Subject: imx8m: composite clock wrong clock parent ?

Hi,

I am working on a i.MX8MM based board and I got issue to make the Ethernet phy work. I noticed that the MDIO clock is not configured properly and the FEC outputs a 26,6MHz MDIO clock. That's because the clk_get_rate() call at line 1389 returns 24MHz whereas it should returns 266MHz as it is set in the device tree and configured in the SoC:

BIOS> md.l 0x30388880 1 30388880: 11000000

With some debug traces we can see that the enet_axi's parent is wrong:

fecmxc_probe 1388 clk_get_rate 447: clk clock-controller@30380000 clk_get_rate 447: clk enet1_root_clk clk_get_rate 447: clk enet_axi clk_get_parent_rate 489: clk enet_axi parent clock-osc-24m clk_get_parent_rate 489: clk enet1_root_clk parent enet_axi fecmxc_probe 1390

Is this a known issue ?

There is an issue in current clk framework in U-Boot, it could not runtime set the parent of a clk, and I have not find time to work on this. I not check whether your issue is related the upper issue in CCF.

Regards, Peng.

Regards,

-- Sébastien Szymanski, Armadeus Systems Software engineer