Issue with Hardware timestamp

sankarsalla — Mon, 07 Jan 2019 06:00:45 GMT

Hi All,

we can feed 125MHz clock to ENET_REF_Clk in three ways

Through EXTERNAL oscillator

Through PHY

Through GPIO_16

As per my hardware design ENET_REF_CLK(V22) is already connected to PHY(KSZ9031) CLK125_NDO/LED_MODE pin,

and Phy(KSZ9031) is generating 125 MHz clock and forwarding it to ENET_REF_CLK(V22).

KSZ9031 having some errata#2

The 125MHz reference clock (CLK125_NDO pin) output has duty cycle variation when the KSZ9031RNX links up in 1000Base-T Slave mode, resulting in wide variation on the falling clock edge.

for workaround, I had applied a patch from below link which Set KSZ9031RNX to always link up in 1000Base-T Master mode by setting register 9h, bits [12:11] to ‘11’.

https://patchwork.ozlabs.org/patch/912742/

But still I'm not able to sync the clock with hardware timestamp using ptp.

Am i missing some thing or ENET_REF_CLK(v22) needs any configurations to be done?

Unfortunately ENET_REF_CLk(V22) ball didn't came out in my design to check whether clock is coming on to this ball.

Is there a way to check whether the clock is coming to ENET mac through software?

Thanks & Regards,

Sankar.

Re: Issue with Hardware timestamp

Yuri — Wed, 16 Jan 2019 09:42:01 GMT

Hello,

Please use Table 2-9 (Gigabit Ethernet Recommendations) of the recent release

of the Hardware Development Guide for i.MX6, where there are explanations how

the GPIO_16 ball must be used / configured for IEEE-1588 timestamp operation.

http://cache.nxp.com/assets/documents/data/en/user-guides/IMX6DQ6SDLHDG.pdf

Have a great day,
Yuri

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