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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>
This commit is contained in:
Christoph Muellner 2019-03-22 12:34:53 +01:00 committed by Heiko Stuebner
parent fb8b7460c9
commit b4e1728232
1 changed files with 1 additions and 0 deletions
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arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
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@ -146,6 +146,7 @@ &cpu_l3 {
&emmc_phy {
status = "okay";
drive-impedance-ohm = <33>;
};
&gmac {