Hi Archit,
Sorry for the late review, but there are a few things I think should be
addressed.
On Wed, 19 Aug 2015 10:19:04 +0530
Archit Taneja <architt@xxxxxxxxxxxxxx> wrote:
> Add DT bindings document for the Qualcomm NAND controller driver.
>
> Cc: devicetree@xxxxxxxxxxxxxxx
>
> v4:
> - No changes
>
> v3:
> - Don't use '0x' when specifying nand controller address space
> - Add optional property for on-flash bbt usage
>
> Acked-by: Andy Gross <agross@xxxxxxxxxxxxxx>
> Signed-off-by: Archit Taneja <architt@xxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/mtd/qcom_nandc.txt | 49 ++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/qcom_nandc.txt
>
> diff --git a/Documentation/devicetree/bindings/mtd/qcom_nandc.txt b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
> new file mode 100644
> index 0000000..1de4643
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
> @@ -0,0 +1,49 @@
> +* Qualcomm NAND controller
> +
> +Required properties:
> +- compatible: should be "qcom,ebi2-nand" for IPQ806x
> +- reg: MMIO address range
> +- clocks: must contain core clock and always on clock
> +- clock-names: must contain "core" for the core clock and "aon" for the
> + always on clock
> +- dmas: DMA specifier, consisting of a phandle to the ADM DMA
> + controller node and the channel number to be used for
> + NAND. Refer to dma.txt and qcom_adm.txt for more details
> +- dma-names: must be "rxtx"
> +- qcom,cmd-crci: must contain the ADM command type CRCI block instance
> + number specified for the NAND controller on the given
> + platform
> +- qcom,data-crci: must contain the ADM data type CRCI block instance
> + number specified for the NAND controller on the given
> + platform
> +
> +Optional properties:
> +- nand-bus-width: bus width. Must be 8 or 16. If not present, 8 is chosen
> + as default
> +
> +- nand-ecc-strength: number of bits to correct per ECC step. Must be 4 or 8
> + bits. If not present, 4 is chosen as default
> +- nand-on-flash-bbt: Create/use on-flash bad block table
> +
> +The device tree may optionally contain sub-nodes describing partitions of the
> +address space. See partition.txt for more detail.
> +
> +Example:
> +
> +nand@1ac00000 {
> + compatible = "qcom,ebi2-nandc";
> + reg = <0x1ac00000 0x800>;
> +
> + clocks = <&gcc EBI2_CLK>,
> + <&gcc EBI2_AON_CLK>;
> + clock-names = "core", "aon";
> +
> + dmas = <&adm_dma 3>;
> + dma-names = "rxtx";
> + qcom,cmd-crci = <15>;
> + qcom,data-crci = <3>;
> +
> + partition@0 {
> + ...
> + };
> +};
According to the registers layout defined in your driver, your NAND
controller can address multiple chips (NAND_DEV_SEL register). Since DT
bindings are supposed to be as stable as possible, I would recommend
separating the NAND controller and NAND chip declaration (as done here
[1] and here [2]).
Best Regards,
Boris
[1]http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt
[2]http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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