Re: [PATCH V3 8/8] ARM: dts: sunxi: add support for Anbernic RG-Nano

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

On Wed, 23 Aug 2023 16:25:54 -0500
Chris Morgan <macroalpha82@gmail.com> wrote:

Hi,

> 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.
> 
> Working/Tested:
> - SDMMC
> - UART (for debugging)
> - Buttons
> - Charging/battery/PMIC
> - Speaker
> - USB Host and Gadget
> - Display (at 60hz)

So this works now purely in software, by the panel driver constantly
scanning out a framebuffer region via SPI?
I wonder if enabling DMA support for SPI then helps the CPU load?
Though this might be a performance optimisation in a later patch set
(as it requires adding support for the V3s DMA controller).

> 
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> ---
>  arch/arm/boot/dts/allwinner/Makefile          |   1 +
>  .../allwinner/sun8i-v3s-anbernic-rg-nano.dts  | 275 ++++++++++++++++++
>  2 files changed, 276 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..c2866a884f0e
> --- /dev/null
> +++ b/arch/arm/boot/dts/allwinner/sun8i-v3s-anbernic-rg-nano.dts
> @@ -0,0 +1,275 @@
> +// 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";
> +		brightness-levels = <0 1 2 3 8 14 21 32 46 60 80 100>;
> +		default-brightness-level = <11>;
> +		power-supply = <&reg_vcc5v0>;
> +		pwms = <&pwm 0 40000 1>;
> +	};
> +
> +	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)>;

Can you please specify the pin number (PF6) as a comment here, as done
in the other DTs? Because reading this "5 6" is not very intuitive.
Same for the other &pio GPIO references.

> +	status = "okay";
> +};
> +
> +&ehci {
> +	status = "okay";
> +};
> +
> +&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"
> +
> +/* Out of alphabetical order for dependencies sake. */

I think you don't need this comment here.

> +&battery_power_supply {
> +	status = "okay";
> +};
> +
> +&mmc0 {
> +	broken-cd;
> +	bus-width = <4>;
> +	disable-wp;
> +	vmmc-supply = <&reg_vcc3v3>;
> +	vqmmc-supply = <&reg_vcc3v3>;
> +	status = "okay";
> +};
> +
> +&ohci {
> +	status = "okay";
> +};
> +
> +&pio {
> +	vcc-pb-supply = <&reg_vcc3v3>;
> +	vcc-pc-supply = <&reg_vcc3v3>;
> +	vcc-pf-supply = <&reg_vcc3v3>;
> +	vcc-pg-supply = <&reg_vcc3v3>;
> +
> +	spi0_3wire_pins: spi0-3wire-pins {
> +		pins = "PC1", "PC2", "PC3";

Huh, interesting, is that because the display chip is purely
unidirectional? In any case, can you add a comment saying what's going
on, I guess: "MISO is not connected"?
And I wonder if "3 wire mode" is somewhat misleading here, since this
seems to refer to bidirectional SPI over a combined MISO/MOSI line, and
requires explicit controller support? Which the Allwinner controllers
lack?
I think for the node and alias name that's fine, but a comment would
clear things up.

The rest looks fine, though we would still need to fix the USB PHY
issue.

Cheers,
Andre

> +		function = "spi0";
> +	};
> +};
> +
> +&pwm {
> +	pinctrl-0 = <&pwm0_pin>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +};
> +
> +/* DCDC2 wired into vdd-cpu, vdd-sys, and vdd-ephy. */
> +&reg_dcdc2 {
> +	regulator-always-on;
> +	regulator-max-microvolt = <1250000>;
> +	regulator-min-microvolt = <1250000>;
> +	regulator-name = "vdd-cpu";
> +};
> +
> +/* DCDC3 wired into every 3.3v input that isn't the RTC. */
> +&reg_dcdc3 {
> +	regulator-always-on;
> +	regulator-max-microvolt = <3300000>;
> +	regulator-min-microvolt = <3300000>;
> +	regulator-name = "vcc-io";
> +};
> +
> +/*
> + * LDO1 wired into RTC, voltage is hard-wired at 3.3v and cannot be
> + * software modified. Note that setting voltage here to 3.3v for accuracy
> + * sake causes an issue with the driver that causes it to fail to probe
> + * because of a voltage constraint in the driver.
> + */
> +&reg_ldo1 {
> +	regulator-always-on;
> +	regulator-name = "vcc-rtc";
> +};
> +
> +/* LDO2 wired into VCC-PLL and audio codec. */
> +&reg_ldo2 {
> +	regulator-always-on;
> +	regulator-max-microvolt = <3000000>;
> +	regulator-min-microvolt = <3000000>;
> +	regulator-name = "vcc-pll";
> +};
> +
> +/* LDO3, LDO4, and LDO5 unused. */
> +&reg_ldo3 {
> +	status = "disabled";
> +};
> +
> +&reg_ldo4 {
> +	status = "disabled";
> +};
> +
> +&spi0 {
> +	pinctrl-0 = <&spi0_3wire_pins>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +
> +	display@0 {
> +		compatible = "saef,sftc154b", "panel-mipi-dbi-spi";
> +		reg = <0>;
> +		backlight = <&backlight>;
> +		dc-gpios = <&pio 2 0 GPIO_ACTIVE_HIGH>;
> +		reset-gpios = <&pio 1 2 GPIO_ACTIVE_HIGH>;
> +		spi-max-frequency = <100000000>;
> +
> +		height-mm = <39>;
> +		width-mm = <39>;
> +
> +		/* Set hb-porch to compensate for non-visible area */
> +		panel-timing {
> +			hactive = <240>;
> +			vactive = <240>;
> +			hback-porch = <80>;
> +			vback-porch = <0>;
> +			clock-frequency = <0>;
> +			hfront-porch = <0>;
> +			hsync-len = <0>;
> +			vfront-porch = <0>;
> +			vsync-len = <0>;
> +		};
> +	};
> +};
> +
> +&uart0 {
> +	pinctrl-0 = <&uart0_pb_pins>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +};
> +
> +&usb_otg {
> +	dr_mode = "otg";
> +	status = "okay";
> +};
> +
> +&usb_power_supply {
> +	status = "okay";
> +};
> +
> +&usbphy {
> +	usb0_id_det-gpios = <&pio 6 5 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +	status = "okay";
> +};