[patch 2.6.25-rc2-git] make i2c_register_board_info() a NOP when CONFIG_I2C=n

[patch 2.6.25-rc2-git] make i2c_register_board_info() a NOP when CONFIG_I2C=n

[David Brownell]

Don't require platform code to be #ifdeffed according to whether
I2C is enabled or not ... if it's not enabled, let GCC compile out
all I2C device declarations.  (Issue noted on an NSLU2 build that
didn't configure I2C.)

Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
---
 include/linux/i2c.h |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- at91.orig/include/linux/i2c.h	2008-02-21 22:58:53.000000000 -0800
+++ at91/include/linux/i2c.h	2008-02-21 23:02:57.000000000 -0800
@@ -271,9 +271,16 @@ extern void i2c_unregister_device(struct
  * This is done at arch_initcall time, before declaring any i2c adapters.
  * Modules for add-on boards must use other calls.
  */
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 extern int
 i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n);
-
+#else
+static inline int
+i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n)
+{
+	return 0;
+}
+#endif
 
 /*
  * The following structs are for those who like to implement new bus drivers:

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Re: [patch 2.6.25-rc2-git] make i2c_register_board_info() a NOP when CONFIG_I2C=n

[Jean Delvare]

Hi David,

On Fri, 22 Feb 2008 00:23:16 -0800, David Brownell wrote:
> Don't require platform code to be #ifdeffed according to whether
> I2C is enabled or not ... if it's not enabled, let GCC compile out
> all I2C device declarations.  (Issue noted on an NSLU2 build that
> didn't configure I2C.)
> 
> Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
> ---
>  include/linux/i2c.h |    9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> --- at91.orig/include/linux/i2c.h	2008-02-21 22:58:53.000000000 -0800
> +++ at91/include/linux/i2c.h	2008-02-21 23:02:57.000000000 -0800
> @@ -271,9 +271,16 @@ extern void i2c_unregister_device(struct
>   * This is done at arch_initcall time, before declaring any i2c adapters.
>   * Modules for add-on boards must use other calls.
>   */
> +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)

I'm fairly certain that #ifdef CONFIG_I2C is enough.

>  extern int
>  i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n);
> -
> +#else
> +static inline int
> +i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n)
> +{
> +	return 0;
> +}
> +#endif
>  
>  /*
>   * The following structs are for those who like to implement new bus drivers:

Other than that I am fine with this patch. Want it in 2.6.25 or 2.6.26
is enough?

-- 
Jean Delvare

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Re: [patch 2.6.25-rc2-git] make i2c_register_board_info() a NOP when CONFIG_I2C=n

[David Brownell]

On Friday 22 February 2008, Jean Delvare wrote:
> Hi David,
> 
> On Fri, 22 Feb 2008 00:23:16 -0800, David Brownell wrote:
> > Don't require platform code to be #ifdeffed according to whether
> > I2C is enabled or not ... if it's not enabled, let GCC compile out
> > all I2C device declarations.  (Issue noted on an NSLU2 build that
> > didn't configure I2C.)
> > 
> > Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
> > ---
> >  include/linux/i2c.h |    9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > --- at91.orig/include/linux/i2c.h	2008-02-21 22:58:53.000000000 -0800
> > +++ at91/include/linux/i2c.h	2008-02-21 23:02:57.000000000 -0800
> > @@ -271,9 +271,16 @@ extern void i2c_unregister_device(struct
> >   * This is done at arch_initcall time, before declaring any i2c adapters.
> >   * Modules for add-on boards must use other calls.
> >   */
> > +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
> 
> I'm fairly certain that #ifdef CONFIG_I2C is enough.

No; if I2C is modular, CONFIG_I2C isn't defined.

Though maybe it could use CONFIG_I2C_BOARDINFO, which
is defined as boolean.  In fact that's what the I2C
Makefile uses, but it'd be less obvious here.


> >  extern int
> >  i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n);
> > -
> > +#else
> > +static inline int
> > +i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n)
> > +{
> > +	return 0;
> > +}
> > +#endif
> >  
> >  /*
> >   * The following structs are for those who like to implement new bus drivers:
> 
> Other than that I am fine with this patch. Want it in 2.6.25 or 2.6.26
> is enough?

I'd go for 2.6.25, since it's a build fix.

- Dave

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Re: [patch 2.6.25-rc2-git] make i2c_register_board_info() a NOP when CONFIG_I2C=n

[Jean Delvare]

On Fri, 22 Feb 2008 02:22:18 -0800, David Brownell wrote:
> On Friday 22 February 2008, Jean Delvare wrote:
> > Hi David,
> > 
> > On Fri, 22 Feb 2008 00:23:16 -0800, David Brownell wrote:
> > > Don't require platform code to be #ifdeffed according to whether
> > > I2C is enabled or not ... if it's not enabled, let GCC compile out
> > > all I2C device declarations.  (Issue noted on an NSLU2 build that
> > > didn't configure I2C.)
> > > 
> > > Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
> > > ---
> > >  include/linux/i2c.h |    9 ++++++++-
> > >  1 file changed, 8 insertions(+), 1 deletion(-)
> > > 
> > > --- at91.orig/include/linux/i2c.h	2008-02-21 22:58:53.000000000 -0800
> > > +++ at91/include/linux/i2c.h	2008-02-21 23:02:57.000000000 -0800
> > > @@ -271,9 +271,16 @@ extern void i2c_unregister_device(struct
> > >   * This is done at arch_initcall time, before declaring any i2c adapters.
> > >   * Modules for add-on boards must use other calls.
> > >   */
> > > +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
> > 
> > I'm fairly certain that #ifdef CONFIG_I2C is enough.
> 
> No; if I2C is modular, CONFIG_I2C isn't defined.

Mpff, you're right. I wonder why it was done this way, sounds totally
stupid to me given that in 99% of the cases you don't care if the thing
is modular or not. Oh well.

> Though maybe it could use CONFIG_I2C_BOARDINFO, which
> is defined as boolean.  In fact that's what the I2C
> Makefile uses, but it'd be less obvious here.

Now that you mention it, given that i2c_register_board_info() is
defined in i2c-boardinfo.c, it would indeed make a lot of sense to make
the conditional depend on CONFIG_I2C_BOARDINFO rather that CONFIG_I2C.

> > >  extern int
> > >  i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n);
> > > -
> > > +#else
> > > +static inline int
> > > +i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n)
> > > +{
> > > +	return 0;
> > > +}
> > > +#endif
> > >  
> > >  /*
> > >   * The following structs are for those who like to implement new bus drivers:
> > 
> > Other than that I am fine with this patch. Want it in 2.6.25 or 2.6.26
> > is enough?
> 
> I'd go for 2.6.25, since it's a build fix.

OK, will do.

-- 
Jean Delvare

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