[PATCH v20 0/5] usb: misc: Add onboard_usb_hub driver

[PATCH v20 0/5] usb: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke]

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 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 (5):
  of/platform: Add stubs for of_platform_device_create/destroy()
  driver core: Export device_is_bound()
  usb: misc: Add onboard_usb_hub driver
  usb: core: hcd: Create platform devices 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 +-
 .../dts/qcom/sc7180-trogdor-pompom-r1.dts     |  11 +-
 .../arm64/boot/dts/qcom/sc7180-trogdor-r1.dts |  19 +-
 arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi  |  20 +-
 drivers/base/dd.c                             |   1 +
 drivers/usb/core/hcd.c                        |   6 +
 drivers/usb/misc/Kconfig                      |  23 +
 drivers/usb/misc/Makefile                     |   1 +
 drivers/usb/misc/onboard_usb_hub.c            | 511 ++++++++++++++++++
 include/linux/of_platform.h                   |  22 +-
 include/linux/usb/hcd.h                       |   1 +
 include/linux/usb/onboard_hub.h               |  18 +
 15 files changed, 638 insertions(+), 41 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

-- 
2.34.1.703.g22d0c6ccf7-goog

[PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Matthias Kaehlcke]

Add nodes for the onboard USB hub on trogdor devices. Remove the
'always-on' property from the hub regulator, since the regulator
is now managed by the onboard_usb_hub driver.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v20:
- renamed hub labels to 'usb_hub_2/3_x'
- added comment for 'regulator-boot-on' of 'pp3300_hub'
- added 'Reviewed-by' tags from Stephen and Doug

Changes in v19:
- none

Changes in v18:
- also adjust config for pompom rev1

Changes in v17:
- none

Changes in v16:
- none

Changes in v15:
- none

Changes in v14:
- none

Changes in v13:
- none

Changes in v12:
- none

Changes in v11:
- rebased on qcom/arm64-for-5.14 (with the rest of the series)

Changes in v10:
- keep 'regulator-boot-on' property
- updated commit message

Changes in v9:
- none

Changes in v8:
- none

Changes in v7:
- rebased on qcom/arm64-for-5.13 (with the rest of the series)

Changes in v6:
- added 'companion-hub' entry to both USB devices
- added 'vdd-supply' also to hub@2

Changes in v5:
- patch added to the series

 .../boot/dts/qcom/sc7180-trogdor-lazor-r0.dts | 19 ++++++++----------
 .../boot/dts/qcom/sc7180-trogdor-lazor-r1.dts | 12 +++++------
 .../dts/qcom/sc7180-trogdor-pompom-r1.dts     | 11 ++++------
 .../arm64/boot/dts/qcom/sc7180-trogdor-r1.dts | 19 ++++++++----------
 arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi  | 20 ++++++++++++++++++-
 5 files changed, 44 insertions(+), 37 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r0.dts b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r0.dts
index 30e3e769d2b4..b69590a17cab 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r0.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r0.dts
@@ -14,17 +14,6 @@ / {
 	compatible = "google,lazor-rev0", "qcom,sc7180";
 };
 
-&pp3300_hub {
-	/* pp3300_l7c is used to power the USB hub */
-	/delete-property/regulator-always-on;
-	/delete-property/regulator-boot-on;
-};
-
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
-};
-
 &sn65dsi86_out {
 	/*
 	 * Lane 0 was incorrectly mapped on the cable, but we've now decided
@@ -33,3 +22,11 @@ &sn65dsi86_out {
 	 */
 	lane-polarities = <1 0>;
 };
+
+&usb_hub_2_x {
+	 vdd-supply = <&pp3300_l7c>;
+};
+
+&usb_hub_3_x {
+	 vdd-supply = <&pp3300_l7c>;
+};
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r1.dts b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r1.dts
index c2ef06367baf..25f178c3c6eb 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r1.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor-r1.dts
@@ -14,13 +14,11 @@ / {
 	compatible = "google,lazor-rev1", "google,lazor-rev2", "qcom,sc7180";
 };
 
