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

[miquel.raynal@bootlin.com (Miquel Raynal)]

Hi Maxime,

On Fri, 9 Mar 2018 09:26:56 +0100, Maxime Ripard
<maxime.ripard@bootlin.com> wrote:

> 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@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";

I will change a bit the visual organization.

> > +				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.

Ok.

> 
> Also, these will generate dtc warnings.

I will remove the trailing @0.

> 
> 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.

There is only one, I will name it nand_pins: nand-pins.

For CS and RB pins, there are two of them each time, I will declare
them all:
nand_pins_cs0 PC4
nand_pins_cs1 PC3
nand_pins_rb0 PC6
nand_pins_rb1 PC7

> 
> >  			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@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.

Sure. I will add that port PB and PF can both mux UART0, but PF can
also be used for the SD card, so PB is preferred (
> 
> > +	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>;

I'll move this in the DTSI also.

> > +	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.

So, what you would prefer is:
1/ Move this entire DTS but the usb_otg node into a
"sun8i-r16-nintendo-nes.dtsi"
2/ Include that DTSI from a
"sun8i-r16-nintendo-super-nes-classic-edition.dts" that would add the
usb_otg node as it is above.

Right?

Thanks,
Miqu?l

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