[PATCH 6.19 109/220] arm64: dts: renesas: rzv2-evk-cn15-sd: Add ramp delay for SD0 regulator

Greg Kroah-Hartman
2026-03-23T13:55:03Z

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

[ Upstream commit 5c03465ecf6a56b7b261df9594f0e10612f53a50 ]

Set an appropriate ramp delay for the SD0 I/O voltage regulator in the
CN15 SD overlay to make UHS-I voltage switching reliable during card
initialization.

This issue was observed on the RZ/V2H EVK, while the same UHS-I cards
worked on the RZ/V2N EVK without problems. Adding the ramp delay makes
the behavior consistent and avoids SD init timeouts.

Before this change SD0 could fail with:

mmc0: error -110 whilst initialising SD card

With the delay in place UHS-I cards enumerate correctly:

mmc0: new UHS-I speed SDR104 SDXC card at address aaaa
mmcblk0: mmc0:aaaa SR64G 59.5 GiB
mmcblk0: p1

Fixes: 3d6c2bc7629c8 ("arm64: dts: renesas: Add CN15 eMMC and SD overlays for RZ/V2H and RZ/V2N EVKs")
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260123225957.1007089-5-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/boot/dts/renesas/rzv2-evk-cn15-sd.dtso | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/renesas/rzv2-evk-cn15-sd.dtso b/arch/arm64/boot/dts/renesas/rzv2-evk-cn15-sd.dtso
index 0af1e0a6c7f48..fc53c1aae3b52 100644
--- a/arch/arm64/boot/dts/renesas/rzv2-evk-cn15-sd.dtso
+++ b/arch/arm64/boot/dts/renesas/rzv2-evk-cn15-sd.dtso
@@ -25,6 +25,7 @@
regulator-max-microvolt = <3300000>;
gpios-states = <0>;
states = <3300000 0>, <1800000 1>;
+ regulator-ramp-delay = <60>;
};
};

--
2.51.0