[i2c] [PATCH] i2c-s3c2410.c: Fix build warning

[Jean Delvare]

Hi Ben,

On Sun, 6 May 2007 14:51:24 +0000, Ben Dooks wrote:
> On Sat, May 05, 2007 at 09:58:37PM +0200, Jean Delvare wrote:
> > On Sat, 05 May 2007 16:02:20 +0200, Arnaud Patard (Rtp) wrote:
> > > 
> > > Fix for the following build warning :
> > >   CC      drivers/i2c/busses/i2c-s3c2410.o drivers/i2c/busses/i2c-s3c2410.c: In function 's3c24xx_i2c_probe':
> > >   drivers/i2c/busses/i2c-s3c2410.c:839: warning: format '%ld' expects type 'long int', but argument 4 has type 'resource_size_t'
> > > 
> > > Signed-off-by: Arnaud Patard <arnaud.patard at rtp-net.org>
> > 
> > > ---
> > > diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
> > > index 556f244..674ca30 100644
> > > --- a/drivers/i2c/busses/i2c-s3c2410.c
> > > +++ b/drivers/i2c/busses/i2c-s3c2410.c
> > > @@ -836,7 +836,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
> > >  
> > >  	i2c->irq = res;
> > >  		
> > > -	dev_dbg(&pdev->dev, "irq resource %p (%ld)\n", res, res->start);
> > > +	dev_dbg(&pdev->dev, "irq resource %p (%zd)\n", res, res->start);
> > >  
> > >  	ret = i2c_add_adapter(&i2c->adap);
> > >  	if (ret < 0) {
> > 
> > I'm not sure this is the right fix. resource_size_t might be either u32
> > or u64 depending on CONFIG_RESOURCES_64BIT, so I suspect that you are
> > clearing the warning in one case but adding it in the other. As a
> > matter of fact, I couldn't find any other example in the kernel tree of
> > %zd, %zu or %zx being used to print a resource boundary.
> > 
> > So I think that it would be better to keep %ld and cast res->start to
> > an unsigned long. Ben, what do you think?
> 
> I think the best fix is to cast to (unsigned long long) and use %llu
> as this means you are not truncating 64bit resources... although why
> anyone would want to use 64bit resources on an ARM chip that is 32bit
> only is a little strange.

long longs are costly to handle so I'd rather avoid that. This is an
IRQ we're talking about, so I'd be very surprised if it didn't fit in
32 bits.

I can't tell you why anyone would want to use 64-bit resources on ARM.
In fact I simply don't get why CONFIG_RESOURCES_64BIT exists for 32-bit
architectures.

-- 
Jean Delvare