clk: gate: Add some kunit test suites

Test various parts of the clk gate implementation with the kunit testing
framework.
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Daniel Latypov <dlatypov@google.com>
Cc: <kunit-dev@googlegroups.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20220120175902.2165958-1-sboyd@kernel.org

drivers/clk/.kunitconfig

+CONFIG_KUNIT=y
+CONFIG_COMMON_CLK=y
+CONFIG_CLK_GATE_KUNIT_TEST=y

drivers/clk/Kconfig

@@ -428,4 +428,12 @@ source "drivers/clk/x86/Kconfig"
 source "drivers/clk/xilinx/Kconfig"
 source "drivers/clk/zynqmp/Kconfig"
 
+# Kunit test cases
+config CLK_GATE_KUNIT_TEST
+	tristate "Basic gate type Kunit test" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Kunit test for the basic clk gate type.
+
 endif

drivers/clk/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_COMMON_CLK)	+= clk-divider.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-fixed-factor.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-fixed-rate.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-gate.o
+obj-$(CONFIG_CLK_GATE_KUNIT_TEST) += clk-gate_test.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-multiplier.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-mux.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-composite.o