Jun, as we discussed before, any conclusion on how to handle the USB OTG ID pin in RM?
BR
Jacky Bai
> Subject: imx8mp USB OTG/dual-role
>
> Greetings,
>
> I have an imx8mp board (imx8mp-venice-gw74xx) which has a DWC3 USB
> host controller using imx8mp PHY
> (drivers/phy/freescale/phy-fsl-imx8mq-usb.c fsl,imx8mp-usb-phy) and
> DWC3 host controller core (drivers/usb/dwc3/core.c snps,dwc3) with imx8mp
> glue (drivers/usb/dwc3/dwc3-imx8mp.c fsl,imx8mp-dwc3).
>
> One of the 2x USB 3.0 hosts is connected to a USB Type C connector using a
> TPS25821 USB power switch and config controller which handles the CC pins
> on and VBUS enable as well as drives the mux sel pin of a
> USB3 mux to route the USB SS pairs to the appropriate half of the Type C
> connector. This device has no I2C or other management bus - only VBUS,
> FAULT#, SINK#, and POL# outputs based on CC pins.
>
> I'm not clear how to describe this in the device-tree in order for it to function
> as a dual-role controller for host vs device mode.
>
> The TPS25821 has a FAULT# signal that routes to IMX8MP GPIO1_IO13
> pinmuxed as MX8MP_IOMUXC_GPIO1_IO13__USB1_OTG_OC and a SINK#
> signal that routes to IMX8MP GPIO1_IO10 pinmuxed as
> MX8MP_IOMUXC_GPIO1_IO10__USB1_OTG_ID. Additionally the VBUS
> output of the TPS25821 also connected to the TypeC VBUS pin routes to the
> IMX8MP USB1_VBUS pin.
>
> I've noticed there are currently only 2 other IMX8MP boards in Linux mainline
> that specify dr_mode="otg"; the DH electronics i.MX8M Plus DHCOM SOM
> (imx8mp-dhcom-som.dtsi), and the Toradex i.MX8M Plus Verdin SOM
> (imx8mp-verdin.dtsi). I'm not clear how these are hooked up or if USB
> dual-role work on these currently. I did notice that imx8mp-verdin.dtsi looks
> like it does not enable the phy or core via status prop and uses invalid
> 'over-current-active-low' and 'disable-over-current' dt props.
>
> I am currently using the following with imx8mp-venice-gw74xx:
>
> /* USB1 - Type C front panel */
> &usb3_phy0 {
> status = "okay";
> };
>
> /* USB1 dwc3 glue */
> &usb3_0 {
> fsl,over-current-active-low;
> status = "okay";
> };
>
> /* USB1 dwc3 core */
> &usb_dwc3_0 {
> pinctrl-names = "default";
> pinctrl-0 = <&pinctrl_usb1>;
> dr_mode = "otg";
> };
>
> &iomuxc {
> pinctrl_usb1: usb1grp {
> fsl,pins = <
>
> MX8MP_IOMUXC_GPIO1_IO13__USB1_OTG_OC 0x140
>
> MX8MP_IOMUXC_GPIO1_IO10__USB1_OTG_ID 0x140
> >;
> };
> };
>
> And currently v6.0-rc2 enumerates the host controller even without a Type-C
> to host cable attached which tells me that OTG_ID isn't doing its job. I vaguely
> recall some confusing statements on the IMX community forum that these
> pins might not even be used on the IMX8MP.
>
> How should I be describing the device-tree for this scenario in order to get
> dual-role behavior?
>
> Best Regards,
>
> Tim
