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From:   Jan Kiszka <jan.kiszka@web.de>
Subject: [PATCH v2] arm64: dts: hikey: Give wifi some time after power-on
To:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Wei Xu <xuwei5@hisilicon.com>
Cc:     Ryan Grachek <ryan@edited.us>,
        John Stultz <john.stultz@linaro.org>,
        linux-wireless@vger.kernel.org, "Reizer, Eyal" <eyalr@ti.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        Tony Lindgren <tony@atomide.com>
Message-ID: <e944650d-514f-3727-2e68-b318aab9ee7f@web.de>
Date:   Thu, 24 Jan 2019 08:52:33 +0100
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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 would already be happy with 1 ms. Still, we use the safer 10 ms,
like on the Ultra96.

Fixes: ea452678734e ("arm64: dts: hikey: Fix WiFi support")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
=2D--

Changes in v2:
 - set delay to 10 ms
 - updated changelog

Who will take care of updating also the Hikey firmware dts with this
change?

 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/b=
oot/dts/hisilicon/hi6220-hikey.dts
index 610235028cc7..ba946543dd0a 100644
=2D-- a/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
+++ b/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts
@@ -118,6 +118,7 @@
 		reset-gpios =3D <&gpio0 5 GPIO_ACTIVE_LOW>;
 		clocks =3D <&pmic>;
 		clock-names =3D "ext_clock";
+		post-power-on-delay-ms =3D <10>;
 		power-off-delay-us =3D <10>;
 	};

=2D-
2.16.4