Merge tag 'driver-core-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of changes to the driver core, and some drivers
  using the changes, for 5.9-rc1.

  "Biggest" thing in here is the device link exposure in sysfs, to help
  to tame the madness that is SoC device tree representations and driver
  interactions with it.

  Other stuff in here that is interesting is:

   - device probe log helper so that drivers can report problems in a
     unified way easier.

   - devres functions added

   - DEVICE_ATTR_ADMIN_* macro added to make it harder to write
     incorrect sysfs file permissions

   - documentation cleanups

   - ability for debugfs to be present in the kernel, yet not exposed to
     userspace. Needed for systems that want it enabled, but do not
     trust users, so they can still use some kernel functions that were
     otherwise disabled.

   - other minor fixes and cleanups

  The patches outside of drivers/base/ all have acks from the respective
  subsystem maintainers to go through this tree instead of theirs.

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

* tag 'driver-core-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (39 commits)
  drm/bridge: lvds-codec: simplify error handling
  drm/bridge/sii8620: fix resource acquisition error handling
  driver core: add deferring probe reason to devices_deferred property
  driver core: add device probe log helper
  driver core: Avoid binding drivers to dead devices
  Revert "test_firmware: Test platform fw loading on non-EFI systems"
  firmware_loader: EFI firmware loader must handle pre-allocated buffer
  selftest/firmware: Add selftest timeout in settings
  test_firmware: Test platform fw loading on non-EFI systems
  driver core: Change delimiter in devlink device's name to "--"
  debugfs: Add access restriction option
  tracefs: Remove unnecessary debug_fs checks.
  driver core: Fix probe_count imbalance in really_probe()
  kobject: remove unused KOBJ_MAX action
  driver core: Fix sleeping in invalid context during device link deletion
  driver core: Add waiting_for_supplier sysfs file for devices
  driver core: Add state_synced sysfs file for devices that support it
  driver core: Expose device link details in sysfs
  driver core: Drop mention of obsolete bus rwsem from kernel-doc
  debugfs: file: Remove unnecessary cast in kfree()
  ...

lib/Kconfig.debug

@@ -476,6 +476,38 @@ config DEBUG_FS
 
 	  If unsure, say N.
 
+choice
+	prompt "Debugfs default access"
+	depends on DEBUG_FS
+	default DEBUG_FS_ALLOW_ALL
+	help
+	  This selects the default access restrictions for debugfs.
+	  It can be overridden with kernel command line option
+	  debugfs=[on,no-mount,off]. The restrictions apply for API access
+	  and filesystem registration.
+
+config DEBUG_FS_ALLOW_ALL
+	bool "Access normal"
+	help
+	  No restrictions apply. Both API and filesystem registration
+	  is on. This is the normal default operation.
+
+config DEBUG_FS_DISALLOW_MOUNT
+	bool "Do not register debugfs as filesystem"
+	help
+	  The API is open but filesystem is not loaded. Clients can still do
+	  their work and read with debug tools that do not need
+	  debugfs filesystem.
+
+config DEBUG_FS_ALLOW_NONE
+	bool "No access"
+	help
+	  Access is off. Clients get -PERM when trying to create nodes in
+	  debugfs tree and debugfs is not registered as a filesystem.
+	  Client can then back-off or continue without debugfs access.
+
+endchoice
+
 source "lib/Kconfig.kgdb"
 
 source "lib/Kconfig.ubsan"
@@ -844,10 +876,10 @@ config DEBUG_SHIRQ
 	bool "Debug shared IRQ handlers"
 	depends on DEBUG_KERNEL
 	help
-	  Enable this to generate a spurious interrupt as soon as a shared
-	  interrupt handler is registered, and just before one is deregistered.
-	  Drivers ought to be able to handle interrupts coming in at those
-	  points; some don't and need to be caught.
+	  Enable this to generate a spurious interrupt just before a shared
+	  interrupt handler is deregistered (generating one when registering
+	  is currently disabled). Drivers need to handle this correctly. Some
+	  don't and need to be caught.
 
 menu "Debug Oops, Lockups and Hangs"