From: ryan@bluewatersys•com (Ryan Mallon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/3 v2] at91/atmel-mci: inclusion of sd/mmc driver in at91sam9g45 chip and board
Date: Tue, 03 Nov 2009 15:30:56 +1300 [thread overview]
Message-ID: <4AEF95E0.7040602@bluewatersys.com> (raw)
In-Reply-To: <4AEF12B7.3040704@atmel.com>
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 at bluewatersys.com PO Box 13 889, Christchurch 8013
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next prev parent reply other threads:[~2009-11-03 2:30 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090930155557.7dae503b@hskinnemoen-d830>
2009-10-23 16:34 ` [PATCH 0/2 v2]mmc: atmel-mci: introduce MCI2 support on at91 Nicolas Ferre
2009-10-23 16:34 ` [PATCH 1/3 v2] atmel-mci: change use of dma slave interface Nicolas Ferre
2009-10-23 16:34 ` [PATCH 2/3 v2] mmc: atmel-mci: New MCI2 module support in atmel-mci driver Nicolas Ferre
2009-11-02 17:18 ` Nicolas Ferre
2009-11-18 13:33 ` Nicolas Ferre
2009-10-23 16:34 ` [PATCH 3/3 v2] at91/atmel-mci: inclusion of sd/mmc driver in at91sam9g45 chip and board Nicolas Ferre
2009-10-26 8:15 ` Yegor Yefremov
2009-11-02 17:14 ` Nicolas Ferre
2009-10-27 19:43 ` Andrew Victor
2009-10-28 0:35 ` Haavard Skinnemoen
2009-10-28 0:53 ` Thiago A. Corrêa
2009-10-28 1:31 ` Haavard Skinnemoen
2009-10-28 19:53 ` Andrew Victor
2009-10-28 20:50 ` Ben Nizette
2009-11-02 17:11 ` Nicolas Ferre
2009-11-02 22:10 ` Ben Nizette
2009-11-02 22:14 ` Ben Nizette
2009-11-03 2:30 ` Ryan Mallon [this message]
2009-11-03 2:55 ` Ben Nizette
2009-11-07 11:20 ` Haavard Skinnemoen
2010-08-23 15:01 ` [PATCH] pio: add arch specific gpio_is_valid() function Nicolas Ferre
2010-08-23 16:36 ` David Brownell
2010-08-24 8:19 ` Nicolas Ferre
2010-09-06 14:21 ` [PATCH v2] AT91: pio: add " Nicolas Ferre
2010-09-07 1:51 ` David Brownell
2010-09-03 16:41 ` [PATCH] pio: add arch specific " Jean-Christophe PLAGNIOL-VILLARD
2010-09-07 2:23 ` David Brownell
2010-09-07 2:44 ` Ryan Mallon
2010-09-07 3:54 ` Eric Miao
2010-09-07 4:07 ` Ryan Mallon
2010-09-07 4:19 ` Eric Miao
2010-09-07 4:26 ` Ryan Mallon
2010-09-07 18:10 ` David Brownell
2010-09-07 19:13 ` avictor.za at gmail.com
2010-09-07 19:30 ` Ryan Mallon
2010-09-07 21:22 ` Alan Cox
2010-09-07 23:44 ` David Brownell
2010-09-08 0:11 ` Alan Cox
2010-09-07 6:33 ` David Brownell
2010-09-07 8:41 ` Ben Nizette
2010-09-07 17:32 ` David Brownell
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