linux-kernel - Re: [PATCH 1/1] arm64: dts: imx8mn-tqma8mqnl-mba8mx-usbot: fix coexistence of output-low and output-high in GPIO

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Message-ID: <CAMuHMdW-tXFYSfTerb-eYmmbJHYN9xNyiGMPoeGArmDnAajUmg@mail.gmail.com>
Date: Fri, 25 Oct 2024 15:52:58 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Frank Li <Frank.Li@....com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
	Sascha Hauer <s.hauer@...gutronix.de>, Pengutronix Kernel Team <kernel@...gutronix.de>, 
	Fabio Estevam <festevam@...il.com>, Alexander Stein <alexander.stein@...tq-group.com>, 
	"open list:TQ SYSTEMS BOARD & DRIVER SUPPORT" <linux@...tq-group.com>, 
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>, 
	"open list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" <imx@...ts.linux.dev>, 
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" <linux-arm-kernel@...ts.infradead.org>, 
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] arm64: dts: imx8mn-tqma8mqnl-mba8mx-usbot: fix
 coexistence of output-low and output-high in GPIO

Hi Frank,

On Wed, Oct 23, 2024 at 11:07 PM Frank Li <Frank.Li@....com> wrote:
> Fix the issue where both 'output-low' and 'output-high' exist under GPIO
> hog nodes  (rst_usb_hub_hog and sel_usb_hub_hog) when applying device
> tree overlays. Since /delete-property/ is not supported in the overlays,
> setting 'output-low' results in both properties being present. The
> workaround is to disable these hogs and create new ones with 'output-low'
> as needed.
>
> Fix below CHECK_DTBS warning:
> arch/arm64/boot/dts/freescale/imx8mn-tqma8mqnl-mba8mx-usbotg.dtb: sel-usb-hub-hog:
>    {'output-low': True, 'gpio-hog': True, 'gpios': [[1, 0]], 'output-high': True, 'phandle': 108, '$nodename': ['sel-usb-hub-hog']}
>        is valid under each of {'required': ['output-low']}, {'required': ['output-high']
>
> Fixes: 3f6fc30abebc ("arm64: dts: imx8mn: tqma8mqnl-mba8mx: Add USB DR overlay")
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> Alex:
>         I have not hardware to run it. I check dtb output is correct.
> ---
>  .../imx8mn-tqma8mqnl-mba8mx-usbotg.dtso       | 29 +++++++++++++++++--
>  1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mn-tqma8mqnl-mba8mx-usbotg.dtso b/arch/arm64/boot/dts/freescale/imx8mn-tqma8mqnl-mba8mx-usbotg.dtso
> index 96db07fc9bece..1f2a0fe70a0a2 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mn-tqma8mqnl-mba8mx-usbotg.dtso
> +++ b/arch/arm64/boot/dts/freescale/imx8mn-tqma8mqnl-mba8mx-usbotg.dtso
> @@ -29,12 +29,37 @@ usb_dr_connector: endpoint {
>         };
>  };
>
> +/*
> + * rst_usb_hub_hog and sel_usb_hub_hog have property 'output-high',
> + * dt overlay don't support /delete-property/. Both 'output-low' and
> + * 'output-high' will be exist under hog nodes if overlay file set
> + * 'output-low'. Workaround is disable these hog and create new hog with
> + * 'output-low'.
> + */
> +
>  &rst_usb_hub_hog {
> -       output-low;
> +       status = "disabled";
> +};
> +
> +&expander0 {
> +       rst-usb-low-hub-hog {
> +               gpio-hog;
> +               gpios = <13 0>;
> +               output-low;
> +               line-name = "RST_USB_HUB#";
> +       };
>  };
>
>  &sel_usb_hub_hog {
> -       output-low;
> +       status = "disabled";
> +};
> +
> +&gpio2 {
> +       sel-usb-low-hub-hog {
> +               gpio-hog;
> +               gpios = <1 GPIO_ACTIVE_HIGH>;
> +               output-low;
> +       };
>  };
>
>  &usbotg1 {

Note that after this, there is still

    /delete-property/ disable-over-current;

left, which does not actually remove the property.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds