linux-kernel - [PATCH] clk: imx: use div64_u64() instead of do

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Date:   Wed,  9 Feb 2022 00:36:58 -0800
From:   Qing Wang <wangqing@...o.com>
To:     Abel Vesa <abel.vesa@....com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     Wang Qing <wangqing@...o.com>
Subject: [PATCH] clk: imx: use div64_u64() instead of do_div()

From: Wang Qing <wangqing@...o.com>

do_div() does a 64-by-32 division.
When the divisor is u64, do_div() truncates it to 32 bits, this means it
can test non-zero and be truncated to zero for division.

fix do_div.cocci warning:
WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.

Signed-off-by: Wang Qing <wangqing@...o.com>
---
 drivers/clk/imx/clk-frac-pll.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c
index c703056..90b25e3
--- a/drivers/clk/imx/clk-frac-pll.c
+++ b/drivers/clk/imx/clk-frac-pll.c
@@ -129,11 +129,11 @@ static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 	parent_rate *= 8;
 	rate *= 2;
 	temp64 = rate;
-	do_div(temp64, parent_rate);
+	div64_u64(temp64, parent_rate);
 	divfi = temp64;
 	temp64 = rate - divfi * parent_rate;
 	temp64 *= PLL_FRAC_DENOM;
-	do_div(temp64, parent_rate);
+	div64_u64(temp64, parent_rate);
 	divff = temp64;
 
 	temp64 = parent_rate;
-- 
2.7.4