Re: [PATCH v8 1/3] DMA: Freescale: revise device tree bindingdocument
From: Mark Rutland
Date: Tue Aug 27 2013 - 07:25:29 EST
On Tue, Aug 27, 2013 at 11:42:01AM +0100, hongbo.zhang@xxxxxxxxxxxxx wrote:
> From: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
>
> This patch updates the discription of each type of DMA controller and its
> channels, it is preparation for adding another new DMA controller binding, it
> also fixes some defects of indent for text alignment at the same time.
>
> Signed-off-by: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/powerpc/fsl/dma.txt | 62 +++++++++-----------
> 1 file changed, 27 insertions(+), 35 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> index 2a4b4bc..ddf17af 100644
> --- a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> +++ b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> @@ -1,33 +1,29 @@
> -* Freescale 83xx DMA Controller
> +* Freescale DMA Controllers
>
> -Freescale PowerPC 83xx have on chip general purpose DMA controllers.
> +** Freescale Elo DMA Controller
> + This is a little-endian DMA controller, used in Freescale mpc83xx series
> + chips such as mpc8315, mpc8349, mpc8379 etc.
>
> Required properties:
>
> -- compatible : compatible list, contains 2 entries, first is
> - "fsl,CHIP-dma", where CHIP is the processor
> - (mpc8349, mpc8360, etc.) and the second is
> - "fsl,elo-dma"
> -- reg : <registers mapping for DMA general status reg>
> -- ranges : Should be defined as specified in 1) to describe the
> - DMA controller channels.
> +- compatible : must include "fsl,elo-dma"
We should list the other values that may be in the list also, unless
they are really of no consequence, in which case their presence in dt is
questionable.
> +- reg : <registers specifier for DMA general status reg>
> +- ranges : describes the mapping between the address space of the
> + DMA channels and the address space of the DMA controller
> - cell-index : controller index. 0 for controller @ 0x8100
> -- interrupts : <interrupt mapping for DMA IRQ>
> +- interrupts : <interrupt specifier for DMA IRQ>
> - interrupt-parent : optional, if needed for interrupt mapping
>
> -
> - DMA channel nodes:
> - - compatible : compatible list, contains 2 entries, first is
> - "fsl,CHIP-dma-channel", where CHIP is the processor
> - (mpc8349, mpc8350, etc.) and the second is
> - "fsl,elo-dma-channel". However, see note below.
> - - reg : <registers mapping for channel>
> + - compatible : must include "fsl,elo-dma-channel"
> + However, see note below.
Again, I think we should list the other entries that may be in the list.
Otherwise it's not clear what the binding defines. Similarly for the
other compatible list definitions below...
> + - reg : <registers specifier for channel>
> - cell-index : dma channel index starts at 0.
I realise you haven't changed it, but it's unclear what the cell-index
property is (and somewhat confusingly there seem to be multiple
defnitions). It might be worth clarifying it while performing the other
cleanup.
>
> Optional properties:
> - - interrupts : <interrupt mapping for DMA channel IRQ>
> - (on 83xx this is expected to be identical to
> - the interrupts property of the parent node)
> + - interrupts : <interrupt specifier for DMA channel IRQ>
> + (on 83xx this is expected to be identical to
> + the interrupts property of the parent node)
> - interrupt-parent : optional, if needed for interrupt mapping
>
> Example:
> @@ -70,30 +66,26 @@ Example:
> };
> };
>
> -* Freescale 85xx/86xx DMA Controller
> -
> -Freescale PowerPC 85xx/86xx have on chip general purpose DMA controllers.
> +** Freescale EloPlus DMA Controller
> + This is DMA controller with extended addresses and chaining, mainly used in
> + Freescale mpc85xx/86xx, Pxxx and BSC series chips, such as mpc8540, mpc8641
> + p4080, bsc9131 etc.
>
> Required properties:
>
> -- compatible : compatible list, contains 2 entries, first is
> - "fsl,CHIP-dma", where CHIP is the processor
> - (mpc8540, mpc8540, etc.) and the second is
> - "fsl,eloplus-dma"
> -- reg : <registers mapping for DMA general status reg>
> +- compatible : must include "fsl,eloplus-dma"
> +- reg : <registers specifier for DMA general status reg>
> - cell-index : controller index. 0 for controller @ 0x21000,
> 1 for controller @ 0xc000
> -- ranges : Should be defined as specified in 1) to describe the
> - DMA controller channels.
> +- ranges : describes the mapping between the address space of the
> + DMA channels and the address space of the DMA controller
>
> - DMA channel nodes:
> - - compatible : compatible list, contains 2 entries, first is
> - "fsl,CHIP-dma-channel", where CHIP is the processor
> - (mpc8540, mpc8560, etc.) and the second is
> - "fsl,eloplus-dma-channel". However, see note below.
> + - compatible : must include "fsl,eloplus-dma-channel"
> + However, see note below.
> - cell-index : dma channel index starts at 0.
> - - reg : <registers mapping for channel>
> - - interrupts : <interrupt mapping for DMA channel IRQ>
> + - reg : <registers specifier for channel>
> + - interrupts : <interrupt specifier for DMA channel IRQ>
> - interrupt-parent : optional, if needed for interrupt mapping
>
> Example:
> --
> 1.7.9.5
Thanks,
Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/