clk: Add test managed clk provider/consumer APIs

Unit tests are more ergonomic and simpler to understand if they don't
have to hoist a bunch of code into the test harness init and exit
functions. Ad

clk: Add test managed clk provider/consumer APIs

Unit tests are more ergonomic and simpler to understand if they don't
have to hoist a bunch of code into the test harness init and exit
functions. Add some test managed wrappers for the clk APIs so that clk
unit tests can write more code in the actual test and less code in the
harness.

Only add APIs that are used for now. More wrappers can be added in the
future as necessary.

Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-7-sboyd@kernel.org

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platform: Add test managed platform_device/driver APIs

Introduce KUnit resource wrappers around platform_driver_register(),
platform_device_alloc(), and platform_device_add() so that test authors
ca

platform: Add test managed platform_device/driver APIs

Introduce KUnit resource wrappers around platform_driver_register(),
platform_device_alloc(), and platform_device_add() so that test authors
can register platform drivers/devices from their tests and have the
drivers/devices automatically be unregistered when the test is done.

This makes test setup code simpler when a platform driver or platform
device is needed. Add a few test cases at the same time to make sure the
APIs work as intended.

Cc: Brendan Higgins <brendan.higgins@linux.dev>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-6-sboyd@kernel.org

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of: Add test managed wrappers for of_overlay_apply()/of_node_put()

Add test managed wrappers for of_overlay_apply() that automatically
removes the overlay when the test is finished. This API is inte

of: Add test managed wrappers for of_overlay_apply()/of_node_put()

Add test managed wrappers for of_overlay_apply() that automatically
removes the overlay when the test is finished. This API is intended for
use by KUnit tests that test code which relies on 'struct device_node's
and of_*() APIs.

KUnit tests will call of_overlay_apply_kunit() to load an overlay that's
been built into the kernel image. When the test is complete, the overlay
will be removed.

This has a few benefits:

1) It keeps the tests hermetic because the overlay is removed when the
test is complete. Tests won't even be aware that an overlay was
loaded in another test.

2) The overlay code can live right next to the unit test that loads it.
The overlay and the unit test can be compiled into one kernel module
if desired.

3) We can test different device tree configurations by loading
different overlays. The overlays can be written for a specific test,
and there can be many of them loaded per-test without needing to jam
all possible combinations into one DTB.

4) It also allows KUnit to test device tree dependent code on any
architecture, not just UML. This allows KUnit tests to test
architecture specific device tree code.

There are some potential pitfalls though. Test authors need to be
careful to not overwrite properties in the live tree. The easiest way to
do this is to add and remove nodes with a 'kunit-' prefix, almost
guaranteeing that the same node won't be present in the tree loaded at
boot.

Suggested-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-3-sboyd@kernel.org

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