Date:   Tue, 17 May 2022 12:36:03 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Kaehlcke <mka@...omium.org>
CC:     Doug Anderson <dianders@...omium.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Felipe Balbi <balbi@...nel.org>,
        Linux USB List <linux-usb@...r.kernel.org>,
        Ravi Chandra Sadineni <ravisadineni@...omium.org>,
        Roger Quadros <rogerq@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Bastien Nocera <hadess@...ess.net>,
        Michal Simek <michal.simek@...inx.com>,
        Stephen Boyd <swboyd@...omium.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Peter Chen <peter.chen@...nel.org>,
        Guo Zhengkui <guozhengkui@...o.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Li Jun <jun.li@....com>, Peter Chen <peter.chen@....com>,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>
Subject: Re: [PATCH v21 0/3] usb: misc: Add onboard_usb_hub driver

Hi Greg,

On 4/26/22 14:01, Greg Kroah-Hartman wrote:
> On Thu, Apr 21, 2022 at 11:13:08AM -0700, Matthias Kaehlcke wrote:
>> Hi,
>>
>> On Thu, Apr 07, 2022 at 12:41:22PM -0700, Doug Anderson wrote:
>>> Hi,
>>>
>>> On Thu, Feb 17, 2022 at 10:43 AM Matthias Kaehlcke <mka@...omium.org> wrote:
>>>>
>>>> This series adds:
>>>> - the onboard_usb_hub_driver
>>>> - glue in the generic HCD code to create and destroy the
>>>>    onboard_usb_hub platform devices if needed
>>>> - 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 v21:
>>>> - dropped patch 'driver core: Export device_is_bound()'
>>>> - refactored _find_onboard_hub()
>>>> - removed 'onboard_hub_dev' symlinks from USB devices
>>>> - dropped patch 'arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub'
>>>>    (will be sent separately)
>>>> - rebased series on v5.17-rc4
>>>>
>>>> Changes in v20:
>>>> - addressed review comments from Stephen
>>>> - changed DT node names for hubs
>>>>
>>>> Changes in v19:
>>>> - added VID:PID pairs and compatible strings for RTS5414 hub
>>>> - updated comments with RTS5411 USB versions to reflect those
>>>>    reported/supported by the hub
>>>> - rebased series on v5.16
>>>>
>>>> Changes in v18:
>>>> - introduced hidden Kconfig option to align module vs. builtin
>>>>    choice with CONFIG_USB (thanks Doug!)
>>>> - added patch 'driver core: Export device_is_bound()'
>>>> - also adjust device tree of pompom rev1
>>>> - dropped the following patches, which aren't needed anymore by this
>>>>    series (though they might still be useful on their own):
>>>>    - usb: Specify dependencies on USB_XHCI_PLATFORM with 'depends on'
>>>>    - arm64: defconfig: Explicitly enable USB_XHCI_PLATFORM
>>>>    - ARM: configs: Explicitly enable USB_XHCI_PLATFORM where needed
>>>>
>>>> Changes in v17:
>>>> - rebased on top of v5.16-rc1
>>>> - moved creation of onboard_hub platform devices from xhci_platform
>>>>    to the generic HCD code
>>>> - addressed review comments for the onboard_hub driver
>>>> - moved Kconfig/defconfig changes to the end of the series. The
>>>>    onboard_hub driver doesn't depend on XHCI_PLATFORM anymore,
>>>>    hence these changes aren't really required for the driver, but
>>>>    they still seem to be a worthwhile improvement
>>>>
>>>> Changes in v16:
>>>> - added patch 'ARM: configs: Explicitly enable USB_XHCI_PLATFORM
>>>>    where needed' to keep arm32 defconfigs effectively unchanged
>>>>
>>>> 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 (3):
>>>>    of/platform: Add stubs for of_platform_device_create/destroy()
>>>>    usb: misc: Add onboard_usb_hub driver
>>>>    usb: core: hcd: Create platform devices for onboard hubs in probe()
>>>>
>>>>   .../sysfs-bus-platform-onboard-usb-hub        |   8 +
>>>>   MAINTAINERS                                   |   7 +
>>>>   drivers/usb/core/hcd.c                        |   6 +
>>>>   drivers/usb/misc/Kconfig                      |  23 +
>>>>   drivers/usb/misc/Makefile                     |   1 +
>>>>   drivers/usb/misc/onboard_usb_hub.c            | 510 ++++++++++++++++++
>>>>   include/linux/of_platform.h                   |  22 +-
>>>>   include/linux/usb/hcd.h                       |   1 +
>>>>   include/linux/usb/onboard_hub.h               |  18 +
>>>>   9 files changed, 592 insertions(+), 4 deletions(-)
>>>>   create mode 100644 Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub
>>>>   create mode 100644 drivers/usb/misc/onboard_usb_hub.c
>>>>   create mode 100644 include/linux/usb/onboard_hub.h
>>>
>>> With v5.18-rc1 out the door, I wonder if it's a good time to look at
>>> this series again. Are there any hidden blockers that it's waiting
>>> for?
>>
>> Greg, please let me know if any further changes are needed or if this
>> series can be landed.
> 
> After 21 different versions, there's nothing left for me to object to,
> so I'll go queue it up.  Thanks for sticking with it.

I just checked linux-next and this series is still not there. Are you going to 
merge it or are you waiting for v22?

Thanks,
Michal

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