IO, ANSI vs GCC structs

[Wolfgang Denk]

In message <20030725134734.J29161 at borg.org> you wrote:
>
> How important is it to the kernel coding style that hardware be

I cannot speak for the powers that be, but...

> accessed through a structure?  Is it acceptable to do:
>
>   #define MYHW  (MY_MBAR+42)
>
>   ...
>
>   out_be32(MYHW, 0xco1df00d);

...I would not accept such code.

There is one fundamental difference: a field in a struct has a  type,
i.  e.  the  compiler "knows" how big it is (8, 16, 32, ... bits), if
special attributes apply (volatile), etc.

There is no such information with a #define like yours above.

OK, you can write

	#define FOO	((volatile uint32_t *)(FOO_BASE+FOO_OFFSET))

but this isn't really readable, is it?

Just my $0.02


Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
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