Re: [PATCH] arm64: dts: imx8mq-nitrogen: add USB support

[Gary Bisson <gary.bisson@boundarydevices.com>]

Hi Adrien,

Thanks for improving Nitrogen upstream, much appreciated.

On Tue, Jan 26, 2021 at 10:55:11PM +0100, Adrien Grassein wrote:
> add USB support for imx8mq-nitrogen. It consists
> in 2 phys: OTG and host.
> 
> The OTG port uses a dedicated regulator for vbus.
> 
> Signed-off-by: Adrien Grassein <adrien.grassein@gmail.com>
> ---
>  .../boot/dts/freescale/imx8mq-nitrogen.dts    | 36 +++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mq-nitrogen.dts b/arch/arm64/boot/dts/freescale/imx8mq-nitrogen.dts
> index 81d269296610..fb8acd83a280 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mq-nitrogen.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mq-nitrogen.dts
> @@ -34,6 +34,17 @@ power {
>  		};
>  	};
>  
> +	reg_usb_otg_vbus: regulator-usb-otg-vbus {
> +		compatible = "regulator-fixed";
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_reg_usbotg_vbus>;
> +		regulator-name = "usb_otg_vbus";
> +		regulator-min-microvolt = <5000000>;
> +		regulator-max-microvolt = <5000000>;
> +		gpio = <&gpio1 12 GPIO_ACTIVE_HIGH>;
> +		enable-active-high;
> +	};
> +
>  	reg_vref_0v9: regulator-vref-0v9 {
>  		compatible = "regulator-fixed";
>  		regulator-name = "vref-0v9";
> @@ -190,6 +201,25 @@ &uart2 {
>  	status = "okay";
>  };
>  
> +&usb_dwc3_0 {
> +	dr_mode = "otg";
> +	status = "okay";

Please add a pinctrl here to mux GPIO1_IO13 as over current pin.
But I confirm the port is working.

> +};
> +
> +&usb3_phy0 {
> +	vbus-supply = <&reg_usb_otg_vbus>;
> +	status = "okay";
> +};
> +
> +&usb_dwc3_1 {
> +	dr_mode = "host";
> +	status = "okay";
> +};

The Host port doesn't work for me. This is because of the missing reset
signal. Maybe it's time to revive the gpio-reset driver [1]?

Anyway, here is how to fix the USB Host ports:
# gpioset 0 14=1

I guess it'd be best to have a proper reset solution before merging the
host port addition.

Regards,
Gary

[1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/1374834384-8071-1-git-send-email-p.zabel@pengutronix.de/