[PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base

Linus Walleij linus.walleij at linaro.org
Tue Feb 5 12:21:06 EST 2013

On Sat, Feb 2, 2013 at 5:29 PM, Alexandre Courbot <acourbot at nvidia.com> wrote:

> Re-implement gpiochip_find_base using the list of chips instead of the
> global gpio_desc[] array. This makes it both simpler and more efficient,
> and is needed to remove the global descriptors array.
> Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>

So Haojian just submitted a different patch to the same piece of
code staring to search for GPIO number in ascending order instead,
but I NACKed it.

This looks like it is preserving this userspace-sensitive semantic
so that dynamically added chips will still get the same assigned

But I want some guarantees, so state clearly in the commit
that any dynamically assigned chip will get the same base
address after this change as it got before it, and please take
this opportunity to add a comment stating that this search
method is vital for userspace ABIs, and must be preserved.

Linus Walleij

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