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: <2005735.usQuhbGJ8B@steina-w>
Date: Fri, 25 Oct 2024 16:00:33 +0200
From: Alexander Stein <alexander.stein@...tq-group.com>
To: Frank Li <Frank.Li@....com>, Geert Uytterhoeven <geert@...ux-m68k.org>
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>, "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 Geert,

Am Freitag, 25. Oktober 2024, 15:52:58 CEST schrieb Geert Uytterhoeven:
> 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.

This is true, I noticed myself. As this patch does not concern about
disable-over-current, it still is an improvement.

Unfortunately there is currently no way to fix this right now. This is a
boolean property, which is impossible to remove in overlays.

Best regards,
Alexander
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