[PATCH v3 01/15] clk: scmi: Fix clock rate rounding

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

While the do_div() helper used for rounding expects its divisor argument
to be a 32bits quantity, the currently provided divisor parameter is a
64bit value that, as a consequence, is silently truncated and a possible
source of bugs.

Fix by using the proper div64_ul helper.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Fixes: 7a8655e19bdb ("clk: scmi: Fix the rounding of clock rate")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/clk/clk-scmi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index 6b286ea6f121..b6a12f3bc123 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -10,9 +10,9 @@
#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>
-#include <asm/div64.h>

#define NOT_ATOMIC false
#define ATOMIC true
@@ -83,7 +83,7 @@ static int scmi_clk_determine_rate(struct clk_hw *hw,

ftmp = req->rate - fmin;
ftmp += clk->info->range.step_size - 1; /* to round up */
- do_div(ftmp, clk->info->range.step_size);
+ ftmp = div64_ul(ftmp, clk->info->range.step_size);

req->rate = ftmp * clk->info->range.step_size + fmin;

--
2.53.0