[PATCH v19 0/5] usb: misc: Add onboard_usb_hub driver

[PATCH v19 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 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  |  19 +-
 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            | 494 ++++++++++++++++++
 include/linux/of_platform.h                   |  22 +-
 include/linux/usb/hcd.h                       |   1 +
 include/linux/usb/onboard_hub.h               |  18 +
 15 files changed, 620 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

-- 
2.34.1.575.g55b058a8bb-goog

[PATCH v19 1/5] 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>
---

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,
-- 
2.34.1.575.g55b058a8bb-goog

[PATCH v19 2/5] driver core: Export device_is_bound()

[Matthias Kaehlcke]

Export device_is_bound() to enable its use by drivers that are
built as modules.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

Changes in v19:
- none

Changes in v18:
- patch added to the series

 drivers/base/dd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 68ea1f949daa..07eefddd4a77 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -370,6 +370,7 @@ bool device_is_bound(struct device *dev)
 {
 	return dev->p && klist_node_attached(&dev->p->knode_driver);
 }
+EXPORT_SYMBOL_GPL(device_is_bound);
 
 static void driver_bound(struct device *dev)
 {
-- 
2.34.1.575.g55b058a8bb-goog

[PATCH v19 3/5] 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).

Note: the current series only supports hubs connected directly to
a root hub, support for other configurations could be added if
needed.

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>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
---

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/misc/Kconfig                      |  23 +
 drivers/usb/misc/Makefile                     |   1 +
 drivers/usb/misc/onboard_usb_hub.c            | 494 ++++++++++++++++++
 include/linux/usb/onboard_hub.h               |  18 +
 6 files changed, 551 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 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..39fa2ed29fed
--- /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:		November 2021
+KernelVersion:	5.17
+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 dd36acc87ce6..68bc6efaad3f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14183,6 +14183,13 @@ 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/misc/Kconfig b/drivers/usb/misc/Kconfig
index 8f1144359012..bbced519499a 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -284,3 +284,26 @@ 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 nontrivial 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.
+
+if USB_ONBOARD_HUB
+config USB_ONBOARD_HUB_ACTUAL
+	tristate
+	default m if USB=m
+	default y if USB=y
+endif
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 5f4e598573ab..9549b88c2cc1 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -32,3 +32,4 @@ 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_ACTUAL)	+= 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..4e88e3089def
--- /dev/null
+++ b/drivers/usb/misc/onboard_usb_hub.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Driver for onboard USB hubs
+ *
+ * Copyright (c) 2020, Google LLC
+ */
+
+#include <linux/device.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/suspend.h>
+#include <linux/sysfs.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/of.h>
+#include <linux/usb/onboard_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 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;
+
+	if (hub->always_powered_in_suspend)
+		return 0;
+
+	power_off = true;
+
+	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 set_udev_link_name(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 ret = 0;
+
+	mutex_lock(&hub->lock);
+
+	if (hub->going_away) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	node = devm_kzalloc(hub->dev, sizeof(*node), GFP_KERNEL);
+	if (!node) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	node->udev = udev;
+
+	list_add(&node->list, &hub->udev_list);
+
+	set_udev_link_name(udev, link_name, sizeof(link_name));
+	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));
+
+unlock:
+	mutex_unlock(&hub->lock);
+
+	return ret;
+}
+
+static void onboard_hub_remove_usbdev(struct onboard_hub *hub, struct usb_device *udev)
+{
+	struct usbdev_node *node;
+	char link_name[64];
+
+	set_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);
+			break;
+		}
+	}
+
+	mutex_unlock(&hub->lock);
+}
+
+static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	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 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(), make sure to re-attach it if needed.
+	 */
+	err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver);
+	if (err) {
+		onboard_hub_power_off(hub);
+		return err;
+	}
+
+	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;
+
+	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);
+}
+
+static const struct of_device_id onboard_hub_match[] = {
+	{ .compatible = "usbbda,411" },
+	{ .compatible = "usbbda,5411" },
+	{ .compatible = "usbbda,414" },
+	{ .compatible = "usbbda,5414" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, onboard_hub_match);
+
+static bool of_is_onboard_usb_hub(const struct device_node *np)
+{
+	return !!of_match_node(onboard_hub_match, np);
+}
+
+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;
+
+	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 || !device_is_bound(&pdev->dev))
+			return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	put_device(&pdev->dev);
+
+	return dev_get_drvdata(&pdev->dev);
+}
+
+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;
+
+	err = sysfs_create_link(&udev->dev.kobj, &hub->dev->kobj, "onboard_hub_dev");
+	if (err)
+		dev_warn(&udev->dev, "failed to create symlink to platform device: %d\n", err);
+
+	return 0;
+}
+
+static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
+{
+	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
+
+	sysfs_remove_link(&udev->dev.kobj, "onboard_hub_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,
+};
+
+/*** Helpers for creating/destroying platform devices for onboard hubs ***/
+
+struct pdev_list_entry {
+	struct platform_device *pdev;
+	struct list_head node;
+};
+
+/*
+ * Creates a platform device for each supported onboard hub that is connected to
+ * the given parent hub. 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 device_node *np, *npc;
+	struct platform_device *pdev = NULL;
+	struct pdev_list_entry *pdle;
+
+	INIT_LIST_HEAD(pdev_list);
+
+	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) {
+			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 = devm_kzalloc(&pdev->dev, 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);
+
+/*
+ * 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);
+	}
+}
+EXPORT_SYMBOL_GPL(onboard_hub_destroy_pdevs);
+
+/************************** Driver (de)registration **************************/
+
+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/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 */
-- 
2.34.1.575.g55b058a8bb-goog

