linux-kernel - Re: [PATCH] ARM: dts: colibri-imx6ull: Enable dual-role switching

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Message-ID: <4964263.31r3eYUQgx@steina-w>
Date:   Thu, 03 Nov 2022 08:46:58 +0100
From:   Alexander Stein <alexander.stein@...tq-group.com>
To:     Philippe Schenker <philippe.schenker@...adex.com>
Cc:     Shawn Guo <shawnguo@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Fabio Estevam <festevam@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        NXP Linux Team <linux-imx@....com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Philippe Schenker <dev@...henker.ch>
Subject: Re: [PATCH] ARM: dts: colibri-imx6ull: Enable dual-role switching

Hi Philippe,

Am Mittwoch, 2. November 2022, 16:52:26 CET schrieb Philippe Schenker:
> From: Philippe Schenker <philippe.schenker@...adex.com>
> 
> The Colibri standard provides a GPIO called USBC_DET to switch from
> USB Host to USB Device and back. The Colibri iMX6ULL does have the SoC
> ball USB_OTG1_VBUS connected in series with a capacitor to ground.
> 
> This means that we need to provide to the extcon framework VBUS and ID
> events using the single GPIO we have. The Extcon USB GPIO driver does
> use id-gpio also for VBUS event, as in our case where vbus-gpio is
> absent.
> 
> Signed-off-by: Philippe Schenker <philippe.schenker@...adex.com>
> 
> ---
> 
>  arch/arm/boot/dts/imx6ull-colibri.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/imx6ull-colibri.dtsi
> b/arch/arm/boot/dts/imx6ull-colibri.dtsi index 577a424b0e1d..feb1fcd9a684
> 100644
> --- a/arch/arm/boot/dts/imx6ull-colibri.dtsi
> +++ b/arch/arm/boot/dts/imx6ull-colibri.dtsi
> @@ -24,6 +24,13 @@ backlight: backlight {
>  		status = "okay";
>  	};
> 
> +	extcon_usbc_det: usbc-det {
> +		compatible = "linux,extcon-usb-gpio";
> +		id-gpio = <&gpio5 2 GPIO_ACTIVE_HIGH>; /* SODIMM 137 / 
USBC_DET */
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_snvs_usbc_det>;
> +	};
> +
>  	gpio-keys {
>  		compatible = "gpio-keys";
>  		pinctrl-names = "default";
> @@ -275,6 +282,7 @@ &uart5 {
>  /* Colibri USBC */
>  &usbotg1 {
>  	dr_mode = "otg";
> +	extcon = <&extcon_usbc_det>, <&extcon_usbc_det>;

How came you up with this double entries? Is there some documentation you need 
two phandles?
I have a problem on imx8mm (same USB host controller) where on USB device mode 
no device is attached on host side. I fixed it by using usb-role-switch 
instead [1].
But it also works on imx8mm using extcon with two phandles instead of just 
one.

Regards,
Alexander

[1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/
20221101093031.278241-1-alexander.stein@...tq-group.com/
>  	srp-disable;
>  	hnp-disable;
>  	adp-disable;