[PATCH v9 4/8] iio: buffer-dmaengine: add dev-managed calls for buffer alloc

Alexandru Ardelean
2020-03-12T08:35:27Z

Currently, when using a 'iio_dmaengine_buffer_alloc()', an matching call to
'iio_dmaengine_buffer_free()' must be made.

With this change, this can be avoided by using
'devm_iio_dmaengine_buffer_alloc()'. The buffer will get free'd via the
device's devres handling.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
.../buffer/industrialio-buffer-dmaengine.c | 39 +++++++++++++++++++
include/linux/iio/buffer-dmaengine.h | 3 ++
2 files changed, 42 insertions(+)

diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
index 94da3b1ca3a2..6dedf12b69a4 100644
--- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
+++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
@@ -229,6 +229,45 @@ void iio_dmaengine_buffer_free(struct iio_buffer *buffer)
}
EXPORT_SYMBOL_GPL(iio_dmaengine_buffer_free);

+static void __devm_iio_dmaengine_buffer_free(struct device *dev, void *res)
+{
+ iio_dmaengine_buffer_free(*(struct iio_buffer **)res);
+}
+
+/**
+ * devm_iio_dmaengine_buffer_alloc() - Resource-managed iio_dmaengine_buffer_alloc()
+ * @dev: Parent device for the buffer
+ * @channel: DMA channel name, typically "rx".
+ *
+ * This allocates a new IIO buffer which internally uses the DMAengine framework
+ * to perform its transfers. The parent device will be used to request the DMA
+ * channel.
+ *
+ * The buffer will be automatically de-allocated once the device gets destroyed.
+ */
+struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
+ const char *channel)
+{
+ struct iio_buffer **bufferp, *buffer;
+
+ bufferp = devres_alloc(__devm_iio_dmaengine_buffer_free,
+ sizeof(*bufferp), GFP_KERNEL);
+ if (!bufferp)
+ return ERR_PTR(-ENOMEM);
+
+ buffer = iio_dmaengine_buffer_alloc(dev, channel);
+ if (IS_ERR(buffer)) {
+ devres_free(bufferp);
+ return buffer;
+ }
+
+ *bufferp = buffer;
+ devres_add(dev, bufferp);
+
+ return buffer;
+}
+EXPORT_SYMBOL_GPL(devm_iio_dmaengine_buffer_alloc);
+
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("DMA buffer for the IIO framework");
MODULE_LICENSE("GPL");
diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h
index b3a57444a886..0e503db71289 100644
--- a/include/linux/iio/buffer-dmaengine.h
+++ b/include/linux/iio/buffer-dmaengine.h
@@ -14,4 +14,7 @@ struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
const char *channel);
void iio_dmaengine_buffer_free(struct iio_buffer *buffer);

+struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
+ const char *channel);
+
#endif
--
2.20.1