[PATCH v19 4/5] usb: core: hcd: Create platform devices for onboard hubs in probe()

[Matthias Kaehlcke]

Call onboard_hub_create/destroy_pdevs() from usb_add/remove_hcd()
for primary HCDs to create/destroy platform devices for onboard
USB hubs that may be connected to the root hub of the controller.
These functions are a NOP unless CONFIG_USB_ONBOARD_HUB=y/m.

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

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

Changes in v19:
- none

Changes in v18:
- none

Changes in v17:
- create the platform devices in the generic HCD code instead of
  the xhci_platform driver
- updated subject and commit message to reflect the above change
- dropped initialization of platform device list, which is now
  done in onboard_hub_create_pdevs()

Changes in v16:
- none

Changes in v15:
- none

Changes in v14:
- none

Changes in v13:
- added comment for 'depends on USB_ONBOARD_HUB || !USB_ONBOARD_HUB'
  construct

Changes in v12:
- none

Changes in v11:
- use onboard_hub_create/destroy_pdevs() to support multiple onboard
  hubs that are connected to the same root hub
- moved field/list to keep track of platform devices from struct
  usb_hcd to struct xhci_hcd
- updated commit message

Changes in v10:
- none

Changes in v9:
- added dependency on USB_ONBOARD_HUB (or !!USB_ONBOARD_HUB) to
  USB_XHCI_PLATFORM

Changes in v8:
- none

Changes in v7:
- none

Changes in v6:
- none

Changes in v5:
- patch added to the series

 drivers/usb/core/hcd.c  | 6 ++++++
 include/linux/usb/hcd.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 4d326ee12c36..b8220e411e07 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -36,6 +36,7 @@
 #include <linux/phy/phy.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/usb/onboard_hub.h>
 #include <linux/usb/otg.h>
 
 #include "usb.h"
@@ -2963,6 +2964,9 @@ int usb_add_hcd(struct usb_hcd *hcd,
 	if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
 		usb_hcd_poll_rh_status(hcd);
 
