Hi Maxime,

Thank you for the patch.

On Thursday 16 October 2014 12:17:02 Maxime Ripard wrote:
> 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 <[email protected]>
> ---
>  include/linux/dmaengine.h | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index f4b71ce1a0a6..7937f81e5e2e 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -608,6 +608,8 @@ struct dma_tx_state {
>   *   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
> @@ -662,7 +664,6 @@ struct dma_device {
>               struct scatterlist *dst_sg, unsigned int dst_nents,
>               struct scatterlist *src_sg, unsigned int src_nents,
>               unsigned long flags);
> -

That's an unrelated change.

>       struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
>               struct dma_chan *chan, struct scatterlist *sgl,
>               unsigned int sg_len, enum dma_transfer_direction direction,
> @@ -674,9 +675,11 @@ struct dma_device {
>       struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)(
>               struct dma_chan *chan, struct dma_interleaved_template *xt,
>               unsigned long flags);
> -     int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> -             unsigned long arg);
> 
> +     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);

As you'll move device_control in the last patch of this series I would avoid 
the cosmetic modification here.

Apart from that,

Acked-by: Laurent Pinchart <[email protected]>

>       enum dma_status (*device_tx_status)(struct dma_chan *chan,
>                                           dma_cookie_t cookie,
>                                           struct dma_tx_state *txstate);
> @@ -697,6 +700,9 @@ static inline int dmaengine_device_control(struct
> dma_chan *chan, 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);
>  }

-- 
Regards,

Laurent Pinchart

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