iio: buffer-dma: Rename iio_dma_buffer_data_available()

Change its name to iio_dma_buffer_usage(), as this function can be used
both for the .data_available and the .space_available callbacks.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240419-iio-backend-axi-dac-v4-2-5ca45b4de294@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/buffer/industrialio-buffer-dma.c

@@ -547,13 +547,14 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
 EXPORT_SYMBOL_GPL(iio_dma_buffer_read);
 
 /**
- * iio_dma_buffer_data_available() - DMA buffer data_available callback
+ * iio_dma_buffer_usage() - DMA buffer data_available and
+ * space_available callback
  * @buf: Buffer to check for data availability
  *
- * Should be used as the data_available callback for iio_buffer_access_ops
- * struct for DMA buffers.
+ * Should be used as the data_available and space_available callbacks for
+ * iio_buffer_access_ops struct for DMA buffers.
  */
-size_t iio_dma_buffer_data_available(struct iio_buffer *buf)
+size_t iio_dma_buffer_usage(struct iio_buffer *buf)
 {
 	struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buf);
 	struct iio_dma_buffer_block *block;
@@ -586,7 +587,7 @@ size_t iio_dma_buffer_data_available(struct iio_buffer *buf)
 
 	return data_available;
 }
-EXPORT_SYMBOL_GPL(iio_dma_buffer_data_available);
+EXPORT_SYMBOL_GPL(iio_dma_buffer_usage);
 
 /**
  * iio_dma_buffer_set_bytes_per_datum() - DMA buffer set_bytes_per_datum callback

drivers/iio/buffer/industrialio-buffer-dmaengine.c

@@ -117,7 +117,7 @@ static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = {
 	.request_update = iio_dma_buffer_request_update,
 	.enable = iio_dma_buffer_enable,
 	.disable = iio_dma_buffer_disable,
-	.data_available = iio_dma_buffer_data_available,
+	.data_available = iio_dma_buffer_usage,
 	.release = iio_dmaengine_buffer_release,
 
 	.modes = INDIO_BUFFER_HARDWARE,

include/linux/iio/buffer-dma.h

@@ -132,7 +132,7 @@ int iio_dma_buffer_disable(struct iio_buffer *buffer,
 	struct iio_dev *indio_dev);
 int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
 	char __user *user_buffer);
-size_t iio_dma_buffer_data_available(struct iio_buffer *buffer);
+size_t iio_dma_buffer_usage(struct iio_buffer *buffer);
 int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd);
 int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length);
 int iio_dma_buffer_request_update(struct iio_buffer *buffer);