Re: [PATCH 3/3 v2] at91/atmel-mci: inclusion of sd/mmc driver inat91sam9g45 chip and board
From: Ryan Mallon
Date: Mon Nov 02 2009 - 21:34:36 EST
Nicolas Ferre wrote:
> Ben Nizette :
>> On Wed, 2009-10-28 at 21:53 +0200, Andrew Victor wrote:
>>>> Then I think it would be best to use GPIO_PIN_NONE. Makes it clear
>>>> what is expected and avoids confusion on what should be the proper
>>>> I hope I'm not saying non-sense, but even if I am, I guess you can see
>>>> that I'm advocating against the magic numbers :)
>>> What magic numbers ?
>> I think Thiago was referring to the "-1" in the original patch as the
>> magic number.
>> Leaving the field blank to be initialised to 0 is certainly the
>> cleanest, I agree, but it doesn't actually /work/. On many archs 0 is a
>> valid gpio number; the gpio_is_valid check used throughout the kernel
>> (including atmel-mci.c) looks like
>> static inline int gpio_is_valid(int number)
>> /* only some non-negative numbers are valid */
>> return ((unsigned)number) < ARCH_NR_GPIOS;
> I understand that the better way to solve this issue is to:
> - keep the AT91 way of specifying not connected pins (= 0)
> - code the gpio_is_valid() function for at91 that tests this way of
> handling not connected gpio
It doesn't appear that the gpio_is_valid function can be overridden by a
platform specific version. However, as you point out, on AT91 it appears
broken since anything less than AT91_PIN_PA0 (32) is not a valid gpio.
IIRC, we can't mark static inline functions as weak, and we don't want
to turn gpio_is_valid into an actual function call. We could do some
preprocessor magic, but that gets a bit messy.
CC'ed David Brownell, who does most of the gpiolib stuff. Any ideas?
Bluewater Systems Ltd - ARM Technology Solution Centre
Ryan Mallon 5 Amuri Park, 404 Barbadoes St
ryan@xxxxxxxxxxxxxxxx PO Box 13 889, Christchurch 8013
http://www.bluewatersys.com New Zealand
Phone: +64 3 3779127 Freecall: Australia 1800 148 751
Fax: +64 3 3779135 USA 1800 261 2934
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/