| From fb561c51d9c36afdb42ba891d153e104fb2507c1 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 3 Jul 2020 21:48:42 +0200 |
| Subject: arm64: dts: sun50i-pinephone: dldo4 must not be >= 1.8V |
| |
| From: Ondrej Jirman <megous@megous.com> |
| |
| [ Upstream commit 86be5c789690eb08656b08c072c50a7b02bf41f1 ] |
| |
| Some outputs from the RTL8723CS are connected to the PL port (BT_WAKE_AP), |
| which runs at 1.8V. When BT_WAKE_AP is high, the PL pin this signal is |
| connected to is overdriven, and the whole PL port's voltage rises |
| somewhat. This results in changing voltage on the R_PWM pin (PL10), |
| which is the cause for backlight flickering very noticeably when typing |
| on a Bluetooth keyboard, because backlight intensity is highly sensitive |
| to the voltage of the R_PWM pin. |
| |
| Limit the maximum WiFi/BT I/O voltage to 1.8V to avoid overdriving |
| the PL port pins via BT and WiFi IO port signals. WiFi and BT |
| functionality is unaffected by this change. |
| |
| This completely stops the backlight flicker when using bluetooth. |
| |
| Fixes: 91f480d40942 ("arm64: dts: allwinner: Add initial support for Pine64 PinePhone") |
| Signed-off-by: Ondrej Jirman <megous@megous.com> |
| Link: https://lore.kernel.org/r/20200703194842.111845-4-megous@megous.com |
| Signed-off-by: Maxime Ripard <maxime@cerno.tech> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi |
| index cefda145c3c9d..342733a20c337 100644 |
| --- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi |
| +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi |
| @@ -279,7 +279,7 @@ ®_dldo3 { |
| |
| ®_dldo4 { |
| regulator-min-microvolt = <1800000>; |
| - regulator-max-microvolt = <3300000>; |
| + regulator-max-microvolt = <1800000>; |
| regulator-name = "vcc-wifi-io"; |
| }; |
| |
| -- |
| 2.25.1 |
| |