Re: [PATCH] dt-bindings: misc: add schema for USB hub on Kirin devices
From: Rob Herring
Date: Fri Aug 13 2021 - 14:52:52 EST
On Thu, Aug 05, 2021 at 12:31:00PM +0200, Mauro Carvalho Chehab wrote:
> From: Yu Chen <chenyu56@xxxxxxxxxx>
>
> This patch adds binding documentation to support USB HUB and
> USB data role switch of HiSilicon HiKey960 and HiKey970 boards.
Like PCIe, there's a standard way to describe USB devices in DT. Though
PCI is easy compared to USB. :(
Also like PCIe on Hikey, I'm less than thrilled to define how this
should look for a board that's generally not widely available or well
supported.
>
> [mchehab: updated OF names and added support for HiKey970]
> Signed-off-by: Yu Chen <chenyu56@xxxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
> ---
> .../bindings/misc/hisilicon,hikey-usb.yaml | 95 +++++++++++++++++++
> 1 file changed, 95 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/misc/hisilicon,hikey-usb.yaml
>
> diff --git a/Documentation/devicetree/bindings/misc/hisilicon,hikey-usb.yaml b/Documentation/devicetree/bindings/misc/hisilicon,hikey-usb.yaml
> new file mode 100644
> index 000000000000..857f9bd802fe
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/hisilicon,hikey-usb.yaml
> @@ -0,0 +1,95 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2019 Linaro Ltd.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/misc/hisilicon,hikey-usb.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: HiKey960/970 onboard USB GPIO Hub
> +
> +maintainers:
> + - John Stultz <john.stultz@xxxxxxxxxx>
> +
> +description: |
> + Supports the onboard USB GPIO hub found on HiKey960/970.
> + The HUB, which acts as a role-switch intermediary to detect the state of
> + the USB-C port, to switch the hub into dual-role USB-C or host mode,
> + which enables the onboard USB-A host ports.
> +
> + Schematics about the hub can be found here:
> + https://github.com/96boards/documentation/raw/master/consumer/hikey/hikey960/hardware-docs/HiKey960_Schematics.pdf
> + https://www.96boards.org/documentation/consumer/hikey/hikey970/hardware-docs/files/hikey970-schematics.pdf
> +
> +properties:
> + compatible:
> + enum:
> + - hisilicon,gpio_hubv1
> + - hisilicon,kirin970_hikey_usbhub
s/_/-/
Why is one compatible pretty generic and the other very specific?
> +
> + typec-vbus:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + description: phandle to the typec-vbus gpio
If a GPIO, why is it not using a GPIO DT property?
> +
> + otg-switch:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + description: phandle to the otg-switch gpio
Ditto?
> +
> + hub-vdd33-en:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + description: phandle to the hub 3.3v power enablement gpio
GPIOs controlling a power rail should use a gpio-regulator.
> +
> + hub_reset_en_gpio:
s/_/-/
And still, not a GPIO DT property...
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description: phandle to the hub reset gpio
> +
> + usb-role-switch:
> + $ref: /schemas/types.yaml#/definitions/flag
> + description: Support role switch.
> +
> + hub-vdd-supply:
> + description: regulator for hub power
> +
> + port:
> + description: |
> + any connector to the data bus of this controller should be modelled
> + using the OF graph bindings specified, if the "usb-role-switch"
> + property is used. Note for this driver, two ports are supported,
> + the first being the endpoint that will be notified by this driver,
> + and the second being the endpoint that notifies this driver of a
> + role switch.
You're describing this in terms of driver connections rather than h/w
connections.
But we've already got ways to describe the data connections. For
starters, it should be a child of the USB host.
And how does all this tie in with the USB connector binding?
> +
> +
> +required:
> + - compatible
> + - typec-vbus
> + - otg-switch
> + - usb-role-switch
> + - port
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/gpio/gpio.h>
> +
> + hisi_hikey_usb: hisi_hikey_usb {
> + compatible = "hisilicon,gpio_hubv1";
> + typec-vbus = <&gpio25 2 GPIO_ACTIVE_HIGH>;
> + otg-switch = <&gpio25 6 GPIO_ACTIVE_HIGH>;
> + hub-vdd33-en = <&gpio5 6 GPIO_ACTIVE_HIGH>;
> + usb-role-switch;
> +
> + port {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + hikey_usb_ep0: endpoint@0 {
> + reg = <0>;
> + remote-endpoint = <&dwc3_role_switch>;
> + };
> + hikey_usb_ep1: endpoint@1 {
> + reg = <1>;
> + remote-endpoint = <&rt1711h_ep>;
> + };
> + };
> + };
> --
> 2.31.1
>
>