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* [PATCH] arm64: dts: rockchip: rk3399pro-vmarc-som: add i2c2 scl timing
@ 2026-08-24  3:06 Rudi Heitbaum
  0 siblings, 0 replies; only message in thread
From: Rudi Heitbaum @ 2026-08-24  3:06 UTC (permalink / raw)
  To: heiko
  Cc: robh, krzk+dt, conor+dt, devicetree, linux-rockchip,
	linux-arm-kernel, linux-kernel, rudi

The hym8563 on i2c2 does not ack:

  rtc-hym8563 2-0051: could not init device, -6

It is also the ext_clock for sdio-pwrseq, so wifi does not come up
either.

i2c2 runs at 400 kHz with no scl edge times. The core defaults both to
300 ns and rk3x-i2c calculates a 900 ns high period, which is short for
this bus - it acks at 100 kHz. Set the edges to the values i2c3 already
uses, giving 1050 ns at 400 kHz.

Tested on a Radxa ROCK Pi N10: rtc0 registers and keeps time across a
reboot, and wifi activates.

Signed-off-by: Rudi Heitbaum <rudi@heitbaum.com>
---
 arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi b/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
index 64e6ba345739..074f09c6d11c 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
@@ -296,6 +296,8 @@ &i2c1 {
 
 &i2c2 {
 	clock-frequency = <400000>;
+	i2c-scl-falling-time-ns = <15>;
+	i2c-scl-rising-time-ns = <450>;
 	status = "okay";
 
 	hym8563: rtc@51 {
-- 
2.53.0


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