-&pp3300_hub {
-	/* pp3300_l7c is used to power the USB hub */
-	/delete-property/regulator-always-on;
-	/delete-property/regulator-boot-on;
+
+&usb_hub_2_x {
+	 vdd-supply = <&pp3300_l7c>;
 };
 
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
+&usb_hub_3_x {
+	 vdd-supply = <&pp3300_l7c>;
 };
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom-r1.dts b/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom-r1.dts
index 76a130bad60a..8467ff41e6d5 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom-r1.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom-r1.dts
@@ -34,13 +34,10 @@ &pm6150_adc_tm {
 	/delete-node/ charger-thermistor@0;
 };
 
-&pp3300_hub {
-	/* pp3300_l7c is used to power the USB hub */
-	/delete-property/regulator-always-on;
-	/delete-property/regulator-boot-on;
+&usb_hub_2_x {
+	 vdd-supply = <&pp3300_l7c>;
 };
 
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
+&usb_hub_3_x {
+	 vdd-supply = <&pp3300_l7c>;
 };
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-r1.dts b/arch/arm64/boot/dts/qcom/sc7180-trogdor-r1.dts
index 457c25499863..0cbb7a68d58b 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-r1.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-r1.dts
@@ -43,17 +43,6 @@ &panel {
 	compatible = "auo,b116xa01";
 };
 
-&pp3300_hub {
-	/* pp3300_l7c is used to power the USB hub */
-	/delete-property/regulator-always-on;
-	/delete-property/regulator-boot-on;
-};
-
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
-};
-
 &sdhc_2 {
 	status = "okay";
 };
@@ -62,6 +51,14 @@ &trackpad {
 	interrupts = <58 IRQ_TYPE_EDGE_FALLING>;
 };
 
+&usb_hub_2_x {
+	 vdd-supply = <&pp3300_l7c>;
+};
+
+&usb_hub_3_x {
+	 vdd-supply = <&pp3300_l7c>;
+};
+
 /* PINCTRL - modifications to sc7180-trogdor.dtsi */
 
 &trackpad_int_1v8_odl {
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
index d4f4441179fc..be06938872ca 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
@@ -202,7 +202,7 @@ pp3300_hub: pp3300-hub {
 		pinctrl-names = "default";
 		pinctrl-0 = <&en_pp3300_hub>;
 
-		regulator-always-on;
+		/* The BIOS leaves this regulator on */
 		regulator-boot-on;
 
 		vin-supply = <&pp3300_a>;
@@ -839,6 +839,24 @@ &usb_1 {
 
 &usb_1_dwc3 {
 	dr_mode = "host";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	/* 2.x hub on port 1 */
+	usb_hub_2_x: hub@1 {
+		compatible = "usbbda,5411";
+		reg = <1>;
+		vdd-supply = <&pp3300_hub>;
+		companion-hub = <&usb_hub_3_x>;
+	};
+
+	/* 3.x hub on port 2 */
+	usb_hub_3_x: hub@2 {
+		compatible = "usbbda,411";
+		reg = <2>;
+		vdd-supply = <&pp3300_hub>;
+		companion-hub = <&usb_hub_2_x>;
+	};
 };
 
 &usb_1_hsphy {
-- 
2.34.1.703.g22d0c6ccf7-goog

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Greg Kroah-Hartman]

On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> Add nodes for the onboard USB hub on trogdor devices. Remove the
> 'always-on' property from the hub regulator, since the regulator
> is now managed by the onboard_usb_hub driver.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---

No DT maintainer approval yet?  :(

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Matthias Kaehlcke]

On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
> On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> > Add nodes for the onboard USB hub on trogdor devices. Remove the
> > 'always-on' property from the hub regulator, since the regulator
> > is now managed by the onboard_usb_hub driver.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > ---
> 
> No DT maintainer approval yet?  :(

Bjorn usually just picks DT changes into the QCOM tree when they are
ready, so I wouldn't interpret anything into the lack of an explicit
Ack.

