[PATCH 08/13] arm64: dts: ti: k3-am69-sk: 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: ff7b5e93f16a ("arm64: dts: ti: k3-am69-sk: Add USB SuperSpeed support")
Cc: <stable at vger.kernel.org>
Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>
---
 arch/arm64/boot/dts/ti/k3-am69-sk.dts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am69-sk.dts b/arch/arm64/boot/dts/ti/k3-am69-sk.dts
index e56772a334c5..0412552a927f 100644
--- a/arch/arm64/boot/dts/ti/k3-am69-sk.dts
+++ b/arch/arm64/boot/dts/ti/k3-am69-sk.dts
@@ -971,6 +971,11 @@ &serdes_ln_ctrl {
 
 &serdes_wiz0 {
 	status = "okay";
+	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 */
 };
 
 &serdes0 {
@@ -997,6 +1002,7 @@ serdes0_usb_link: phy at 3 {
 		cdns,num-lanes = <1>;
 		#phy-cells = <0>;
 		cdns,phy-type = <PHY_TYPE_USB3>;
+		cdns,ssc-mode = <2>; /* 2 for internal SSC */
 		resets = <&serdes_wiz0 4>;
 	};
 };
-- 
2.51.1