[PATCH 3/8] clk: test: introduce test suite for sibling rate changes on a divider

[Brian Masney <bmasney@redhat.com>]

Introduce a test suite that creates a parent with two divider-only
children, and ensure that changing the rate of one child does not
affect the rate of the sibling.

Some of the tests are disabled until the relevant issue(s) are fixed in
the clk core.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk_test.c | 135 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)

diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index 4908fb9c0c46..7d4dd1a559db 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -653,6 +653,140 @@ clk_multiple_parents_mux_test_suite = {
 	.test_cases = clk_multiple_parents_mux_test_cases,
 };
 
+struct clk_rate_change_sibling_div_div_context {
+	struct clk_dummy_context parent;
+	struct clk_dummy_div child1, child2;
+	struct clk *parent_clk, *child1_clk, *child2_clk;
+};
+
+static int clk_rate_change_sibling_div_div_test_init(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx;
+	int ret;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	test->priv = ctx;
+
+	ctx->parent.hw.init = CLK_HW_INIT_NO_PARENT("parent", &clk_dummy_rate_ops, 0);
+	ctx->parent.rate = DUMMY_CLOCK_RATE_24_MHZ;
+	ret = clk_hw_register_kunit(test, NULL, &ctx->parent.hw);
+	if (ret)
+		return ret;
+
+	ctx->child1.hw.init = CLK_HW_INIT_HW("child1", &ctx->parent.hw,
+					     &clk_dummy_div_ops,
+					     CLK_SET_RATE_PARENT);
+	ret = clk_hw_register_kunit(test, NULL, &ctx->child1.hw);
+	if (ret)
+		return ret;
+
+	ctx->child2.hw.init = CLK_HW_INIT_HW("child2", &ctx->parent.hw,
+					     &clk_dummy_div_ops,
+					     CLK_SET_RATE_PARENT);
+	ret = clk_hw_register_kunit(test, NULL, &ctx->child2.hw);
+	if (ret)
+		return ret;
+
+	ctx->parent_clk = clk_hw_get_clk(&ctx->parent.hw, NULL);
+	ctx->child1_clk = clk_hw_get_clk(&ctx->child1.hw, NULL);
+	ctx->child2_clk = clk_hw_get_clk(&ctx->child2.hw, NULL);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), DUMMY_CLOCK_RATE_24_MHZ);
+
+	return 0;
+}
+
+static void clk_rate_change_sibling_div_div_test_exit(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+
+	clk_put(ctx->parent_clk);
+	clk_put(ctx->child1_clk);
+	clk_put(ctx->child2_clk);
+}
+
+/*
+ * Test that, for a parent with two divider-only children and one requests a
+ * rate compatible with the existing parent rate, the parent and sibling rates
+ * are not affected.
+ */
+static void clk_test_rate_change_sibling_div_div_1(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	ret = clk_set_rate(ctx->child1_clk, DUMMY_CLOCK_RATE_6_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), DUMMY_CLOCK_RATE_24_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), DUMMY_CLOCK_RATE_6_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), DUMMY_CLOCK_RATE_24_MHZ);
+}
+
+/*
+ * Test that, for a parent with two divider-only children and one requests a
+ * rate incompatible with the existing parent rate, the sibling rate is not
+ * affected.
+ */
+static void clk_test_rate_change_sibling_div_div_2(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	ret = clk_set_rate(ctx->child1_clk, DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_GE(test, clk_get_rate(ctx->parent_clk), DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), DUMMY_CLOCK_RATE_24_MHZ);
+}
+
+/*
+ * Test that, for a parent with two divider-only children that request rates
+ * incompatible with the existing parent rate, both children end up with the
+ * requested rates.
+ */
+static void clk_test_rate_change_sibling_div_div_3(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	ret = clk_set_rate(ctx->child1_clk, DUMMY_CLOCK_RATE_16_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = clk_set_rate(ctx->child2_clk, DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_GE(test, clk_get_rate(ctx->parent_clk), DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), DUMMY_CLOCK_RATE_48_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), DUMMY_CLOCK_RATE_16_MHZ);
+}
+
+static struct kunit_case clk_rate_change_sibling_div_div_cases[] = {
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_1),
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_2),
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_3),
+	{}
+};
+
+/*
+ * Test suite that creates a parent with two divider-only children, and
+ * ensures that changing the rate of one child does not affect the rate
+ * of the other child.
+ */
+static struct kunit_suite clk_rate_change_sibling_div_div_test_suite = {
+	.name = "clk-rate-change-sibling-div-div",
+	.init = clk_rate_change_sibling_div_div_test_init,
+	.exit = clk_rate_change_sibling_div_div_test_exit,
+	.test_cases = clk_rate_change_sibling_div_div_cases,
+};
+
 static int
 clk_orphan_transparent_multiple_parent_mux_test_init(struct kunit *test)
 {
@@ -3445,6 +3579,7 @@ kunit_test_suites(
 	&clk_leaf_mux_set_rate_parent_test_suite,
 	&clk_test_suite,
 	&clk_multiple_parents_mux_test_suite,
+	&clk_rate_change_sibling_div_div_test_suite,
 	&clk_mux_no_reparent_test_suite,
 	&clk_mux_notifier_test_suite,
 	&clk_orphan_transparent_multiple_parent_mux_test_suite,
-- 
2.49.0