Re: [PATCH v15 0/6] usb: misc: Add onboard_usb_hub driver

[Roger Quadros <rogerq@kernel.org>]

Hi Matthias,

On 09/08/2021 18:49, Matthias Kaehlcke wrote:
> Hi Greg,
> 
> Just wanted to check if this series is still on your radar. Is
> there anything that blocks it from landing (further ACKs, ...)?
> 
> Thanks
> 
> Matthias
> 
> On Mon, Jul 26, 2021 at 05:41:12PM -0700, Matthias Kaehlcke wrote:
>> This series adds:
>> - the onboard_usb_hub_driver
>> - glue in the xhci-plat driver to create and destroy the
>>   onboard_usb_hub platform devices 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 v15:
>> - adjusted dependencies of USB_DWC3_CORE to make sure it can only
>>   be enabled when at least one of USB_DWC3_HOST, USB_DWC3_GADGET
>>   or USB_DWC3_DUAL_ROLE is selectable
>>
>> Changes in v14:
>> - rebased on top of v5.14-rc1
>> - dropped DT binding patch which landed in v5.13
>>
>> Changes in v13:
>> - added patch "usb: Specify dependency on USB_XHCI_PLATFORM with
>>   'depends on'" to the series to avoid Kconfig conflicts
>> - added patch "arm64: defconfig: Explicitly enable USB_XHCI_PLATFORM"
>>   to the series to keep effective defconfig unchanged
>>
>> Changes in v12:
>> - onboard_hub driver: use IS_ENABLED(CONFIG_USB_ONBOARD_HUB_MODULE)
>>   in onboard_hub.h to also check for the driver built as module
>> - onboard_hub_driver: include onboard_hub.h again to make sure there
>>   are prototype declarations for the public functions
>>
>> Changes in v11:
>> - support multiple onboard hubs connected to the same parent
>> - don't include ‘onboard_hub.h’ from the onboard hub driver
>>
>> 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 (6):
>>   usb: misc: Add onboard_usb_hub driver
>>   of/platform: Add stubs for of_platform_device_create/destroy()
>>   arm64: defconfig: Explicitly enable USB_XHCI_PLATFORM
>>   usb: Specify dependencies on USB_XHCI_PLATFORM with 'depends on'
>>   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 +
>>  MAINTAINERS                                   |   7 +
>>  .../boot/dts/qcom/sc7180-trogdor-lazor-r0.dts |  19 +-
>>  .../boot/dts/qcom/sc7180-trogdor-lazor-r1.dts |  12 +-
>>  .../arm64/boot/dts/qcom/sc7180-trogdor-r1.dts |  19 +-
>>  arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi  |  19 +-
>>  arch/arm64/configs/defconfig                  |   1 +
>>  drivers/usb/cdns3/Kconfig                     |   2 +-
>>  drivers/usb/dwc3/Kconfig                      |   5 +-
>>  drivers/usb/host/Kconfig                      |   5 +-

These Kconfig changes are causing the resulting .config to be different.
For example, if I start with omap2plus_defconfig, the resulting .config
before and after your series is different as shown below

:/work/linux$ diff /tmp/.config .config
1902d1901
< # CONFIG_HISI_HIKEY_USB is not set
4992c4991
< CONFIG_USB_XHCI_PLATFORM=m
---
> # CONFIG_USB_XHCI_PLATFORM is not set
5073,5075c5072
< # CONFIG_USB_DWC3_HOST is not set
< # CONFIG_USB_DWC3_GADGET is not set
< CONFIG_USB_DWC3_DUAL_ROLE=y
---
> CONFIG_USB_DWC3_GADGET=y
5173a5171
> # CONFIG_USB_ONBOARD_HUB is not set
5285c5283
< CONFIG_USB_ROLE_SWITCH=m
---
> # CONFIG_USB_ROLE_SWITCH is not set

I would expect the same issues for multi_v7_defconfig and multi_v8_defconfig as well.
I'm ok to update the relevant defconfigs files so that the resulting .config is identical to
before your series. Thanks!

--
cheers,
-roger