From 663bfe77b6f70bcb33b2607e16c94fcb1029580e Mon Sep 17 00:00:00 2001 From: Valerio Setti Date: Mon, 8 Sep 2025 21:50:03 +0200 Subject: [PATCH] arm64: dts: amlogic: gxbb-odroidc2: remove UHS capability for SD card This is meant to resolve reboot not working on this board. The problem is as follows. In order to be able to switch from HS to UHS mode the bus voltage needs to be reduced from 3.3V down to 1.8V and this is achieved by the "vqmmc-supply" regulator. The ROM bootloader is only able to manage the card in HS mode (3.3V) and the switch HS->UHS happen at boottime in the kernel. The problem appears when the reboot command is issued or watchdog expires because in this case the "vqmmc-supply" voltage is not returned back at 3.3V before rebooting the board so the ROM bootloader will be completely stuck. Therefore this commit removes all UHS modes which would cause "vqmmc-summply" to switch from 3.3V to 1.8V. In terms of performance the main drawback of this commit is limiting the SD card bus speed to HS (25 MB/s) instead of UHS DDR50 (50 MB/s). However this comes with the benefit of being able to reboot the board, so it sounds like a reasonable compromise. Reviewed-by: Jerome Brunet Signed-off-by: Valerio Setti Link: https://lore.kernel.org/r/20250908-fix-reboot-v2-1-354d0e57c855@baylibre.com Signed-off-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts b/arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts index 959bd8d77a82e..12e26f99d4f08 100644 --- a/arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts @@ -348,10 +348,6 @@ bus-width = <4>; cap-sd-highspeed; - sd-uhs-sdr12; - sd-uhs-sdr25; - sd-uhs-sdr50; - sd-uhs-ddr50; max-frequency = <100000000>; disable-wp; -- 2.47.3