From: Nick Xie <xieqinick@gmail.com>
To: neil.armstrong@linaro.org, khilman@baylibre.com,
jbrunet@baylibre.com, martin.blumenstingl@googlemail.com,
xianwei.zhao@amlogic.com, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: krzk+dt@kernel.org, conor+dt@kernel.org, robh@kernel.org,
nick@khadas.com
Subject: [PATCH] arm64: dts: amlogic: S4: fix SD card initialization failure
Date: Tue, 13 Jan 2026 09:19:31 +0800 [thread overview]
Message-ID: <20260113011931.40424-1-nick@khadas.com> (raw)
The SD controller (sd@fe08a000) requires a clock source capable of
generating a 400kHz frequency for the identification phase.
Currently, the sd node uses CLKID_SD_EMMC_B as clkin0 and CLKID_FCLK_DIV2
as clkin1. Both of these are high-frequency clocks (e.g., ~1GHz).
The internal divider of the SD controller is limited to a maximum value
of 64 (2^6). With input frequencies significantly higher than 25.6MHz
(400kHz * 64), the driver is unable to generate the required 400kHz
clock, causing the probe to fail with -EINVAL.
Fix this by reparenting clkin0 to the 24MHz XTAL clock, consistent with
the configuration of the sdio and emmc nodes. This allows the divider
to successfully generate 400kHz (24MHz / 60).
Verified on Khadas VIM1S with SoC S4 S905Y4.
Fixes: 3ab9d54b5d847 ("arm64: dts: amlogic: enable some device nodes for S4")
Signed-off-by: Nick Xie <nick@khadas.com>
---
arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
index 9d99ed2994dfa..b87bc83b5a9bb 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
@@ -833,7 +833,7 @@ sd: mmc@fe08a000 {
reg = <0x0 0xfe08a000 0x0 0x800>;
interrupts = <GIC_SPI 177 IRQ_TYPE_EDGE_RISING>;
clocks = <&clkc_periphs CLKID_SDEMMC_B>,
- <&clkc_periphs CLKID_SD_EMMC_B>,
+ <&xtal>,
<&clkc_pll CLKID_FCLK_DIV2>;
clock-names = "core", "clkin0", "clkin1";
resets = <&reset RESET_SD_EMMC_B>;
--
2.34.1
next reply other threads:[~2026-01-13 1:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-13 1:19 Nick Xie [this message]
2026-01-13 8:57 ` [PATCH] arm64: dts: amlogic: S4: fix SD card initialization failure Jerome Brunet
2026-01-13 9:38 ` Nick Xie
2026-01-13 10:01 ` neil.armstrong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260113011931.40424-1-nick@khadas.com \
--to=xieqinick@gmail.com \
--cc=conor+dt@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=jbrunet@baylibre.com \
--cc=khilman@baylibre.com \
--cc=krzk+dt@kernel.org \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.blumenstingl@googlemail.com \
--cc=neil.armstrong@linaro.org \
--cc=nick@khadas.com \
--cc=robh@kernel.org \
--cc=xianwei.zhao@amlogic.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox