Re: [PATCH] gpio: keep the GPIO line names internal

[Johan Hovold <johan@kernel.org>]

On Wed, Sep 23, 2015 at 04:27:33PM -0700, Linus Walleij wrote:
> This refactors the changes to the GPIO line naming mechanism to
> not have so widespread effects, instead we conclude the patch series
> by having created a name attribute in the GPIO descriptor, that need
> not be globally unique, and it will be initialized from the old
> .names array in struct gpio_chip if it exists, then used in the legacy
> sysfs code like the array was used previously.
> 
> The associated changes to name lines from the device tree are
> controversial and need to stand alone from this. Resulting changes:
> 
> 1. Remove the export and the header for the gpio_name_to_desc() as so
> far the only use is inside gpiolib.c. Staticize gpio_name_to_desc()
> and move it above the only function using it.
> 
> 2. Only print a warning if there are two GPIO lines with the same name.
> The reason is to preserve current behaviour: before the previous
> changes to the naming mechanism this would not reject probing the
> driver, instead the error would occur when trying to export the line
> in sysfs, so restore this behaviour, but print a friendly warning
> if names collide.

This looks good (apart from the checkpatch warning for the warning
message string).

You also need to revert ddd5404007b8 ("gpio-sysfs: Use gpio descriptor
name instead of gpiochip names array") however as this is an ABI change.  
Otherwise pins with a name in DT will now be exported using the gpio name
rather than number as they used to be. [ The current behaviour is
maintained by exporting names from chip->names for hard coded names
only. ]

Thanks,
Johan