[PATCH v23 0/3] usb: misc: Add onboard_usb_hub driver

[PATCH v23 0/3] usb: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke]

This series adds:
- the onboard_usb_hub_driver
- glue in the generic hub 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 v23:
- refactored onboard_hub_create_pdevs()
- got rid of CONFIG_USB_ONBOARD_HUB_ACTUAL

Changes in v22:
- call onboard_hub_create/destroy_pdevs() from hub_probe/disconnect()
  instead of doing it from the HCD. When the pdevs are create from the
  HCD usb_of_get_device_node() (called by onboard_hub_create_pdevs())
  may return NULL because the USB device for the root hub doesn't
  exist yet. Creating the pdevs from the hub code also has the
  advantage of enabling support for nested onboard hubs (as long as
  all hubs in the chain have DT nodes and are supported by the driver).
- moved onboard_hub_create_pdevs(), onboard_hub_destroy_pdevs() and
  of_is_onboard_usb_hub() into a separate file to allow them to be
  linked into the USB core module (if CONFIG_USB=m)
- Added extra checks to ensure only one platform device is created
  for each physical hub. This is necessary because
  onboard_hub_create_pdevs() is now called from hub_probe() instead
  of usb_add_hcd(). As a result the function is called twice for
  typical USB3 hub, once for the USB3 part of the hub, and once for
  USB <= 2.x. Generally the parent hub downstream of the primary HCD
  creates the onboard hub platform device.
- use kzalloc() instead of devm_kzalloc() to allocate list entries. Using
  managed memory can cause issues since the managed memory is allocated
  before the device is probed.
- use a workqueue to (re-)attach the USB driver during/after _probe().
  This is necessary to avoid self-deadlocks on systems with nested
  onboard hubs.
- don't initialize list_head in onboard_hub_create_pdevs(), this needs
  to be done by the owner, to ensure that onboard_hub_destroy_pdevs()
  is called with a struct that was properly initialized even when
  onboard_hub_create_pdevs() is not called.
- rebased series on v5.19-rc1

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: hub: Create platform devices for onboard hubs in
    hub_probe()

 .../sysfs-bus-platform-onboard-usb-hub        |   8 +
 MAINTAINERS                                   |   7 +
 drivers/usb/core/Makefile                     |   1 +
 drivers/usb/core/hub.c                        |   9 +-
 drivers/usb/core/hub.h                        |   1 +
 drivers/usb/misc/Kconfig                      |  16 +
 drivers/usb/misc/Makefile                     |   1 +
 drivers/usb/misc/onboard_usb_hub.c            | 427 ++++++++++++++++++
 drivers/usb/misc/onboard_usb_hub.h            |  17 +
 drivers/usb/misc/onboard_usb_hub_pdevs.c      | 137 ++++++
 include/linux/of_platform.h                   |  22 +-
 include/linux/usb/onboard_hub.h               |  18 +
 12 files changed, 659 insertions(+), 5 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 drivers/usb/misc/onboard_usb_hub.h
 create mode 100644 drivers/usb/misc/onboard_usb_hub_pdevs.c
 create mode 100644 include/linux/usb/onboard_hub.h

-- 
2.37.0.rc0.104.g0611611a94-goog

[PATCH v23 1/3] of/platform: Add stubs for of_platform_device_create/destroy()

[Matthias Kaehlcke]

Code for platform_device_create() and of_platform_device_destroy() is
only generated if CONFIG_OF_ADDRESS=y. Add stubs to avoid unresolved
symbols when CONFIG_OF_ADDRESS is not set.

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

Changes in v23:
- none

Changes in v22:
- none

Changes in v21:
- none

Changes in v20:
- added 'Reviewed-by' tags from Stephen and Doug

Changes in v19:
- still no changes ...

Changes in v18:
- still no changes ...

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:
- none

Changes in v10:
- none

Changes in v9:
- added Rob's 'Acked-by' tag

Changes in v8:
- fixed C&P error in commit message

Changes in v7:
- none

Changes in v6:
- patch added to the series

 include/linux/of_platform.h | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 84a966623e78..d15b6cd5e1c3 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -61,16 +61,18 @@ static inline struct platform_device *of_find_device_by_node(struct device_node
 }
 #endif
 
+extern int of_platform_bus_probe(struct device_node *root,
+				 const struct of_device_id *matches,
+				 struct device *parent);
+
+#ifdef CONFIG_OF_ADDRESS
 /* Platform devices and busses creation */
 extern struct platform_device *of_platform_device_create(struct device_node *np,
 						   const char *bus_id,
 						   struct device *parent);
 
 extern int of_platform_device_destroy(struct device *dev, void *data);
-extern int of_platform_bus_probe(struct device_node *root,
-				 const struct of_device_id *matches,
-				 struct device *parent);
-#ifdef CONFIG_OF_ADDRESS
+
 extern int of_platform_populate(struct device_node *root,
 				const struct of_device_id *matches,
 				const struct of_dev_auxdata *lookup,
@@ -84,6 +86,18 @@ extern int devm_of_platform_populate(struct device *dev);
 
 extern void devm_of_platform_depopulate(struct device *dev);
 #else
+/* Platform devices and busses creation */
+static inline struct platform_device *of_platform_device_create(struct device_node *np,
+								const char *bus_id,
+								struct device *parent)
+{
+	return NULL;
+}
+static inline int of_platform_device_destroy(struct device *dev, void *data)
+{
+	return -ENODEV;
+}
+
 static inline int of_platform_populate(struct device_node *root,
 					const struct of_device_id *matches,
 					const struct of_dev_auxdata *lookup,
-- 
2.37.0.rc0.104.g0611611a94-goog

[PATCH v23 2/3] usb: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke]

The main issue this 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.

Technically the driver consists of two drivers, the platform driver
described above and a very thin USB driver that subclasses the
generic driver. The purpose of this driver is to provide the platform
driver with the USB devices corresponding to the hub(s) (a hub
controller may provide multiple 'logical' hubs, e.g. one to support
USB 2.0 and another for USB 3.x).

