Hi all

I have a device driver question and it isn't quite suitable in any other forums, so I post it here. Hope someone can point me to the right direction.

I'm trying to use the linux I2C driver to access a device on the I2C bus. I opened the device (in /dev/) with no problem. I also used ioctl to set the 7-bit device address without encountering any problem. However, whenever I use the read_word_data function to access an register of the device, I receive a "-EPERM" error.

Does anyone have any idea? Would like to know the cause of this error. I need help from someone who is familiar with the I2C driver. Or... at least, someone can point me to the right forum to post this question.

Thanks in advance.