[PATCH v3 1/1] arm64: dts: tqma8mpql: add USB DR support

[Jun Li]

> -----Original Message-----
> From: Tim Harvey <tharvey at gateworks.com>
> Sent: Tuesday, October 18, 2022 3:31 AM
> To: Ahmad Fatoum <a.fatoum at pengutronix.de>
> Cc: Alexander Stein <alexander.stein at ew.tq-group.com>; Shawn Guo
> <shawnguo at kernel.org>; Sascha Hauer <s.hauer at pengutronix.de>;
> devicetree at vger.kernel.org; dl-linux-imx <linux-imx at nxp.com>; Pengutronix
> Kernel Team <kernel at pengutronix.de>; Fabio Estevam <festevam at gmail.com>;
> linux-arm-kernel at lists.infradead.org; Jun Li <jun.li at nxp.com>
> Subject: Re: [PATCH v3 1/1] arm64: dts: tqma8mpql: add USB DR support
> 
> On Fri, Oct 14, 2022 at 7:18 AM Ahmad Fatoum <a.fatoum at pengutronix.de> wrote:
> >
> > Hello Alexander,
> >
> > On 05.09.22 09:37, Alexander Stein wrote:
> > > +     pinctrl_usb0: usb0grp {
> > > +             fsl,pins = <MX8MP_IOMUXC_GPIO1_IO13__USB1_OTG_OC
> 0x1c0>,
> > > +                        <MX8MP_IOMUXC_GPIO1_IO12__USB1_OTG_PWR
> 0x1c0>;
> > > +     };
> > > +
> > > +     pinctrl_usbcon0: usb0congrp {
> > > +             fsl,pins = <MX8MP_IOMUXC_GPIO1_IO10__GPIO1_IO10
> 0x1c0>;
> > > +     };
> >
> > I am wondering: You can mux for MX8MP_IOMUXC_GPIO1_IO10__USB1_OTG_ID,
> > why did you decide against using the hardware function here?
> >
> 
> Ahmad,
> 
> The IMX8MP USB OTG_ID pins are internally not connected. I can't recall where
> this is mentioned but due to this they can not be used to select host/device
> mode.

There is no *OTG* block in iMX8MP HW due to dwc3 IP upgrade, the OTG ID pin
cannot generate a normal USB irq for host/device selection, instead, we can
use GPIO function to generate ID state change event for it, this is well
supported via usb-conn-gpio.c like this patch is using.

Li Jun
  
> 
> Best Regards,
> 
> Tim