Co-developed-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
Signed-off-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

Changes in v23:
- refactored onboard_hub_create_pdevs()
  - bail out before the loop for root hubs connected to
    the secondary HCD
  - check for exisiting pdev in the companion hub branch
    instead of doing it afterwards
- added note about the role of the platform devices to
  documentation of onboard_hub_create_pdevs()
- got rid of CONFIG_USB_ONBOARD_HUB_ACTUAL, it's not needed anymore
  now that onboard_hub_create/destroy_pdevs() are linked into the USB
  core
- added some more details to comment about the need to re-attach the
  USB driver

Changes in v22:
- moved onboard_hub_create_pdevs(), onboard_hub_destroy_pdevs() and
  of_is_onboard_usb_hub() into a separate file to allow them to be
  linked into the USB core module (if CONFIG_USB=m)
- Added extra checks to ensure only one platform device is created
  for each physical hub. This is necessary because
  onboard_hub_create_pdevs() is now called from hub_probe() instead
  of usb_add_hcd(). As a result the function is called twice for
  typical USB3 hub, once for the USB3 part of the hub, and once for
  USB <= 2.x. Generally the parent hub downstream of the primary HCD
  creates the onboard hub platform device.
- use kzalloc() instead of devm_kzalloc() to allocate list entries. Using
  managed memory can cause issues since the managed memory is allocated
  before the device is probed.
- use a workqueue to (re-)attach the USB driver during/after _probe().
  This is necessary to avoid self-deadlocks on systems with nested
  onboard hubs.
- don't initialize list_head in onboard_hub_create_pdevs(), this needs
  to be done by the owner, to ensure that onboard_hub_destroy_pdevs()
  is called with a struct that was properly initialized even when
  onboard_hub_create_pdevs() is not called.
- moved 'onboard_hub_match' into an include, so it can be used
  by both the the onboard hub driver and of_is_onboard_usb_hub()
- removed note from the commit message which said that currently only
  onboard hubs connected to a root hub are supported. This isn't the
  case anymore.
- updated kernel version and date in sysfs documentation
- removed tags from Doug and Alan since this version changes quite
  a few things

Changes in v21:
- refactored _find_onboard_hub()
  - check presence of drvdata instead of using device_is_bound()
  - return -ENODEV if the platform device can't be found
  - always check drvdata, not only when looking for the companion
    hub
  - added comment explaining probe deferral
- removed 'onboard_hub_dev' symlinks from USB devices
- updated documentation of 'always_powered_in_suspend' sysfs attribute

Changes in v20:
- s/nontrivial/non-trivial/ in Kconfig doc
- added include of 'export.h'
- initialize variable 'power_off' in onboard_hub_suspend() at
  declaration time
- renamed set_udev_link_name() to get_udev_link_name()
- use kzalloc to allocate struct usbdev_node instead of devm_kzalloc()
- release the lock in onboard_hub_add_usbdev() before calling
  get_udev_link_name()
- free struct usbdev_node in onboard_hub_remove_usbdev(), now that
  it doesn't used managed memory
- make struct onboard_hub const in always_powered_in_suspend_show()
- call put_device() if pdev is not bound in _find_onboard_hub()
- get driver data before calling put_device() in _find_onboard_hub()
- log platform device name when sysfs link creation fails in
  onboard_hub_usbdev_probe()
- added kernel doc for onboard_hub_create_pdevs() and
  onboard_hub_destroy_pdevs()
- added 'Reviewed-by' tag from Doug

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

Changes in v18:
- introduced hidden Kconfig option to align module vs. builtin
  choice with CONFIG_USB (thanks Doug!)
- refactored onboard_hub_create_pdevs()

Changes in v17:
- updated date and kernel version in ABI documentation for
  'always_powered_in_suspend' attribute
- removed obsolete .yaml entry from MAINTAINERS file
- added entry for ABI documentation to MAINTAINERS file
- renamed struct 'udev_node' to 'usbdev_node'
- changed return logic in onboard_hub_suspend/resume() to
  get rid of 'rc' variable
- added helper set_udev_link_name() to set link names for
  onboard hub USB devices
- use of_parse_phandle() instead of of_property_read_u32() +
  of_find_node_by_phandle() combo
- defer probing in _find_onboard_hub() if the platform device
  isn't bound yet
- initialize list head passed as parameter to
  onboard_hub_create_pdevs() instead of relying on the caller
  to do so
- don't require the 'companion-hub' property to be specified.
  This is needed to support hubs without companion hub
- use devm_kzalloc() to allocate platform device list entries
  and stop freeing them explicitly
- remove unnecessary INIT_LIST_HEAD() of platform device list
  entries
- use '%pOF' to print DT node name
- delete platform device list entries from the list of devices
  in onboard_hub_destroy_pdevs(). It shouldn't be strictly
  necessary, but better be on the safe side.

Changes in v16:
- none

Changes in v15:
- none

Changes in v14:
- none

Changes in v13:
- none

Changes in v12:
- use IS_ENABLED(CONFIG_USB_ONBOARD_HUB_MODULE) in onboard_hub.h to
  also check for the driver built as module
- include onboard_hub.h again from the driver to make sure there are
  prototype declarations for the public functions
- remove indentation from label in onboard_hub_create_pdevs()

Changes in v11:
- added onboard_hub_create/destroy_pdevs() helpers, to support multiple onboard
  hubs connected to the same parent hub
- don't include ‘onboard_hub.h’ from the onboard hub driver
- updated commit message
- added ‘Acked-by' from Alan

Changes in v10:
- always use of_is_onboard_usb_hub() stub unless ONBOARD_USB_HUB=y/m

Changes in v9:
- none

Changes in v8:
- none

Changes in v7:
- don't declare stub for of_is_onboard_usb_hub() when
  CONFIG_COMPILE_TEST is defined

Changes in v6:
- use 'companion-hub' to locate the platform device, instead of
  scanning through the nodes of the parent
- added ABI documentation for 'always_powered_in_suspend'
- sysfs_emit() instead of sprintf() in always_powered_in_suspend_show()
- register sysfs attribute through driver.dev_groups
- evaluate return value of driver_attach() in _probe()
- use dev_warn() instead of WARN_ON() in _probe()
- include 'onboard_hub.h'

