iio: inkern: API for reading available iio channel attribute values

Extend the inkern API with a function for reading available
attribute values of iio channels.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

2 files changed, 34 insertions, 0 deletions

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index 06ca3f7fcc44..f19dbde3c945 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -733,6 +733,26 @@ static int iio_channel_read_avail(struct iio_channel *chan,
                                                  vals, type, length, info);
 }
 
+int iio_read_avail_channel_attribute(struct iio_channel *chan,
+                                     const int **vals, int *type, int *length,
+                                     enum iio_chan_info_enum attribute)
+{
+        int ret;
+
+        mutex_lock(&chan->indio_dev->info_exist_lock);
+        if (!chan->indio_dev->info) {
+                ret = -ENODEV;
+                goto err_unlock;
+        }
+
+        ret = iio_channel_read_avail(chan, vals, type, length, attribute);
+err_unlock:
+        mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(iio_read_avail_channel_attribute);
+
 int iio_read_avail_channel_raw(struct iio_channel *chan,
                                const int **vals, int *length)
 {
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 9887f4f8e2a8..b2d34831ed7c 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -291,6 +291,20 @@ int iio_read_avail_channel_raw(struct iio_channel *chan,
                                const int **vals, int *length);
 
 /**
+ * iio_read_avail_channel_attribute() - read available channel attribute values
+ * @chan:               The channel being queried.
+ * @vals:               Available values read back.
+ * @type:               Type of values read back.
+ * @length:             Number of entries in vals.
+ * @attribute:          info attribute to be read back.
+ *
+ * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
+ */
+int iio_read_avail_channel_attribute(struct iio_channel *chan,
+                                     const int **vals, int *type, int *length,
+                                     enum iio_chan_info_enum attribute);
+
+/**
  * iio_get_channel_type() - get the type of a channel
  * @channel:            The channel being queried.
  * @type:               The type of the channel.