On Wed, Jul 27, 2016 at 01:02:41PM +0300, stefan.mavrodiev@xxxxxxxxx wrote:
> On Wednesday, July 27, 2016 8:21:46 AM EEST Maxime Ripard wrote:
> > On Wed, Jul 27, 2016 at 08:12:29AM +0300, stefan.mavrodiev@xxxxxxxxx wrote:
> > > > > +®_dcdc1 {
> > > > > + regulator-always-on;
> > > > > + regulator-min-microvolt = <3300000>;
> > > > > + regulator-max-microvolt = <3300000>;
> > > > > + regulator-name = "vcc-dsi";
> > > > > +};
> > > >
> > > > What is it used for? Is it really necessary to keep it on at all time?
> > >
> > > I think so.
> > > This is the supply for the MMC.
> >
> > Then it's poorly named, and you should tie it to the MMC, and remove
> > the always-on if it's only used by the mmc. always-on is supposed to
> > be for regulators that shouldn't but turned off for the system to stay
> > running. Some MMC regulator doesn't fit that description.
>
> It's named upon the A33 power pin - "VCC-DSI".
Usually, it's based on the name of the output in the schematics,
precisely because, from one board to another, it might have different
usage.
> If I remove "always-on" the board still will work, since dcdc1 is tied to
> mmc0.
> vmmc-supply = <®_dcdc1>;
>
> We assume this voltage will be always present and there are some pullups that
> are tied to it (on i2c0 and i2c1 bus). In this case should I remove "always-
> on" from the regulator node?
No, you should just tie that regulator to the i2c buses as well.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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