Merge tag 'usb-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB/PHY updates from Greg KH:
 "Here is the big USB and phy driver patch set for 4.19-rc1.

  Nothing huge but there was a lot of work that happened this
  development cycle:

   - lots of type-c work, with drivers graduating out of staging, and
     displayport support being added.

   - new PHY drivers

   - the normal collection of gadget driver updates and fixes

   - code churn to work on the urb handling path, using irqsave()
     everywhere in anticipation of making this codepath a lot simpler in
     the future.

   - usbserial driver fixes and reworks

   - other misc changes

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

* tag 'usb-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (159 commits)
  USB: serial: pl2303: add a new device id for ATEN
  usb: renesas_usbhs: Kconfig: convert to SPDX identifiers
  usb: dwc3: gadget: Check MaxPacketSize from descriptor
  usb: dwc2: Turn on uframe_sched on "stm32f4x9_fsotg" platforms
  usb: dwc2: Turn on uframe_sched on "amlogic" platforms
  usb: dwc2: Turn on uframe_sched on "his" platforms
  usb: dwc2: Turn on uframe_sched on "bcm" platforms
  usb: dwc2: gadget: ISOC's starting flow improvement
  usb: dwc2: Make dwc2_readl/writel functions endianness-agnostic.
  usb: dwc3: core: Enable AutoRetry feature in the controller
  usb: dwc3: Set default mode for dwc_usb31
  usb: gadget: udc: renesas_usb3: Add register of usb role switch
  usb: dwc2: replace ioread32/iowrite32_rep with dwc2_readl/writel_rep
  usb: dwc2: Modify dwc2_readl/writel functions prototype
  usb: dwc3: pci: Intel Merrifield can be host
  usb: dwc3: pci: Supply device properties via driver data
  arm64: dts: dwc3: description of incr burst type
  usb: dwc3: Enable undefined length INCR burst type
  usb: dwc3: add global soc bus configuration reg0
  usb: dwc3: Describe 'wakeup_work' field of struct dwc3_pci
  ...

1 files changed, 136 insertions, 0 deletions

diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
new file mode 100644
index 000000000000..d5eec1715b5b
--- /dev/null
+++ b/Documentation/driver-api/usb/typec_bus.rst
@@ -0,0 +1,136 @@
+
+API for USB Type-C Alternate Mode drivers
+=========================================
+
+Introduction
+------------
+
+Alternate modes require communication with the partner using Vendor Defined
+Messages (VDM) as defined in USB Type-C and USB Power Delivery Specifications.
+The communication is SVID (Standard or Vendor ID) specific, i.e. specific for
+every alternate mode, so every alternate mode will need a custom driver.
+
+USB Type-C bus allows binding a driver to the discovered partner alternate
+modes by using the SVID and the mode number.
+
+USB Type-C Connector Class provides a device for every alternate mode a port
+supports, and separate device for every alternate mode the partner supports.
+The drivers for the alternate modes are bound to the partner alternate mode
+devices, and the port alternate mode devices must be handled by the port
+drivers.
+
+When a new partner alternate mode device is registered, it is linked to the
+alternate mode device of the port that the partner is attached to, that has
+matching SVID and mode. Communication between the port driver and alternate mode
+driver will happen using the same API.
+
+The port alternate mode devices are used as a proxy between the partner and the
+alternate mode drivers, so the port drivers are only expected to pass the SVID
+specific commands from the alternate mode drivers to the partner, and from the
+partners to the alternate mode drivers. No direct SVID specific communication is
+needed from the port drivers, but the port drivers need to provide the operation
+callbacks for the port alternate mode devices, just like the alternate mode
+drivers need to provide them for the partner alternate mode devices.
+
+Usage:
+------
+
+General
+~~~~~~~
+
+By default, the alternate mode drivers are responsible for entering the mode.
+It is also possible to leave the decision about entering the mode to the user
+space (See Documentation/ABI/testing/sysfs-class-typec). Port drivers should not
+enter any modes on their own.
+
+``->vdm`` is the most important callback in the operation callbacks vector. It
+will be used to deliver all the SVID specific commands from the partner to the
+alternate mode driver, and vice versa in case of port drivers. The drivers send
+the SVID specific commands to each other using :c:func:`typec_altmode_vmd()`.
+
+If the communication with the partner using the SVID specific commands results
+in need to reconfigure the pins on the connector, the alternate mode driver
+needs to notify the bus using :c:func:`typec_altmode_notify()`. The driver
+passes the negotiated SVID specific pin configuration value to the function as
+parameter. The bus driver will then configure the mux behind the connector using
+that value as the state value for the mux, and also call blocking notification
+chain to notify the external drivers about the state of the connector that need
+to know it.
+
+NOTE: The SVID specific pin configuration values must always start from
+``TYPEC_STATE_MODAL``. USB Type-C specification defines two default states for
+the connector: ``TYPEC_STATE_USB`` and ``TYPEC_STATE_SAFE``. These values are
+reserved by the bus as the first possible values for the state. When the
+alternate mode is entered, the bus will put the connector into
+``TYPEC_STATE_SAFE`` before sending Enter or Exit Mode command as defined in USB
+Type-C Specification, and also put the connector back to ``TYPEC_STATE_USB``
+after the mode has been exited.
+
+An example of working definitions for SVID specific pin configurations would
+look like this:
+
+enum {
+	ALTMODEX_CONF_A = TYPEC_STATE_MODAL,
+	ALTMODEX_CONF_B,
+	...
+};
+
+Helper macro ``TYPEC_MODAL_STATE()`` can also be used:
+
+#define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0);
+#define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1);
+
+Notification chain
+~~~~~~~~~~~~~~~~~~
+
+The drivers for the components that the alternate modes are designed for need to
+get details regarding the results of the negotiation with the partner, and the
+pin configuration of the connector. In case of DisplayPort alternate mode for
+example, the GPU drivers will need to know those details. In case of
+Thunderbolt alternate mode, the thunderbolt drivers will need to know them, and
+so on.
+
+The notification chain is designed for this purpose. The drivers can register
+notifiers with :c:func:`typec_altmode_register_notifier()`.
+
+Cable plug alternate modes
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The alternate mode drivers are not bound to cable plug alternate mode devices,
+only to the partner alternate mode devices. If the alternate mode supports, or
+requires, a cable that responds to SOP Prime, and optionally SOP Double Prime
+messages, the driver for that alternate mode must request handle to the cable
+plug alternate modes using :c:func:`typec_altmode_get_plug()`, and take over
+their control.
+
+Driver API
+----------
+
+Alternate mode driver registering/unregistering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_register_driver typec_altmode_unregister_driver
+
+Alternate mode driver operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_enter typec_altmode_exit typec_altmode_attention typec_altmode_vdm typec_altmode_notify
+
+API for the port drivers
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_match_altmode
+
+Cable Plug operations
+~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_get_plug typec_altmode_put_plug
+
+Notifications
+~~~~~~~~~~~~~
+.. kernel-doc:: drivers/usb/typec/class.c
+   :functions: typec_altmode_register_notifier typec_altmode_unregister_notifier