I2c devices list of wp768

mangOH Red
1

Hi Team,

This question is in relation to the below topic

In brief, in linux below are the list of i2c devices

root@swi-mdm9x28:~# i2cdetect -r -y 4
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – 04 05 06 07 – – – – – – – –
10: – – – – – – – – – – UU – – – – –
20: – – – – – – – – – – – – – – – –
30: – – – – – – – – – – UU – – – – –
40: – – – – – – – – – – – – – – – –
50: – 51 – – – – – – – – – – – – – –
60: – – – – – – – – 68 – – – – – – –
70: – 71 – – – – 76 –

How ever, From the schematic has the below snapshot

https://discourse-cdn-sjc1.com/business5/uploads/legato1/original/1X/489ba7812b8f8e498866a3444790ecdc42b15e21.png

I am not able to correlate both the devices. Why there is a difference in the i2c devices ?
Is there any document to outline what are the available I2C devices with address ?

Thanks

2

Some of the devices are behind the i2c hub. You need to enable all the ports on the hub:
root@swi-mdm9x28:/dev# i2cset -y 4 0x71 0x0f
root@swi-mdm9x28:/dev# i2cdetect -y -r 4
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – 04 05 06 07 – – – – – – – –
10: – – – – – – – – – – UU – – – – –
20: – – – – – – – – – – – – – – – –
30: – – – – – – – – – – UU – – – 3e –
40: – – – – – – – – – – – – – – – –
50: – 51 – – – – – – – – – – – – – –
60: – – – – – – – – 68 – – 6b – – – –
70: – 71 – – – – 76 –

3

What Ashish said about enabling all ports on the I2C switch is true, but it’s generally not a good idea to do this because there’s already a Linux kernel driver that is controlling the device and things could go wrong if the driver’s understanding of the hardware configuration and the actual hardware configuration get out of sync. It’s better to just run i2cdetect against each of the switch ports by using i2cdetect -y -r N where N is 5, 6, 7, 8 for segments 0, 1, 2, 3 respectively.

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