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>
From:   Jan Kiszka <jan.kiszka@web.de>
Subject: [PATCH] arm64: dts: hikey: Give wifi some time after power-on
Message-ID: <6ccac7db-3ab7-e396-90be-8681a8ee336b@web.de>
Date:   Sun, 30 Dec 2018 12:38:11 +0100
User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12)
 Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

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.

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