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Doug Anderson]

Hi,

On Tue, Feb 8, 2022 at 11:21 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
> > On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> > > Add nodes for the onboard USB hub on trogdor devices. Remove the
> > > 'always-on' property from the hub regulator, since the regulator
> > > is now managed by the onboard_usb_hub driver.
> > >
> > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > > ---
> >
> > No DT maintainer approval yet?  :(
>
> Bjorn usually just picks DT changes into the QCOM tree when they are
> ready, so I wouldn't interpret anything into the lack of an explicit
> Ack.

Right, so the expectation is that this patch wouldn't land through the
USB tree but would instead land through the Qualcomm tree, probably a
revision after the code lands in the USB tree to avoid dependency
problems.

-Doug

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Greg Kroah-Hartman]

On Tue, Feb 15, 2022 at 09:54:54AM -0800, Doug Anderson wrote:
> Hi,
> 
> On Tue, Feb 8, 2022 at 11:21 AM Matthias Kaehlcke <mka@chromium.org> wrote:
> >
> > On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
> > > On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> > > > Add nodes for the onboard USB hub on trogdor devices. Remove the
> > > > 'always-on' property from the hub regulator, since the regulator
> > > > is now managed by the onboard_usb_hub driver.
> > > >
> > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > > > ---
> > >
> > > No DT maintainer approval yet?  :(
> >
> > Bjorn usually just picks DT changes into the QCOM tree when they are
> > ready, so I wouldn't interpret anything into the lack of an explicit
> > Ack.
> 
> Right, so the expectation is that this patch wouldn't land through the
> USB tree but would instead land through the Qualcomm tree, probably a
> revision after the code lands in the USB tree to avoid dependency
> problems.

But our tools pick up the whole series.  I can't just do "i will pick
patches 1-4 only" easily, and neither can any other maintainer.

Why not just get their ack so that I know it can come through the USB
tree?  That's what normally happens for other changes like this where a
driver change is required first.

thanks,

greg k-h

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Doug Anderson]

Hi,

On Tue, Feb 15, 2022 at 10:55 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Feb 15, 2022 at 09:54:54AM -0800, Doug Anderson wrote:
> > Hi,
> >
> > On Tue, Feb 8, 2022 at 11:21 AM Matthias Kaehlcke <mka@chromium.org> wrote:
> > >
> > > On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
> > > > On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> > > > > Add nodes for the onboard USB hub on trogdor devices. Remove the
> > > > > 'always-on' property from the hub regulator, since the regulator
> > > > > is now managed by the onboard_usb_hub driver.
> > > > >
> > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > > > > ---
> > > >
> > > > No DT maintainer approval yet?  :(
> > >
> > > Bjorn usually just picks DT changes into the QCOM tree when they are
> > > ready, so I wouldn't interpret anything into the lack of an explicit
> > > Ack.
> >
> > Right, so the expectation is that this patch wouldn't land through the
> > USB tree but would instead land through the Qualcomm tree, probably a
> > revision after the code lands in the USB tree to avoid dependency
> > problems.
>
> But our tools pick up the whole series.  I can't just do "i will pick
> patches 1-4 only" easily, and neither can any other maintainer.
>
> Why not just get their ack so that I know it can come through the USB
> tree?  That's what normally happens for other changes like this where a
> driver change is required first.

Huh. That's the first time I've heard that and I'm pretty used to
patches in a series going through different trees, but it would be OK
w/ me if Bjorn was willing to Ack this. Bjorn: what say you? I guess
alternatively Matthias could send two series: one with the code and a
later one with the dts.

