Re: [PATCH] arm64: dts: hikey: Give wifi some time after power-on

[Jan Kiszka]

On 03.01.19 22:32, Ulf Hansson wrote:
> On Wed, 2 Jan 2019 at 23:21, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> > Adding a few folks to cc from the thread here:
> > https://patchwork.kernel.org/patch/10734021/
> >
> > As this sounds like a very similar issue.
> > thanks
> > -john
>
> John, thanks for looping me in.
>
> > On Sun, Dec 30, 2018 at 3:38 AM Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> > > From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> > >
> > > Somewhere along recent changes to power control of the wl1835, power-on
> > > became very unreliable on the hikey, failing like this:
> > >
> > > wl1271_sdio: probe of mmc2:0001:1 failed with error -16
> > > wl1271_sdio: probe of mmc2:0001:2 failed with error -16
> > >
> > > After playing with some dt parameters and comparing to other users of
> > > this chip, it turned out we need some power-on delay to make things
> > > stable again. In contrast to those other users which define 200 ms, the
> > > hikey is already very happy with 1 ms.
>
> According to the discussions we had so far, this doesn't sound like
> the correct solution.
>
> I am intending to post patch soon, however, I am not sure exactly what
> solution to pick yet. I will keep you on cc - and of course I
> appreciate if you could help to test.

FWIW, the Ultra96 is also affected. Here I worked around it by using a 10 ms 
power-on delay. The original workaround from the other thread did not help. 
Looking forward to the proper fix now!

Jan

> Kind regards
> Uffe
>
> > > Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> > > ---
> > >
> > > Tested with 4.19 and linus/master.
> > >
> > >    arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts | 1 +
> > >    1 file changed, 1 insertion(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
> > > b/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
> > > index f4964bee6a1a..1e771bf201b9 100644
> > > --- a/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
> > > +++ b/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
> > > @@ -118,6 +118,7 @@
> > >                  reset-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
> > >                  clocks = <&pmic>;
> > >                  clock-names = "ext_clock";
> > > +               post-power-on-delay-ms = <1>;
> > >                  power-off-delay-us = <10>;
> > >          };
> > >
> > > --
> > > 2.16.4