Re: [PATCH 1/3] ACPICA: Introduce ACPI_ACCESS_BIT_WIDTH() macro

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Feb 12, 2020 at 12:52:44PM +0100, Jean Delvare wrote:
> On Wed, 12 Feb 2020 14:05:38 +0300, Mika Westerberg wrote:
> > Sometimes it is useful to find the access_width field value in bytes and
> > not in bits so add a helper that can be used for this purpose.
> 
> s/ACPI_ACCESS_BIT_WIDTH/ACPI_ACCESS_BYTE_WIDTH/ in the subject.

Indeed.

> > Suggested-by: Jean Delvare <jdelvare@suse.de>
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  include/acpi/actypes.h | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
> > index a2583c2bc054..77d40b02f62a 100644
> > --- a/include/acpi/actypes.h
> > +++ b/include/acpi/actypes.h
> > @@ -537,6 +537,7 @@ typedef u64 acpi_integer;
> >   * struct acpi_resource_generic_register.
> >   */
> >  #define ACPI_ACCESS_BIT_WIDTH(size)     (1 << ((size) + 2))
> > +#define ACPI_ACCESS_BYTE_WIDTH(size)    (ACPI_ACCESS_BIT_WIDTH(size) / 8)
> 
> One of the points of having this macro being to avoid needless math,
> I'd rather do:
> 
> #define ACPI_ACCESS_BYTE_WIDTH(size)    (1 << ((size) - 1))
> 
> Some compilers might be able to optimize it, but maybe not all, and I
> see little point in giving the compiler more work anyway when it can be
> easily avoided.
> 
> You may also want to replace "bit" by "bit or byte in the comment right
> before the macros.

OK, I'll do that.

> >  
> >  /*******************************************************************************
> >   *
> 
> Reviewed-by: Jean Delvare <jdelvare@suse.de>

Thanks!