Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 154 insertions, 0 deletions

diff --git a/Documentation/driver-api/usb/hotplug.rst b/Documentation/driver-api/usb/hotplug.rst
new file mode 100644
index 000000000..12260f704
--- /dev/null
+++ b/Documentation/driver-api/usb/hotplug.rst
@@ -0,0 +1,154 @@
+USB hotplugging
+~~~~~~~~~~~~~~~
+
+Linux Hotplugging
+=================
+
+
+In hotpluggable buses like USB (and Cardbus PCI), end-users plug devices
+into the bus with power on.  In most cases, users expect the devices to become
+immediately usable.  That means the system must do many things, including:
+
+    - Find a driver that can handle the device.  That may involve
+      loading a kernel module; newer drivers can use module-init-tools
+      to publish their device (and class) support to user utilities.
+
+    - Bind a driver to that device.  Bus frameworks do that using a
+      device driver's probe() routine.
+
+    - Tell other subsystems to configure the new device.  Print
+      queues may need to be enabled, networks brought up, disk
+      partitions mounted, and so on.  In some cases these will
+      be driver-specific actions.
+
+This involves a mix of kernel mode and user mode actions.  Making devices
+be immediately usable means that any user mode actions can't wait for an
+administrator to do them:  the kernel must trigger them, either passively
+(triggering some monitoring daemon to invoke a helper program) or
+actively (calling such a user mode helper program directly).
+
+Those triggered actions must support a system's administrative policies;
+such programs are called "policy agents" here.  Typically they involve
+shell scripts that dispatch to more familiar administration tools.
+
+Because some of those actions rely on information about drivers (metadata)
+that is currently available only when the drivers are dynamically linked,
+you get the best hotplugging when you configure a highly modular system.
+
+Kernel Hotplug Helper (``/sbin/hotplug``)
+=========================================
+
+There is a kernel parameter: ``/proc/sys/kernel/hotplug``, which normally
+holds the pathname ``/sbin/hotplug``.  That parameter names a program
+which the kernel may invoke at various times.
+
+The /sbin/hotplug program can be invoked by any subsystem as part of its
+reaction to a configuration change, from a thread in that subsystem.
+Only one parameter is required: the name of a subsystem being notified of
+some kernel event.  That name is used as the first key for further event
+dispatch; any other argument and environment parameters are specified by
+the subsystem making that invocation.
+
+Hotplug software and other resources is available at:
+
+	http://linux-hotplug.sourceforge.net
+
+Mailing list information is also available at that site.
+
+
+USB Policy Agent
+================
+
+The USB subsystem currently invokes ``/sbin/hotplug`` when USB devices
+are added or removed from system.  The invocation is done by the kernel
+hub workqueue [hub_wq], or else as part of root hub initialization
+(done by init, modprobe, kapmd, etc).  Its single command line parameter
+is the string "usb", and it passes these environment variables:
+
+========== ============================================
+ACTION     ``add``, ``remove``
+PRODUCT    USB vendor, product, and version codes (hex)
+TYPE       device class codes (decimal)
+INTERFACE  interface 0 class codes (decimal)
+========== ============================================
+
+If "usbdevfs" is configured, DEVICE and DEVFS are also passed.  DEVICE is
+the pathname of the device, and is useful for devices with multiple and/or
+alternate interfaces that complicate driver selection.  By design, USB
+hotplugging is independent of ``usbdevfs``:  you can do most essential parts
+of USB device setup without using that filesystem, and without running a
+user mode daemon to detect changes in system configuration.
+
+Currently available policy agent implementations can load drivers for
+modules, and can invoke driver-specific setup scripts.  The newest ones
+leverage USB module-init-tools support.  Later agents might unload drivers.
+
+
+USB Modutils Support
+====================
+
+Current versions of module-init-tools will create a ``modules.usbmap`` file
+which contains the entries from each driver's ``MODULE_DEVICE_TABLE``.  Such
+files can be used by various user mode policy agents to make sure all the
+right driver modules get loaded, either at boot time or later.
+
+See ``linux/usb.h`` for full information about such table entries; or look
+at existing drivers.  Each table entry describes one or more criteria to
+be used when matching a driver to a device or class of devices.  The
+specific criteria are identified by bits set in "match_flags", paired
+with field values.  You can construct the criteria directly, or with
+macros such as these, and use driver_info to store more information::
+
+    USB_DEVICE (vendorId, productId)
+	... matching devices with specified vendor and product ids
+    USB_DEVICE_VER (vendorId, productId, lo, hi)
+	... like USB_DEVICE with lo <= productversion <= hi
+    USB_INTERFACE_INFO (class, subclass, protocol)
+	... matching specified interface class info
+    USB_DEVICE_INFO (class, subclass, protocol)
+	... matching specified device class info
+
+A short example, for a driver that supports several specific USB devices
+and their quirks, might have a MODULE_DEVICE_TABLE like this::
+
+    static const struct usb_device_id mydriver_id_table[] = {
+	{ USB_DEVICE (0x9999, 0xaaaa), driver_info: QUIRK_X },
+	{ USB_DEVICE (0xbbbb, 0x8888), driver_info: QUIRK_Y|QUIRK_Z },
+	...
+	{ } /* end with an all-zeroes entry */
+    };
+    MODULE_DEVICE_TABLE(usb, mydriver_id_table);
+
+Most USB device drivers should pass these tables to the USB subsystem as
+well as to the module management subsystem.  Not all, though: some driver
+frameworks connect using interfaces layered over USB, and so they won't
+need such a struct usb_driver.
+
+Drivers that connect directly to the USB subsystem should be declared
+something like this::
+
+    static struct usb_driver mydriver = {
+	.name		= "mydriver",
+	.id_table	= mydriver_id_table,
+	.probe		= my_probe,
+	.disconnect	= my_disconnect,
+
+	/*
+	if using the usb chardev framework:
+	    .minor		= MY_USB_MINOR_START,
+	    .fops		= my_file_ops,
+	if exposing any operations through usbdevfs:
+	    .ioctl		= my_ioctl,
+	*/
+    };
+
+When the USB subsystem knows about a driver's device ID table, it's used when
+choosing drivers to probe().  The thread doing new device processing checks
+drivers' device ID entries from the ``MODULE_DEVICE_TABLE`` against interface
+and device descriptors for the device.  It will only call ``probe()`` if there
+is a match, and the third argument to ``probe()`` will be the entry that
+matched.
+
+If you don't provide an ``id_table`` for your driver, then your driver may get
+probed for each new device; the third parameter to ``probe()`` will be
+``NULL``.