On 03.01.19 22:32, Ulf Hansson wrote:
On Wed, 2 Jan 2019 at 23:21, John Stultz <[email protected]> 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 <[email protected]> wrote:

From: Jan Kiszka <[email protected]>

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 <[email protected]>
---

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

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