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Groups > linux.kernel > #1710148 > unrolled thread
| Started by | icenowy@aosc.io |
|---|---|
| First post | 2017-08-12 05:10 +0200 |
| Last post | 2017-08-12 07:00 +0200 |
| Articles | 3 — 2 participants |
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Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider icenowy@aosc.io - 2017-08-12 05:10 +0200
Re: [linux-sunxi] Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider Chen-Yu Tsai <wens@csie.org> - 2017-08-12 06:20 +0200
Re: [linux-sunxi] Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider icenowy@aosc.io - 2017-08-12 07:00 +0200
| From | icenowy@aosc.io |
|---|---|
| Date | 2017-08-12 05:10 +0200 |
| Subject | Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider |
| Message-ID | <uduYh-3CJ-5@gated-at.bofh.it> |
在 2017-07-17 16:52，Maxime Ripard 写道：
> On Fri, Jul 14, 2017 at 05:49:23PM +0300, Priit Laes wrote:
>> SATA clock on sun4i/sun7i is of type (parent) / M / 6 where
>> 6 is fixed post-divider.
>>
>> Signed-off-by: Priit Laes <plaes@plaes.org>
>> ---
>> drivers/clk/sunxi-ng/ccu_div.c | 15 +++++++++++++--
>> drivers/clk/sunxi-ng/ccu_div.h | 3 ++-
>> 2 files changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_div.c
>> b/drivers/clk/sunxi-ng/ccu_div.c
>> index c0e5c10..744502a 100644
>> --- a/drivers/clk/sunxi-ng/ccu_div.c
>> +++ b/drivers/clk/sunxi-ng/ccu_div.c
>> @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct
>> ccu_mux_internal *mux,
>> {
>> struct ccu_div *cd = data;
>>
>> + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV)
>> + rate *= cd->fixed_post_div;
>> +
>> return divider_round_rate_parent(&cd->common.hw, parent,
>> rate, parent_rate,
>> cd->div.table, cd->div.width,
>
>
> You still haven't addressed the biggest issue with this patch, see:
> https://patchwork.kernel.org/patch/9825565/
I think he has already did the changes suggested in the review.
(P.S. during developing R40 CCU driver I found that pll-periph0-sata
also needs this patch, so I'm rechecking it)
>
> Maxime
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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| From | Chen-Yu Tsai <wens@csie.org> |
|---|---|
| Date | 2017-08-12 06:20 +0200 |
| Subject | Re: [linux-sunxi] Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider |
| Message-ID | <udw41-4eI-1@gated-at.bofh.it> |
| In reply to | #1710148 |
On Sat, Aug 12, 2017 at 11:07 AM, <icenowy@aosc.io> wrote:
> 在 2017-07-17 16:52，Maxime Ripard 写道：
>>
>> On Fri, Jul 14, 2017 at 05:49:23PM +0300, Priit Laes wrote:
>>>
>>> SATA clock on sun4i/sun7i is of type (parent) / M / 6 where
>>> 6 is fixed post-divider.
>>>
>>> Signed-off-by: Priit Laes <plaes@plaes.org>
>>> ---
>>> drivers/clk/sunxi-ng/ccu_div.c | 15 +++++++++++++--
>>> drivers/clk/sunxi-ng/ccu_div.h | 3 ++-
>>> 2 files changed, 15 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/clk/sunxi-ng/ccu_div.c
>>> b/drivers/clk/sunxi-ng/ccu_div.c
>>> index c0e5c10..744502a 100644
>>> --- a/drivers/clk/sunxi-ng/ccu_div.c
>>> +++ b/drivers/clk/sunxi-ng/ccu_div.c
>>> @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct
>>> ccu_mux_internal *mux,
>>> {
>>> struct ccu_div *cd = data;
>>>
>>> + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV)
>>> + rate *= cd->fixed_post_div;
>>> +
>>> return divider_round_rate_parent(&cd->common.hw, parent,
>>> rate, parent_rate,
>>> cd->div.table, cd->div.width,
>>
>>
>>
>> You still haven't addressed the biggest issue with this patch, see:
>> https://patchwork.kernel.org/patch/9825565/
>
>
> I think he has already did the changes suggested in the review.
