Does the I2C driver give accurate clock frequency for you? It doesn't for me.
I'm testing the I2C functionality (using an Aardvark as an I2C slave, a Pi 3 as the master, a Saleae watching the lines, and some C code I'm putting together). Write and read work fine but the clock frequency is much lower than I'm asking for with /etc/modprobe.d/i2c.conf.
I set 100KHz and I get 62.5 KHz (62.5% of expected). I set 650KHz and I get 406KHz (62.5% of expected).
Is there some system clock configuration that has changed for the Pi3 that might have thrown the clock frequencies off?
I notice the datasheet says the typical IO bus clock is 150 MHz. I see people talking about 250 MHz and 500 MHz for some of the Pi clocks. 150 MHz to 250 MHz is 60%
It makes me thing I have a clock set wrong but I have no idea what or where.