Messages in this thread | | | Date | Tue, 03 Nov 2009 15:30:56 +1300 | From | Ryan Mallon <> | Subject | Re: [PATCH 3/3 v2] at91/atmel-mci: inclusion of sd/mmc driver in at91sam9g45 chip and board |
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Nicolas Ferre wrote: > Ben Nizette : > >> On Wed, 2009-10-28 at 21:53 +0200, Andrew Victor wrote: >> >>> hi, >>> >>> >>>> 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 >>>> value. >>>> 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?
~Ryan
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Ryan Mallon 5 Amuri Park, 404 Barbadoes St ryan@bluewatersys.com 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
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