Re: [PATCH V2 4/4] ARM: dts: sunxi: add support for Anbernic RG-Nano

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 18 Aug 2023 22:21:05 -0500
Chris Morgan <macroalpha82@gmail.com> wrote:

Hi Chris,

thanks for the update!

> From: Chris Morgan <macromorgan@hotmail.com>
> 
> The Anbernic RG-Nano is a small portable game device based on the
> Allwinner V3s SoC. It has GPIO buttons on the face and side for
> input, a single mono speaker, a 240x240 SPI controlled display, a USB-C
> OTG port, an SD card slot for booting, and 64MB of RAM included in the
> SoC.
> 
> The SPI display is currently unsupported, as it will either require
> a new tinydrm driver or changes to the staging fbtft driver to support.
> I plan on working on a tinydrm driver to properly support it. The USB-C
> port currently only works as a peripheral port, however in the BSP
> kernel it also works in host mode allowing included USB-C headphones
> with a built-in DAC to work.
> 
> Working:
> - SDMMC
> - UART (for debugging)
> - Buttons
> - Charging/battery/PMIC
> - Speaker
> - USB Gadget
> 
> Not working:
> - Display
> - USB Host
> 
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> ---
>  arch/arm/boot/dts/allwinner/Makefile          |   1 +
>  .../allwinner/sun8i-v3s-anbernic-rg-nano.dts  | 219 ++++++++++++++++++
>  2 files changed, 220 insertions(+)
>  create mode 100644 arch/arm/boot/dts/allwinner/sun8i-v3s-anbernic-rg-nano.dts
> 
> diff --git a/arch/arm/boot/dts/allwinner/Makefile b/arch/arm/boot/dts/allwinner/Makefile
> index 589a1ce1120a..2be83a1edcbb 100644
> --- a/arch/arm/boot/dts/allwinner/Makefile
> +++ b/arch/arm/boot/dts/allwinner/Makefile
> @@ -237,6 +237,7 @@ dtb-$(CONFIG_MACH_SUN8I) += \
>  	sun8i-t113s-mangopi-mq-r-t113.dtb \
>  	sun8i-t3-cqa3t-bv3.dtb \
>  	sun8i-v3-sl631-imx179.dtb \
> +	sun8i-v3s-anbernic-rg-nano.dtb \
>  	sun8i-v3s-licheepi-zero.dtb \
>  	sun8i-v3s-licheepi-zero-dock.dtb \
>  	sun8i-v40-bananapi-m2-berry.dtb
> diff --git a/arch/arm/boot/dts/allwinner/sun8i-v3s-anbernic-rg-nano.dts b/arch/arm/boot/dts/allwinner/sun8i-v3s-anbernic-rg-nano.dts
> new file mode 100644
> index 000000000000..c49b5431d04e
> --- /dev/null
> +++ b/arch/arm/boot/dts/allwinner/sun8i-v3s-anbernic-rg-nano.dts
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +
> +/dts-v1/;
> +#include <dt-bindings/input/linux-event-codes.h>
> +#include "sun8i-v3s.dtsi"
> +#include "sunxi-common-regulators.dtsi"
> +
> +/ {
> +	model = "Anbernic RG Nano";
> +	compatible = "anbernic,rg-nano", "allwinner,sun8i-v3s";
> +
> +	aliases {
> +		serial0 = &uart0;
> +	};
> +
> +	backlight: backlight {
> +		compatible = "pwm-backlight";
> +		pwms = <&pwm 0 40000 1>;
> +		brightness-levels = <0 1 2 3 8 14 21 32 46 60 80 100>;
> +		default-brightness-level = <11>;
> +		power-supply = <&reg_vcc5v0>;
> +	};
> +
> +	chosen {
> +		stdout-path = "serial0:115200n8";
> +	};
> +
> +	gpio_keys: gpio-keys {
> +		compatible = "gpio-keys";
> +
> +		button-a {
> +			gpios = <&gpio_expander 12 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-A";
> +			linux,code = <BTN_EAST>;
> +		};
> +
> +		button-b {
> +			gpios = <&gpio_expander 14 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-B";
> +			linux,code = <BTN_SOUTH>;
> +		};
> +
> +		button-down {
> +			gpios = <&gpio_expander 1 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "DPAD-DOWN";
> +			linux,code = <BTN_DPAD_DOWN>;
> +		};
> +
> +		button-left {
> +			gpios = <&gpio_expander 4 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "DPAD-LEFT";
> +			linux,code = <BTN_DPAD_LEFT>;
> +		};
> +
> +		button-right {
> +			gpios = <&gpio_expander 0 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "DPAD-RIGHT";
> +			linux,code = <BTN_DPAD_RIGHT>;
> +		};
> +
> +		button-se {
> +			gpios = <&gpio_expander 7 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-SELECT";
> +			linux,code = <BTN_SELECT>;
> +		};
> +
> +		button-st {
> +			gpios = <&gpio_expander 6 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-START";
> +			linux,code = <BTN_START>;
> +		};
> +
> +		button-tl {
> +			gpios = <&gpio_expander 2 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-L";
> +			linux,code = <BTN_TL>;
> +		};
> +
> +		button-tr {
> +			gpios = <&gpio_expander 15 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-R";
> +			linux,code = <BTN_TR>;
> +		};
> +
> +		button-up {
> +			gpios = <&gpio_expander 3 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "DPAD-UP";
> +			linux,code = <BTN_DPAD_UP>;
> +		};
> +
> +		button-x {
> +			gpios = <&gpio_expander 11 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-X";
> +			linux,code = <BTN_NORTH>;
> +		};
> +
> +		button-y {
> +			gpios = <&gpio_expander 13 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +			label = "BTN-Y";
> +			linux,code = <BTN_WEST>;
> +		};
> +	};
> +};
> +
> +&codec {
> +	allwinner,audio-routing = "Speaker", "HP",
> +				  "MIC1", "Mic",
> +				  "Mic", "HBIAS";
> +	allwinner,pa-gpios = <&pio 5 6 (GPIO_ACTIVE_HIGH | GPIO_PULL_UP)>;
> +	status = "okay";
> +};
> +
> +&cpu0 {
> +	clock-frequency = <1296000>;

