From 7e93719067dce93363529a7cc13f478c6b6d9158 Mon Sep 17 00:00:00 2001
From: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Date: Thu, 28 Feb 2019 16:06:40 +0100
Subject: arm64: dts: rockchip: Decrease emmc-phy's drive impedance on
 rk3399-puma

The RK3399-Q7 (Puma) requires 33 Ohm drive strength to ensure signal
integrity at HS-400 (200MHz clock, DDR signalling).

A repeated EMC testing run validates that this increase does not
negatively impact EMC compliance (emissions have ample distance to
the regulatory limits).

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>
---
 arch/arm64/boot/dts/rockchip/rk3399-puma.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dts b/arch/arm64/boot/dts/rockchip/rk3399-puma.dts
index b8e316eed69d..481a30d182ee 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dts
@@ -366,6 +366,7 @@
 
 &emmc_phy {
 	status = "okay";
+	drive-impedance-ohm = <33>;
 };
 
 &gmac {
-- 
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