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Groups > linux.kernel > #1621608 > unrolled thread

Re: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie

Started byMark Brown <broonie@kernel.org>
First post2017-04-11 22:50 +0200
Last post2017-04-12 18:20 +0200
Articles 6 — 3 participants

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  Re: [PATCH 6/6] regulator: anatop: set default voltage selector for  pcie Mark Brown <broonie@kernel.org> - 2017-04-11 22:50 +0200
    Re: [PATCH 6/6] regulator: anatop: set default voltage selector for  pcie Mark Brown <broonie@kernel.org> - 2017-04-12 17:50 +0200
      Re: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie Dong Aisheng <dongas86@gmail.com> - 2017-04-12 18:20 +0200
    Re: [PATCH 6/6] regulator: anatop: set default voltage selector for  pcie Dong Aisheng <dongas86@gmail.com> - 2017-04-12 17:50 +0200
      Re: [PATCH 6/6] regulator: anatop: set default voltage selector for  pcie Lucas Stach <l.stach@pengutronix.de> - 2017-04-12 18:20 +0200
        Re: [PATCH 6/6] regulator: anatop: set default voltage selector for  pcie Mark Brown <broonie@kernel.org> - 2017-04-12 18:20 +0200

#1621608 — Re: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie

FromMark Brown <broonie@kernel.org>
Date2017-04-11 22:50 +0200
SubjectRe: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie
Message-ID<tvaTE-3ut-21@gated-at.bofh.it>

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On Wed, Apr 12, 2017 at 09:58:47AM +0800, Dong Aisheng wrote:
> Set the initial voltage selector for vddpcie in case it's disabled
> by default.

Why is this the only anatop regulator which can have this problem and
how do we know this is a good value?

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#1622256

FromMark Brown <broonie@kernel.org>
Date2017-04-12 17:50 +0200
Message-ID<tvsGS-6f3-17@gated-at.bofh.it>
In reply to#1621608

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On Thu, Apr 13, 2017 at 03:41:03PM +0800, Dong Aisheng wrote:
> On Tue, Apr 11, 2017 at 09:40:03PM +0100, Mark Brown wrote:

> > Why is this the only anatop regulator which can have this problem and
> > how do we know this is a good value?

> Anatop regulator has no separate gate bit.
> e.g.
> 00000 Power gated off
> 00001 Target core voltage = 0.725V
> ...
> So it may have no valid default voltage in case it's disabled in
> bootloader.
> e.g. regulator_enable() may not work.

That doesn't answer my question.  What I'm asking is why another anatop
regulator might not end up disabled like this one.

> The default voltage 1.100v this patch sets is defined in reference
> manual.

For the SoC you're currently looking at...  might another have a
different value?

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#1622285 — Re: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie

FromDong Aisheng <dongas86@gmail.com>
Date2017-04-12 18:20 +0200
SubjectRe: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie
Message-ID<tvt9T-6Fh-3@gated-at.bofh.it>
In reply to#1622256
On Wed, Apr 12, 2017 at 11:49 PM, Mark Brown <broonie@kernel.org> wrote:
> On Thu, Apr 13, 2017 at 03:41:03PM +0800, Dong Aisheng wrote:
>> On Tue, Apr 11, 2017 at 09:40:03PM +0100, Mark Brown wrote:
>
>> > Why is this the only anatop regulator which can have this problem and
>> > how do we know this is a good value?
>
>> Anatop regulator has no separate gate bit.
>> e.g.
>> 00000 Power gated off
>> 00001 Target core voltage = 0.725V
>> ...
>> So it may have no valid default voltage in case it's disabled in
>> bootloader.
>> e.g. regulator_enable() may not work.
>
> That doesn't answer my question.  What I'm asking is why another anatop
> regulator might not end up disabled like this one.
>

Well, that's true and i once thought of it.
Currently it is probably a quick fix and we did not see any others up till now
for all MX6&7 platforms based on NXP internal tree.

If we do see it in the future, then probably a better solution is constructing
a staticly defined default voltage table in anatop driver and do dynamically
check.

>> The default voltage 1.100v this patch sets is defined in reference
>> manual.
>
> For the SoC you're currently looking at...  might another have a
> different value?

No, only MX6SX has it currently.

Regards
Dong Aisheng

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#1622260

FromDong Aisheng <dongas86@gmail.com>
Date2017-04-12 17:50 +0200
Message-ID<tvsGS-6f3-19@gated-at.bofh.it>
In reply to#1621608
On Tue, Apr 11, 2017 at 09:40:03PM +0100, Mark Brown wrote:
> On Wed, Apr 12, 2017 at 09:58:47AM +0800, Dong Aisheng wrote:
> > Set the initial voltage selector for vddpcie in case it's disabled
> > by default.
> 
> Why is this the only anatop regulator which can have this problem and
> how do we know this is a good value?

Anatop regulator has no separate gate bit.
e.g.
00000 Power gated off
00001 Target core voltage = 0.725V
...
So it may have no valid default voltage in case it's disabled in
bootloader.
e.g. regulator_enable() may not work.

The default voltage 1.100v this patch sets is defined in reference
manual.

Regards
Dong Aisheng

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#1622287

FromLucas Stach <l.stach@pengutronix.de>
Date2017-04-12 18:20 +0200
Message-ID<tvt9T-6Fh-7@gated-at.bofh.it>
In reply to#1622260
Am Donnerstag, den 13.04.2017, 15:41 +0800 schrieb Dong Aisheng:
> On Tue, Apr 11, 2017 at 09:40:03PM +0100, Mark Brown wrote:
> > On Wed, Apr 12, 2017 at 09:58:47AM +0800, Dong Aisheng wrote:
> > > Set the initial voltage selector for vddpcie in case it's disabled
> > > by default.
> > 
> > Why is this the only anatop regulator which can have this problem and
> > how do we know this is a good value?
> 
> Anatop regulator has no separate gate bit.
> e.g.
> 00000 Power gated off
> 00001 Target core voltage = 0.725V
> ...
> So it may have no valid default voltage in case it's disabled in
> bootloader.
> e.g. regulator_enable() may not work.
> 
> The default voltage 1.100v this patch sets is defined in reference
> manual.

Huh? Shouldn't regulator_enable bring the voltage in a range defined by
the constraints in the DT?

Regards,
Lucas

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#1622291

FromMark Brown <broonie@kernel.org>
Date2017-04-12 18:20 +0200
Message-ID<tvt9U-6Fh-27@gated-at.bofh.it>
In reply to#1622287

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On Wed, Apr 12, 2017 at 06:11:54PM +0200, Lucas Stach wrote:
> Am Donnerstag, den 13.04.2017, 15:41 +0800 schrieb Dong Aisheng:

> > The default voltage 1.100v this patch sets is defined in reference
> > manual.

> Huh? Shouldn't regulator_enable bring the voltage in a range defined by
> the constraints in the DT?

As part of that process it checks what the current voltage is but with
this regulator you can't read the voltage if the regulator is powered
off and we don't just ignore that error.

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