How to know the speed of i2c?

[linhsun]

Dear all

My board is sabresd. I have some questions about i2c speed.

The dtsi sets  clock-frequency is 100k, but the result from cat /d/clk/clk_summary is 66000000.

Could  you tell me how speed i2c is?

My dtsi is as follows:

&i2c1 {
   clock-frequency = <100000>;
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_i2c1>;

cat /d/clk/clk_summary is as follows:

sabresd_6dq:/ # cat /d/clk/clk_summary | grep i2c
i2c3 0 0 66000000 0 0
i2c2 0 0 66000000 0 0
i2c1 0 0 66000000 0 0

[igorpadykov]

Hi Lin

PERCLK_CLK_ROOT/IPG_CLK_ROOT is used for i2c according to
Figure 18-2. Clock Tree - Part 1 i.MX6DQ Reference Manual  
and one can check with oscilloscope that clock on CLKO1,2 pins (use Table 4-1
Pin Assignments) using CCM_CCOSR register.

http://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf

Best regards
igor
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