Replace IS_ENABLED() with IS_REACHABLE() to substitute empty stubs for:
    i2c_acpi_get_i2c_resource()
    i2c_acpi_client_count()
    i2c_acpi_find_bus_speed()
    i2c_acpi_new_device_by_fwnode()
    i2c_adapter *i2c_acpi_find_adapter_by_handle()
    i2c_acpi_waive_d0_probe()

commit f17c06c6608a ("i2c: Fix conditional for substituting empty ACPI
functions") partially fixed this conditional to depend on CONFIG_I2C,
but used IS_ENABLED(), which is wrong since CONFIG_I2C is tristate.

CONFIG_ACPI is boolean but let's also change it to use IS_REACHABLE()
to future-proof it against becoming tristate.

Somehow despite testing various combinations of CONFIG_I2C and CONFIG_ACPI
we missed the combination CONFIG_I2C=m, CONFIG_ACPI=y.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: f17c06c6608a ("i2c: Fix conditional for substituting empty ACPI functions")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202408141333.gYnaitcV-lkp@intel.com/
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Add IS_ENABLED(CONFIG_I2C) to the conditional around a bunch of ACPI
functions.

The conditional around these functions depended only on CONFIG_ACPI.
But the functions are implemented in I2C core, so are only present if
CONFIG_I2C is enabled.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Pull driver core updates from Greg KH:
 "Here is the big set of driver core changes for 6.11-rc1.

  Lots of stuff in here, with not a huge diffstat, but apis are evolving
  which required lots of files to be touched. Highlights of the changes
  in here are:

   - platform remove callback api final fixups (Uwe took many releases
     to get here, finally!)

   - Rust bindings for basic firmware apis and initial driver-core
     interactions.

     It's not all that useful for a "write a whole driver in rust" type
     of thing, but the firmware bindings do help out the phy rust
     drivers, and the driver core bindings give a solid base on which
     others can start their work.

     There is still a long way to go here before we have a multitude of
     rust drivers being added, but it's a great first step.

   - driver core const api changes.

     This reached across all bus types, and there are some fix-ups for
     some not-common bus types that linux-next and 0-day testing shook
     out.

     This work is being done to help make the rust bindings more safe,
     as well as the C code, moving toward the end-goal of allowing us to
     put driver structures into read-only memory. We aren't there yet,
     but are getting closer.

   - minor devres cleanups and fixes found by code inspection

   - arch_topology minor changes

   - other minor driver core cleanups

  All of these have been in linux-next for a very long time with no
  reported problems"

* tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
  ARM: sa1100: make match function take a const pointer
  sysfs/cpu: Make crash_hotplug attribute world-readable
  dio: Have dio_bus_match() callback take a const *
  zorro: make match function take a const pointer
  driver core: module: make module_[add|remove]_driver take a const *
  driver core: make driver_find_device() take a const *
  driver core: make driver_[create|remove]_file take a const *
  firmware_loader: fix soundness issue in `request_internal`
  firmware_loader: annotate doctests as `no_run`
  devres: Correct code style for functions that return a pointer type
  devres: Initialize an uninitialized struct member
  devres: Fix memory leakage caused by driver API devm_free_percpu()
  devres: Fix devm_krealloc() wasting memory
  driver core: platform: Switch to use kmemdup_array()
  driver core: have match() callback in struct bus_type take a const *
  MAINTAINERS: add Rust device abstractions to DRIVER CORE
  device: rust: improve safety comments
  MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer
  MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER
  firmware: rust: improve safety comments
  ...

Reword the explanation of @xfer, the old one was confusing and mixing up
terminology. Other than that, capitalize some words correctly and use
full line length.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

The forward declaration is not needed anymore. The sentence about
"following structs" became obsolete when struct i2c_algorithm became a
kdoc. The paragraph about return values can go because we have this
information in kdoc already.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

When updating the callbacks, adding their kernel-doc was forgotten. Add
it now.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/r/20240712165527.75e4ddc9@canb.auug.org.au
Fixes: a93c2e5fe766 ("i2c: reword i2c_algorithm according to newest specification")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Start changing the wording of the I2C main header wrt. the newest I2C
v7 and SMBus 3.2 specifications and replace "master/slave" with more
appropriate terms. The first step renames the members of struct
i2c_algorithm. Once all in-tree users are converted, the anonymous union
will go away again. All this work will also pave the way for finally
seperating the monolithic header into more fine-grained headers like
"i2c/clients.h" etc.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *.  This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.

Because the match() callback is in all busses, all busses are modified
to handle this properly.  This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.

For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add nop variants of i2c_find_device_by_fwnode(),
i2c_find_adapter_by_fwnode() and i2c_get_adapter_by_fwnode() for use
without CONFIG_I2C.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Remove this class after all users have been gone.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>