i use the basic schematic with a crystal 25MHz(Fundamental)+1M resistor and two 18pF capacitors ( like the schematic of M52259DEMO board ).
the quartz is: CITIZEN HCM49 25.000MABJ-UT
because it is the first time i use a PHY, then i did a test endurance.
that's when i found errors ethernet.
by putting traps, i have found losses of LINK (status register, bit LINK STATUS).
to get everything correct, i had to increase the 18pF capacitors on quartz.
now the test is done without errors (several hours).
Henri