[PATCH] clk: sunxi: Fix M factor computation for APB1

[PATCH] clk: sunxi: Fix M factor computation for APB1

[Stéphan Rafin]

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.

Signed-off-by: St?phan Rafin <stephan@soliotek.com>
---
 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 838b22a..f2c9274 100644
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -373,7 +373,7 @@ static void sun4i_get_apb1_factors(struct factors_request *req)
 	else
 		calcp = 3;
 
-	calcm = (req->parent_rate >> calcp) - 1;
+	calcm = (div >> calcp) - 1;
 
 	req->rate = (req->parent_rate >> calcp) / (calcm + 1);
 	req->m = calcm;
-- 
2.6.6

[PATCH] clk: sunxi: Fix M factor computation for APB1

[Maxime Ripard]

On Fri, Nov 04, 2016 at 12:53:56AM +0100, St?phan Rafin wrote:
> 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.
> 
> Signed-off-by: St?phan Rafin <stephan@soliotek.com>

Applied (added a Fixes tag), thanks

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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