channel_processed(struct iio_channel *chan, int *val)
+{
+ int val2, ret;
+
+ mutex_lock(&chan->indio_dev->info_exist_lock);
+ if (chan->indio_dev->info == NULL) {
+ ret = -ENODEV;
+ goto err_unlock;
+ }
+
+ ret = chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
+ val, &val2, IIO_CHAN_INFO_PROCESSED);
+ if (ret < 0) {
+ ret = chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
+ val, &val2, IIO_CHAN_INFO_RAW);
+ if (ret < 0)
+ goto err_unlock;
+ ret = iio_convert_raw_to_processed_unlocked(chan, *val, val);
+ }
+err_unlock:
+ mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_read_channel_processed);
+
int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
{
int ret;
@@ -258,10 +370,8 @@ int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
goto err_unlock;
}
- ret = chan->indio_dev->info->read_raw(chan->indio_dev,
- chan->channel,
- val, val2,
- IIO_CHAN_INFO_SCALE);
+ ret = iio_read_channel_scale_unlocked(chan, val, val2);
+
err_unlock:
mutex_unlock(&chan->indio_dev->info_exist_lock);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index e2657e6..ef99ceb 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -93,4 +93,8 @@ int iio_get_channel_type(struct iio_channel *channel,
int iio_read_channel_scale(struct iio_channel *chan, int *val,
int *val2);
+int iio_read_channel_processed(struct iio_channel *chan, int *val);
+int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
+ int *processed);
+
#endif
--
1.7.10.4
--
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