Changes in v5:
- the platform device is now instantiated from the same DT node
  as the 'primary' USB hub device
  - use the USB compatible strings for the platform device
  - refactored _find_onboard_hub() to search the parents child
    nodes for a platform device with a matching compatible string
  - added exported function of_is_onboard_usb_hub() to allow other
    drivers (like xhci_plat) to check if one of their child DT nodes
    is a supported hub
- use late suspend to make sure info about wakeup enabled descendants
  is updated
- call driver_attach() for the USB driver in onboard_hub_probe() to
  make sure the driver is re-attached after the device_release_driver()
  calls in onboard_hub_remove()
- renamed sysfs attribute 'power_off_in_suspend' to
  'always_powered_in_suspend'
- added sysfs symlinks between platform device and USB devices
- marked 'onboard_hub_pm_ops' as __maybe_unused
- removed 'realtek' compatible string which is not needed at this
  point
- fix log for regulator_disable() failure

Changes in v4:
- updated Kconfig documentation
- changed the loop in onboard_hub_remove() to release the hub lock
  before unbinding the USB device and make self deadlock prevention
  less clunky
- fixed return value in onboard_hub_usbdev_probe()
- added entry to MAINTAINERS file

Changes in v3:
- updated the commit message
- updated description in Kconfig
- remove include of 'core/usb.h'
- use 'is_powered_on' flag instead of 'has_wakeup_capable_descendants'
- added 'going_away' flag to struct onboard_hub
  - don't allow adding new USB devices when the platform device is going away
  - don't bother with deleting the list item in onboard_hub_remove_usbdev()
    when the platform device is going away
- don't assume in onboard_hub_suspend() that all USB hub devices are
  connected to the same controller
- removed unnecessary devm_kfree() from onboard_hub_remove_usbdev()
- fixed error handling in onboard_hub_remove_usbdev()
- use kstrtobool() instead of strtobool() in power_off_in_suspend_store()
- unbind USB devices in onboard_hub_remove() to avoid dangling references
  to the platform device
- moved put_device() for platform device to _find_onboard_hub()
- changed return value of onboard_hub_remove_usbdev() to void
- evaluate return value of onboard_hub_add_usbdev()
- register 'power_off_in_suspend' as managed device attribute
- use USB_DEVICE macro instead manual initialization
- add unwinding to onboard_hub_init()
- updated MODULE_DESCRIPTION
- use module_init() instead of device_initcall()

Changes in v2:
- check wakeup enabled state of the USB controller instead of
  using 'wakeup-source' property
- use sysfs attribute instead of DT property to determine if
  the hub should be powered off at all during system suspend
- added missing brace in onboard_hub_suspend()
- updated commit message
- use pm_ptr for pm_ops as suggested by Alan

Changes in v1:
- renamed the driver to 'onboard_usb_hub'
- single file for platform and USB driver
- USB hub devices register with the platform device
  - the DT includes a phandle of the platform device
- the platform device now controls when power is turned off
- the USB driver became a very thin subclass of the generic USB
  driver
- enabled autosuspend support

 .../sysfs-bus-platform-onboard-usb-hub        |   8 +
 MAINTAINERS                                   |   7 +
 drivers/usb/core/Makefile                     |   1 +
 drivers/usb/misc/Kconfig                      |  16 +
 drivers/usb/misc/Makefile                     |   1 +
 drivers/usb/misc/onboard_usb_hub.c            | 427 ++++++++++++++++++
 drivers/usb/misc/onboard_usb_hub.h            |  17 +
 drivers/usb/misc/onboard_usb_hub_pdevs.c      | 137 ++++++
 include/linux/usb/onboard_hub.h               |  18 +
 9 files changed, 632 insertions(+)
 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 drivers/usb/misc/onboard_usb_hub.h
 create mode 100644 drivers/usb/misc/onboard_usb_hub_pdevs.c
 create mode 100644 include/linux/usb/onboard_hub.h

diff --git a/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub b/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub
new file mode 100644
index 000000000000..42deb0552065
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub
@@ -0,0 +1,8 @@
+What:		/sys/bus/platform/devices/<dev>/always_powered_in_suspend
+Date:		June 2022
+KernelVersion:	5.20
+Contact:	Matthias Kaehlcke <matthias@kaehlcke.net>
+		linux-usb@vger.kernel.org
+Description:
+		(RW) Controls whether the USB hub remains always powered
+		during system suspend or not.
\ No newline at end of file
diff --git a/MAINTAINERS b/MAINTAINERS
index 3cf9842d9233..8ae44cd423a3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14795,6 +14795,13 @@ S:	Maintained
 T:	git git://linuxtv.org/media_tree.git
 F:	drivers/media/i2c/ov9734.c
 
+ONBOARD USB HUB DRIVER
+M:	Matthias Kaehlcke <mka@chromium.org>
+L:	linux-usb@vger.kernel.org
+S:	Maintained
+F:	Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub
+F:	drivers/usb/misc/onboard_usb_hub.c
+
 ONENAND FLASH DRIVER
 M:	Kyungmin Park <kyungmin.park@samsung.com>
 L:	linux-mtd@lists.infradead.org
diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 18e874b0441e..0ce219f5a343 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -11,6 +11,7 @@ usbcore-y += phy.o port.o
 usbcore-$(CONFIG_OF)		+= of.o
 usbcore-$(CONFIG_USB_PCI)		+= hcd-pci.o
 usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
+usbcore-$(CONFIG_USB_ONBOARD_HUB)	+= ../misc/onboard_usb_hub_pdevs.o
 
