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SubjectRe: [RFC PATCH v3 1/2] dt-bindings: nand: meson: add Amlogic NAND controller driver
On Fri, 7 Sep 2018 18:57:10 +0800
Jianxin Pan <jianxin.pan@amlogic.com> wrote:

> From: Liang Yang <liang.yang@amlogic.com>
>
> Add Amlogic NAND controller dt-bindings for Meson SoC,
> Current this driver support GXBB/GXL/AXG platform.
>
> Signed-off-by: Liang Yang <liang.yang@amlogic.com>
> Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
> ---
> .../devicetree/bindings/mtd/amlogic,meson-nand.txt | 91 ++++++++++++++++++++++
> 1 file changed, 91 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/amlogic,meson-nand.txt
>
> diff --git a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.txt b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.txt
> new file mode 100644
> index 0000000..655a778
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.txt
> @@ -0,0 +1,91 @@
> +Amlogic NAND Flash Controller (NFC) for GXBB/GXL/AXG family SoCs
> +
> +This file documents the properties in addition to those available in
> +the MTD NAND bindings.
> +
> +Required properties:
> +- compatible : contains one of:
> + - "amlogic,meson-gxl-nfc"
> + - "amlogic,meson-axg-nfc"
> +- clocks :
> + A list of phandle + clock-specifier pairs for the clocks listed
> + in clock-names.
> +
> +- clock-names: Should contain the following:
> + "core" - NFC module gate clock
> + "device" - device clock from eMMC sub clock controller
> +
> +- pins : Select pins which NFC need.
> +- nand_pins: Detail NAND pins information.

You mean pinctrl-names and pinctrl-0, right? Not sure it's necessary to
document that, but if you do, please use the correct DT prop names.

> +- amlogic,mmc-syscon : Required for NAND clocks, it's shared with SD/eMMC
> + controller port C
> +
> +Optional children nodes:
> +Children nodes represent the available nand chips.
> +
> +
> +

One too many blank lines here.

> +Other properties:
> +see Documentation/devicetree/bindings/mtd/nand.txt for generic bindings.
> +
> +Example demonstrate on AXG SoC:
> +
> + sd_emmc_c_clkc: mmc@7000 {
> + compatible = "amlogic,meson-axg-mmc-clkc", "syscon";
> + reg = <0x0 0x7000 0x0 0x800>;
> + status = "okay";
> + };
> +
> + nand: nfc@7800 {
> + compatible = "amlogic,meson-axg-nfc";
> + reg = <0x0 0x7800 0x0 0x100>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> + interrupts = <GIC_SPI 34 IRQ_TYPE_EDGE_RISING>;
> + status = "disabled";
> +
> + clocks = <&clkc CLKID_SD_EMMC_C>,
> + <&sd_emmc_c_clkc CLKID_MMC_DIV>;
> + clock-names = "core", "device";
> + amlogic,mmc-syscon = <&sd_emmc_c_clkc>;
> +
> + status = "okay";
> +
> + pinctrl-names = "default";
> + pinctrl-0 = <&nand_pins>;
> +
> + nand@0 {
> + reg = <0>;
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + nand-on-flash-bbt;
> + nand-ecc-mode = "hw";
> + nand-ecc-strength = <8>;
> + nand-ecc-step-size = <1024>;

Drop nand-ecc- props. I guess you have a sensible default value and I
prefer when ECC requirements are directly extracted during chip
detection. Defining that in the DT is a bad habit. The only one that
could make sense (assuming you support it) is nand-ecc-maximize.

> +
> + amlogic,nand-enable-scrambler;

Please drop this property (it's not longer documented).

> +
> + partition@0 {
> + label = "boot";
> + reg = <0x00000000 0x00200000>;
> + read-only;
> + };
> + partition@200000 {
> + label = "env";
> + reg = <0x00200000 0x00400000>;
> + };
> + partition@600000 {
> + label = "system";
> + reg = <0x00600000 0x00a00000>;
> + };
> + partition@1000000 {
> + label = "rootfs";
> + reg = <0x01000000 0x03000000>;
> + };
> + partition@4000000 {
> + label = "media";
> + reg = <0x04000000 0x8000000>;
> + };

No need to define the partitions in your example, especially since they
should be placed in a partitions subnode with a "fixed-partitions"
compat.

> + };
> + };

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