Messages in this thread Patch in this message | | | From | Christoph Muellner <> | Subject | [PATCH v3 4/4] arm64: dts: rockchip: Decrease emmc-phy's drive impedance on rk3399-puma | Date | Fri, 22 Mar 2019 12:34:53 +0100 |
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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.dtsi | 1 + 1 file changed, 1 insertion(+)
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 { -- 2.11.0
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