 obj-$(CONFIG_USB)		+= usbcore.o
 
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index 4c5ddbd75b7e..7fd40183a395 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -295,3 +295,19 @@ config BRCM_USB_PINMAP
 	  This option enables support for remapping some USB external
 	  signals, which are typically on dedicated pins on the chip,
 	  to any gpio.
+
+config USB_ONBOARD_HUB
+	bool "Onboard USB hub support"
+	depends on OF || COMPILE_TEST
+	help
+	  Say Y here if you want to support discrete onboard USB hubs that
+	  don't require an additional control bus for initialization, but
+	  need some non-trivial form of initialization, such as enabling a
+	  power regulator. An example for such a hub is the Realtek
+	  RTS5411.
+
+	  This driver can be used as a module but its state (module vs
+	  builtin) must match the state of the USB subsystem. Enabling
+	  this config will enable the driver and it will automatically
+	  match the state of the USB subsystem. If this driver is a
+	  module it will be called onboard_usb_hub.
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 35bdb4b6c3b6..93581baec3a8 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -33,3 +33,4 @@ obj-$(CONFIG_USB_CHAOSKEY)		+= chaoskey.o
 obj-$(CONFIG_USB_SISUSBVGA)		+= sisusbvga/
 obj-$(CONFIG_USB_LINK_LAYER_TEST)	+= lvstest.o
 obj-$(CONFIG_BRCM_USB_PINMAP)		+= brcmstb-usb-pinmap.o
+obj-$(CONFIG_USB_ONBOARD_HUB)		+= onboard_usb_hub.o
diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
new file mode 100644
index 000000000000..024885419b6d
--- /dev/null
+++ b/drivers/usb/misc/onboard_usb_hub.c
@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for onboard USB hubs
+ *
+ * Copyright (c) 2022, Google LLC
+ */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/sysfs.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/onboard_hub.h>
+#include <linux/workqueue.h>
+
+#include "onboard_usb_hub.h"
+
+static struct usb_device_driver onboard_hub_usbdev_driver;
+
+/************************** Platform driver **************************/
+
+struct usbdev_node {
+	struct usb_device *udev;
+	struct list_head list;
+};
+
+struct onboard_hub {
+	struct regulator *vdd;
+	struct device *dev;
+	bool always_powered_in_suspend;
+	bool is_powered_on;
+	bool going_away;
+	struct list_head udev_list;
+	struct work_struct attach_usb_driver_work;
+	struct mutex lock;
+};
+
+static int onboard_hub_power_on(struct onboard_hub *hub)
+{
+	int err;
+
+	err = regulator_enable(hub->vdd);
+	if (err) {
+		dev_err(hub->dev, "failed to enable regulator: %d\n", err);
+		return err;
+	}
+
+	hub->is_powered_on = true;
+
+	return 0;
+}
+
+static int onboard_hub_power_off(struct onboard_hub *hub)
+{
+	int err;
+
+	err = regulator_disable(hub->vdd);
+	if (err) {
+		dev_err(hub->dev, "failed to disable regulator: %d\n", err);
+		return err;
+	}
+
+	hub->is_powered_on = false;
+
+	return 0;
+}
+
+static int __maybe_unused onboard_hub_suspend(struct device *dev)
+{
+	struct onboard_hub *hub = dev_get_drvdata(dev);
+	struct usbdev_node *node;
+	bool power_off = true;
+
+	if (hub->always_powered_in_suspend)
+		return 0;
+
+	mutex_lock(&hub->lock);
+
+	list_for_each_entry(node, &hub->udev_list, list) {
+		if (!device_may_wakeup(node->udev->bus->controller))
+			continue;
+
+		if (usb_wakeup_enabled_descendants(node->udev)) {
+			power_off = false;
+			break;
+		}
+	}
+
+	mutex_unlock(&hub->lock);
+
+	if (!power_off)
+		return 0;
+
+	return onboard_hub_power_off(hub);
+}
+
+static int __maybe_unused onboard_hub_resume(struct device *dev)
+{
+	struct onboard_hub *hub = dev_get_drvdata(dev);
+
+	if (hub->is_powered_on)
+		return 0;
+
+	return onboard_hub_power_on(hub);
+}
+
+static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size)
+{
+	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
+}
+
+static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev)
+{
+	struct usbdev_node *node;
+	char link_name[64];
+	int err;
+
+	mutex_lock(&hub->lock);
+
+	if (hub->going_away) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	node->udev = udev;
+
+	list_add(&node->list, &hub->udev_list);
+
+	mutex_unlock(&hub->lock);
+
+	get_udev_link_name(udev, link_name, sizeof(link_name));
+	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));
+
+	return 0;
+
+error:
+	mutex_unlock(&hub->lock);
+
+	return err;
+}
+
+static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev)
+{
+	struct usbdev_node *node;
+	char link_name[64];
+
+	get_udev_link_name(udev, link_name, sizeof(link_name));
+	sysfs_remove_link(&hub->dev->kobj, link_name);
+
+	mutex_lock(&hub->lock);
+
+	list_for_each_entry(node, &hub->udev_list, list) {
+		if (node->udev == udev) {
+			list_del(&node->list);
+			kfree(node);
+			break;
+		}
+	}
+
+	mutex_unlock(&hub->lock);
+}
+
+static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	const struct onboard_hub *hub = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend);
+}
+
+static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct onboard_hub *hub = dev_get_drvdata(dev);
+	bool val;
+	int ret;
+
+	ret = kstrtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	hub->always_powered_in_suspend = val;
+
+	return count;
+}
+static DEVICE_ATTR_RW(always_powered_in_suspend);
+
+static struct attribute *onboard_hub_attrs[] = {
+	&dev_attr_always_powered_in_suspend.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(onboard_hub);
+
+static void onboard_hub_attach_usb_driver(struct work_struct *work)
+{
+	int err;
+
+	err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver);
+	if (err)
+		pr_err("Failed to attach USB driver: %d\n", err);
+}
+
+static int onboard_hub_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct onboard_hub *hub;
+	int err;
+
+	hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL);
+	if (!hub)
+		return -ENOMEM;
+
+	hub->vdd = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(hub->vdd))
+		return PTR_ERR(hub->vdd);
+
+	hub->dev = dev;
+	mutex_init(&hub->lock);
+	INIT_LIST_HEAD(&hub->udev_list);
+
+	dev_set_drvdata(dev, hub);
+
+	err = onboard_hub_power_on(hub);
+	if (err)
+		return err;
+
+	/*
+	 * The USB driver might have been detached from the USB devices by
+	 * onboard_hub_remove() (e.g. through an 'unbind' by userspace),
+	 * make sure to re-attach it if needed.
+	 *
+	 * This needs to be done deferred to avoid self-deadlocks on systems
+	 * with nested onboard hubs.
+	 */
+	INIT_WORK(&hub->attach_usb_driver_work, onboard_hub_attach_usb_driver);
+	schedule_work(&hub->attach_usb_driver_work);
+
+	return 0;
+}
+
+static int onboard_hub_remove(struct platform_device *pdev)
+{
+	struct onboard_hub *hub = dev_get_drvdata(&pdev->dev);
+	struct usbdev_node *node;
+	struct usb_device *udev;
+
+	hub->going_away = true;
+
+	cancel_work_sync(&hub->attach_usb_driver_work);
+
+	mutex_lock(&hub->lock);
+
+	/* unbind the USB devices to avoid dangling references to this device */
+	while (!list_empty(&hub->udev_list)) {
+		node = list_first_entry(&hub->udev_list, struct usbdev_node, list);
+		udev = node->udev;
+
+		/*
+		 * Unbinding the driver will call onboard_hub_remove_usbdev(),
+		 * which acquires hub->lock.  We must release the lock first.
+		 */
+		get_device(&udev->dev);
+		mutex_unlock(&hub->lock);
+		device_release_driver(&udev->dev);
+		put_device(&udev->dev);
+		mutex_lock(&hub->lock);
+	}
+
+	mutex_unlock(&hub->lock);
+
+	return onboard_hub_power_off(hub);
+}
+
+MODULE_DEVICE_TABLE(of, onboard_hub_match);
+
+static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume)
+};
+
+static struct platform_driver onboard_hub_driver = {
+	.probe = onboard_hub_probe,
+	.remove = onboard_hub_remove,
+
+	.driver = {
+		.name = "onboard-usb-hub",
+		.of_match_table = onboard_hub_match,
+		.pm = pm_ptr(&onboard_hub_pm_ops),
+		.dev_groups = onboard_hub_groups,
+	},
+};
+
+/************************** USB driver **************************/
+
+#define VENDOR_ID_REALTEK	0x0bda
+
+/*
+ * Returns the onboard_hub platform device that is associated with the USB
