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From: Rikard Falkeborn <rikard.falkeborn@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	"Rikard Falkeborn" <rikard.falkeborn@gmail.com>,
	"Emilio López" <emilio@elopez.com.ar>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Chen-Yu Tsai" <wens@csie.org>
Subject: [PATCH RESEND] clk: sunxi: Fix incorrect usage of round_down()
Date: Tue, 17 Mar 2020 22:13:32 +0100	[thread overview]
Message-ID: <20200317211333.2597793-1-rikard.falkeborn@gmail.com> (raw)

round_down() can only round to powers of 2. If round_down() is asked
to round to something that is not a power of 2, incorrect results are
produced. The incorrect results can be both too large and too small.

Instead, use rounddown() which can round to any number.

Fixes: 6a721db180a2 ("clk: sunxi: Add A31 clocks support")
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
---
Resend to include lists, appologies for missing that.

Patch has only been compile tested, I don't have the hardware.

 drivers/clk/sunxi/clk-sunxi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
index 27201fd26e44..e1aa1fbac48a 100644
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -90,7 +90,7 @@ static void sun6i_a31_get_pll1_factors(struct factors_request *req)
 	 * Round down the frequency to the closest multiple of either
 	 * 6 or 16
 	 */
-	u32 round_freq_6 = round_down(freq_mhz, 6);
+	u32 round_freq_6 = rounddown(freq_mhz, 6);
 	u32 round_freq_16 = round_down(freq_mhz, 16);
 
 	if (round_freq_6 > round_freq_16)
-- 
2.25.1


             reply	other threads:[~2020-03-17 21:13 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-17 21:13 Rikard Falkeborn [this message]
2020-03-24 15:37 ` [PATCH RESEND] clk: sunxi: Fix incorrect usage of round_down() Maxime Ripard

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