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authorChristoph Muellner <christoph.muellner@theobroma-systems.com>2019-03-22 12:34:53 +0100
committerHeiko Stuebner <heiko@sntech.de>2019-03-27 13:45:27 +0100
commitb4e1728232d64b8040dae9b5405cf2db7ebd4e8b (patch)
treec9962ce3cb5160170621c03d183bfb98af4e8049
parentfb8b7460c9950001b923da446f393c452d0ccf09 (diff)
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> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
-rw-r--r--arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
index 0130b9f98c9d..4f75bb6b2f14 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
@@ -146,6 +146,7 @@
&emmc_phy {
status = "okay";
+ drive-impedance-ohm = <33>;
};
&gmac {