From: Alexander Dahl <ada@thorsis.com>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Michal Simek <michal.simek@xilinx.com>,
devicetree@vger.kernel.org,
Douglas Anderson <dianders@chromium.org>,
linux-usb@vger.kernel.org, Peter Chen <peter.chen@kernel.org>,
linux-kernel@vger.kernel.org, Stephen Boyd <swboyd@chromium.org>,
Ravi Chandra Sadineni <ravisadineni@chromium.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
Bastien Nocera <hadess@hadess.net>,
Al Cooper <alcooperx@gmail.com>,
"Alexander A. Klimov" <grandmaster@al2klimov.de>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Christian Lamparter <chunkeey@googlemail.com>,
Colin Ian King <colin.king@canonical.com>,
Dmitry Osipenko <digetx@gmail.com>,
Fabio Estevam <festevam@gmail.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Mathias Nyman <mathias.nyman@intel.com>,
Vinod Koul <vkoul@kernel.org>,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v10 0/5] USB: misc: Add onboard_usb_hub driver
Date: Wed, 12 May 2021 09:19:54 +0200 [thread overview]
Message-ID: <YJuBmlPSaJlyVuzW@ada-deb-carambola.ifak-system.com> (raw)
In-Reply-To: <20210511225223.550762-1-mka@chromium.org>
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
>
next prev parent reply other threads:[~2021-05-12 7:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 22:52 [PATCH v10 0/5] USB: misc: Add onboard_usb_hub driver Matthias Kaehlcke
2021-05-11 22:52 ` [PATCH v10 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub Matthias Kaehlcke
2021-05-12 7:19 ` Alexander Dahl [this message]
2021-05-12 16:37 ` [PATCH v10 0/5] USB: misc: Add onboard_usb_hub driver Matthias Kaehlcke
2021-05-21 12:30 ` Greg Kroah-Hartman
2021-05-25 17:42 ` Matthias Kaehlcke
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