+ * device passed as parameter.
+ */
+static struct onboard_hub *_find_onboard_hub(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+	struct onboard_hub *hub;
+
+	pdev = of_find_device_by_node(dev->of_node);
+	if (!pdev) {
+		np = of_parse_phandle(dev->of_node, "companion-hub", 0);
+		if (!np) {
+			dev_err(dev, "failed to find device node for companion hub\n");
+			return ERR_PTR(-EINVAL);
+		}
+
+		pdev = of_find_device_by_node(np);
+		of_node_put(np);
+
+		if (!pdev)
+			return ERR_PTR(-ENODEV);
+	}
+
+	hub = dev_get_drvdata(&pdev->dev);
+	put_device(&pdev->dev);
+
+	/*
+	 * The presence of drvdata ('hub') indicates that the platform driver
+	 * finished probing. This handles the case where (conceivably) we could
+	 * be running at the exact same time as the platform driver's probe. If
+	 * we detect the race we request probe deferral and we'll come back and
+	 * try again.
+	 */
+	if (!hub)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return hub;
+}
+
+static int onboard_hub_usbdev_probe(struct usb_device *udev)
+{
+	struct device *dev = &udev->dev;
+	struct onboard_hub *hub;
+	int err;
+
+	/* ignore supported hubs without device tree node */
+	if (!dev->of_node)
+		return -ENODEV;
+
+	hub = _find_onboard_hub(dev);
+	if (IS_ERR(hub))
+		return PTR_ERR(hub);
+
+	dev_set_drvdata(dev, hub);
+
+	err = onboard_hub_add_usbdev(hub, udev);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
+{
+	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
+
+	onboard_hub_remove_usbdev(hub, udev);
+}
+
+static const struct usb_device_id onboard_hub_id_table[] = {
+	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */
+	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */
+	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */
+	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */
+	{}
+};
+MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);
+
+static struct usb_device_driver onboard_hub_usbdev_driver = {
+	.name = "onboard-usb-hub",
+	.probe = onboard_hub_usbdev_probe,
+	.disconnect = onboard_hub_usbdev_disconnect,
+	.generic_subclass = 1,
+	.supports_autosuspend =	1,
+	.id_table = onboard_hub_id_table,
+};
+
+static int __init onboard_hub_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&onboard_hub_driver);
+	if (ret)
+		return ret;
+
+	ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE);
+	if (ret)
+		platform_driver_unregister(&onboard_hub_driver);
+
+	return ret;
+}
+module_init(onboard_hub_init);
+
+static void __exit onboard_hub_exit(void)
+{
+	usb_deregister_device_driver(&onboard_hub_usbdev_driver);
+	platform_driver_unregister(&onboard_hub_driver);
+}
+module_exit(onboard_hub_exit);
+
+MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
+MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/usb/misc/onboard_usb_hub.h b/drivers/usb/misc/onboard_usb_hub.h
new file mode 100644
index 000000000000..d3a5b6938582
--- /dev/null
+++ b/drivers/usb/misc/onboard_usb_hub.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2022, Google LLC
+ */
+
+#ifndef _USB_MISC_ONBOARD_USB_HUB_H
+#define _USB_MISC_ONBOARD_USB_HUB_H
+
+static const struct of_device_id onboard_hub_match[] = {
+	{ .compatible = "usbbda,411" },
+	{ .compatible = "usbbda,5411" },
+	{ .compatible = "usbbda,414" },
+	{ .compatible = "usbbda,5414" },
+	{}
+};
+
+#endif /* _USB_MISC_ONBOARD_USB_HUB_H */
diff --git a/drivers/usb/misc/onboard_usb_hub_pdevs.c b/drivers/usb/misc/onboard_usb_hub_pdevs.c
new file mode 100644
index 000000000000..5456f883315b
--- /dev/null
+++ b/drivers/usb/misc/onboard_usb_hub_pdevs.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * API for creating and destroying USB onboard hub platform devices
+ *
+ * Copyright (c) 2022, Google LLC
+ */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/of.h>
+
+#include "onboard_usb_hub.h"
+
+struct pdev_list_entry {
+	struct platform_device *pdev;
+	struct list_head node;
+};
+
+static bool of_is_onboard_usb_hub(const struct device_node *np)
+{
+	return !!of_match_node(onboard_hub_match, np);
+}
+
+/**
+ * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs
+ * @parent_hub	: parent hub to scan for connected onboard hubs
+ * @pdev_list	: list of onboard hub platform devices owned by the parent hub
+ *
+ * Creates a platform device for each supported onboard hub that is connected to
+ * the given parent hub. The platform device is in charge of initializing the
+ * hub (enable regulators, take the hub out of reset, ...) and can optionally
+ * control whether the hub remains powered during system suspend or not.
+
+ * To keep track of the platform devices they are added to
+ * a list that is owned by the parent hub.
+ */
+void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
+{
+	int i;
+	struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus);
+	struct device_node *np, *npc;
+	struct platform_device *pdev;
+	struct pdev_list_entry *pdle;
+
+	if (!parent_hub->dev.of_node)
+		return;
+
+	/*
+	 * We only want one platform device for each physical hub. For root hubs
+	 * this function can be called multiple times with the same root hub
+	 * node (the HCD node). Only create pdevs if the root hub is the one of
+	 * the primary HCD.
+	 */
+	if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd))
+		return;
+
+	for (i = 1; i <= parent_hub->maxchild; i++) {
+		np = usb_of_get_device_node(parent_hub, i);
+		if (!np)
+			continue;
+
+		if (!of_is_onboard_usb_hub(np))
+			goto node_put;
+
+		npc = of_parse_phandle(np, "companion-hub", 0);
+		if (npc) {
+			/*
+			 * Hubs with companions share the same platform device.
+			 * Create the plaform device only if 'parent_hub' is
+			 * connected to the primary HCD (directly or through
+			 * other hubs).
+			 */
+			if (!usb_hcd_is_primary_hcd(hcd)) {
+				of_node_put(npc);
+				goto node_put;
+			}
+
+			pdev = of_find_device_by_node(npc);
+			of_node_put(npc);
+
+			if (pdev) {
+				/*
+				 * The companion hub already has a platform device,
+				 * nothing to do here.
+				 */
+				put_device(&pdev->dev);
+				goto node_put;
+			}
+		}
+
+		pdev = of_platform_device_create(np, NULL, &parent_hub->dev);
+		if (!pdev) {
+			dev_err(&parent_hub->dev,
+				"failed to create platform device for onboard hub '%pOF'\n", np);
+			goto node_put;
+		}
+
+		pdle = kzalloc(sizeof(*pdle), GFP_KERNEL);
+		if (!pdle) {
+			of_platform_device_destroy(&pdev->dev, NULL);
+			goto node_put;
+		}
+
+		pdle->pdev = pdev;
+		list_add(&pdle->node, pdev_list);
+
+node_put:
+		of_node_put(np);
+	}
+}
+EXPORT_SYMBOL_GPL(onboard_hub_create_pdevs);
+
+/**
+ * onboard_hub_destroy_pdevs -- free resources of onboard hub platform devices
+ * @pdev_list	: list of onboard hub platform devices
+ *
+ * Destroys the platform devices in the given list and frees the memory associated
+ * with the list entry.
+ */
+void onboard_hub_destroy_pdevs(struct list_head *pdev_list)
+{
+	struct pdev_list_entry *pdle, *tmp;
+
+	list_for_each_entry_safe(pdle, tmp, pdev_list, node) {
+		list_del(&pdle->node);
+		of_platform_device_destroy(&pdle->pdev->dev, NULL);
+		kfree(pdle);
+	}
+}
+EXPORT_SYMBOL_GPL(onboard_hub_destroy_pdevs);
diff --git a/include/linux/usb/onboard_hub.h b/include/linux/usb/onboard_hub.h
new file mode 100644
index 000000000000..d9373230556e
--- /dev/null
+++ b/include/linux/usb/onboard_hub.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __LINUX_USB_ONBOARD_HUB_H
+#define __LINUX_USB_ONBOARD_HUB_H
+
+struct usb_device;
+struct list_head;
+
+#if IS_ENABLED(CONFIG_USB_ONBOARD_HUB)
+void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list);
+void onboard_hub_destroy_pdevs(struct list_head *pdev_list);
+#else
+static inline void onboard_hub_create_pdevs(struct usb_device *parent_hub,
+					    struct list_head *pdev_list) {}
+static inline void onboard_hub_destroy_pdevs(struct list_head *pdev_list) {}
+#endif
+
+#endif /* __LINUX_USB_ONBOARD_HUB_H */
-- 
2.37.0.rc0.104.g0611611a94-goog

