Hello @cmnxp ,
The MDIO access APIs are available in the S32K3 RTD, but they are provided under the GMAC driver rather than as a separate standalone MDIO module. In the GMAC RTD API, the relevant functions are Gmac_Ip_MDIOWrite() and Gmac_Ip_MDIORead().
For your specific use case with SJA1110 SMI_AP, please note that the internal 100BASE-T1 PHY subsystem is managed through a Clause 45 register map, so you will typically need the Clause 45 APIs - Gmac_Ip_MDIOReadMMD(), Gmac_Ip_MDIOWriteMMD().
Best regards,
Pavel