dmaengine: Introduce a device_config callback
The fact that the channel configuration is done in device_control is rather
misleading, since it's not really advertised as such, plus, the fact that the
framework exposes a function of its own makes it not really intuitive, while
we're losing the type checking whenever we pass that unsigned long argument.
Add a device_config callback to dma_device, with a fallback on the old
behaviour for now for existing drivers to opt in.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 03a1feb..cf7c85d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -608,6 +608,8 @@
* The function takes a buffer of size buf_len. The callback function will
* be called after period_len bytes have been transferred.
* @device_prep_interleaved_dma: Transfer expression in a generic way.
+ * @device_config: Pushes a new configuration to a channel, return 0 or an error
+ * code
* @device_control: manipulate all pending operations on a channel, returns
* zero or error code
* @device_tx_status: poll for transaction completion, the optional
@@ -674,6 +676,9 @@
struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)(
struct dma_chan *chan, struct dma_interleaved_template *xt,
unsigned long flags);
+
+ int (*device_config)(struct dma_chan *chan,
+ struct dma_slave_config *config);
int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg);
@@ -697,6 +702,9 @@
static inline int dmaengine_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
+ if (chan->device->device_config)
+ return chan->device->device_config(chan, config);
+
return dmaengine_device_control(chan, DMA_SLAVE_CONFIG,
(unsigned long)config);
}