From 765246a18c9e9971632327488097b63d60a1943e Mon Sep 17 00:00:00 2001 From: Philipp Tomsich Date: Fri, 30 Nov 2018 18:58:58 +0100 Subject: [PATCH] rockchip: rk3399-puma: reduce sd card max-frequency to 40MHz Some SanDisk Ultra cards trigger intermittent errors on detection resulting in an -EOPNOTSUPP, when running at 50MHz. Waveform analysis suggest that the level shifters that are used on the RK3399-Q7 module (for voltage translation between the on-module voltages and the 3.3V required on the card-edge) don't handle clock rates at or above 48MHz properly. This change reduces the maximum frequency on the external SD-interface to 40MHz (for a safety margin of 20%). Reported-by: Jakob Unterwurzacher Signed-off-by: Philipp Tomsich Tested-by: Christoph Muellner --- arch/arm/dts/rk3399-puma.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/dts/rk3399-puma.dtsi b/arch/arm/dts/rk3399-puma.dtsi index 6e7e1e3..11ffcb7 100644 --- a/arch/arm/dts/rk3399-puma.dtsi +++ b/arch/arm/dts/rk3399-puma.dtsi @@ -503,7 +503,7 @@ &sdmmc { u-boot,dm-pre-reloc; clock-frequency = <150000000>; - clock-freq-min-max = <100000 150000000>; + max-frequency = <40000000>; supports-sd; bus-width = <4>; cap-mmc-highspeed; -- 2.7.4