+	if (usb_hcd_is_primary_hcd(hcd))
+		onboard_hub_create_pdevs(hcd->self.root_hub, &hcd->onboard_hub_devs);
+
 	return retval;
 
 err_register_root_hub:
@@ -3041,6 +3045,8 @@ void usb_remove_hcd(struct usb_hcd *hcd)
 	if (usb_hcd_is_primary_hcd(hcd)) {
 		if (hcd->irq > 0)
 			free_irq(hcd->irq, hcd);
+
+		onboard_hub_destroy_pdevs(&hcd->onboard_hub_devs);
 	}
 
 	usb_deregister_bus(&hcd->self);
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 548a028f2dab..4ebc91c09182 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -198,6 +198,7 @@ struct usb_hcd {
 	struct usb_hcd		*shared_hcd;
 	struct usb_hcd		*primary_hcd;
 
+	struct list_head	onboard_hub_devs;
 
 #define HCD_BUFFER_POOLS	4
 	struct dma_pool		*pool[HCD_BUFFER_POOLS];
-- 
2.34.1.575.g55b058a8bb-goog

[PATCH v19 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>
---

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  | 19 ++++++++++++++++++-
 5 files changed, 43 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..5fb8e12af1a0 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_0 {
+	 vdd-supply = <&pp3300_l7c>;
+};
+
+&usb_hub_3_0 {
+	 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..1dae714250f5 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_0 {
+	 vdd-supply = <&pp3300_l7c>;
 };
 
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
+&usb_hub_3_0 {
+	 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..c913bb5677e5 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_0 {
+	 vdd-supply = <&pp3300_l7c>;
 };
 
-&pp3300_l7c {
-	regulator-always-on;
-	regulator-boot-on;
+&usb_hub_3_0 {
+	 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..8477c82c410a 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_0 {
+	 vdd-supply = <&pp3300_l7c>;
+};
+
+&usb_hub_3_0 {
+	 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..cd31460b3bd6 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
@@ -202,7 +202,6 @@ pp3300_hub: pp3300-hub {
 		pinctrl-names = "default";
 		pinctrl-0 = <&en_pp3300_hub>;
 
-		regulator-always-on;
 		regulator-boot-on;
 
 		vin-supply = <&pp3300_a>;
@@ -839,6 +838,24 @@ &usb_1 {
 
 &usb_1_dwc3 {
 	dr_mode = "host";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	/* 2.0 hub on port 1 */
+	usb_hub_2_0: hub@1 {
+		compatible = "usbbda,5411";
+		reg = <1>;
+		vdd-supply = <&pp3300_hub>;
+		companion-hub = <&usb_hub_3_0>;
+	};
+
+	/* 3.0 hub on port 2 */
+	usb_hub_3_0: hub@2 {
+		compatible = "usbbda,411";
+		reg = <2>;
+		vdd-supply = <&pp3300_hub>;
+		companion-hub = <&usb_hub_2_0>;
+	};
 };
 
 &usb_1_hsphy {
-- 
2.34.1.575.g55b058a8bb-goog

Re: [PATCH v19 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 11:10:48)
> 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>
> ---

One question below

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

>
>  .../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  | 19 ++++++++++++++++++-
>  5 files changed, 43 insertions(+), 37 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> index d4f4441179fc..cd31460b3bd6 100644
> --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> @@ -202,7 +202,6 @@ pp3300_hub: pp3300-hub {
>                 pinctrl-names = "default";
>                 pinctrl-0 = <&en_pp3300_hub>;
>
> -               regulator-always-on;
>                 regulator-boot-on;

Is regulator-boot-on necessary?

>
>                 vin-supply = <&pp3300_a>;

Re: [PATCH v19 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Matthias Kaehlcke]

On Wed, Jan 12, 2022 at 12:47:15PM -0800, Stephen Boyd wrote:
> Quoting Matthias Kaehlcke (2022-01-12 11:10:48)
> > 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>
> > ---
> 
> One question below
> 
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>

Thanks!

> >  .../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  | 19 ++++++++++++++++++-
> >  5 files changed, 43 insertions(+), 37 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > index d4f4441179fc..cd31460b3bd6 100644
> > --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > @@ -202,7 +202,6 @@ pp3300_hub: pp3300-hub {
> >                 pinctrl-names = "default";
> >                 pinctrl-0 = <&en_pp3300_hub>;
> >
> > -               regulator-always-on;
> >                 regulator-boot-on;
> 
> Is regulator-boot-on necessary?

