This reverts commit 56a50667cbcfaf95eea9128d5676af94e54b51a8. Mux
handling is not sufficiently implemented. It needs more time.

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

This reverts commit 3cfe39b3a845593a485ab1c716615979004ef9f6. Mux
handling is not sufficiently implemented. It needs more time.

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

When adding the new debugfs entry, its kdoc equivalent was forgotten.
Add it now.

Fixes: d06905d68610 ("i2c: add core-managed per-client directory in debugfs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/r/20250115163146.6c48f066@canb.auug.org.au
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

More and more I2C client drivers use debugfs entries and currently they
need to manage a subdir for their files on their own. This means
inconsistent naming for these subdirs and they are scattered all over
the debugfs-tree as well. Not to mention the duplicated code.

Let the I2C core provide and maintain a proper directory per client.

Note: It was considered to save the additional pointer in 'struct
i2c_client' and only provide a subdir when requested via a helper
function. When sketching this approach, more and more corner cases
appeared, though, so the current solution with its simple and unabiguous
code was chosen.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Similar to the list of auto-detected clients, we can also replace the
list of userspace-created clients with flagging such client devices.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: fixed description of the new flag; reordered new code in
'device_store' to have single exit point; fixed whitespace errors;
 folded cleanup patch into this one]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

So far a list is used to track auto-detected clients per driver.
The same functionality can be achieved much simpler by flagging
auto-detected clients.

Two notes regarding the usage of driver_for_each_device:
In our case it can't fail, however the function is annotated __must_check.
So a little workaround is needed to avoid a compiler warning.
Then we may remove nodes from the list over which we iterate.
This is safe, see the explanation at the beginning of lib/klist.c.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: fixed description of the new flag]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

The DesignWare and the Renesas I2C drivers have received most of
the changes in this pull request.

The first has has undergone through a series of cleanups that
have been sent to the mailing list a year ago for the first time
and finally get merged in this pull request. They are many, from
typos (e.g. i2/i2c), to cosmetics, to refactoring (e.g. move
inline functions to librarieas) and many others.

Besides that, all the DesignWare Kconfig options have been
grouped under the I2C_DESIGNWARE_CORE and this required some
adaptation in many of the kernel configuration files for
different arm and mips boards.

Follows the list of the rest of the changes grouped by type of
change.

Cleanups
--------
The Qualcomm Geni platform improves the exit path in the runtime
resume function.

The Intel LJCA driver loses "target_addr" parameter in
ljca_i2c_stop() because it was unused.

The MediaTek controller intializes the restart_flag in the
transfer function using the ternary conditional operator ("? :")
instead of initializing it in different parts.

Constified a few global data structures in the virtio driver.

The Renesas driver simplifies the bus speed handling in the init
function making it more readable.

Improved an if/else statement in probe function of the Renesas
R-Car driver.

The iMX/MXC driver switches to using the RUNTIME_PM_OPS() instead
of SET_RUNTIME_PM_OPS().

Still in the iMX/MXC driver a comma ',' has been replaced by a
semicolon ';', while in different drivers the ',' has been
removed from the '{ }' delimiters.

Finally three devm_clk_get_enabled() have been used to simplify
the devm_clk_get/clk_prepare_enable tuple in the Renesas EMEV2,
Ingenic and MPC drivers.

Refactors
---------
The Nuvoton fixes a potential out of boundary array access. This
is not a bug fix because the issue could never occur due to
hardware not having the properties listed in the array. The
change makes the driver more future proof and, at the same time,
silences code analyzers.

Improvements
------------
The Renesas I2C (riic) driver undergoes several patches improving
the runtime power management handling.

The Intel i801 driver uses a more descriptive adapter's name to
show the presence of the IDF feature.

In the Intel Denverton (ismt) adapter the pending transactions
are killed when irq's can't complete their handling, triggering a
timeout. This could have been considered as a bug fix, but
because, standing to Vasily, it's very sporadic, I preferred
considering the patch rather as an improvement.

New Feature
-----------
The Renesas I2C (riic) driver now supports the fast mode plus.

New support
-----------
Added support for:

    - Renesas R9A08G045
    - Rockchip RK3576
    - KEBA I2C
    - Theobroma Systems Mule Multiplexer.

The Keba comes with a new driver, i2c-keba.c.
The Mule is an i2c multiplexer and it also comes with a new
driver, mux/i2c-mux-mule.c.

Core patch
----------
This pull request includes also a patch in the I2C framework, in
i2c-core-base.c where the runtime PM functions have been replaced
in order to allow to be accessed during the device add.

Devicetree
----------
Some cleanups in the devicetree, as well. nVidia and Qualcomm
bindings improve their "if:then:" blocks. While the aspeed
binding loses the "multi-master" property because it was
redundant.

The i2c-sprd binding has been converted to YAML.

Krzysztof reported an issue [0] which is caused by parallel attempts to
instantiate the same I2C client device. This can happen if driver
supports auto-detection, but certain devices are also instantiated
explicitly.
The original change isn't actually wrong, it just revealed that I2C core
isn't prepared yet to handle this scenario.
Calls to i2c_new_client_device() can be nested, therefore we can't use a
simple mutex here. Parallel instantiation of devices at different addresses
is ok, so we just have to prevent parallel instantiation at the same address.
We can use a bitmap with one bit per 7-bit I2C client address, and atomic
bit operations to set/check/clear bits.
Now a parallel attempt to instantiate a device at the same address will
result in -EBUSY being returned, avoiding the "sysfs: cannot create duplicate
filename" splash.

Note: This patch version includes small cosmetic changes to the Tested-by
      version, only functional change is that address locking is supported
      for slave addresses too.

[0] https://lore.kernel.org/linux-i2c/9479fe4e-eb0c-407e-84c0-bd60c15baf74@ans.pl/T/#m12706546e8e2414d8f1a0dc61c53393f731685cc

Fixes: caba40ec3531 ("eeprom: at24: Probe for DDR3 thermal sensor in the SPD case")
Cc: stable@vger.kernel.org
Tested-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

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>