About problem of Rrk3399's I2C being not able to driven up

zengqiluo@yahoo

We encountered some problem of Camera integration. Currently our R&D progress is blocked at I2C being not able to driven up。 Even we are using official open-source code project and Devicetree file：


The phenomenon is any enabled I2C bus, SDA SCLkeep low. If externally connect to pull-up circuit，SDA become high voltage，but SCL is still less than 0.2V.
Check dmesg, it reports: “rk3x-i2c ff120000.i2c: timeout, ipd: 0x00, state:1”


Does anyone know the reaosn?

leung先森

I thought if you have not changed the code of the i2c2,  it might be the hardware broken.

wizama

Hi,
I have got the same problem (same error message), but on I2C4.
When you say "It might be the hardware broken" : does Firefly change the board ? It's a brand new one received one week ago !!!

penguin

@wizama

I2C4_SDA & I2C4_CLK are pulled up by the VCC_3V0 regulator.
Plz describe your problem more specifically.
It might be the same error message, but might not be the same reason.

wizama

Hi penguin,
Thank you for your message.

I have got 3 boards AIO-3399C, and the issue only concerns one of them.
All three run the same customized firmware which is compiled from the sources with only the LVDS screen resolution modified in the DTS and the boot animation updated with customized logo. No changes have been made about I2C configuration.
On the I2C4 port, a NFC reader is connected, but is never detected whereas it is on the 2 other boards.

Here is the log I got from debug serial port on launch :

1. [    1.878134] rk3x-i2c ff3d0000.i2c: Initialized RK3xxx I2C bus at ffffff800994a000

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which suppose it seems to correctly initialized;
however, when i run "i2cdetect -y 4" command as root, it runs very slow, and for each tested address, I have the following in the logs :

1. [  288.691942] rk3x-i2c ff3d0000.i2c: timeout, ipd: 0x00, state: 1

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SDA is 3V and SCL is 0V, but should be 3V also

On the 2 other boards, this command is fast and displays for each address if a device is connected or not.

Any idea ?

penguin

You need to have the hardware guy check that.  SDA and SCL are pulled up to 3V. If no communication is in place, the voltage should be both 3V.
While communicating, there should be a square clock/signal.

ballsystemlord

See: https://robot-electronics.co.uk/i2c-tutorial
In particular:
It shows how to wire up the I2C bus.

ballsystemlord

Addendum: I've not tested the I2C bus yet, but I plan to.

penguin

Thanks ballsystemlord , for attaching a clear picture and tutorial link.