It tells the kernel that the regulator is already on at boot, and avoids an
off-on cycle that would happen otherwise (internal reference: b/185972336).

Re: [PATCH v19 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 12:51:41)
> On Wed, Jan 12, 2022 at 12:47:15PM -0800, Stephen Boyd wrote:
> > Quoting Matthias Kaehlcke (2022-01-12 11:10:48)
>
> > > diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > > index d4f4441179fc..cd31460b3bd6 100644
> > > --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> > > @@ -202,7 +202,6 @@ pp3300_hub: pp3300-hub {
> > >                 pinctrl-names = "default";
> > >                 pinctrl-0 = <&en_pp3300_hub>;
> > >
> > > -               regulator-always-on;
> > >                 regulator-boot-on;
> >
> > Is regulator-boot-on necessary?
>
> It tells the kernel that the regulator is already on at boot, and avoids an
> off-on cycle that would happen otherwise (internal reference: b/185972336).

Got it! A comment here would be helpful so we know the BIOS leaves the
regulator on.

Re: [PATCH v19 1/5] of/platform: Add stubs for of_platform_device_create/destroy()

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 11:10:44)
> 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>

Re: [PATCH v19 3/5] usb: misc: Add onboard_usb_hub driver

[Doug Anderson]

Hi,

On Wed, Jan 12, 2022 at 11:11 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> 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).
>
> Note: the current series only supports hubs connected directly to
> a root hub, support for other configurations could be added if
> needed.
>
> 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>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> ---
>
> 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/misc/Kconfig                      |  23 +
>  drivers/usb/misc/Makefile                     |   1 +
>  drivers/usb/misc/onboard_usb_hub.c            | 494 ++++++++++++++++++
>  include/linux/usb/onboard_hub.h               |  18 +
>  6 files changed, 551 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 include/linux/usb/onboard_hub.h

Sorry for not reviewing v18, but this looks peachy to me now.

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Re: [PATCH v19 1/5] of/platform: Add stubs for of_platform_device_create/destroy()

[Doug Anderson]

Hi,

On Wed, Jan 12, 2022 at 11:10 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> 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>
> ---
>
> 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(-)

I was assuming it didn't matter with Rob's Ack, but for completeness:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Re: [PATCH v19 2/5] driver core: Export device_is_bound()

[Doug Anderson]

Hi,

On Wed, Jan 12, 2022 at 11:11 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> Export device_is_bound() to enable its use by drivers that are
> built as modules.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
> Changes in v19:
> - none
>
> Changes in v18:
> - patch added to the series
>
>  drivers/base/dd.c | 1 +
>  1 file changed, 1 insertion(+)

Though it's probably above my pay grade to do so:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Re: [PATCH v19 4/5] usb: core: hcd: Create platform devices for onboard hubs in probe()

[Doug Anderson]

