Hello Matthias, just a curious informal question, see below. Am Tue, May 11, 2021 at 03:52:18PM -0700 schrieb Matthias Kaehlcke: > This series adds: > - the onboard_usb_hub_driver > - glue in the xhci-plat driver to create the onboard_usb_hub > platform device if needed > - a device tree binding for the Realtek RTS5411 USB hub controller > - device tree changes that add RTS5411 entries for the QCA SC7180 > based boards trogdor and lazor > - a couple of stubs for platform device functions to avoid > unresolved symbols with certain kernel configs > > The main issue the driver addresses is that a USB hub needs to be > powered before it can be discovered. For discrete onboard hubs (an > example for such a hub is the Realtek RTS5411) this is often solved > by supplying the hub with an 'always-on' regulator, which is kind > of a hack. Some onboard hubs may require further initialization > steps, like changing the state of a GPIO or enabling a clock, which > requires even more hacks. This driver creates a platform device > representing the hub which performs the necessary initialization. > Currently it only supports switching on a single regulator, support > for multiple regulators or other actions can be added as needed. > Different initialization sequences can be supported based on the > compatible string. This sounds like it would be useful for other hub controllers as well? For example, would the Microchip USB3503 (former SMSC, drivers/usb/misc/usb3503.c, [1]) fall into this category? That chip is used on the "Cubietech Cubietruck Plus" for example. > Besides performing the initialization the driver can be configured > to power the hub off during system suspend. This can help to extend > battery life on battery powered devices which have no requirements > to keep the hub powered during suspend. The driver can also be > configured to leave the hub powered when a wakeup capable USB device > is connected when suspending, and power it off otherwise. Sounds interesting. Greets Alex [1] https://www.microchip.com/wwwproducts/en/USB3503 > Changes in v10: > - always use of_is_onboard_usb_hub() stub unless ONBOARD_USB_HUB=y/m > - keep 'regulator-boot-on' property for pp3300_hub > > Changes in v9: > - added dependency on ONBOARD_USB_HUB (or !!ONBOARD_USB_HUB) to > USB_PLATFORM_XHCI > > Changes in v7: > - updated DT binding > - series rebased on qcom/arm64-for-5.13 > > Changes in v6: > - updated summary > > Changes in v5: > - cover letter added > > Matthias Kaehlcke (5): > dt-bindings: usb: Add binding for Realtek RTS5411 hub controller > USB: misc: Add onboard_usb_hub driver > of/platform: Add stubs for of_platform_device_create/destroy() > usb: host: xhci-plat: Create platform device for onboard hubs in > probe() > arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub > > .../sysfs-bus-platform-onboard-usb-hub | 8 + > .../bindings/usb/realtek,rts5411.yaml | 62 +++ > MAINTAINERS | 7 + > .../boot/dts/qcom/sc7180-trogdor-lazor-r0.dts | 19 +- > .../boot/dts/qcom/sc7180-trogdor-lazor-r1.dts | 11 +- > .../arm64/boot/dts/qcom/sc7180-trogdor-r1.dts | 19 +- > arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 19 +- > drivers/usb/host/Kconfig | 1 + > drivers/usb/host/xhci-plat.c | 16 + > drivers/usb/misc/Kconfig | 17 + > drivers/usb/misc/Makefile | 1 + > drivers/usb/misc/onboard_usb_hub.c | 415 ++++++++++++++++++ > include/linux/of_platform.h | 22 +- > include/linux/usb/hcd.h | 2 + > include/linux/usb/onboard_hub.h | 15 + > 15 files changed, 600 insertions(+), 34 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub > create mode 100644 Documentation/devicetree/bindings/usb/realtek,rts5411.yaml > create mode 100644 drivers/usb/misc/onboard_usb_hub.c > create mode 100644 include/linux/usb/onboard_hub.h > > -- > 2.31.1.607.g51e8a6a459-goog >
