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Patch "clk: sunxi: Fix M factor computation for APB1" has been added to the 4.8-stable tree

PATCH [email protected] 1 participant 1 message Dec 5, 2016

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This is a note to let you know that I've just added the patch titled

clk: sunxi: Fix M factor computation for APB1

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
clk-sunxi-fix-m-factor-computation-for-apb1.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From ac95330b96376550ae7a533d1396272d675adfa2 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?St=C3=A9phan=20Rafin?= <[email protected]>
Date: Fri, 4 Nov 2016 00:53:56 +0100
Subject: clk: sunxi: Fix M factor computation for APB1
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From: Stéphan Rafin <[email protected]>

commit ac95330b96376550ae7a533d1396272d675adfa2 upstream.

commit cfa636886033 ("clk: sunxi: factors: Consolidate get_factors parameters into a struct") introduced a regression for m factor computation in sun4i_get_apb1_factors function.

The old code reassigned the "parent_rate" parameter to the targeted divisor value and was buggy for the returned frequency but not for the computed factors. Now, returned frequency is good but m factor is incorrectly computed (its max value 31 is always set resulting in a significantly slower frequency than the requested one...)

This patch simply restores the original proper computation for m while keeping the good changes for returned rate.

Fixes cfa636886033 ("clk: sunxi: factors: Consolidate get_factors parameters into a struct")
---
 drivers/clk/sunxi/clk-sunxi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/clk/sunxi/clk-sunxi.c +1 -1
@@ -373,7 +373,7 @@ static void sun4i_get_apb1_factors(struc
 	else
 		calcp = 3;
 
-	calcm = (req->parent_rate >> calcp) - 1;
+	calcm = (div >> calcp) - 1;
 
 	req->rate = (req->parent_rate >> calcp) / (calcm + 1);
 	req->m = calcm;

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/clk-sunxi-fix-m-factor-computation-for-apb1.patch