iio:inkern: Add function to read the processed value

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

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 30affa533a1f..c0ae76ac4e0b 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -40,6 +40,8 @@ enum iio_chan_info_enum {
 
 #define IIO_CHAN_INFO_SHARED_BIT(type) BIT(type*2)
 #define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
+#define IIO_CHAN_INFO_BITS(type) (IIO_CHAN_INFO_SHARED_BIT(type) | \
+                                    IIO_CHAN_INFO_SEPARATE_BIT(type))
 
 #define IIO_CHAN_INFO_RAW_SEPARATE_BIT                  \
         IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_RAW)
@@ -261,6 +263,21 @@ struct iio_chan_spec {
         unsigned                differential:1;
 };
 
+
+/**
+ * iio_channel_has_info() - Checks whether a channel supports a info attribute
+ * @chan: The channel to be queried
+ * @type: Type of the info attribute to be checked
+ *
+ * Returns true if the channels supports reporting values for the given info
+ * attribute type, false otherwise.
+ */
+static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
+        enum iio_chan_info_enum type)
+{
+        return chan->info_mask & IIO_CHAN_INFO_BITS(type);
+}
+
 #define IIO_ST(si, rb, sb, sh)                                          \
         { .sign = si, .realbits = rb, .storagebits = sb, .shift = sh }