Hi,

On Wed, Jan 12, 2022 at 11:11 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> Call onboard_hub_create/destroy_pdevs() from usb_add/remove_hcd()
> for primary HCDs to create/destroy platform devices for onboard
> USB hubs that may be connected to the root hub of the controller.
> These functions are a NOP unless CONFIG_USB_ONBOARD_HUB=y/m.
>
> Also add a field to struct usb_hcd to keep track of the onboard hub
> platform devices that are owned by the HCD.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
> Changes in v19:
> - none
>
> Changes in v18:
> - none
>
> Changes in v17:
> - create the platform devices in the generic HCD code instead of
>   the xhci_platform driver
> - updated subject and commit message to reflect the above change
> - dropped initialization of platform device list, which is now
>   done in onboard_hub_create_pdevs()
>
> Changes in v16:
> - none
>
> Changes in v15:
> - none
>
> Changes in v14:
> - none
>
> Changes in v13:
> - added comment for 'depends on USB_ONBOARD_HUB || !USB_ONBOARD_HUB'
>   construct
>
> Changes in v12:
> - none
>
> Changes in v11:
> - use onboard_hub_create/destroy_pdevs() to support multiple onboard
>   hubs that are connected to the same root hub
> - moved field/list to keep track of platform devices from struct
>   usb_hcd to struct xhci_hcd
> - updated commit message
>
> Changes in v10:
> - none
>
> Changes in v9:
> - added dependency on USB_ONBOARD_HUB (or !!USB_ONBOARD_HUB) to
>   USB_XHCI_PLATFORM
>
> Changes in v8:
> - none
>
> Changes in v7:
> - none
>
> Changes in v6:
> - none
>
> Changes in v5:
> - patch added to the series
>
>  drivers/usb/core/hcd.c  | 6 ++++++
>  include/linux/usb/hcd.h | 1 +
>  2 files changed, 7 insertions(+)

No changes since v17 which I gave my tag for [1], but happy to give it again:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

[1] https://lore.kernel.org/r/CAD=FV=VcAdSWWVykGrw2r5BFMe4Esotb+ieggczcrY2TH-4VSA@mail.gmail.com/

Re: [PATCH v19 5/5] arm64: dts: qcom: sc7180-trogdor: Add nodes for onboard USB hub

[Doug Anderson]

Hi,

On Wed, Jan 12, 2022 at 11:11 AM Matthias Kaehlcke <mka@chromium.org> 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>
> ---
>
> 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  | 19 ++++++++++++++++++-
>  5 files changed, 43 insertions(+), 37 deletions(-)

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Re: [PATCH v19 3/5] usb: misc: Add onboard_usb_hub driver

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 11:10:46)
> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> index 8f1144359012..bbced519499a 100644
> --- a/drivers/usb/misc/Kconfig
> +++ b/drivers/usb/misc/Kconfig
> @@ -284,3 +284,26 @@ 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 nontrivial form of initialization, such as enabling a

s/nontrivial/non-trivial/

> +         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.
> +
> +if USB_ONBOARD_HUB
> +config USB_ONBOARD_HUB_ACTUAL
> +       tristate
> +       default m if USB=m
> +       default y if USB=y
> +endif
> diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
> new file mode 100644
> index 000000000000..4e88e3089def
> --- /dev/null
> +++ b/drivers/usb/misc/onboard_usb_hub.c
> @@ -0,0 +1,494 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + *  Driver for onboard USB hubs
> + *
> + * Copyright (c) 2020, Google LLC
> + */
> +
> +#include <linux/device.h>

Add export.h for EXPORT_SYMBOL_GPL usage

> +#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/suspend.h>
> +#include <linux/sysfs.h>
> +#include <linux/usb.h>
> +#include <linux/usb/hcd.h>

Is this include used?

> +#include <linux/usb/of.h>
> +#include <linux/usb/onboard_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 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;
> +
> +       if (hub->always_powered_in_suspend)
> +               return 0;
> +
> +       power_off = true;

Nitpick: Move this up to the declaration.

> +
> +       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 set_udev_link_name(struct usb_device *udev, char *buf, size_t size)

const udev?

> +{
> +       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 ret = 0;
> +
> +       mutex_lock(&hub->lock);
> +
> +       if (hub->going_away) {
> +               ret = -EINVAL;
> +               goto unlock;
> +       }
> +
> +       node = devm_kzalloc(hub->dev, sizeof(*node), GFP_KERNEL);
> +       if (!node) {
> +               ret = -ENOMEM;
> +               goto unlock;
> +       }
> +
> +       node->udev = udev;
> +
> +       list_add(&node->list, &hub->udev_list);
> +
> +       set_udev_link_name(udev, link_name, sizeof(link_name));

It feels like udev is being modified by the name of the function. Maybe
get_udev_link_name() is better or set_link_name_from_udev() or pass
link_name first instead of udev?

