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[PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers

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  [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers Chen-Yu Tsai <wens@csie.org> - 2017-01-24 03:40 +0100
    Re: [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux  clocks with pre-dividers Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-01-26 11:00 +0100
      Re: [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux  clocks with pre-dividers Chen-Yu Tsai <wens@csie.org> - 2017-01-26 12:30 +0100

#1565428 — [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers

The determine_rate helper used ccu_mux_helper_adjust_parent_for_prediv()
to adjust the parent_rate to account for pre-dividers, but then passed
the pristine parent clock rate from clk_hw_get_rate() to the round()
callback, thereby ignoring the pre-divider adjustment. In addition,
it was saving the adjusted parent rate back into struct
clk_rate_request.

This patch fixes this by saving the pristine parent clock rate, and
adding a copy that is adjusted and passed to the round() callback.
The pristine copy, if it is the best solution, would be saved back
to struct clk_rate_request.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/clk/sunxi-ng/ccu_mux.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
index 858a48621631..3445041894e7 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.c
+++ b/drivers/clk/sunxi-ng/ccu_mux.c
@@ -71,7 +71,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
 	unsigned int i;
 
 	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
-		unsigned long tmp_rate, parent_rate;
+		unsigned long tmp_rate, parent_rate, adj_parent_rate;
 		struct clk_hw *parent;
 
 		parent = clk_hw_get_parent_by_index(hw, i);
@@ -79,10 +79,11 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
 			continue;
 
 		parent_rate = clk_hw_get_rate(parent);
+		adj_parent_rate = parent_rate;
 		ccu_mux_helper_adjust_parent_for_prediv(common, cm, i,
-							&parent_rate);
+							&adj_parent_rate);
 
-		tmp_rate = round(cm, clk_hw_get_rate(parent), req->rate, data);
+		tmp_rate = round(cm, parent_rate, req->rate, data);
 		if (tmp_rate == req->rate) {
 			best_parent = parent;
 			best_parent_rate = parent_rate;
-- 
2.11.0

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#1567247 — Re: [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers

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Hi Chen-Yu,

On Tue, Jan 24, 2017 at 10:32:20AM +0800, Chen-Yu Tsai wrote:
> The determine_rate helper used ccu_mux_helper_adjust_parent_for_prediv()
> to adjust the parent_rate to account for pre-dividers, but then passed
> the pristine parent clock rate from clk_hw_get_rate() to the round()
> callback, thereby ignoring the pre-divider adjustment. In addition,
> it was saving the adjusted parent rate back into struct
> clk_rate_request.
> 
> This patch fixes this by saving the pristine parent clock rate, and
> adding a copy that is adjusted and passed to the round() callback.
> The pristine copy, if it is the best solution, would be saved back
> to struct clk_rate_request.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>  drivers/clk/sunxi-ng/ccu_mux.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 858a48621631..3445041894e7 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -71,7 +71,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>  	unsigned int i;
>  
>  	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> -		unsigned long tmp_rate, parent_rate;
> +		unsigned long tmp_rate, parent_rate, adj_parent_rate;
>  		struct clk_hw *parent;
>  
>  		parent = clk_hw_get_parent_by_index(hw, i);
> @@ -79,10 +79,11 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>  			continue;
>  
>  		parent_rate = clk_hw_get_rate(parent);
> +		adj_parent_rate = parent_rate;
>  		ccu_mux_helper_adjust_parent_for_prediv(common, cm, i,
> -							&parent_rate);
> +							&adj_parent_rate);
>  
> -		tmp_rate = round(cm, clk_hw_get_rate(parent), req->rate, data);
> +		tmp_rate = round(cm, parent_rate, req->rate, data);

Shouldn't you use the adjusted rate here too?

Thanks,
Maxime

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

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#1567341 — Re: [PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers

On Thu, Jan 26, 2017 at 5:55 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi Chen-Yu,
>
> On Tue, Jan 24, 2017 at 10:32:20AM +0800, Chen-Yu Tsai wrote:
>> The determine_rate helper used ccu_mux_helper_adjust_parent_for_prediv()
>> to adjust the parent_rate to account for pre-dividers, but then passed
>> the pristine parent clock rate from clk_hw_get_rate() to the round()
>> callback, thereby ignoring the pre-divider adjustment. In addition,
>> it was saving the adjusted parent rate back into struct
>> clk_rate_request.
>>
>> This patch fixes this by saving the pristine parent clock rate, and
>> adding a copy that is adjusted and passed to the round() callback.
>> The pristine copy, if it is the best solution, would be saved back
>> to struct clk_rate_request.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>  drivers/clk/sunxi-ng/ccu_mux.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
>> index 858a48621631..3445041894e7 100644
>> --- a/drivers/clk/sunxi-ng/ccu_mux.c
>> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
>> @@ -71,7 +71,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>>       unsigned int i;
>>
>>       for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
>> -             unsigned long tmp_rate, parent_rate;
>> +             unsigned long tmp_rate, parent_rate, adj_parent_rate;
>>               struct clk_hw *parent;
>>
>>               parent = clk_hw_get_parent_by_index(hw, i);
>> @@ -79,10 +79,11 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>>                       continue;
>>
>>               parent_rate = clk_hw_get_rate(parent);
>> +             adj_parent_rate = parent_rate;
>>               ccu_mux_helper_adjust_parent_for_prediv(common, cm, i,
>> -                                                     &parent_rate);
>> +                                                     &adj_parent_rate);
>>
>> -             tmp_rate = round(cm, clk_hw_get_rate(parent), req->rate, data);
>> +             tmp_rate = round(cm, parent_rate, req->rate, data);
>
> Shouldn't you use the adjusted rate here too?

You're right. Thanks!

ChenYu

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