In article <4e7e14f0.2050...@msys.ch>, Marc Balmer <m...@msys.ch> wrote: >On 09/23/11 12:38, Marc Balmer wrote: >> With gpio(4) we still carry an old API with us, which I want to >remove. While working on it, I will also introduce a third locator to >device drivers that attach to gpio pins, flags. It will be needed for >e.g. gpioiic(4) to invert the SDA/SCL pin numbers. >> >> WIll documenting the changes be enough? > >I want to make it clear that this will change the binary ABI and break >backwards compatability: > >*** Please note that gpio(4) is not enabled in GENERIC kernels by >default, so users of GENERIC or MONOLITHIC kernels are not affected by >this change. *** > >- the old and deprecated API, which is not documented and not used by >our own tools, will be removed > >- one current ioctl, GPIOATTACH, will be changed, as a third locator >will be introduced for flags (this is needed e.g. to reverse the pin >ordering of SDA and SCL pins in gpioiic(4)) > >- maybe I will just rearrange all ioctls. > >The consequences are: > >- if you use an older gpioctl(8) it will not work with gpio(4) anymore. > You need to rebuild gpioctl(8) > >- if you have your own software that talks to gpio(4) (and that excludes >drivers), you will have to recompile them.
I vote to do it without keeping backwards compatibility. The impact is really limited to worth the trouble and the kernel bloat. christos