> +       WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));

Does this need to be done underneath the 'hub->lock'? It would be nice
to only hold the mutex while modifying the 'udev_list'. Same applies for
calling set_udev_link_name().

> +
> +unlock:
> +       mutex_unlock(&hub->lock);
> +
> +       return ret;
> +}
> +
> +static void onboard_hub_remove_usbdev(struct onboard_hub *hub, struct usb_device *udev)

const udev?

> +{
> +       struct usbdev_node *node;
> +       char link_name[64];
> +
> +       set_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);

Maybe worth noting here that we don't free 'node' because it will be
freed when the hub platform driver is unbound. Of course, we could shave
some bytes and free the node here instead of later by not using devm.

> +                       break;
> +               }
> +       }
> +
> +       mutex_unlock(&hub->lock);
> +}
> +
> +static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
> +                          char *buf)
> +{
> +       struct onboard_hub *hub = dev_get_drvdata(dev);

const?

> +
> +       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 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(), make sure to re-attach it if needed.
> +        */
> +       err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver);
> +       if (err) {
> +               onboard_hub_power_off(hub);
> +               return err;

drop return

> +       }
> +
> +       return 0;

and then

	return err;

> +}
> +
> +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;
> +
> +       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);
> +}
> +
> +static const struct of_device_id onboard_hub_match[] = {
> +       { .compatible = "usbbda,411" },
> +       { .compatible = "usbbda,5411" },
> +       { .compatible = "usbbda,414" },
> +       { .compatible = "usbbda,5414" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, onboard_hub_match);
> +
> +static bool of_is_onboard_usb_hub(const struct device_node *np)
> +{
> +       return !!of_match_node(onboard_hub_match, np);
> +}
> +
> +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;
> +
> +       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 || !device_is_bound(&pdev->dev))

Should we put_device(pdev) if !device_is_bound()?

> +                       return ERR_PTR(-EPROBE_DEFER);
> +       }
> +
> +       put_device(&pdev->dev);
> +
> +       return dev_get_drvdata(&pdev->dev);

Should we hold pdev reference until we extract driver data out of it?
i.e.

	ret = dev_get_drvdata(&pdev->dev);
	put_device(&pdev->dev);

	return ret;

> +}
> +
> +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;
> +
> +       err = sysfs_create_link(&udev->dev.kobj, &hub->dev->kobj, "onboard_hub_dev");
> +       if (err)
> +               dev_warn(&udev->dev, "failed to create symlink to platform device: %d\n", err);

Might be useful to know which platform device this is trying to link to.
Can the devname(hub->dev) be printed as well?

> +
> +       return 0;
> +}
> +
> +static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
> +{
> +       struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
> +
> +       sysfs_remove_link(&udev->dev.kobj, "onboard_hub_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 */
> +       {},

Nitpick: Drop comma so nothing can come after without a compile error.

> +};
> +

Nitpick: Drop newline here.

> +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,
> +};
> +
> +/*** Helpers for creating/destroying platform devices for onboard hubs ***/
> +
> +struct pdev_list_entry {
> +       struct platform_device *pdev;
> +       struct list_head node;
> +};
> +
> +/*
> + * Creates a platform device for each supported onboard hub that is connected to
> + * the given parent hub. To keep track of the platform devices they are added to
> + * a list that is owned by the parent hub.
> + */

As this is an exported symbol can you please add kernel doc?

> +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)

Can parent_hub be const?

> +{
> +       int i;
> +       struct device_node *np, *npc;
> +       struct platform_device *pdev = NULL;
> +       struct pdev_list_entry *pdle;
> +
> +       INIT_LIST_HEAD(pdev_list);
> +
> +       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) {
> +                       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 = devm_kzalloc(&pdev->dev, 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);
> +
> +/*
> + * Destroys the platform devices in the given list and frees the memory associated
> + * with the list entry.

kerneldoc?

