[PATCH 4.20 154/171] arm64: dts: zcu100-revC: Give wifi some time after power-on

Greg Kroah-Hartman
2019-03-12T17:58:25Z

From: Jan Kiszka <jan.kiszka@siemens.com>

commit 35a4f89cd4731ac6ec985cd29ddc1630903006b7 upstream.

Somewhere along recent changes to power control of the wl1831, power-on
became very unreliable on the Ultra96, 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,
Ultra96 is already happy with 10 ms.

Fixes: 5869ba0653b9 ("arm64: zynqmp: Add support for Xilinx zcu100-revC")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm64/boot/dts/xilinx/zynqmp-zcu100-revC.dts | 1 +
1 file changed, 1 insertion(+)

--- a/arch/arm64/boot/dts/xilinx/zynqmp-zcu100-revC.dts
+++ b/arch/arm64/boot/dts/xilinx/zynqmp-zcu100-revC.dts
@@ -101,6 +101,7 @@
sdio_pwrseq: sdio_pwrseq {
compatible = "mmc-pwrseq-simple";
reset-gpios = <&gpio 7 GPIO_ACTIVE_LOW>; /* WIFI_EN */
+ post-power-on-delay-ms = <10>;
};
};