Re: [PATCH v6 0/5] USB: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke <mka@chromium.org>]

> Subject: [PATCH v6 0/5] USB: misc: Add onboard_usb_hub driver

Argh, that should have been v7 :/ Not sure if it's worth/required to
resend.

On Mon, Apr 05, 2021 at 01:18:12PM -0700, Matthias Kaehlcke wrote:
> 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.
> 
> 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.
> 
> Changes in v7:
> - 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         |  59 +++
>  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  |  21 +-
>  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 +
>  14 files changed, 596 insertions(+), 36 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
> 
> -- 
> 2.31.0.208.g409f899ff0-goog
>