> + */
> +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);
> +       }
> +}
> +EXPORT_SYMBOL_GPL(onboard_hub_destroy_pdevs);
> +

Re: [PATCH v19 2/5] driver core: Export device_is_bound()

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 11:10:45)
> Export device_is_bound() to enable its use by drivers that are
> built as modules.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

Re: [PATCH v19 4/5] usb: core: hcd: Create platform devices for onboard hubs in probe()

[Stephen Boyd]

Quoting Matthias Kaehlcke (2022-01-12 11:10:47)
> Call onboard_hub_create/destroy_pdevs() from usb_add/remove_hcd()
> for primary HCDs to create/destroy platform devices for onboard
> USB hubs that may be connected to the root hub of the controller.
> These functions are a NOP unless CONFIG_USB_ONBOARD_HUB=y/m.
>
> Also add a field to struct usb_hcd to keep track of the onboard hub
> platform devices that are owned by the HCD.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

Re: [PATCH v19 3/5] usb: misc: Add onboard_usb_hub driver

[Matthias Kaehlcke]

Hi Stephen,

thanks for the review!

On Wed, Jan 12, 2022 at 07:49:40PM -0800, Stephen Boyd wrote:
> Quoting Matthias Kaehlcke (2022-01-12 11:10:46)
> > diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> > index 8f1144359012..bbced519499a 100644
> > --- a/drivers/usb/misc/Kconfig
> > +++ b/drivers/usb/misc/Kconfig
> > @@ -284,3 +284,26 @@ 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 nontrivial form of initialization, such as enabling a
> 
> s/nontrivial/non-trivial/

ack

> > +         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.
> > +
> > +if USB_ONBOARD_HUB
> > +config USB_ONBOARD_HUB_ACTUAL
> > +       tristate
> > +       default m if USB=m
> > +       default y if USB=y
> > +endif
> > diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
> > new file mode 100644
> > index 000000000000..4e88e3089def
> > --- /dev/null
> > +++ b/drivers/usb/misc/onboard_usb_hub.c
> > @@ -0,0 +1,494 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + *  Driver for onboard USB hubs
> > + *
> > + * Copyright (c) 2020, Google LLC
> > + */
> > +
> > +#include <linux/device.h>
> 
> Add export.h for EXPORT_SYMBOL_GPL usage

will do

> > +#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/suspend.h>
> > +#include <linux/sysfs.h>
> > +#include <linux/usb.h>
> > +#include <linux/usb/hcd.h>
> 
> Is this include used?

Yes, it is needed for calling usb_wakeup_enabled_descendants()

> > ...
> >
> > +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;
> > +
> > +       if (hub->always_powered_in_suspend)
> > +               return 0;
> > +
> > +       power_off = true;
> 
> Nitpick: Move this up to the declaration.

ok

> > ...
> >
> > +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 set_udev_link_name(struct usb_device *udev, char *buf, size_t size)
> 
> const udev?

ack

> > +{
> > +       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 ret = 0;
> > +
> > +       mutex_lock(&hub->lock);
> > +
> > +       if (hub->going_away) {
> > +               ret = -EINVAL;
> > +               goto unlock;
> > +       }
> > +
> > +       node = devm_kzalloc(hub->dev, sizeof(*node), GFP_KERNEL);
> > +       if (!node) {
> > +               ret = -ENOMEM;
> > +               goto unlock;
> > +       }
> > +
> > +       node->udev = udev;
> > +
> > +       list_add(&node->list, &hub->udev_list);
> > +
> > +       set_udev_link_name(udev, link_name, sizeof(link_name));
> 
> It feels like udev is being modified by the name of the function. Maybe
> get_udev_link_name() is better or set_link_name_from_udev() or pass
> link_name first instead of udev?

Agreed, the name be confusing, I'll change it to get_udev_link_name().

> > +       WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));
> 
> Does this need to be done underneath the 'hub->lock'? It would be nice
> to only hold the mutex while modifying the 'udev_list'. Same applies for
> calling set_udev_link_name().

Not strictly speaking, it just makes the code flow a bit simpler and there
shouldn't be much contention. I can change the code to have a dedicated
error path instead.

