Hi,

I would like to change the i2c frequency from 100 kHz to 400 kHz for the 
i2c busses which are not used for HDMI.

If I check the dmesg during boot I get:

(dmese | grep "i2c")
    0.134577] omap_i2c 44e0b000.i2c: bus 0 rev0.11 at 400 kHz
[    0.135557] input: tps65217_pwr_but as 
/devices/ocp.3/44e0b000.i2c/i2c-0/0-0024/input/input0
[    0.144248] omap_i2c 44e0b000.i2c: unable to select pin group
[    0.144783] omap_i2c 4819c000.i2c: bus 1 rev0.11 at 100 kHz
[    0.146172] omap_i2c 4819c000.i2c: unable to select pin group
[    0.742131] i2c /dev entries driver
[    9.442219] omap_i2c 4802a000.i2c: bus 2 rev0.11 at 100 kHz
[    9.442248] omap_i2c 4802a000.i2c: unable to select pin group


So I changed the all clock frequencies from 100 k to 400 k inside the dtb 
files which are loaded during boot:
am335x-bone.dtb
am335x-boneblack.dtb
omap3-beagle.dtb

But no reaction at all. I double checked with the osci but still only 10 us 
clock period (100 k). 
Then I ve checked the the clock frequency register and there it is the same 
too:

od -bc /proc/device-tree/ocp/i2c\@4802a000/clock-frequency

I could try to change the values there using mmap but I would prefer a 
solution using the overlays.
Or is it not possible to change it.

Kind regards,

Constantin


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