diff mbox series

[v2] clk: Use div64_ul instead of do_div

Message ID 20211118082858.165538-1-deng.changcheng@zte.com.cn (mailing list archive)
State Changes Requested, archived
Headers show
Series [v2] clk: Use div64_ul instead of do_div | expand

Commit Message

CGEL Nov. 18, 2021, 8:28 a.m. UTC 
From: Changcheng Deng <deng.changcheng@zte.com.cn>

do_div() does a 64-by-32 division. Here the divisor is an unsigned long
which on some platforms is 64 bit wide. So use div64_ul instead of do_div
to avoid a possible truncation.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
---
 drivers/clk/clk-npcm7xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Stephen Boyd Dec. 2, 2021, 11:15 p.m. UTC | #1 
Please fix the subject. It should be "clk: npcm7xx: Use ..."

Quoting cgel.zte@gmail.com (2021-11-18 00:28:58)
> From: Changcheng Deng <deng.changcheng@zte.com.cn>
> 
> do_div() does a 64-by-32 division. Here the divisor is an unsigned long
> which on some platforms is 64 bit wide. So use div64_ul instead of do_div
> to avoid a possible truncation.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
diff mbox series

Patch

diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
index e677bb5a784b..c75880af2b74 100644
--- a/drivers/clk/clk-npcm7xx.c
+++ b/drivers/clk/clk-npcm7xx.c
@@ -56,7 +56,7 @@  static unsigned long npcm7xx_clk_pll_recalc_rate(struct clk_hw *hw,
 	otdv2 = FIELD_GET(PLLCON_OTDV2, val);
 
 	ret = (u64)parent_rate * fbdv;
-	do_div(ret, indv * otdv1 * otdv2);
+	ret = div64_ul(ret, indv * otdv1 * otdv2);
 
 	return ret;
 }