linux-kernel - Re: [PATCH] arm64: dts: imx8mn-var-som-symphony: fix USB OTG

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Message-Id: <20230704125541.f361cab8de3faacd830418ab@hugovil.com>
Date:   Tue, 4 Jul 2023 12:55:41 -0400
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     Fabio Estevam <festevam@...il.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Pierluigi Passaro <pierluigi.p@...iscite.com>,
        Nate Drude <nate.d@...iscite.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        NXP Linux Team <linux-imx@....com>,
        Hugo Villeneuve <hvilleneuve@...onoff.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: dts: imx8mn-var-som-symphony: fix USB OTG

On Tue, 4 Jul 2023 13:33:10 -0300
Fabio Estevam <festevam@...il.com> wrote:

> Adding some Variscite folks in case they can help to clarify.
> 
> On Tue, Jul 4, 2023 at 1:20 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@...aro.org> wrote:
> >
> > On 04/07/2023 17:31, Hugo Villeneuve wrote:
> > > On Tue, 4 Jul 2023 17:08:12 +0200
> > > Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:
> > >
> > >> On 04/07/2023 17:02, Hugo Villeneuve wrote:
> > >>> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > >>>
> > >>> USB OTG is currently broken on the Variscite Symphony EVK and imx8mn
> > >>> nano SOM.
> > >>>
> > >>> Import changes from linux-5.15 branch of  doen't giveto fix it.
> > >>>
> > >>> Link: https://github.com/varigit/linux-imx.git
> > >>> Fixes: 7358e05bddca ("arm64: dts: imx8mn-var-som-symphony: Add Variscite Symphony board with VAR-SOM-MX8MN")
> > >>> Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > >>> ---
> > >>>  .../dts/freescale/imx8mn-var-som-symphony.dts | 37 ++++++++++++++++++-
> > >>>  1 file changed, 35 insertions(+), 2 deletions(-)
> > >>>
> > >>> diff --git a/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony.dts b/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony.dts
> > >>> index 406a711486da..aef89198f24c 100644
> > >>> --- a/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony.dts
> > >>> +++ b/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony.dts
> > >>> @@ -6,6 +6,7 @@
> > >>>
> > >>>  /dts-v1/;
> > >>>
> > >>> +#include <dt-bindings/usb/pd.h>
> > >>>  #include "imx8mn-var-som.dtsi"
> > >>>
> > >>>  / {
> > >>> @@ -104,10 +105,29 @@ extcon_usbotg1: typec@3d {
> > >>>             compatible = "nxp,ptn5150";
> > >>>             reg = <0x3d>;
> > >>>             interrupt-parent = <&gpio1>;
> > >>> -           interrupts = <11 IRQ_TYPE_LEVEL_LOW>;
> > >>> +           interrupts = <11 IRQ_TYPE_NONE>;
> > >>
> > >> That's surprising, why?
> > >
> > > Hi,
> > > the varigit repos log or source code has no information about this
> > > particular configuration.
> > >
> > > In the schematics, the interrupt output pin of the PTN5150 is connected
> > > to two different resistors, one of these being connected to GPIO1 pin
> > > 11. But these two resistors are not assembled on any versions of the
> > > board, so the interrupt pin is currently not used.
> >
> > OK, so there is no interrupt, but not interrupt of type none. Just drop
> > the property and make it optional in the bindings. The driver however
> > requires the interrupt, so I wonder how the device is going to work
> > without it?
> >
> > Are you sure that interrupt line is not shorted instead of missing resistor?

Hi,
Link for schematics:
https://www.variscite.com/wp-content/uploads/2019/07/Symphony-Board-Schematics.zip

In the schematics, both resistors R106 (connected to PTN5150 on one
side and GPIO1 pin 11 on the other size) and R131 have the text "NC"
near their reference designator. And I visually confirm that R106
and R131 are not soldered on the board.

However, GPIO1 pin 11 (the interrupt pin configured in the DTS) is
also connected to PTN5150 pin 9 (ID), which has a simple pull-up to
3.3V. So from what I can see/deduce, the DTS interrupt pin
will always be 3.3V, and never pulled to GND.

Hugo.