Ethernet PHY reset using the GPIO drive

[rprronad]

Dear Experts,

How can the Ethernet PHY be reset when it hangs or stops communicating after booting a custom i.MX board using the GPIO driver?

Ethernet PHY: KSZ8041

Specifically, How can the driver reset the Ethernet PHY using GPIO?

Could someone please guide me through the process in the driver code or share the useful link to understand ?


Thanks & Regards,

Ravikumar

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

Try attaching the GPIO to the MDIO bus (the interface MDIO bus) with this guide.

Otherwise, try to attaching the GPIO to the FEC driver or the EQOS driver.

Regards

[rprronad]

Hi Joseph
Thanks for your response.

I've reviewed several sources regarding the Ethernet PHY reset. There are two types of reset for the Ethernet PHY: one is via MDIO GPIO, and the other is through a normal hard external reset GPIO.

Currently, I'm trying to understand how the hard external reset GPIO controls the Ethernet PHY (KSZ9131 & similar driver code). The part I'm struggling with is determining when the driver code triggers the external reset-gpio condition. How does this flow work, and how is it integrated into the Linux driver code?

I've been looking at the source code for the Ethernet PHY here: https://github.com/torvalds/linux/blob/master/drivers/net/phy/micrel.c.


Could you clarify how the reset-gpio works and which part of the function enables the reset-gpio (as specified in the device tree files)?

Please clarify my doubts, and thanks in advance for your help

[rprronad]

How the reset-gpio will drive Ethernet PHY driver ? When that ksz9130 micrel Ethernet PHY will enable the reset-gpio functionality?

So please guide the steps to understand much better.



Thanks
Ravikumar

[rprronad]

Dear Experts,

I need help understanding the scenarios mentioned above for the Ethernet PHY.

Could someone provide useful information?

Thanks & Regards,
Ravikumar