Merge tag 'char-misc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big set of char/misc/other driver patches for 5.7-rc1.

  Lots of things in here, and it's later than expected due to some
  reverts to resolve some reported issues. All is now clean with no
  reported problems in linux-next.

  Included in here is:
   - interconnect updates
   - mei driver updates
   - uio updates
   - nvmem driver updates
   - soundwire updates
   - binderfs updates
   - coresight updates
   - habanalabs updates
   - mhi new bus type and core
   - extcon driver updates
   - some Kconfig cleanups
   - other small misc driver cleanups and updates

  As mentioned, all have been in linux-next for a while, and with the
  last two reverts, all is calm and good"

* tag 'char-misc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (174 commits)
  Revert "driver core: platform: Initialize dma_parms for platform devices"
  Revert "amba: Initialize dma_parms for amba devices"
  amba: Initialize dma_parms for amba devices
  driver core: platform: Initialize dma_parms for platform devices
  bus: mhi: core: Drop the references to mhi_dev in mhi_destroy_device()
  bus: mhi: core: Initialize bhie field in mhi_cntrl for RDDM capture
  bus: mhi: core: Add support for reading MHI info from device
  misc: rtsx: set correct pcr_ops for rts522A
  speakup: misc: Use dynamic minor numbers for speakup devices
  mei: me: add cedar fork device ids
  coresight: do not use the BIT() macro in the UAPI header
  Documentation: provide IBM contacts for embargoed hardware
  nvmem: core: remove nvmem_sysfs_get_groups()
  nvmem: core: use is_bin_visible for permissions
  nvmem: core: use device_register and device_unregister
  nvmem: core: add root_only member to nvmem device struct
  extcon: axp288: Add wakeup support
  extcon: Mark extcon_get_edev_name() function as exported symbol
  extcon: palmas: Hide error messages if gpio returns -EPROBE_DEFER
  dt-bindings: extcon: usbc-cros-ec: convert extcon-usbc-cros-ec.txt to yaml format
  ...

1 files changed, 60 insertions, 0 deletions

diff --git a/Documentation/mhi/topology.rst b/Documentation/mhi/topology.rst
new file mode 100644
index 000000000000..dc7799d03294
--- /dev/null
+++ b/Documentation/mhi/topology.rst
@@ -0,0 +1,60 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+MHI Topology
+============
+
+This document provides information about the MHI topology modeling and
+representation in the kernel.
+
+MHI Controller
+--------------
+
+MHI controller driver manages the interaction with the MHI client devices
+such as the external modems and WiFi chipsets. It is also the MHI bus master
+which is in charge of managing the physical link between the host and device.
+It is however not involved in the actual data transfer as the data transfer
+is taken care by the physical bus such as PCIe. Each controller driver exposes
+channels and events based on the client device type.
+
+Below are the roles of the MHI controller driver:
+
+* Turns on the physical bus and establishes the link to the device
+* Configures IRQs, IOMMU, and IOMEM
+* Allocates struct mhi_controller and registers with the MHI bus framework
+  with channel and event configurations using mhi_register_controller.
+* Initiates power on and shutdown sequence
+* Initiates suspend and resume power management operations of the device.
+
+MHI Device
+----------
+
+MHI device is the logical device which binds to a maximum of two MHI channels
+for bi-directional communication. Once MHI is in powered on state, the MHI
+core will create MHI devices based on the channel configuration exposed
+by the controller. There can be a single MHI device for each channel or for a
+couple of channels.
+
+Each supported device is enumerated in::
+
+        /sys/bus/mhi/devices/
+
+MHI Driver
+----------
+
+MHI driver is the client driver which binds to one or more MHI devices. The MHI
+driver sends and receives the upper-layer protocol packets like IP packets,
+modem control messages, and diagnostics messages over MHI. The MHI core will
+bind the MHI devices to the MHI driver.
+
+Each supported driver is enumerated in::
+
+        /sys/bus/mhi/drivers/
+
+Below are the roles of the MHI driver:
+
+* Registers the driver with the MHI bus framework using mhi_driver_register.
+* Prepares the device for transfer by calling mhi_prepare_for_transfer.
+* Initiates data transfer by calling mhi_queue_transfer.
+* Once the data transfer is finished, calls mhi_unprepare_from_transfer to
+  end data transfer.