accessing ioctl

Jim232 · 04-11-2018, 10:12 AM

After device file is opened for read / write the
ioctl is accessed this way

ioctl(FileDescriptor, I2C_SLAVE, address);

The I2C spec calls for 8 bits format where the actual I2C device address could be shifted to MSByte and "write" bit of zero value thus becomes LSBit.

It is not clear if ioctl should be modified to follow the spec for write

ioctl(FileDescriptor, I2C_SLAVE, address << 1 );

Jim232 · 04-11-2018, 11:59 AM

When I shift the address in ioctl call the subsequent write(...) will fail.
Not sure how, but it does answer this question.