Tests may want to unregister a platform device as part of the test case
logic. Using the regular platform_device_register() with kunit
assertions may result in a platform device leak or otherwise requires
cumbersome error handling. Provide a function that unregisters a
kunit-managed platform device and drops the release action from the
test's list.

Reviewed-by: David Gow <david@davidgow.net>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260522-gpiolib-kunit-v3-2-b15fe6987430@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Provide a kunit-managed variant of platform_device_register_full().

Reviewed-by: David Gow <david@davidgow.net>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260522-gpiolib-kunit-v3-1-b15fe6987430@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

If the <kunit/platform_device.h> header is included in a test without
certain other headers, it produces compiler warnings like:

In file included from [...]
../include/kunit/platform_device.h:15:57: warning: ‘struct completion’
declared inside parameter list will not be visible outside of this
definition or declaration
   15 |                                                  struct completion *x);
      |                                                         ^~~~~~~~~~

Add a 'struct completion' forward declaration to resolve this.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

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