[RFC PATCH 3/5] iio: buffer-dma: Allow to provide custom buffer ops

[Alexandru Ardelean]

From: Lars-Peter Clausen <lars@xxxxxxxxxx>

Some devices that want to make use of the DMA buffer might need to do
something special, like write a register when the buffer is enabled.

Extend the API to allow those drivers to provide their own buffer ops.

Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
 drivers/iio/adc/adi-axi-adc.c                      |  2 +-
 drivers/iio/buffer/industrialio-buffer-dma.c       |  4 +++-
 drivers/iio/buffer/industrialio-buffer-dmaengine.c | 14 ++++++++++----
 include/linux/iio/buffer-dma.h                     |  5 ++++-
 include/linux/iio/buffer-dmaengine.h               |  4 +++-
 5 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 74a6da35fd69..45ce97d1f41e 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -116,7 +116,7 @@ static int adi_axi_adc_config_dma_buffer(struct device *dev,
 		dma_name = "rx";
 
 	buffer = devm_iio_dmaengine_buffer_alloc(indio_dev->dev.parent,
-						 dma_name);
+						 dma_name, NULL, NULL);
 	if (IS_ERR(buffer))
 		return PTR_ERR(buffer);
 
diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c
index befb0a3d2def..57f2284a292f 100644
--- a/drivers/iio/buffer/industrialio-buffer-dma.c
+++ b/drivers/iio/buffer/industrialio-buffer-dma.c
@@ -883,13 +883,15 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_set_length);
  * allocations are done from a memory region that can be accessed by the device.
  */
 int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
-	struct device *dev, const struct iio_dma_buffer_ops *ops)
+	struct device *dev, const struct iio_dma_buffer_ops *ops,
+	void *driver_data)
 {
 	iio_buffer_init(&queue->buffer);
 	queue->buffer.length = PAGE_SIZE;
 	queue->buffer.watermark = queue->buffer.length / 2;
 	queue->dev = dev;
 	queue->ops = ops;
+	queue->driver_data = driver_data;
 
 	INIT_LIST_HEAD(&queue->incoming);
 	INIT_LIST_HEAD(&queue->outgoing);
diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
index bb022922ec23..0736526b36ec 100644
--- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
+++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
@@ -163,6 +163,8 @@ static const struct attribute *iio_dmaengine_buffer_attrs[] = {
  * iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine
  * @dev: Parent device for the buffer
  * @channel: DMA channel name, typically "rx".
+ * @ops: Custom iio_dma_buffer_ops, if NULL default ops will be used
+ * @driver_data: Driver data to be passed to custom iio_dma_buffer_ops
  *
  * 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
@@ -172,7 +174,8 @@ static const struct attribute *iio_dmaengine_buffer_attrs[] = {
  * release it.
  */
 static struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
-	const char *channel)
+	const char *channel, const struct iio_dma_buffer_ops *ops,
+	void *driver_data)
 {
 	struct dmaengine_buffer *dmaengine_buffer;
 	unsigned int width, src_width, dest_width;
@@ -211,7 +214,7 @@ static struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
 	dmaengine_buffer->max_size = dma_get_max_seg_size(chan->device->dev);
 
 	iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev,
-		&iio_dmaengine_default_ops);
+		ops ? ops : &iio_dmaengine_default_ops, driver_data);
 
 	dmaengine_buffer->queue.buffer.attrs = iio_dmaengine_buffer_attrs;
 	dmaengine_buffer->queue.buffer.access = &iio_dmaengine_buffer_ops;
@@ -249,6 +252,8 @@ static void __devm_iio_dmaengine_buffer_free(struct device *dev, void *res)
  * devm_iio_dmaengine_buffer_alloc() - Resource-managed iio_dmaengine_buffer_alloc()
  * @dev: Parent device for the buffer
  * @channel: DMA channel name, typically "rx".
+ * @ops: Custom iio_dma_buffer_ops, if NULL default ops will be used
+ * @driver_data: Driver data to be passed to custom iio_dma_buffer_ops
  *
  * 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
@@ -257,7 +262,8 @@ static void __devm_iio_dmaengine_buffer_free(struct device *dev, void *res)
  * 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)
+	const char *channel, const struct iio_dma_buffer_ops *ops,
+	void *driver_data)
 {
 	struct iio_buffer **bufferp, *buffer;
 
@@ -266,7 +272,7 @@ struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
 	if (!bufferp)
 		return ERR_PTR(-ENOMEM);
 
-	buffer = iio_dmaengine_buffer_alloc(dev, channel);
+	buffer = iio_dmaengine_buffer_alloc(dev, channel, ops, driver_data);
 	if (IS_ERR(buffer)) {
 		devres_free(bufferp);
 		return buffer;
diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h
index 315a8d750986..c23fad847f0d 100644
--- a/include/linux/iio/buffer-dma.h
+++ b/include/linux/iio/buffer-dma.h
@@ -110,6 +110,8 @@ struct iio_dma_buffer_queue {
 
 	bool active;
 
+	void *driver_data;
+
 	unsigned int num_blocks;
 	struct iio_dma_buffer_block **blocks;
 	unsigned int max_offset;
@@ -144,7 +146,8 @@ int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length);
 int iio_dma_buffer_request_update(struct iio_buffer *buffer);
 
 int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
-	struct device *dma_dev, const struct iio_dma_buffer_ops *ops);
+	struct device *dma_dev, const struct iio_dma_buffer_ops *ops,
+	void *driver_data);
 void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue);
 void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue);
 
diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h
index 5b502291d6a4..464adee95d4b 100644
--- a/include/linux/iio/buffer-dmaengine.h
+++ b/include/linux/iio/buffer-dmaengine.h
@@ -7,10 +7,12 @@
 #ifndef __IIO_DMAENGINE_H__
 #define __IIO_DMAENGINE_H__
 
+struct iio_dma_buffer_ops;
 struct iio_buffer;
 struct device;
 
 struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
-						   const char *channel);
+	const char *channel, const struct iio_dma_buffer_ops *ops,
+	void *driver_data);
 
 #endif
-- 
2.17.1