From: David Brownell <david-b@pacbell•net>
To: cbouatmailru@gmail•com, avorontsov@ru•mvista.com
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [PATCH RFC 4/7] [GPIO] Let drivers link if they support GPIO API as an addition
Date: Fri, 22 Feb 2008 15:42:03 -0800 [thread overview]
Message-ID: <200802221542.03359.david-b@pacbell.net> (raw)
In-Reply-To: <20071210230445.GA1141@zarina>
On Monday 10 December 2007, Anton Vorontsov wrote:
> On Mon, Dec 10, 2007 at 02:55:24PM -0800, David Brownell wrote:
> > The point of CONFIG_GENERIC_GPIO is to be *the* conditional used to
> > tell whether that programming interface is available ... starting
> > from "#include <asm/gpio.h>", and including all gpio_*() calls.
> >
> > So my first reaction is to not like this patch. It changes semantics
> > in an incompatible way. And AFAICT, needlessly so.
>
> Why incompatible? gpio-aware drivers will get -ENOSYS on gpio_request,
> thus they will not do anything wrong. GPIO-only drivers could still
> depend on GENERIC_GPIO, and their behaviour will not change.
If you still want this, I think a better approach would be:
http://marc.info/?l=linux-kernel&m=120295461410848&w=2
That is, #include <linux/gpio.h> and have *that* do the relevant
switch, based on GENERIC_GPIO. No semantic changes at all, if
one discounts the implicit switch to <linux/gpio.h> (important
for platforms that don't *have* any <asm/gpio.h> header), which
won't affect any existing code.
So your NAND code could use that, and work equally well on
SOC variants that have generic GPIOs and those that don't.
Comments?
- Dave
next prev parent reply other threads:[~2008-02-22 23:42 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-10 20:47 [PATCH RFC 0/7] "NAND on UPM" and related patches Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 1/7] [POWERPC] Implement GPIO API embryo Anton Vorontsov
2007-12-12 16:48 ` Scott Wood
2007-12-12 17:10 ` Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 2/7] [POWERPC] QE: implement GPIO API Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 3/7] [POWERPC] CPM2: " Anton Vorontsov
2007-12-12 15:49 ` Jochen Friedrich
2007-12-12 16:03 ` Anton Vorontsov
2007-12-12 16:56 ` Scott Wood
2007-12-10 20:49 ` [PATCH RFC 4/7] [GPIO] Let drivers link if they support GPIO API as an addition Anton Vorontsov
2007-12-10 22:55 ` David Brownell
2007-12-10 23:04 ` Anton Vorontsov
2008-02-22 23:42 ` David Brownell [this message]
2008-02-22 23:35 ` Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 5/7] [POWERPC] FSL UPM: routines to manage FSL UPMs Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 6/7] [POWERPC][NAND] FSL UPM NAND driver Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 7/7] [POWERPC] MPC8360E-RDK: add support for NAND on UPM Anton Vorontsov
2007-12-10 23:03 ` David Gibson
2007-12-10 23:16 ` Anton Vorontsov
2007-12-12 16:59 ` Scott Wood
2007-12-10 23:04 ` [PATCH RFC 0/7] "NAND on UPM" and related patches David Gibson
2007-12-10 23:10 ` Anton Vorontsov
2007-12-11 0:36 ` David Gibson
2007-12-12 12:47 ` Anton Vorontsov
2007-12-16 6:44 ` David Gibson
2007-12-12 16:39 ` Scott Wood
2007-12-12 16:40 ` Scott Wood
2007-12-12 16:55 ` Anton Vorontsov
2007-12-12 16:54 ` Scott Wood
2007-12-12 20:58 ` Anton Vorontsov
2007-12-12 21:06 ` Scott Wood
2007-12-12 21:13 ` Scott Wood
2007-12-13 14:09 ` Anton Vorontsov
2007-12-13 3:01 ` Chris Fester
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