clk: add kunit tests and correct rate change bug in the clk core

[PATCH v2 04/10] clk: test: introduce clk_dummy_div for a mock divider

Posted by Brian Masney 6 months, 3 weeks ago

This is used to mock up a divider in the clk kunit tests.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk_test.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index 1b34d54ec9c610ffa3e91b06f5a5180e0395e26f..4908fb9c0c46e34063ecf696e49b48510da44538 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -140,6 +140,47 @@ static const struct clk_ops clk_dummy_single_parent_ops = {
 	.get_parent = clk_dummy_single_get_parent,
 };
 
+// 4 ought to be enough for anybody
+#define CLK_DUMMY_DIV_WIDTH 4
+
+struct clk_dummy_div {
+	struct clk_hw hw;
+	unsigned int div;
+};
+
+static unsigned long clk_dummy_div_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct clk_dummy_div *div = container_of(hw, struct clk_dummy_div, hw);
+
+	return divider_recalc_rate(hw, parent_rate, div->div, NULL,
+				   CLK_DIVIDER_ROUND_CLOSEST, CLK_DUMMY_DIV_WIDTH);
+}
+
+static long clk_dummy_div_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	return divider_round_rate(hw, rate, parent_rate, NULL,
+				  CLK_DUMMY_DIV_WIDTH, CLK_DIVIDER_ROUND_CLOSEST);
+}
+
+static int clk_dummy_div_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct clk_dummy_div *div = container_of(hw, struct clk_dummy_div, hw);
+
+	div->div = divider_get_val(rate, parent_rate, NULL, CLK_DUMMY_DIV_WIDTH,
+				   CLK_DIVIDER_ROUND_CLOSEST);
+
+	return 0;
+}
+
+static const struct clk_ops clk_dummy_div_ops = {
+	.recalc_rate = clk_dummy_div_recalc_rate,
+	.round_rate = clk_dummy_div_round_rate,
+	.set_rate = clk_dummy_div_set_rate,
+};
+
 struct clk_multiple_parent_ctx {
 	struct clk_dummy_context parents_ctx[2];
 	struct clk_hw hw;

-- 
2.49.0

Re: [PATCH v2 04/10] clk: test: introduce clk_dummy_div for a mock divider

Posted by Maxime Ripard 6 months, 1 week ago

On Wed, May 28, 2025 at 07:16:50PM -0400, Brian Masney wrote:
> This is used to mock up a divider in the clk kunit tests.
> 
> Signed-off-by: Brian Masney <bmasney@redhat.com>
> ---
>  drivers/clk/clk_test.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
> index 1b34d54ec9c610ffa3e91b06f5a5180e0395e26f..4908fb9c0c46e34063ecf696e49b48510da44538 100644
> --- a/drivers/clk/clk_test.c
> +++ b/drivers/clk/clk_test.c
> @@ -140,6 +140,47 @@ static const struct clk_ops clk_dummy_single_parent_ops = {
>  	.get_parent = clk_dummy_single_get_parent,
>  };
>  
> +// 4 ought to be enough for anybody
> +#define CLK_DUMMY_DIV_WIDTH 4
> +
> +struct clk_dummy_div {
> +	struct clk_hw hw;
> +	unsigned int div;
> +};
> +
> +static unsigned long clk_dummy_div_recalc_rate(struct clk_hw *hw,
> +					       unsigned long parent_rate)
> +{
> +	struct clk_dummy_div *div = container_of(hw, struct clk_dummy_div, hw);
> +
> +	return divider_recalc_rate(hw, parent_rate, div->div, NULL,
> +				   CLK_DIVIDER_ROUND_CLOSEST, CLK_DUMMY_DIV_WIDTH);
> +}
> +
> +static long clk_dummy_div_round_rate(struct clk_hw *hw, unsigned long rate,
> +				     unsigned long *parent_rate)
> +{
> +	return divider_round_rate(hw, rate, parent_rate, NULL,
> +				  CLK_DUMMY_DIV_WIDTH, CLK_DIVIDER_ROUND_CLOSEST);
> +}
> +
> +static int clk_dummy_div_set_rate(struct clk_hw *hw, unsigned long rate,
> +				  unsigned long parent_rate)
> +{
> +	struct clk_dummy_div *div = container_of(hw, struct clk_dummy_div, hw);
> +
> +	div->div = divider_get_val(rate, parent_rate, NULL, CLK_DUMMY_DIV_WIDTH,
> +				   CLK_DIVIDER_ROUND_CLOSEST);
> +
> +	return 0;
> +}

I wonder if we should use CLK_DIVIDER_ONE_BASED too, that way we would
catch any improperly initialized structure.

Maxime