PMOD I2C clk rate - how to adjust?

Hi,

I can use the PMOD I2C and assign the SCL/SDA pins to PMOD and it works. I have a question about the clock rate, is it possible to adjust the clk rate to e.g. 100K, or 400K, or customized like 1MHz? I do not see an option from pynq.lib.pmod.pmod_iic.Pmod_IIC.

From the python code, Pmod_IIC is inherited from microblaze, may I know where is the block design or code of microblaze? Thanks.