On Wed, May 22, 2019 at 10:33:29AM +0200, Benjamin Beckmeyer wrote: > Hi all, > > I'm currently working on a custom board with the imx6ull processor and the > 6390 > switching chip. This is our hardware setup. > > ------------ --------- --------- MAC ------------ > | i.MX | MAC | PHY | PHY | PHY |------------| 88E6390 | > | 6ULL |-----|KSZ8081|---------|LAN8742| MDIO |P0 | > | | |ID 0x1 | | ID0x0 |------------| | > | | --------- --------- | | > | | | |MULTI CHIP| > | | |MDIO |ADDR MODE | > | | | | | > | |--------------------------------------------| PHY ID | > | | MDIO | 0x2 | > ------------ ------------
Hi Benjamin KSZ8081 is a 10/100 PHY, i think. LAN8742 is also a 10/100 PHY. However, DSA will configure the CPU port MAC to its maximum speed. So port 0 will be doing 1G. I don't know if specifying phy-mode = "rmii" is enough. You should take a look at the port status and configuration registers, see if the MAC is being forced to 1G, or 100M. You could add a fixed-phy to port 0 with speed 100. That will at least get the MAC part configured correctly. Is the LAN8742 strapped so that on power on it will auto-neg? I've seen a few board with this back-to-back PHY setup, and they just rely on the PHYs doing the right thing on power up, no software involved. Andrew
