Re: [PATCH v1 2/3] arm64: dts: rockchip: rk3588-rock-5b-5bp-5t: Fix USB host phy-supply on Rock 5b-5bp-5t SbC

Anand Moon
2026-01-08T06:55:32Z

Hi Sebastian,

Thanks for your review comments.
On Sat, 3 Jan 2026 at 19:35, Sebastian Reichel
<sebastian.reichel@collabora.com> wrote:
>
> Hi,
>
> On Sat, Jan 03, 2026 at 02:01:18PM +0530, Anand Moon wrote:
> > The USB host USB2 and USB3 on the Rock 5B, 5BP, and 5T is powered by the
> > USB_HOST_PWREN_H gpio pin which is used to enable vcc5v0_host host
> > regulator which ensures proper power sequencing and management for onboard
> > Double-USB-HOST.
> >
> > Update the u2phy2_host node to reference the correct phy-supply.
> >
> > Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
> > Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> > ---
>
> u2phy2_host is connected to an onboard USB hub chip, which is
> powered by &vcc5v0_sys as the comment says.
>
> You can see this on page 9 of the v1.45 ROCK 5B schematics (page
> name USB2HUB). The usb hub chip uses VCC5V0_SYS + VCC_3V3_S0 and is
> connected to USB20_HOST0_DP, USB20_HOST0_DM. The related USB
> controller for that in the upstream DT is &usb_host0_ehci, which
> in turn is using &u2phy2_host. Thus at least for the ROCK 5B the
> existing DT is correct. Properly describing the downstream port
> VBUS regulator would require something like the following series:
>
> https://lore.kernel.org/all/20250911-v6-16-topic-usb-onboard-dev-v4-0-1af288125d74@pengutronix.de/
>
Actually, the Radxa Rock 5 B doesn't have an onboard USB hub chip.

The USB_HOST_PWREN_H GPIO pin acts as the enable signal for both
5V_USB1 and 5V_USB2 regulators.

Data signals from the USB 2.0 Host 1 interface (USB20_HOST1_DM/DP)
are routed through the CON20B chip to the Type-C controller's
TYPEC1_OTG_DM/DP pins.
Additionally, the schematic indicates that the Type-C controller's
power delivery is managed
by the USB2 host (5V_USB2) rail.

From the schematic, I could see that the Type-C controller is controlled
by USB1 host (5V_USB1) and USB2 host (5V_USB2) for power delivery.

[1] https://dl.radxa.com/rock5/5b/docs/hw/radxa_rock_5b_v1450_schematic.pdf
(page 27)

> Greetings,
>
> -- Sebastian
>
Thanks
-Anand