Merge tag 'usb-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB/PHY updates from Greg KH:
 "Here is the big set of USB and PHY driver patches for 4.17-rc1.

  Lots of USB typeC work happened this round, with code moving from the
  staging directory into the "real" part of the kernel, as well as new
  infrastructure being added to be able to handle the different types of
  "roles" that typeC requires.

  There is also the normal huge set of USB gadget controller and driver
  updates, along with XHCI changes, and a raft of other tiny fixes all
  over the USB tree. And the PHY driver updates are merged in here as
  well as they interacted with the USB drivers in some places.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (250 commits)
  Revert "USB: serial: ftdi_sio: add Id for Physik Instrumente E-870"
  usb: musb: gadget: misplaced out of bounds check
  usb: chipidea: imx: Fix ULPI on imx53
  usb: chipidea: imx: Cleanup ci_hdrc_imx_platform_flag
  usb: chipidea: usbmisc: small clean up
  usb: chipidea: usbmisc: evdo can be set e/o reset
  usb: chipidea: usbmisc: evdo is only specific to OTG port
  USB: serial: ftdi_sio: add Id for Physik Instrumente E-870
  usb: dwc3: gadget: never call ->complete() from ->ep_queue()
  usb: gadget: udc: core: update usb_ep_queue() documentation
  usb: host: Remove the deprecated ATH79 USB host config options
  usb: roles: Fix return value check in intel_xhci_usb_probe()
  USB: gadget: f_midi: fixing a possible double-free in f_midi
  usb: core: Add USB_QUIRK_DELAY_CTRL_MSG to usbcore quirks
  usb: core: Copy parameter string correctly and remove superfluous null check
  USB: announce bcdDevice as well as idVendor, idProduct.
  USB:fix USB3 devices behind USB3 hubs not resuming at hibernate thaw
  usb: hub: Reduce warning to notice on power loss
  USB: serial: ftdi_sio: add support for Harman FirmwareHubEmulator
  USB: serial: cp210x: add ELDAT Easywave RX09 id
  ...

1 files changed, 43 insertions, 0 deletions

diff --git a/Documentation/driver-api/device_connection.rst b/Documentation/driver-api/device_connection.rst
new file mode 100644
index 000000000000..affbc5566ab0
--- /dev/null
+++ b/Documentation/driver-api/device_connection.rst
@@ -0,0 +1,43 @@
+==================
+Device connections
+==================
+
+Introduction
+------------
+
+Devices often have connections to other devices that are outside of the direct
+child/parent relationship. A serial or network communication controller, which
+could be a PCI device, may need to be able to get a reference to its PHY
+component, which could be attached for example to the I2C bus. Some device
+drivers need to be able to control the clocks or the GPIOs for their devices,
+and so on.
+
+Device connections are generic descriptions of any type of connection between
+two separate devices.
+
+Device connections alone do not create a dependency between the two devices.
+They are only descriptions which are not tied to either of the devices directly.
+A dependency between the two devices exists only if one of the two endpoint
+devices requests a reference to the other. The descriptions themselves can be
+defined in firmware (not yet supported) or they can be built-in.
+
+Usage
+-----
+
+Device connections should exist before device ``->probe`` callback is called for
+either endpoint device in the description. If the connections are defined in
+firmware, this is not a problem. It should be considered if the connection
+descriptions are "built-in", and need to be added separately.
+
+The connection description consists of the names of the two devices with the
+connection, i.e. the endpoints, and unique identifier for the connection which
+is needed if there are multiple connections between the two devices.
+
+After a description exists, the devices in it can request reference to the other
+endpoint device, or they can request the description itself.
+
+API
+---
+
+.. kernel-doc:: drivers/base/devcon.c
+   : functions: device_connection_find_match device_connection_find device_connection_add device_connection_remove