Messages in this thread | | | Date | Wed, 26 Nov 2014 19:27:06 +0200 | From | Vladimir Zapolskiy <> | Subject | Re: Question about fixed regulator DT properties |
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Hello Mark,
On 25.11.2014 14:17, Mark Brown wrote: > On Wed, Nov 19, 2014 at 04:38:01PM +0200, Vladimir Zapolskiy wrote: >> Hello Mark, >> >> On 18.11.2014 17:00, Vladimir Zapolskiy wrote: > > Your mail is really quite long and all in quotes which makes it hard to > follow, brevity is really helpful to readers.
my sole purpose was to describe the problems I encounter in details, sorry for excessive verbosity.
Just to summarize my findings: a) "enable-active-high" property has no effect on GPIO output, b) "regulator-boot-on" does not mean that the regulator is controlled by bootloader or firmware exclusively.
>>> | regulator-boot-on | enable-active-high | GPIO polarity | GPIO output | >>> +-------------------+--------------------+---------------+-------------+ >>> | no | yes | active high | low | >>> | no | no | active low | high | > >>> I'd rather think that both resulting GPIO outputs are incorrect or >>> better to say do not correspond to my perception of "regulator-boot-on" >>> and "enable-active-high" DTS properties described in the documentation, >>> however above "enable-active-high" and actual GPIO polarity are the same >>> (when they are not, it is another open topic for discussion). > > What you're saying seems sensible.
Good, I read it as a confirmation that the problem exists.
>>> Should documentation be updated to reflect "regulator-boot-on" role that >>> a regulator is re-enabled by the kernel? > > I'm confused about this. That's the sole purpose of the flag and as far > as I can tell it's what the documentation says.
Documentation/devicetree/bindings/regulator/regulator.txt says:
- regulator-boot-on: bootloader/firmware enabled regulator
I would suggest to add Linux kernel to that list of regulator controllers, if it is the intention. In its current state the documentation makes an impression that "regulator-boot-on" property instructs the kernel to ignore regulator setup, since it is already controlled by bootloader or firmware.
>>> Should "enable-active-high" be replaced by getting GPIO flags directly? > > Probably makes sense, it predates those flags by quite some time. >
If you have no objection I'll take a look how to fix it by removing "enable-active-high" flag completely from the driver's logic, fortunately the flag has no tangible effect at the moment as it is shown by my analysis.
-- With best wishes, Vladimir
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