Hi Johan,
On Thu, Mar 16, 2023 at 6:05 AM Johan Hovold <johan@xxxxxxxxxx> wrote:
>
> On Thu, Mar 16, 2023 at 11:26:12AM +0100, Johan Hovold wrote:
> > On Wed, Mar 15, 2023 at 10:47:58PM -0500, Steev Klimaszewski wrote:
> > > The Lenovo Thinkpad X13s has a WCN6855 Bluetooth controller on uart2,
> > > add this.
> > >
> > > Signed-off-by: Steev Klimaszewski <steev@xxxxxxxx>
> > > ---
>
> > > + vreg_s1c: smps1 {
> > > + regulator-name = "vreg_s1c";
> > > + regulator-min-microvolt = <1880000>;
> > > + regulator-max-microvolt = <1900000>;
> > > + regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
> > > + regulator-allowed-modes = <RPMH_REGULATOR_MODE_AUTO>,
> > > + <RPMH_REGULATOR_MODE_RET>;
> > > + regulator-allow-set-load;
> >
> > So this does not look quite right still as you're specifying an initial
> > mode which is not listed as allowed.
> >
> > Also there are no other in-tree users of RPMH_REGULATOR_MODE_RET and
> > AUTO is used to switch mode automatically which seems odd to use with
> > allow-set-load.
> >
> > This regulator is in fact also used by the wifi part of the chip and as
> > that driver does not set any loads so we may end up with a regulator in
> > retention mode while wifi is in use.
> >
> > Perhaps Bjorn can enlighten us, but my guess is that this should just be
> > "intial-mode = AUTO" (or even HPM, but I have no idea where this came
> > from originally).
>
> This one probably also needs to be marked as always-on as we don't
> currently describe the fact that the wifi part also uses s1c.
>
> Johan
I couldn't remember exactly why I chose HPM, and so I recreated what
I'd done. I looked to see what modes were available by git grepping
the kernel sources and since they are in
include/dt-bindings/regulator/qcom,rpmh-regulator.h with a comment
explaining what each mode is, I picked HPM since it starts it at the
full rated current. As to why I chose the others... it was based on
SMPS being mentioned in that comment block. Since I wasn't sure what
PFM is (and admittedly, did not look it up) I skipped it.
And you are right, we probably don't want to yank that regulator out
from under the wifi... will add that in v7, so I guess for v7 we want
HPM, LPM, AUTO with AUTO being initial. I guess I was trying to think
that RET would allow as little power usage as possible when bluetooth
isn't in use.
--steev