[PATCH v23 3/3] usb: core: hub: Create platform devices for onboard hubs in hub_probe()

[Matthias Kaehlcke]

Call onboard_hub_create/destroy_pdevs() from hub_probe/disconnect()
to create/destroy platform devices for onboard USB hubs that may be
connected to the hub. The onboard hubs must have nodes in the
device tree.

onboard_hub_create/destroy_pdevs() are NOPs unless
CONFIG_USB_ONBOARD_HUB=y/m.

Also add a field to struct usb_hub to keep track of the onboard hub
platform devices that are owned by the hub.

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

Changes in v23:
- added Doug's 'Reviewed-by' tag

Changes in v22:
- patch added to the series (moved creation/deletion from HCD)

 drivers/usb/core/hub.c | 9 ++++++++-
 drivers/usb/core/hub.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 68e9121c1878..8055130ee602 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -23,6 +23,7 @@
 #include <linux/usb.h>
 #include <linux/usbdevice_fs.h>
 #include <linux/usb/hcd.h>
+#include <linux/usb/onboard_hub.h>
 #include <linux/usb/otg.h>
 #include <linux/usb/quirks.h>
 #include <linux/workqueue.h>
@@ -1752,6 +1753,8 @@ static void hub_disconnect(struct usb_interface *intf)
 	if (hub->quirk_disable_autosuspend)
 		usb_autopm_put_interface(intf);
 
+	onboard_hub_destroy_pdevs(&hub->onboard_hub_devs);
+
 	kref_put(&hub->kref, hub_release);
 }
 
@@ -1869,6 +1872,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	INIT_DELAYED_WORK(&hub->leds, led_work);
 	INIT_DELAYED_WORK(&hub->init_work, NULL);
 	INIT_WORK(&hub->events, hub_event);
+	INIT_LIST_HEAD(&hub->onboard_hub_devs);
 	spin_lock_init(&hub->irq_urb_lock);
 	timer_setup(&hub->irq_urb_retry, hub_retry_irq_urb, 0);
 	usb_get_intf(intf);
@@ -1889,8 +1893,11 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
 		usb_autopm_get_interface_no_resume(intf);
 	}
 
