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Re: Changing the gpio(4) API/ABI

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.

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