Re: [PATCH] spi: Fix warning about redefinition

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Aug 06, 2014 at 07:19:54PM +0200, Richard Weinberger wrote:
> On Wed, Aug 6, 2014 at 6:55 PM, Nick Krause <xerofoiffy@gmail.com> wrote:
> > Fix the following warnings about redefining READ and write
> >
> > drivers/spi/spi-omap-100k.c:73:0: warning: "WRITE" redefined [enabled by default]
> > include/linux/fs.h:193:0: note: this is the location of the previous definition
> > drivers/spi/spi-omap-100k.c:74:0: warning: "READ" redefined [enabled by default]
> > include/linux/fs.h:192:0: note: this is the location of the previous definition
> >
> > Signed-off-by: Nick Krause <xerofoiffy@gmail.com>
> > ---
> >  drivers/spi/spi-omap-100k.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/spi/spi-omap-100k.c b/drivers/spi/spi-omap-100k.c
> > index 5e91858..eb8ae4e 100644
> > --- a/drivers/spi/spi-omap-100k.c
> > +++ b/drivers/spi/spi-omap-100k.c
> > @@ -70,6 +70,12 @@
> >  #define SPI_STATUS_WE                   (1UL << 1)
> >  #define SPI_STATUS_RD                   (1UL << 0)
> >
> > +#ifdef WRITE
> > +#undef WRITE
> > +#endif
> > +#ifdef READ
> > +#undef READ
> > +#endif
> >  #define WRITE 0
> >  #define READ  1
> 
> Are these symbols even in use?
> 

It is always fun watching those patches flow by :-)

With the following patch:

diff --git a/drivers/spi/spi-omap-100k.c b/drivers/spi/spi-omap-100k.c
index 5e91858..f72ddfc 100644
--- a/drivers/spi/spi-omap-100k.c
+++ b/drivers/spi/spi-omap-100k.c
@@ -70,8 +70,8 @@
 #define SPI_STATUS_WE                   (1UL << 1)
 #define SPI_STATUS_RD                   (1UL << 0)

-#define WRITE 0
-#define READ  1
+#undef WRITE
+#undef READ

[ just to make sure that no existing defines are used instead of the new ones ]

When compiling the resulting code with W=1, I get:

drivers/spi/spi-omap-100k.c: In function 'spi100k_read_data':
drivers/spi/spi-omap-100k.c:148:6: warning: variable 'dataH' set but not used
				[-Wunused-but-set-variable]

So, one might conclude that the defines are not used.

Guenter