[PATCH v3 03/15] clk: scmi: Use new determine_rate clock operation

Cristian Marussi
2026-04-28T20:17:19Z

Use the Clock protocol layer determine_rate logic to calculate the closest
rate that can be supported by a specific clock.

No functional change.

Cc: Brian Masney <bmasney@redhat.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
@brian: I'd modify further this clk-scmi driver, with a patch on top of
this series, to properly use your new CLK_ROUNDING_NOOP flag once your
series AND another (already reviewed) series on clk-scmi from Peng are in.
---
drivers/clk/clk-scmi.c | 31 ++++++-------------------------
1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index b6a12f3bc123..c223e4ef1dd1 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -10,7 +10,6 @@
#include <linux/device.h>
#include <linux/err.h>
#include <linux/of.h>
-#include <linux/math64.h>
#include <linux/module.h>
#include <linux/scmi_protocol.h>

@@ -57,35 +56,17 @@ static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
static int scmi_clk_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
- u64 fmin, fmax, ftmp;
+ int ret;
struct scmi_clk *clk = to_scmi_clk(hw);

/*
- * We can't figure out what rate it will be, so just return the
- * rate back to the caller. scmi_clk_recalc_rate() will be called
- * after the rate is set and we'll know what rate the clock is
+ * If we could not get a better rate scmi_clk_recalc_rate() will be
+ * called after the rate is set and we'll know what rate the clock is
* running at then.
*/
- if (clk->info->rate_discrete)
- return 0;
-
- fmin = clk->info->range.min_rate;
- fmax = clk->info->range.max_rate;
- if (req->rate <= fmin) {
- req->rate = fmin;
-
- return 0;
- } else if (req->rate >= fmax) {
- req->rate = fmax;
-
- return 0;
- }
-
- ftmp = req->rate - fmin;
- ftmp += clk->info->range.step_size - 1; /* to round up */
- ftmp = div64_ul(ftmp, clk->info->range.step_size);
-
- req->rate = ftmp * clk->info->range.step_size + fmin;
+ ret = scmi_proto_clk_ops->determine_rate(clk->ph, clk->id, &req->rate);
+ if (ret)
+ return ret;

return 0;
}
--
2.53.0