> > +
> > +unlock:
> > +       mutex_unlock(&hub->lock);
> > +
> > +       return ret;
> > +}
> > +
> > +static void onboard_hub_remove_usbdev(struct onboard_hub *hub, struct usb_device *udev)
> 
> const udev?

ok

> > +{
> > +       struct usbdev_node *node;
> > +       char link_name[64];
> > +
> > +       set_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);
> 
> Maybe worth noting here that we don't free 'node' because it will be
> freed when the hub platform driver is unbound. Of course, we could shave
> some bytes and free the node here instead of later by not using devm.

Before adding a comment I prefer not to use devm and free the node here.

> > +                       break;
> > +               }
> > +       }
> > +
> > +       mutex_unlock(&hub->lock);
> > +}
> > +
> > +static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
> > +                          char *buf)
> > +{
> > +       struct onboard_hub *hub = dev_get_drvdata(dev);
> 
> const?

will change

> > ...
> >
> > +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(), make sure to re-attach it if needed.
> > +        */
> > +       err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver);
> > +       if (err) {
> > +               onboard_hub_power_off(hub);
> > +               return err;
> 
> drop return
> 
> > +       }
> > +
> > +       return 0;
> 
> and then
> 
> 	return err;

I would prefer to keep things as they are, IMO the code flow is clearer and
the fact that the function has one statement less doesn't have any impact in
practice.

> > ...
> >
> > +/*
> > + * 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;
> > +
> > +       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 || !device_is_bound(&pdev->dev))
> 
> Should we put_device(pdev) if !device_is_bound()?

ack

> 
> > +                       return ERR_PTR(-EPROBE_DEFER);
> > +       }
> > +
> > +       put_device(&pdev->dev);
> > +
> > +       return dev_get_drvdata(&pdev->dev);
> 
> Should we hold pdev reference until we extract driver data out of it?
> i.e.
> 
> 	ret = dev_get_drvdata(&pdev->dev);
> 	put_device(&pdev->dev);
> 
> 	return ret;

will change as suggested

> > +}
> > +
> > +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;
> > +
> > +       err = sysfs_create_link(&udev->dev.kobj, &hub->dev->kobj, "onboard_hub_dev");
> > +       if (err)
> > +               dev_warn(&udev->dev, "failed to create symlink to platform device: %d\n", err);
> 
> Might be useful to know which platform device this is trying to link to.
> Can the devname(hub->dev) be printed as well?

Ok, I'll add the device name

> > +
> > +       return 0;
> > +}
> > +
> > +static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
> > +{
> > +       struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
> > +
> > +       sysfs_remove_link(&udev->dev.kobj, "onboard_hub_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 */
> > +       {},
> 
> Nitpick: Drop comma so nothing can come after without a compile error.

ok

> 
> > +};
> > +
> 
> Nitpick: Drop newline here.

ok

> > ...
> >
> > +/*
> > + * Creates a platform device for each supported onboard hub that is connected to
> > + * the given parent hub. To keep track of the platform devices they are added to
> > + * a list that is owned by the parent hub.
> > + */
> 
> As this is an exported symbol can you please add kernel doc?

will add

> > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list)
> 
> Can parent_hub be const?

That would make the compiler unhappy, since usb_of_get_device_node() and
of_platform_device_create() expect non-const parameters.

> > +{
> > +       int i;
> > +       struct device_node *np, *npc;
> > +       struct platform_device *pdev = NULL;
> > +       struct pdev_list_entry *pdle;
> > +
> > +       INIT_LIST_HEAD(pdev_list);
> > +
> > +       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) {
> > +                       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 = devm_kzalloc(&pdev->dev, 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);
> > +
> > +/*
> > + * Destroys the platform devices in the given list and frees the memory associated
> > + * with the list entry.
> 
> kerneldoc?

will add

> > + */
> > +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);
> > +       }
> > +}
> > +EXPORT_SYMBOL_GPL(onboard_hub_destroy_pdevs);
> > +