-	if (hub_configure(hub, &desc->endpoint[0].desc) >= 0)
+	if (hub_configure(hub, &desc->endpoint[0].desc) >= 0) {
+		onboard_hub_create_pdevs(hdev, &hub->onboard_hub_devs);
+
 		return 0;
+	}
 
 	hub_disconnect(intf);
 	return -ENODEV;
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 22ea1f4f2d66..ccf90052d12a 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -73,6 +73,7 @@ struct usb_hub {
 	spinlock_t		irq_urb_lock;
 	struct timer_list	irq_urb_retry;
 	struct usb_port		**ports;
+	struct list_head        onboard_hub_devs;
 };
 
 /**
-- 
2.37.0.rc0.104.g0611611a94-goog

Re: [PATCH v23 2/3] usb: misc: Add onboard_usb_hub driver

[Doug Anderson]

Hi,

On Wed, Jun 22, 2022 at 2:49 PM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> index 4c5ddbd75b7e..7fd40183a395 100644
> --- a/drivers/usb/misc/Kconfig
> +++ b/drivers/usb/misc/Kconfig
> @@ -295,3 +295,19 @@ config BRCM_USB_PINMAP
>           This option enables support for remapping some USB external
>           signals, which are typically on dedicated pins on the chip,
>           to any gpio.
> +
> +config USB_ONBOARD_HUB
> +       bool "Onboard USB hub support"

The above needs to be "tristate", not bool.

Weirdly the way you have it if you set "CONFIG_USB=m" and
"CONFIG_USB_ONBOARD_HUB=y" you don't get any compile errors, but also
the onboard usb hub doesn't even get compiled (!). Once you switch to
tristate then setting "CONFIG_USB=m" will force the onboard hub to be
a module too (since it's underneath the "if" in the Kconfig).

...ugh, but once you do that then you start getting compile errors if
you have "CONFIG_USB=y" and "CONFIG_USB_ONBOARD_HUB=m". I guess that
can be fixed with something like this

-usbcore-$(CONFIG_USB_ONBOARD_HUB)      += ../misc/onboard_usb_hub_pdevs.o
+ifdef CONFIG_USB_ONBOARD_HUB
+usbcore-y                      += ../misc/onboard_usb_hub_pdevs.o
+endif

Given the problems we've had in the past, please make sure you test
with all combinations of "=y" and "=m" for CONFIG_USB and
CONFIG_USB_ONBOARD_HUB. Note that on sc7180-trogdor devices if you
want CONFIG_USB to be a module don't forget to also set
CONFIG_USB_DWC3=m or DWC3 will force you to gadget mode...


> +/**
> + * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs
> + * @parent_hub : parent hub to scan for connected onboard hubs
> + * @pdev_list  : list of onboard hub platform devices owned by the parent hub
> + *
> + * Creates a platform device for each supported onboard hub that is connected to
> + * the given parent hub. The platform device is in charge of initializing the
> + * hub (enable regulators, take the hub out of reset, ...) and can optionally
> + * control whether the hub remains powered during system suspend or not.
> +
> + * To keep track of the platform devices they are added to
> + * a list that is owned by the parent hub.

super nitty, but the above two lines of comment could be word-wrapped better.


> + */
> +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
> +{
> +       int i;
> +       struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus);

As per my response on v22, would you be willing to rename that to
"parent_hcd"? I'll probably still confuse myself next time I read this
function, but at least maybe this will help me recognize more quickly
that this isn't necessarily the child's hcd in the case of the root
hub.

-Doug

Re: [PATCH v23 2/3] usb: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke]

On Fri, Jun 24, 2022 at 01:33:25PM -0700, Doug Anderson wrote:
> Hi,
> 
> On Wed, Jun 22, 2022 at 2:49 PM Matthias Kaehlcke <mka@chromium.org> wrote:
> >
> > diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> > index 4c5ddbd75b7e..7fd40183a395 100644
> > --- a/drivers/usb/misc/Kconfig
> > +++ b/drivers/usb/misc/Kconfig
> > @@ -295,3 +295,19 @@ config BRCM_USB_PINMAP
> >           This option enables support for remapping some USB external
> >           signals, which are typically on dedicated pins on the chip,
> >           to any gpio.
> > +
> > +config USB_ONBOARD_HUB
> > +       bool "Onboard USB hub support"
> 
> The above needs to be "tristate", not bool.

right, thanks!

> Weirdly the way you have it if you set "CONFIG_USB=m" and
> "CONFIG_USB_ONBOARD_HUB=y" you don't get any compile errors, but also
> the onboard usb hub doesn't even get compiled (!). Once you switch to
> tristate then setting "CONFIG_USB=m" will force the onboard hub to be
> a module too (since it's underneath the "if" in the Kconfig).
> 
> ...ugh, but once you do that then you start getting compile errors if
> you have "CONFIG_USB=y" and "CONFIG_USB_ONBOARD_HUB=m". I guess that
> can be fixed with something like this
> 
> -usbcore-$(CONFIG_USB_ONBOARD_HUB)      += ../misc/onboard_usb_hub_pdevs.o
> +ifdef CONFIG_USB_ONBOARD_HUB
> +usbcore-y                      += ../misc/onboard_usb_hub_pdevs.o
> +endif

Thanks for testing and the suggestion!

> Given the problems we've had in the past, please make sure you test
> with all combinations of "=y" and "=m" for CONFIG_USB and
> CONFIG_USB_ONBOARD_HUB. Note that on sc7180-trogdor devices if you
> want CONFIG_USB to be a module don't forget to also set
> CONFIG_USB_DWC3=m or DWC3 will force you to gadget mode...

ack

I think I did an 'allmodconfig' build only test, but that didn't really help
in this case ...

