MDIO clock speed computation

Jean-Denis Boyer jdboyer at
Tue Jul 23 04:19:41 EST 2002


You have found a interesting problem in the calculation of the MII_SPEED.
And it seems to be there since a long time!

However, your fix seems incomplete.
If I have a frequency of 82,5MHz, for example,
it yields exactly to the same result before and after your patch,
that is an MDIO clock of 2.58MHz.

Since the divisor is 2 * MDCLOCK,
I would suggest something like:

  (((bd->bi_intfreq + (2 * 2500000 - 1 )) / 2500000 / 2) & 0x3F) << 1;


 Jean-Denis Boyer, B.Eng., System Architect
 Mediatrix Telecom Inc.
 4229 Garlock Street
 Sherbrooke (Québec)
 (819)829-8749 x241

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