static int
mpc52xx_i2c_get_best_fdr(int ipb_freq, int i2c_speed)
{
	/* Consts */
	const struct { int scl2tap; int tap2tap; } x2taps[] = {
		{   4,   1 },
		{   4,   2 },
		{   6,   4 },
		{   6,   8 },
		{  14,  16 },
		{  30,  32 },
		{  62,  64 },
		{ 126, 128 },
	};
	const int scl_taps[] = { 9, 10, 12, 15, 5, 6, 7, 8 };

	int best_i, best_j, i, j;
	int scl;
	int best_diff = 0x7fffffff, diff;
	int fdr;

	for ( i=7 ; i>=0 ; i-- ) {
		for ( j=0 ; j<8 ; j++ ) {
			scl = 2 * (x2taps[i].scl2tap + ((scl_taps[j] - 1) * x2taps[i].tap2tap) + 2);
			/* We only want frequency BELOW or EQUAL to */
			/* the target frequency */
			diff = i2c_speed * scl - ipb_freq;
			if ( (diff > 0) && (diff < best_diff) ) {
				best_diff = diff;
				best_i = i;
				best_j = j;
			}
		}
	}

	fdr = ((best_i << 2) | (best_j & 0x03) | ((best_j & 0x04) << 5)) & 0x3f;
	return fdr;
}