[PATCH] arm: dts: nes: add Nintendo NES Classic Edition support

[Maxime Ripard]

Hi Miquel,

On Wed, Mar 07, 2018 at 05:43:36PM +0100, Miquel Raynal wrote:
> The Nintendo NES Classic features an R16 already well supported in
> mainline.
> 
> The console over UART0 may be wired on two ports of the R16, both
> available on the NES Classic PCB.
> 
> USB host can be used after a bit of soldering to wire a 5V power supply
> directly on the PCB, in order to free the micro-USB port from that task
> and allow the plug of any USB device.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---
>  arch/arm/boot/dts/Makefile                         |  1 +
>  arch/arm/boot/dts/sun8i-a23-a33.dtsi               | 18 ++++++
>  .../dts/sun8i-r16-nintendo-nes-classic-edition.dts | 71 ++++++++++++++++++++++
>  3 files changed, 90 insertions(+)
>  create mode 100644 arch/arm/boot/dts/sun8i-r16-nintendo-nes-classic-edition.dts
> 
> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
> index ade7a38543dc..eed4e1222897 100644
> --- a/arch/arm/boot/dts/Makefile
> +++ b/arch/arm/boot/dts/Makefile
> @@ -990,6 +990,7 @@ dtb-$(CONFIG_MACH_SUN8I) += \
>  	sun8i-h3-orangepi-plus.dtb \
>  	sun8i-h3-orangepi-plus2e.dtb \
>  	sun8i-r16-bananapi-m2m.dtb \
> +	sun8i-r16-nintendo-nes-classic-edition.dtb \
>  	sun8i-r16-parrot.dtb \
>  	sun8i-r40-bananapi-m2-ultra.dtb \
>  	sun8i-v3s-licheepi-zero.dtb \
> diff --git a/arch/arm/boot/dts/sun8i-a23-a33.dtsi b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
> index 971f9be699a7..1ad7291581be 100644
> --- a/arch/arm/boot/dts/sun8i-a23-a33.dtsi
> +++ b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
> @@ -315,6 +315,24 @@
>  				bias-pull-up;
>  			};
>  
> +			nand_pins_a: nand-base0 at 0 {
> +				pins = "PC0", "PC1", "PC2",
> +				       "PC5", "PC8", "PC9", "PC10",
> +				       "PC11", "PC12", "PC13", "PC14",
> +				       "PC15";
> +				function = "nand0";
> +			};
> +
> +			nand_cs0_pins_a: nand-cs at 0 {
> +				pins = "PC4";
> +				function = "nand0";
> +			};
> +
> +			nand_rb0_pins_a: nand-rb at 0 {
> +				pins = "PC6";
> +				function = "nand0";
> +			};
> +

This should be in a separate patch.

Also, these will generate dtc warnings.

If there is multiple muxing options, I'd suggest to have the node
names be nand-pc-pins, and the label nand_pc_pins. If there's only
one, you can drop the pc part.

>  			pwm0_pins: pwm0 {
>  				pins = "PH0";
>  				function = "pwm0";
> diff --git a/arch/arm/boot/dts/sun8i-r16-nintendo-nes-classic-edition.dts b/arch/arm/boot/dts/sun8i-r16-nintendo-nes-classic-edition.dts
> new file mode 100644
> index 000000000000..63c289f1f46d
> --- /dev/null
> +++ b/arch/arm/boot/dts/sun8i-r16-nintendo-nes-classic-edition.dts
> @@ -0,0 +1,71 @@
> +// SPDX-License-Identifier: GPL-2.0 OR X11
> +/* Copyright (c) 2016 FUKAUMI Naoki <naobsd at gmail.com> */
> +
> +/dts-v1/;
> +#include "sun8i-a33.dtsi"
> +#include "sunxi-common-regulators.dtsi"
> +
> +/ {
> +	model = "Nintendo NES Classic Edition";
> +	compatible = "nintendo,nes-classic-edition", "allwinner,sun8i-a33";
> +
> +	aliases {
> +		serial0 = &uart0;
> +	};
> +
> +	chosen {
> +		stdout-path = "serial0:115200n8";
> +	};
> +};
> +
> +&uart0 {
> +	/*
> +	 * UART0 is available on two ports, both accessible on the NES Classic
> +	 * PCB. One can use the <&uart0_pins_b> handle instead.
> +	 */

I guess you should mention that the PF pins will also rule out the SD
option that might be convenient.

> +	pinctrl-names = "default";
> +	pinctrl-0 = <&uart0_pins_a>;
> +	status = "okay";
> +};
> +
> +&nfc {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&nand_pins_a &nand_cs0_pins_a &nand_rb0_pins_a>;
> +	status = "okay";
> +
> +	/* 2Gb Macronix MX30LF2G18AC (3V) */
> +	nand at 0 {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		reg = <0>;
> +		allwinner,rb = <0>;
> +		nand-ecc-mode = "hw";
> +		nand-ecc-strength = <16>;
> +		nand-ecc-step-size = <1024>;
> +	};
> +};
> +
> +/*
> + * The NES is powered by the USB port. However it is possible to solder a wire
> + * from the internal side of the connector on VBUS pin to supply the required 5V
> + * without the need of a cable plugged in the micro USB port. This way it is
> + * easy to use any USB device.
> + */
> +&usb_otg {
> +	dr_mode = "host";
> +	status = "okay";
> +};

We want to support the default setup, and not require some hackery to
be done. It will thus be some OTG / peripheral mode, most likely with
an ID pin somewhere.

Since you tested on a SuperNES Classic, I think you should also create
a new DT (possibly include it) with a compatible of its own.

That way, if we ever find some differences, it will be easy to deal
with them.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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