Re: [RFC PATCH v3 1/2] dt-bindings: nand: meson: add Amlogic NAND controller driver

[Liang Yang]

Hi boric,

Thanks for your quick reply.

On 9/7/2018 8:19 PM, Boris Brezillon wrote:
> On Fri, 7 Sep 2018 18:57:10 +0800
> Jianxin Pan <jianxin.pan@xxxxxxxxxxx> wrote:
>
> > From: Liang Yang <liang.yang@xxxxxxxxxxx>
> >
> > Add Amlogic NAND controller dt-bindings for Meson SoC,
> > Current this driver support GXBB/GXL/AXG platform.
> >
> > Signed-off-by: Liang Yang <liang.yang@xxxxxxxxxxx>
> > Signed-off-by: Yixun Lan <yixun.lan@xxxxxxxxxxx>
> > ---
> >   .../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.

I find no documentation for that in other xx_nand.txt; I will consider 
to remove it.

> > +- 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.
ok, i will remove it.

> > +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.
ok, i will drop them.
we adopt auto detection during init stage, it works too.

> > +
> > +			amlogic,nand-enable-scrambler;
>
> Please drop this property (it's not longer documented).
em, we should have removed it when nfc driver never use it.

> > +
> > +			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.

ok, i will remove it.

> > +		};
> > +	};
>
> .