Re: [PATCH 8/9] gpiolib: use gpio_chips list in gpio_to_desc

[Linus Walleij]

On Sat, Feb 2, 2013 at 5:29 PM, Alexandre Courbot <acourbot@xxxxxxxxxx> wrote:

> Parse the list of chips to find the descriptor corresponding to a GPIO
> number instead of directly picking the entry of the global gpio_desc[]
> array, which is due to be removed.
>
> This turns the complexity of converting a GPIO number into a descriptor
> from O(1) to O(n) where n is the number of GPIO chips in the system.
> Since n is ought to be small anyway, there should be no noticeable
> performance impact. Moreover, GPIO users who care for speed already have
> implemented their own gpio_get_value() and gpio_set_value() with a
> fast path for the GPIO numbers that matter and this change does not
> affect such use cases.
>
> The descriptor-based GPIO API, due to be introduced soon, will make this
> lookup unnecessary.
>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

OK it's a nice stepping stone.

Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/