> > +/**
> > + * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs
> > + * @parent_hub : parent hub to scan for connected onboard hubs
> > + * @pdev_list  : list of onboard hub platform devices owned by the parent hub
> > + *
> > + * Creates a platform device for each supported onboard hub that is connected to
> > + * the given parent hub. The platform device is in charge of initializing the
> > + * hub (enable regulators, take the hub out of reset, ...) and can optionally
> > + * control whether the hub remains powered during system suspend or not.
> > +
> > + * To keep track of the platform devices they are added to
> > + * a list that is owned by the parent hub.
> 
> super nitty, but the above two lines of comment could be word-wrapped better.

Sure, I probably rephrased that at some point and forgot to re-wrap.

> > + */
> > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
> > +{
> > +       int i;
> > +       struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus);
> 
> As per my response on v22, would you be willing to rename that to
> "parent_hcd"? I'll probably still confuse myself next time I read this
> function, but at least maybe this will help me recognize more quickly
> that this isn't necessarily the child's hcd in the case of the root
> hub.

See my reply on v22, I think 'parent_hcd' could still be confusing and it
might be best to have a more detailed description of the problem. In any
case I'm open to discuss it :)

Re: [PATCH v23 2/3] usb: misc: Add onboard_usb_hub driver

[kernel test robot]

Hi Matthias,

I love your patch! Perhaps something to improve:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on robh/for-next driver-core/driver-core-testing linus/master v5.19-rc4 next-20220627]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthias-Kaehlcke/usb-misc-Add-onboard_usb_hub-driver/20220623-055345
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
config: powerpc-randconfig-c003-20220626 (https://download.01.org/0day-ci/archive/20220628/202206280628.JyfBwOj6-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project b0d6dd3905db145853c7c744ac92d49b00b1fa20)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/ca463a6be5677cdb098dd5a431dd4aa06da8a0fe
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Matthias-Kaehlcke/usb-misc-Add-onboard_usb_hub-driver/20220623-055345
        git checkout ca463a6be5677cdb098dd5a431dd4aa06da8a0fe
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/usb/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/usb/core/../misc/onboard_usb_hub_pdevs.c:44:6: warning: no previous prototype for function 'onboard_hub_create_pdevs' [-Wmissing-prototypes]
   void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
        ^
   drivers/usb/core/../misc/onboard_usb_hub_pdevs.c:44:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
   ^
   static 
>> drivers/usb/core/../misc/onboard_usb_hub_pdevs.c:127:6: warning: no previous prototype for function 'onboard_hub_destroy_pdevs' [-Wmissing-prototypes]
   void onboard_hub_destroy_pdevs(struct list_head *pdev_list)
        ^
   drivers/usb/core/../misc/onboard_usb_hub_pdevs.c:127:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void onboard_hub_destroy_pdevs(struct list_head *pdev_list)
   ^
   static 
   2 warnings generated.


vim +/onboard_hub_create_pdevs +44 drivers/usb/core/../misc/onboard_usb_hub_pdevs.c

    30	
    31	/**
    32	 * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs
    33	 * @parent_hub	: parent hub to scan for connected onboard hubs
    34	 * @pdev_list	: list of onboard hub platform devices owned by the parent hub
    35	 *
    36	 * Creates a platform device for each supported onboard hub that is connected to
    37	 * the given parent hub. The platform device is in charge of initializing the
    38	 * hub (enable regulators, take the hub out of reset, ...) and can optionally
    39	 * control whether the hub remains powered during system suspend or not.
    40	
    41	 * To keep track of the platform devices they are added to
    42	 * a list that is owned by the parent hub.
    43	 */
  > 44	void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
    45	{
    46		int i;
    47		struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus);
    48		struct device_node *np, *npc;
    49		struct platform_device *pdev;
    50		struct pdev_list_entry *pdle;
    51	
    52		if (!parent_hub->dev.of_node)
    53			return;
    54	
    55		/*
    56		 * We only want one platform device for each physical hub. For root hubs
    57		 * this function can be called multiple times with the same root hub
    58		 * node (the HCD node). Only create pdevs if the root hub is the one of
    59		 * the primary HCD.
    60		 */
    61		if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd))
    62			return;
    63	
    64		for (i = 1; i <= parent_hub->maxchild; i++) {
    65			np = usb_of_get_device_node(parent_hub, i);
    66			if (!np)
    67				continue;
    68	
    69			if (!of_is_onboard_usb_hub(np))
    70				goto node_put;
    71	
    72			npc = of_parse_phandle(np, "companion-hub", 0);
    73			if (npc) {
    74				/*
    75				 * Hubs with companions share the same platform device.
    76				 * Create the plaform device only if 'parent_hub' is
    77				 * connected to the primary HCD (directly or through
    78				 * other hubs).
    79				 */
    80				if (!usb_hcd_is_primary_hcd(hcd)) {
    81					of_node_put(npc);
    82					goto node_put;
    83				}
    84	
    85				pdev = of_find_device_by_node(npc);
    86				of_node_put(npc);
    87	
    88				if (pdev) {
    89					/*
    90					 * The companion hub already has a platform device,
    91					 * nothing to do here.
    92					 */
    93					put_device(&pdev->dev);
    94					goto node_put;
    95				}
    96			}
    97	
    98			pdev = of_platform_device_create(np, NULL, &parent_hub->dev);
    99			if (!pdev) {
   100				dev_err(&parent_hub->dev,
   101					"failed to create platform device for onboard hub '%pOF'\n", np);
   102				goto node_put;
   103			}
   104	
   105			pdle = kzalloc(sizeof(*pdle), GFP_KERNEL);
   106			if (!pdle) {
   107				of_platform_device_destroy(&pdev->dev, NULL);
   108				goto node_put;
   109			}
   110	
   111			pdle->pdev = pdev;
   112			list_add(&pdle->node, pdev_list);
   113	
   114	node_put:
   115			of_node_put(np);
   116		}
   117	}
   118	EXPORT_SYMBOL_GPL(onboard_hub_create_pdevs);
   119	
   120	/**
   121	 * onboard_hub_destroy_pdevs -- free resources of onboard hub platform devices
   122	 * @pdev_list	: list of onboard hub platform devices
   123	 *
   124	 * Destroys the platform devices in the given list and frees the memory associated
   125	 * with the list entry.
   126	 */
 > 127	void onboard_hub_destroy_pdevs(struct list_head *pdev_list)

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp