It's stated on the first page of the Rev10 datasheet the following:
I2C digital output interface (operates to 2.25 MHz with 4.7 kΩ pullup)
Within Section 2.3 table 4 I2C (slave timing values) for SCL clock Low of 1.3 uS and SCL clock High of 600nS.
These are the minimum values.
This implies a maximum clock period of 1.9uS or a Clock speed of 526KHz if you use the minimum time allowed for high and low.
This doesn't correspond to 2.25MHz.
Question1: What am I missing?
Question 2: If my micro can support higher I2C rates what is the maximum clock I can run?