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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Thu, 3 Jan 2019 22:32:35 +0100
Message-ID: <CAPDyKFrY58-x3SsUwhfrLvf=hayhdjQZJWqUpmegArmnEsWATg@mail.gmail.com>
Subject: Re: [PATCH] arm64: dts: hikey: Give wifi some time after power-on
To:     John Stultz <john.stultz@linaro.org>,
        Jan Kiszka <jan.kiszka@web.de>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Wei Xu <xuwei5@hisilicon.com>, Ryan Grachek <ryan@edited.us>,
        linux-wireless@vger.kernel.org, "Reizer, Eyal" <eyalr@ti.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Tony Lindgren <tony@atomide.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        KISHON VIJAY ABRAHAM <kishon@ti.com>,
        "Mishol, Guy" <guym@ti.com>,
        Anders Roxell <anders.roxell@linaro.org>,
        Ricardo Salveti <rsalveti@rsalveti.net>
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On Wed, 2 Jan 2019 at 23:21, John Stultz <john.stultz@linaro.org> 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@web.de> wrote:
> >
> > From: Jan Kiszka <jan.kiszka@siemens.com>
> >
> > 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.

Kind regards
Uffe

> >
> > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> > ---
> >
> > 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