How to mount the MFi chip on imx8mp-evk 's J22

[ChChang]

Hi

I try to connected the MFi chip to J22 on the i.mx8mp-evk and modified the imx8mp-evk.dts as follows:

&flexcan1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_flexcan1>;
xceiver-supply = <&reg_can1_stby>;
pinctrl-assert-gpios = <&pca6416 2 GPIO_ACTIVE_HIGH>; /* set high to select i2c5 instead of flexcan1 */
status = "disable";
};
...
&i2c5 {
clock-frequency = <100000>; /* Lower clock speed for external bus. */
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c5>;
pinctrl-assert-gpios = <&pca6416 2 GPIO_ACTIVE_HIGH>; /* set high to select i2c5 instead of flexcan1 */
status = "okay"; /* can1 pins conflict with i2c5 */

mfi_chip: mfi-chip@10 {
compatible = "apple,MFi";
reg = <0x10>;
};

However, after booting up,
# i2cdetect -y 4
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: 10 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

and, 
cat /sys/bus/i2c/devices/4-0010/name
MFi

but,whenrunning "i2cget -y 4 0x10 0x00" to read the register,
the return value is always 0x00.
What step might I have done incorrectly?"

Regards,

CH

[jimmychan]

Do you add the pinmux setting for I2C5?

[ChChang]

Thanks for your reply,

Do you mean the below section:

pinctrl_i2c5: i2c5grp {
fsl,pins = <
MX8MP_IOMUXC_SPDIF_RX__I2C5_SDA 0x400001c2
MX8MP_IOMUXC_SPDIF_TX__I2C5_SCL 0x400001c2
>;
}; 

It is default setting in imx8mp-evk.dts,
Attachment is my dts file.
Could you help to check? Thanks a lot.

CH

[jimmychan]

In your dts file, there is a typo of flexcan1 status.  You type status = "disable", it should be "disabled".

Also, please double check the signals are output properly.