[PATCH] clk: at91: generated: consider range when calculating best rate

[PATCH] clk: at91: generated: consider range when calculating best rate

[Codrin Ciubotariu]

clk_generated_best_diff() helps in finding the parent and the divisor to
compute a rate closest to the required one. However, it doesn't take into
account the request's range for the new rate. Make sure the new rate
is within the required range.

Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---
 drivers/clk/at91/clk-generated.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 23cc8297ec4c..d429ba52a719 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -117,6 +117,10 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
 		tmp_rate = parent_rate;
 	else
 		tmp_rate = parent_rate / div;
+
+	if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
+		return;
+
 	tmp_diff = abs(req->rate - tmp_rate);
 
 	if (*best_diff < 0 || *best_diff >= tmp_diff) {
-- 
2.32.0

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Claudiu.Beznea]

On 13.04.2022 10:13, Codrin Ciubotariu wrote:
> clk_generated_best_diff() helps in finding the parent and the divisor to
> compute a rate closest to the required one. However, it doesn't take into
> account the request's range for the new rate. Make sure the new rate
> is within the required range.
> 
> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>


> ---
>  drivers/clk/at91/clk-generated.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
> index 23cc8297ec4c..d429ba52a719 100644
> --- a/drivers/clk/at91/clk-generated.c
> +++ b/drivers/clk/at91/clk-generated.c
> @@ -117,6 +117,10 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
>                 tmp_rate = parent_rate;
>         else
>                 tmp_rate = parent_rate / div;
> +
> +       if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
> +               return;
> +
>         tmp_diff = abs(req->rate - tmp_rate);
> 
>         if (*best_diff < 0 || *best_diff >= tmp_diff) {
> --
> 2.32.0
> 

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Stephen Boyd]

Quoting Codrin Ciubotariu (2022-04-13 00:13:18)
> clk_generated_best_diff() helps in finding the parent and the divisor to
> compute a rate closest to the required one. However, it doesn't take into
> account the request's range for the new rate. Make sure the new rate
> is within the required range.
> 
> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> ---

Is this fixing anything real or it's just a thing that you noticed and
sent a patch to fix?

>  drivers/clk/at91/clk-generated.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
> index 23cc8297ec4c..d429ba52a719 100644
> --- a/drivers/clk/at91/clk-generated.c
> +++ b/drivers/clk/at91/clk-generated.c
> @@ -117,6 +117,10 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
>                 tmp_rate = parent_rate;
>         else
>                 tmp_rate = parent_rate / div;
> +
> +       if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
> +               return;
> +
>         tmp_diff = abs(req->rate - tmp_rate);
>  
>         if (*best_diff < 0 || *best_diff >= tmp_diff) {

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Codrin.Ciubotariu]

On 22.04.2022 04:12, Stephen Boyd wrote:
> Quoting Codrin Ciubotariu (2022-04-13 00:13:18)
>> clk_generated_best_diff() helps in finding the parent and the divisor to
>> compute a rate closest to the required one. However, it doesn't take into
>> account the request's range for the new rate. Make sure the new rate
>> is within the required range.
>>
>> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
>> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
>> ---
> 
> Is this fixing anything real or it's just a thing that you noticed and
> sent a patch to fix?

It fixes the clk_set_min/max_rate() calls to a generated clock. Do you 
want me to add this fact in the commit description?

> 
>>   drivers/clk/at91/clk-generated.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
>> index 23cc8297ec4c..d429ba52a719 100644
>> --- a/drivers/clk/at91/clk-generated.c
>> +++ b/drivers/clk/at91/clk-generated.c
>> @@ -117,6 +117,10 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
>>                  tmp_rate = parent_rate;
>>          else
>>                  tmp_rate = parent_rate / div;
>> +
>> +       if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
>> +               return;
>> +
>>          tmp_diff = abs(req->rate - tmp_rate);
>>
>>          if (*best_diff < 0 || *best_diff >= tmp_diff) {

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Stephen Boyd]

Quoting Codrin.Ciubotariu@microchip.com (2022-04-26 00:24:15)
> On 22.04.2022 04:12, Stephen Boyd wrote:
> > Quoting Codrin Ciubotariu (2022-04-13 00:13:18)
> >> clk_generated_best_diff() helps in finding the parent and the divisor to
> >> compute a rate closest to the required one. However, it doesn't take into
> >> account the request's range for the new rate. Make sure the new rate
> >> is within the required range.
> >>
> >> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
> >> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> >> ---
> > 
> > Is this fixing anything real or it's just a thing that you noticed and
> > sent a patch to fix?
> 
> It fixes the clk_set_min/max_rate() calls to a generated clock. Do you 
> want me to add this fact in the commit description?
> 

I wanted to know if there are clk_set_min/max_rate() calls on this clk.
Are there?

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Codrin.Ciubotariu]

On 17.05.2022 10:14, Stephen Boyd wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Quoting Codrin.Ciubotariu@microchip.com (2022-04-26 00:24:15)
>> On 22.04.2022 04:12, Stephen Boyd wrote:
>>> Quoting Codrin Ciubotariu (2022-04-13 00:13:18)
>>>> clk_generated_best_diff() helps in finding the parent and the divisor to
>>>> compute a rate closest to the required one. However, it doesn't take into
>>>> account the request's range for the new rate. Make sure the new rate
>>>> is within the required range.
>>>>
>>>> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
>>>> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
>>>> ---
>>>
>>> Is this fixing anything real or it's just a thing that you noticed and
>>> sent a patch to fix?
>>
>> It fixes the clk_set_min/max_rate() calls to a generated clock. Do you
>> want me to add this fact in the commit description?
>>
> 
> I wanted to know if there are clk_set_min/max_rate() calls on this clk.
> Are there?

Yes, there are:
https://elixir.bootlin.com/linux/latest/source/sound/soc/atmel/mchp-spdifrx.c#L450

Best regards,
Codrin

Re: [PATCH] clk: at91: generated: consider range when calculating best rate

[Stephen Boyd]

Quoting Codrin Ciubotariu (2022-04-13 00:13:18)
> clk_generated_best_diff() helps in finding the parent and the divisor to
> compute a rate closest to the required one. However, it doesn't take into
> account the request's range for the new rate. Make sure the new rate
> is within the required range.
> 
> Fixes: 8a8f4bf0c480 ("clk: at91: clk-generated: create function to find best_diff")
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> ---

Applied to clk-fixes