[PATCH v2 07/13] arm64: dts: ti: k3-am69-aquila: fix USB clocking for compliance

[Siddharth Vadapalli]

According to section "6.5.3 Normative Spread Spectrum Clocking (SSC)" of
the USB 3.2 Specification, SSC should be enabled by default. This protects
against EMI violations. Hence, enable internal SSC for USB SuperSpeed.

Fixes: 39ac6623b1d8 ("arm64: dts: ti: Add Aquila AM69 Support")
Cc: <stable at vger.kernel.org>
Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>
---

v1:
https://lore.kernel.org/r/20260505110631.1144200-8-s-vadapalli@ti.com/
Changes since v1:
- Reordered properties in serdes_wiz0 node to place status at the end.

 arch/arm64/boot/dts/ti/k3-am69-aquila.dtsi | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am69-aquila.dtsi b/arch/arm64/boot/dts/ti/k3-am69-aquila.dtsi
index 5119baf62a4c..a5228a7d8339 100644
--- a/arch/arm64/boot/dts/ti/k3-am69-aquila.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am69-aquila.dtsi
@@ -1423,6 +1423,7 @@ serdes0_usb0_ss_link: phy at 3 {
 		resets = <&serdes_wiz0 4>;
 		cdns,num-lanes = <1>;
 		cdns,phy-type = <PHY_TYPE_USB3>;
+		cdns,ssc-mode = <2>; /* 2 for internal SSC */
 	};
 };
 
@@ -1501,6 +1502,11 @@ &serdes_ln_ctrl {
 };
 
 &serdes_wiz0 {
+	ti,core-clk-sel = <1>;  /* Select internal reference clock */
+	ti,ssc-enable; /* Enable SSC */
+	ti,ssc-type = <1>; /* 1 for Downspread */
+	ti,ssc-frequency-hz = <33000>; /* 33 KHz */
+	ti,ssc-depth-per-mil = <5>; /* 0.5% depth */
 	status = "okay";
 };
 
-- 
2.51.1