* Question about DC-DC frequency handling
@ 2015-04-26 14:31 ` Stefan Wahren
0 siblings, 0 replies; 7+ messages in thread
From: Stefan Wahren @ 2015-04-26 14:31 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
i'm current working on a regulator driver which should be able to change DC-DC
clock frequency.
Now here is my question. What is the prefered way to implement the clock
handling?
Option A):
The regulator driver handles all internally (select clock source, set
frequency).
Option B):
The DC-DC clock domain is implemented in the clock driver and the regulator
driver uses the clock framework.
Best regards
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
@ 2015-04-26 14:31 ` Stefan Wahren
0 siblings, 0 replies; 7+ messages in thread
From: Stefan Wahren @ 2015-04-26 14:31 UTC (permalink / raw)
To: kernelnewbies
Hi,
i'm current working on a regulator driver which should be able to change DC-DC
clock frequency.
Now here is my question. What is the prefered way to implement the clock
handling?
Option A):
The regulator driver handles all internally (select clock source, set
frequency).
Option B):
The DC-DC clock domain is implemented in the clock driver and the regulator
driver uses the clock framework.
Best regards
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
2015-04-26 14:31 ` Stefan Wahren
(?)
@ 2015-04-26 19:07 ` Michael Turquette
2015-04-27 20:44 ` Stefan Wahren
-1 siblings, 1 reply; 7+ messages in thread
From: Michael Turquette @ 2015-04-26 19:07 UTC (permalink / raw)
To: linux-arm-kernel
Quoting Stefan Wahren (2015-04-26 07:31:30)
> Hi,
>
> i'm current working on a regulator driver which should be able to change DC-DC
> clock frequency.
>
> Now here is my question. What is the prefered way to implement the clock
> handling?
Fun question. I have a question for you: who are the consumers of this
DC-DC? Do the downstream, consuming devices care about "clock rate" of
your regulator?
I'll hazard a guess that they do not care. DC-DC switching frequency is
an important aspect of power supply design, but switching frequency of a
power supply is not controlled by the clock framework in any example
that I am aware of.
>
> Option A):
>
> The regulator driver handles all internally (select clock source, set
> frequency).
Mark should weigh in on this, but I think option A is correct. Maybe
something like regulator_set_mode could program your switching
frequency?
>
> Option B):
>
> The DC-DC clock domain is implemented in the clock driver and the regulator
> driver uses the clock framework.
The only reason to use the clock framework is if downstream devices will
call clk_get and do something with the rate (e.g. clk_get_rate,
clk_set_rate, clk_enable, clk_disable, etc).
It sounds like your downstream devices will want to enable & disable the
regulator, but probably that's it?
Of course I could be wrong about the DC-DC switching frequency stuff
above, but that's my guess for now.
Regards,
Mike
>
> Best regards
> Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
2015-04-26 14:31 ` Stefan Wahren
(?)
(?)
@ 2015-04-27 11:01 ` Mark Brown
-1 siblings, 0 replies; 7+ messages in thread
From: Mark Brown @ 2015-04-27 11:01 UTC (permalink / raw)
To: linux-arm-kernel
On Sun, Apr 26, 2015 at 04:31:30PM +0200, Stefan Wahren wrote:
> Option A):
> The regulator driver handles all internally (select clock source, set
> frequency).
This. Nothing outside the regulator cares what clock rate it's
operating at, they just care about how good and efficient the regulation
is.
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
2015-04-26 19:07 ` Michael Turquette
@ 2015-04-27 20:44 ` Stefan Wahren
0 siblings, 0 replies; 7+ messages in thread
From: Stefan Wahren @ 2015-04-27 20:44 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
> Michael Turquette <mturquette@linaro.org> hat am 26. April 2015 um 21:07
> geschrieben:
>
>
> Quoting Stefan Wahren (2015-04-26 07:31:30)
> > Hi,
> >
> > i'm current working on a regulator driver which should be able to change
> > DC-DC
> > clock frequency.
> >
> > Now here is my question. What is the prefered way to implement the clock
> > handling?
>
> Fun question. I have a question for you: who are the consumers of this
> DC-DC? Do the downstream, consuming devices care about "clock rate" of
> your regulator?
>
> I'll hazard a guess that they do not care. DC-DC switching frequency is
> an important aspect of power supply design, but switching frequency of a
> power supply is not controlled by the clock framework in any example
> that I am aware of.
yes the consumers don't care. My intension for changing the switching frequency
is
to avoid interferences on HF band.
>
> >
> > Option A):
> >
> > The regulator driver handles all internally (select clock source, set
> > frequency).
>
> Mark should weigh in on this, but I think option A is correct. Maybe
> something like regulator_set_mode could program your switching
> frequency?
A runtime configuration isn't necessary. In a earlier discussion we decided to
use
a devicetree property.
Thanks
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
@ 2015-04-27 20:44 ` Stefan Wahren
0 siblings, 0 replies; 7+ messages in thread
From: Stefan Wahren @ 2015-04-27 20:44 UTC (permalink / raw)
To: kernelnewbies
Hi,
> Michael Turquette <mturquette@linaro.org> hat am 26. April 2015 um 21:07
> geschrieben:
>
>
> Quoting Stefan Wahren (2015-04-26 07:31:30)
> > Hi,
> >
> > i'm current working on a regulator driver which should be able to change
> > DC-DC
> > clock frequency.
> >
> > Now here is my question. What is the prefered way to implement the clock
> > handling?
>
> Fun question. I have a question for you: who are the consumers of this
> DC-DC? Do the downstream, consuming devices care about "clock rate" of
> your regulator?
>
> I'll hazard a guess that they do not care. DC-DC switching frequency is
> an important aspect of power supply design, but switching frequency of a
> power supply is not controlled by the clock framework in any example
> that I am aware of.
yes the consumers don't care. My intension for changing the switching frequency
is
to avoid interferences on HF band.
>
> >
> > Option A):
> >
> > The regulator driver handles all internally (select clock source, set
> > frequency).
>
> Mark should weigh in on this, but I think option A is correct. Maybe
> something like regulator_set_mode could program your switching
> frequency?
A runtime configuration isn't necessary. In a earlier discussion we decided to
use
a devicetree property.
Thanks
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Question about DC-DC frequency handling
2015-04-27 20:44 ` Stefan Wahren
(?)
@ 2015-04-27 20:57 ` Mark Brown
-1 siblings, 0 replies; 7+ messages in thread
From: Mark Brown @ 2015-04-27 20:57 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Apr 27, 2015 at 10:44:56PM +0200, Stefan Wahren wrote:
> > Michael Turquette <mturquette@linaro.org> hat am 26. April 2015 um 21:07
> > Quoting Stefan Wahren (2015-04-26 07:31:30)
> > I'll hazard a guess that they do not care. DC-DC switching frequency is
> > an important aspect of power supply design, but switching frequency of a
> > power supply is not controlled by the clock framework in any example
> > that I am aware of.
> yes the consumers don't care. My intension for changing the switching frequency
> is
> to avoid interferences on HF band.
You may also find that the switching frequency is dictated by the choice
of passives on the board - you may find there's restrictions there that
mean the user can't freely choose without running into performance
problems.
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-04-27 20:57 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-04-26 14:31 Question about DC-DC frequency handling Stefan Wahren
2015-04-26 14:31 ` Stefan Wahren
2015-04-26 19:07 ` Michael Turquette
2015-04-27 20:44 ` Stefan Wahren
2015-04-27 20:44 ` Stefan Wahren
2015-04-27 20:57 ` Mark Brown
2015-04-27 11:01 ` Mark Brown
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