Nope. Only half of it is fixed. First you "unapply" the post-divider,
i.e. multiply the rate by the divider. Then you pass it to
divider_round_rate_parent. You still have to reapply the divider
to the result. This last part is missing. This means the clock
rate returned by ccu_div_round_rate is going to be off.
Instead the return statement should be
return divider_round_rate_parent(...) / cd->fixed_post_div
ChenYu
>
> (P.S. during developing R40 CCU driver I found that pll-periph0-sata
> also needs this patch, so I'm rechecking it)
>
>>
>> Maxime
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "linux-sunxi" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to linux-sunxi+unsubscribe@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
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| From | icenowy@aosc.io |
|---|---|
| Date | 2017-08-12 07:00 +0200 |
| Subject | Re: [linux-sunxi] Re: [PATCH v6 1/6] clk: sunxi-ng: div: Add support for fixed post-divider |
| Message-ID | <udwGJ-4uj-5@gated-at.bofh.it> |
| In reply to | #1710158 |
在 2017-08-12 12:13，Chen-Yu Tsai 写道：
> On Sat, Aug 12, 2017 at 11:07 AM, <icenowy@aosc.io> wrote:
>> 在 2017-07-17 16:52，Maxime Ripard 写道：
>>>
>>> On Fri, Jul 14, 2017 at 05:49:23PM +0300, Priit Laes wrote:
>>>>
>>>> SATA clock on sun4i/sun7i is of type (parent) / M / 6 where
>>>> 6 is fixed post-divider.
>>>>
>>>> Signed-off-by: Priit Laes <plaes@plaes.org>
>>>> ---
>>>> drivers/clk/sunxi-ng/ccu_div.c | 15 +++++++++++++--
>>>> drivers/clk/sunxi-ng/ccu_div.h | 3 ++-
>>>> 2 files changed, 15 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/clk/sunxi-ng/ccu_div.c
>>>> b/drivers/clk/sunxi-ng/ccu_div.c
>>>> index c0e5c10..744502a 100644
>>>> --- a/drivers/clk/sunxi-ng/ccu_div.c
>>>> +++ b/drivers/clk/sunxi-ng/ccu_div.c
>>>> @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct
>>>> ccu_mux_internal *mux,
>>>> {
>>>> struct ccu_div *cd = data;
>>>>
>>>> + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV)
>>>> + rate *= cd->fixed_post_div;
>>>> +
>>>> return divider_round_rate_parent(&cd->common.hw, parent,
>>>> rate, parent_rate,
>>>> cd->div.table,
>>>> cd->div.width,
>>>
>>>
>>>
>>> You still haven't addressed the biggest issue with this patch, see:
>>> https://patchwork.kernel.org/patch/9825565/
>>
>>
>> I think he has already did the changes suggested in the review.
>
> Nope. Only half of it is fixed. First you "unapply" the post-divider,
> i.e. multiply the rate by the divider. Then you pass it to
> divider_round_rate_parent. You still have to reapply the divider
> to the result. This last part is missing. This means the clock
> rate returned by ccu_div_round_rate is going to be off.
>
> Instead the return statement should be
>
> return divider_round_rate_parent(...) / cd->fixed_post_div
Oh, got it by reading other CCU clock types that has fixed postdiv.
Thanks!
>
> ChenYu
>
>>
>> (P.S. during developing R40 CCU driver I found that pll-periph0-sata
>> also needs this patch, so I'm rechecking it)
>>
>>>
>>> Maxime
>>>
>>> _______________________________________________
>>> linux-arm-kernel mailing list
>>> linux-arm-kernel@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups
>> "linux-sunxi" group.
>> To unsubscribe from this group and stop receiving emails from it, send
>> an
>> email to linux-sunxi+unsubscribe@googlegroups.com.
>> For more options, visit https://groups.google.com/d/optout.
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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