[4/6] dmaengine: rcar-dmac: Add device tree bindings documentation

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Document the device tree bindings for the R-Car Generation 2 DMA
Controller (DMAC).

Cc: devicetree@vger.kernel.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 .../devicetree/bindings/dma/renesas,rcar-dmac.txt  | 98 ++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt

On Thu, Jul 31, 2014 at 2:34 AM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> @@ -0,0 +1,98 @@
> +* Renesas R-Car DMA Controller Device Tree bindings
> +
> +Renesas R-Car Generation 2 SoCs have have multiple multi-channel DMA
> +controller instances named DMAC capable of serving multiple clients. Channels
> +can be dedicated to specific clients or shared between a large number of
> +clients.
> +
> +DMA clients are connected to the DMAC ports referenced by an 8-bit identifier
> +called MID/RID.

I think the above sentence can be removed, as it's superseded by the first
sentence of the successive paragraph:

> +
> +Each DMA client is connected to one dedicated port of the DMAC, identified by
> +an 8-bit port number called the MID/RID. A DMA controller can thus serve up to
> +256 clients in total. When the number of hardware channels is lower than the
> +number of clients to be served, channels must be shared between multiple DMA
> +clients. The association of DMA clients to DMAC channels is fully dynamic and
> +not described in these device tree bindings.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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Hi Geert,

Thank you for the review.

On Monday 04 August 2014 10:05:49 Geert Uytterhoeven wrote:
> On Thu, Jul 31, 2014 at 2:34 AM, Simon Horman wrote:
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> > @@ -0,0 +1,98 @@
> > +* Renesas R-Car DMA Controller Device Tree bindings
> > +
> > +Renesas R-Car Generation 2 SoCs have have multiple multi-channel DMA
> > +controller instances named DMAC capable of serving multiple clients.
> > Channels +can be dedicated to specific clients or shared between a large
> > number of +clients.
> > +
> > +DMA clients are connected to the DMAC ports referenced by an 8-bit
> > identifier +called MID/RID.
> 
> I think the above sentence can be removed, as it's superseded by the first
> sentence of the successive paragraph:

I've probably just forgotten to remove the sentence while reworking the 
documentation. Thanks for reporting it, I'll fix that in the next version.

> > +
> > +Each DMA client is connected to one dedicated port of the DMAC,
> > identified by +an 8-bit port number called the MID/RID. A DMA controller
> > can thus serve up to +256 clients in total. When the number of hardware
> > channels is lower than the +number of clients to be served, channels must
> > be shared between multiple DMA +clients. The association of DMA clients
> > to DMAC channels is fully dynamic and +not described in these device tree
> > bindings.

On Mon, Aug 04, 2014 at 04:01:42PM +0200, Laurent Pinchart wrote:
> Hi Geert,
> 
> Thank you for the review.
> 
> On Monday 04 August 2014 10:05:49 Geert Uytterhoeven wrote:
> > On Thu, Jul 31, 2014 at 2:34 AM, Simon Horman wrote:
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> > > @@ -0,0 +1,98 @@
> > > +* Renesas R-Car DMA Controller Device Tree bindings
> > > +
> > > +Renesas R-Car Generation 2 SoCs have have multiple multi-channel DMA
> > > +controller instances named DMAC capable of serving multiple clients.
> > > Channels +can be dedicated to specific clients or shared between a large
> > > number of +clients.
> > > +
> > > +DMA clients are connected to the DMAC ports referenced by an 8-bit
> > > identifier +called MID/RID.
> > 
> > I think the above sentence can be removed, as it's superseded by the first
> > sentence of the successive paragraph:
> 
> I've probably just forgotten to remove the sentence while reworking the 
> documentation. Thanks for reporting it, I'll fix that in the next version.

BTW, I believe Vinod has already applied this and the previous three
patches of this series to his tree.

As he applied then rather than pulling the pull-request I sent I intend
to drop the entire series from my tree for now.

> > > +
> > > +Each DMA client is connected to one dedicated port of the DMAC,
> > > identified by +an 8-bit port number called the MID/RID. A DMA controller
> > > can thus serve up to +256 clients in total. When the number of hardware
> > > channels is lower than the +number of clients to be served, channels must
> > > be shared between multiple DMA +clients. The association of DMA clients
> > > to DMAC channels is fully dynamic and +not described in these device tree
> > > bindings.
> 
> -- 
> Regards,
> 
> Laurent Pinchart
> 
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Hi Simon,

On Tuesday 05 August 2014 10:46:42 Simon Horman wrote:
> On Mon, Aug 04, 2014 at 04:01:42PM +0200, Laurent Pinchart wrote:
> > On Monday 04 August 2014 10:05:49 Geert Uytterhoeven wrote:
> >> On Thu, Jul 31, 2014 at 2:34 AM, Simon Horman wrote:
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> >>> @@ -0,0 +1,98 @@
> >>> +* Renesas R-Car DMA Controller Device Tree bindings
> >>> +
> >>> +Renesas R-Car Generation 2 SoCs have have multiple multi-channel DMA
> >>> +controller instances named DMAC capable of serving multiple clients.
> >>> Channels
> >>> +can be dedicated to specific clients or shared between a large number
> >>> of
> >>> +clients.
> >>> +
> >>> +DMA clients are connected to the DMAC ports referenced by an 8-bit
> >>> identifier +called MID/RID.
> >> 
> >> I think the above sentence can be removed, as it's superseded by the
> >> first sentence of the successive paragraph:
> >>
> > I've probably just forgotten to remove the sentence while reworking the
> > documentation. Thanks for reporting it, I'll fix that in the next version.
> 
> BTW, I believe Vinod has already applied this and the previous three
> patches of this series to his tree.

Indeed. I'm surprised to see the DT bindings being merged without the driver, 
but given that they seem to be OK, that's not a problem.

> As he applied then rather than pulling the pull-request I sent I intend
> to drop the entire series from my tree for now.

Please do. I'll resubmit the remaining patches.