Hi, I'm Developing Custom Board using i.MX6 Quad AP.
On some board's ethernet PHY using LAN8720 from Microchips continuously toggle Link Up/Down.
Although PHY Resets using ifconfig command, Malfunction doesn't disappear.
Our Kernel Version is 4.19.35 from i.MX6 BSP Code.
Also, I tried to change and test the old Kernel that is Kernel Version of 4.1.15.
It occurs the same malfunction.
that malfunction is like the below picture.
ethernet driver continuously received Link Up/Down Event from PHY.
I check the previous question attached below.
it doesn't work.
Please refer to our device tree source.
I use GPIO_16 Pins to ENET_REF_CLK.
Also, I check Clock from ENET_REF_CLK(50Mhz).
FEC node :
Do you have any idea to solve it?
Regards, Junho Jang
for that issue one can recheck with oscilloscope timings described
in sect.220.127.116.11 RMII Mode Timing i.MX 6Dual/6Quad Applications Processors for Consumer Products - Data Sheet
I'll check RII Mode Timing with the oscilloscope.
But, I change GPIO16_ENET_CLK to provide RMII Clock(50Mhz) from LAN8720.
(GPR Register to IMX6Q_GPR1_ENET_CLK_SEL_PAD)
it works Well on Some Malfunction Board now.
I have to find out the cause. The reason why We generally use this schematic in other projects.
So, I'll reply to a question if have another question in this Message.