iio: backend: add support for data size set

Add backend support for setting the data size used.

Signed-off-by: Antoniu Miclaus <[email protected]>

Author: amiclaus

drivers/iio/industrialio-backend.c

@@ -473,6 +473,27 @@ int iio_backend_interface_type_get(struct iio_backend *back,
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_interface_type_get, IIO_BACKEND);
 
+/**
+ * iio_backend_data_size_set - set the data width/size in the data bus.
+ * @back: Backend device
+ * @size: Size in bits
+ *
+ * Some frontend devices can dynamically control the word/data size on the
+ * interface/data bus. Hence, the backend device needs to be aware of it so
+ * data can be correctly transferred.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_size_set(struct iio_backend *back, ssize_t size)
+{
+	if (!size)
+		return -EINVAL;
+
+	return iio_backend_op_call(back, data_size_set, size);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, IIO_BACKEND);
+
 /**
  * iio_backend_extend_chan_spec - Extend an IIO channel
  * @indio_dev: IIO device

include/linux/iio/backend.h

@@ -87,6 +87,7 @@ enum iio_backend_interface_type {
  * @ext_info_set: Extended info setter.
  * @ext_info_get: Extended info getter.
  * @interface_type_get: Interface type.
+ * @data_size_set: Data size.
  **/
 struct iio_backend_ops {
 	int (*enable)(struct iio_backend *back);
@@ -121,6 +122,7 @@ struct iio_backend_ops {
 			    const struct iio_chan_spec *chan, char *buf);
 	int (*interface_type_get)(struct iio_backend *back,
 				  enum iio_backend_interface_type *type);
+	int (*data_size_set)(struct iio_backend *back, ssize_t size);
 };
 
 int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan);
@@ -152,6 +154,7 @@ ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
 
 int iio_backend_interface_type_get(struct iio_backend *back,
 				   enum iio_backend_interface_type *type);
+int iio_backend_data_size_set(struct iio_backend *back, ssize_t size);
 int iio_backend_extend_chan_spec(struct iio_dev *indio_dev,
 				 struct iio_backend *back,
 				 struct iio_chan_spec *chan);