Re: [RFC PATCH v2 09/14] mtd: nand: add sunxi NFC dt bindings doc

[Boris BREZILLON]

Hello Rob,

Le 29/01/2014 18:11, Rob Herring a écrit :
> On Wed, Jan 29, 2014 at 8:34 AM, Boris BREZILLON
> <b.brezillon.dev@xxxxxxxxx> wrote:
> > Add the sunxi NAND Flash Controller dt bindings documentation.
> >
> > Signed-off-by: Boris BREZILLON <b.brezillon.dev@xxxxxxxxx>
> > ---
> >   .../devicetree/bindings/mtd/sunxi-nand.txt         |   46 ++++++++++++++++++++
> >   1 file changed, 46 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/mtd/sunxi-nand.txt
> >
> > diff --git a/Documentation/devicetree/bindings/mtd/sunxi-nand.txt b/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
> > new file mode 100644
> > index 0000000..b0e55a3
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
> > @@ -0,0 +1,46 @@
> > +Allwinner NAND Flash Controller (NFC)
> > +
> > +Required properties:
> > +- compatible : "allwinner,sun4i-nand".
> > +- reg : shall contain registers location and length for data and reg.
> > +- interrupts : shall define the nand controller interrupt.
> > +- #address-cells: shall be set to 1. Encode the nand CS.
> > +- #size-cells : shall be set to 0.
> > +- clocks : shall reference nand controller clocks.
> > +- clock-names : nand controller internal clock names. Shall contain :
> > +    * "ahb_clk" : AHB gating clock
> > +    * "sclk" : nand controller clock
> > +
> > +Optional children nodes:
> > +Children nodes represent the available nand chips.
> > +
> > +Optional properties:
> For the controller or per nand chip?
>
> > +- onfi,nand-timing-mode : mandatory if the chip does not support the ONFI
> > +  standard.
> Add to generic nand binding.
>
> > +- allwinner,rb : shall contain the native Ready/Busy ids.
> > + or
> > +- rb-gpios : shall contain the gpios used as R/B pins.
> Isn't allwinner,rb implied by a lack of rb-gpios property. Or no R/B
> pin is an option?
Both are optional. In case none of the properties are defined the dev_ready
callback is set to NULL and the nand_base waiting loop is used.

> If so, don't you need some fixed time delay
> properties like max erase time?

This is handled in nand_base (using the chip_delay field), but I guess 
we could
use the information retrieved from nand timings and the operation in 
progress...

> rb-gpios could be added to the generic nand binding as well.
Sure.
> Rob

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