Cannot build vdcd on a Linux VM because i2c and spi are not disabled

[goranpetrovikj]

Trying to build the vdcd on Ubuntu 18.04 (x64) running in Virtualbox resulted in the following error, even though i2c-tools were installed according to the instructions https://github.com/plan44/vdcd/blob/master/docs/How%20to%20build%20vdcd%20on%20Linux.md:

src/p44utils/i2c.cpp:44:4: warning: #warning "Most probably, we have the wrong i2c-dev.h header here - maybe i2c-tools not installed?" [-Wcpp]
   #warning "Most probably, we have the wrong i2c-dev.h header here - maybe i2c-tools not installed?"
    ^~~~~~~
src/p44utils/i2c.cpp: In member function ‘bool p44::I2CBus::I2CReadByte(p44::I2CDevice*, uint8_t&)’:
src/p44utils/i2c.cpp:183:13: error: ‘i2c_smbus_read_byte’ was not declared in this scope
   int res = i2c_smbus_read_byte(busFD);
             ^~~~~~~~~~~~~~~~~~~
...
src/p44utils/i2c.cpp: In member function ‘bool p44::I2CBus::accessDevice(p44::I2CDevice*)’:
src/p44utils/i2c.cpp:348:7: error: ‘ioctl’ was not declared in this scope
   if (ioctl(busFD, I2C_SLAVE, aDeviceP->deviceAddress) < 0) {
       ^~~~~
Makefile:4509: recipe for target 'src/p44utils/vdcd-i2c.o' failed
make[1]: *** [src/p44utils/vdcd-i2c.o] Error 1
make[1]: Leaving directory '/home/user/ds/vdcd'
Makefile:1397: recipe for target 'all' failed
make: *** [all] Error 2

To overcome the issue i had to set #define DISABLE_I2C 1 in /p44utils/i2c.cpp and #define DISABLE_SPI 1in /p44utils/spi.cpp.
I remember I didn't have such an issue when building the vdcd some months ago.

[plan44]

I don’t remember having made a change recently regarding this. I would guess it‘s something platform side that makes the build pick up the wrong i2c-dev.h. It is very unfortunate that there are two different header files of this name in Linux.

[holli73]

hello,

i moved to ubuntu 18.04 x64 and had the same issue - so i copied the files from ubuntu 16.04 (usr/include/linux/i2*) files and the make did work - it looks like the i2c.h file in ubuntu 18.04 x64 is missing some definitions.

i do not know if this is a bug in 18.04 or the new definitions looks like this - so maybe the putils should be adjusted to fit the act release of the ic2-dev package.

i attache both files for your review

i2c-dev-16.04.h.txt
i2c-dev-18.04.h.txt

[plan44]

There are, unfortunately, two versions of i2c-dev.h. The one vdcd needs is a superset of the version usually present in stock linux installations, which contains a number of inline functions for smbus operations. These operations are required by vdcd, so there's no way to fit p44utils with the basic version.

The superset version is part of i2c-tools, and should get installed when you install these tools. However, as the two files both reside in the same location, there's no clean solution I am aware of to make sure the correct header is in place.

To fix the situation for my own (openwrt based) builds, I use a modified i2c-tools openwrt package which puts the correct header under the name lib-i2c-dev.h, and the vdcd openwrt package depends on that i2c-tools package.

I have no idea for a clean solution on generic Linux. Hints are welcome ;-)

[KarlKiel]

Hi, I also had the problem. I just replaced the current i2c-dev.h with the 16.04 version holli73 has posted above for the build and it went through without errors.