I understand that the kernel complains when this is missing, but I
think this property is some ancient legacy, as there is no such thing
as a fixed CPU frequency anymore. That becomes evident with the OPPs
below. So please remove it.

> +	clock-latency = <244144>;
> +	operating-points = <
> +			/* kHz    uV */
> +			1296000 1200000
> +			1008000 1200000
> +			864000  1200000
> +			720000  1100000
> +			480000  1000000>;

Don't you need a cpu-supply property to point to the regulator in
charge of providing the core voltage? Otherwise I don't see how the
kernel would be able to adjust the voltage, to program the OPPs.

> +};
> +
> +&i2c0 {
> +	status = "okay";
> +
> +	gpio_expander: gpio@20 {
> +		compatible = "nxp,pcal6416";
> +		reg = <0x20>;
> +		gpio-controller;
> +		#gpio-cells = <2>;
> +		#interrupt-cells = <2>;
> +		interrupt-controller;
> +		interrupt-parent = <&pio>;
> +		interrupts = <1 3 IRQ_TYPE_EDGE_BOTH>;
> +		vcc-supply = <&reg_vcc3v3>;
> +	};
> +
> +	axp209: pmic@34 {
> +		reg = <0x34>;
> +		interrupt-parent = <&pio>;
> +		interrupts = <1 5 IRQ_TYPE_EDGE_FALLING>;
> +	};
> +
> +	pcf8563: rtc@51 {
> +		compatible = "nxp,pcf8563";
> +		reg = <0x51>;
> +	};
> +};
> +
> +#include "axp209.dtsi"
> +
> +&battery_power_supply {
> +	status = "okay";
> +};
> +
> +&mmc0 {
> +	broken-cd;
> +	bus-width = <4>;
> +	disable-wp;
> +	vmmc-supply = <&reg_vcc3v3>;
> +	vqmmc-supply = <&reg_vcc3v3>;
> +	status = "okay";
> +};
> +
> +&pio {
> +	vcc-pb-supply = <&reg_vcc3v3>;
> +	vcc-pc-supply = <&reg_vcc3v3>;
> +	vcc-pf-supply = <&reg_vcc3v3>;
> +	vcc-pg-supply = <&reg_vcc3v3>;
> +};
> +
> +&pwm {
> +	pinctrl-0 = <&pwm0_pins>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +};
> +
> +&reg_dcdc2 {

Any reason your dropped the regulator-name property? This would help to
identify what this regulator is used for and would explain why it needs
to be always on.
In v1 this was "vdd-cpu-sys-ephy", are you sure about this name? I
guess it supplies the CPU, but I wonder if there are other users of
this rail, which would possibly throw a spanner into DVFS. So what's the
"ephy" doing here? And can you adjust the voltage, if this also driving
VDD-SYS? What does the BSP kernel do?

> +	regulator-always-on;
> +	regulator-max-microvolt = <1250000>;
> +	regulator-min-microvolt = <1250000>;
> +};
> +
> +&reg_dcdc3 {

Same here, please provide a speaking name, or a comment explaining
why this must be always on. There is no need to enumerate every user,
just "vdd-3v3" seems to be a common name for that regulator.

> +	regulator-always-on;
> +	regulator-max-microvolt = <3300000>;
> +	regulator-min-microvolt = <3300000>;
> +};
> +
> +&reg_ldo2 {

Same here, name or comment, please.

> +	regulator-always-on;
> +	regulator-max-microvolt = <3000000>;
> +	regulator-min-microvolt = <3000000>;
> +};
> +
> +&spi0 {

Can you add a comment here mentioning the not-yet-supported display?
And you should specify the pins used here.

Cheers,
Andre


> +	status = "okay";
> +};
> +
> +&uart0 {
> +	pinctrl-0 = <&uart0_pb_pins>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +};
> +
> +&usb_otg {
> +	dr_mode = "otg";
> +	status = "okay";
> +};
> +
> +&usb_power_supply {
> +	status = "okay";
> +};
> +
> +&usbphy {
> +	status = "okay";
> +};