Why jetson nano i2c@546c0000 i2c_client->irq=0? where to set it?

why jetson nano i2c@546c0000 i2c_client->irq=0? where to set it ?

It depend on the device. You can add it by yourself if your HW have INT signal connect to your device.

I2C @ 0x546c0000 is the VI_I2C on the TX1 SoC (T210). It isn’t used on Nano AFAIK. We do use it on Jetson TX1 boards to read the board ID EEPROM on camera add-in boards. So you should be able to ignore that I2C controller on Nano.