-Doug

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Krzysztof Kozlowski]

On 15/02/2022 19:55, Greg Kroah-Hartman wrote:
> On Tue, Feb 15, 2022 at 09:54:54AM -0800, Doug Anderson wrote:
>> Hi,
>>
>> On Tue, Feb 8, 2022 at 11:21 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>>>
>>> On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
>>>> On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
>>>>> Add nodes for the onboard USB hub on trogdor devices. Remove the
>>>>> 'always-on' property from the hub regulator, since the regulator
>>>>> is now managed by the onboard_usb_hub driver.
>>>>>
>>>>> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
>>>>> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
>>>>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>>>>> ---
>>>>
>>>> No DT maintainer approval yet?  :(
>>>
>>> Bjorn usually just picks DT changes into the QCOM tree when they are
>>> ready, so I wouldn't interpret anything into the lack of an explicit
>>> Ack.
>>
>> Right, so the expectation is that this patch wouldn't land through the
>> USB tree but would instead land through the Qualcomm tree, probably a
>> revision after the code lands in the USB tree to avoid dependency
>> problems.
> 
> But our tools pick up the whole series.  I can't just do "i will pick
> patches 1-4 only" easily, and neither can any other maintainer.

I don't have problems picking individual patches - either b4 am on each
patch or on entire series and dropping later unneeded commits.

> 
> Why not just get their ack so that I know it can come through the USB
> tree?  That's what normally happens for other changes like this where a
> driver change is required first.

DTS is a description of the hardware and we take it via separate
branches of SoC-fami0ly repositories. These are always separated from
the driver changes. Always. For several reasons:
1. By convention,
2. To be sure there is no dependency on driver code thus an ABI break,
3. To have a nice and clean history of DTS changes, properly organized.

What is more, if this was coming via my Samsung SoC tree towards SoC
folks, I could not take it in one branch. I would need to physically
split it, otherwise Arnd/Olof would bounce back my pull request saying I
am mixing DTS with driver. Of course you do not have such requirement -
I am just saying that splitting DTS is quite common and proper way.


Best regards,
Krzysztof

Re: [PATCH v20 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Bjorn Andersson]

On Tue 15 Feb 12:55 CST 2022, Greg Kroah-Hartman wrote:

> On Tue, Feb 15, 2022 at 09:54:54AM -0800, Doug Anderson wrote:
> > Hi,
> > 
> > On Tue, Feb 8, 2022 at 11:21 AM Matthias Kaehlcke <mka@chromium.org> wrote:
> > >
> > > On Tue, Feb 08, 2022 at 11:57:20AM +0100, Greg Kroah-Hartman wrote:
> > > > On Wed, Jan 19, 2022 at 12:43:45PM -0800, Matthias Kaehlcke wrote:
> > > > > Add nodes for the onboard USB hub on trogdor devices. Remove the
> > > > > 'always-on' property from the hub regulator, since the regulator
> > > > > is now managed by the onboard_usb_hub driver.
> > > > >
> > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > > > > ---
> > > >
> > > > No DT maintainer approval yet?  :(
> > >
> > > Bjorn usually just picks DT changes into the QCOM tree when they are
> > > ready, so I wouldn't interpret anything into the lack of an explicit
> > > Ack.
> > 
> > Right, so the expectation is that this patch wouldn't land through the
> > USB tree but would instead land through the Qualcomm tree, probably a
> > revision after the code lands in the USB tree to avoid dependency
> > problems.
> 
> But our tools pick up the whole series.  I can't just do "i will pick
> patches 1-4 only" easily, and neither can any other maintainer.
> 

Most other maintainers uses -P to selectively pick the patches that
applies to their subsystem. That said, I really do recognize the
inconvenience on your part and the number of patches being sent your
way.

> Why not just get their ack so that I know it can come through the USB
> tree?  That's what normally happens for other changes like this where a
> driver change is required first.
> 

Because while the change looks good I don't think it's fine to take it
through the USB tree - the dts tree typically looks like a shotgun hit
across the dts files. And you and I have already seen several times that
dts changes do conflict when you take some of them in the USB tree.

Unfortunately I see only two ways around this problem, either you start
picking selectively or I manage to convince all contributors that they
must split their series to keep dts changes separate (which isn't a bad
idea in itself).

Regards,
Bjorn