[PATCH 07/13] arm64: dts: ti: k3-am69-aquila: fix USB clocking for compliance
Francesco Dolcini
francesco at dolcini.it
Tue May 5 04:08:25 PDT 2026
Hi Siddharth,
On Tue, May 05, 2026 at 04:36:08PM +0530, Siddharth Vadapalli wrote:
> 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>
> ---
> 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..7c98ee81ccb5 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 */
> };
> };
>
> @@ -1502,6 +1503,11 @@ &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 */
These properties must go before status. Please see the coding guideline.
Francesco
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