On Wed, 2013-08-28 at 13:48 +0100, Mark Rutland wrote: > On Wed, Aug 28, 2013 at 09:18:55AM +0100, Hongbo Zhang wrote: > > On 08/27/2013 07:25 PM, Mark Rutland wrote: > > > 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. > > Hmm. Stephen questioned here too, it seems this is a default rule. > > Although Scott@freescale had explained our thoughts, I'd like to edit > > this item like this: > > > > "must include "fsl,eloplus-dma", and a "fsl,CHIP-dma" is optional, where > > CHIP is the processor name" > > > > We don't list all the chip name because we have tens of them and we > > cannot list all of them, and it is unnecessary to list them because we > > even don't use "fsl,CHIP-dma" in the new driver, add "fsl,CHIP-dma" here > > just make it questionable when it presents in example and old dts files. > > > > I remove the examples in bracket "(mpc8349, mpc8360, etc.)" because we > > can see the real example below. > > I don't say" if "fsl,CHIP-dma" presents, it should be the first one, and > > the "fsl,eloplus-dma" should be the second" because it is common rule. > > the description language should be clear and concise too I think. > > Actually, you've convinced me for the form as you originally converted > it (must include "fsl,elo-dma"), given that the other strings aren't > used to give information anywhere and "fsl,CHIP-dma" doesn't fully > define a valid string. More generally, bindings should always specify "must include" rather than "must be" for compatible, since by the nature of compatible you could have a derivative device with more features that is compatible with the device described in the binding, and the binding shouldn't preclude identifying the derivative device. -Scott -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
