> On Wed, Oct 14, 2009 at 9:11 AM, G, Manjunath Kondaiah
> <manj...@ti.com> wrote:
>
> > Any advantage of using both enum and register offsets?
> > You can have only register offset macros instead of enum.
>
> This was the appproach proposed by Tony in response to Alistair's
> original query. Tony originally cited something from Russel for the
> reason.
>
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg14918.html
>
> If static #define's were used, then it would probably be impossible to
> support multiple omap1 cpu's with the same binary driver / binary
> kernel. Having a run-time cpu check (referencing static offset arrays)
> makes this possible and in the worst case scenario, it adds ~20 bytes.
> I guess if you really wanted to save those 20 bytes, then you could
> check #ifdef OMAP1_MULTI or something like that.
>
You can acheive the same using only enum with following:
#define OMAP_RTC_REGISTER_SIZE (cpu_is_omap7xx()?1:4)
#define rtc_read(reg)
omap_readb(OMAP_RTC_BASE + (reg * OMAP_RTC_REGISTER_SIZE))
#define rtc_write(val, reg)
omap_writeb(val, OMAP_RTC_BASE + (reg * OMAP_RTC_REGISTER_SIZE))
Russel point is different compared to your scenario.
> > Why 50? Count can be decreased from 50 to 30/35 which will
> increase rtc performance.
>
> No idea, I didn't write the driver, I just patched it, and that is
> completely irrelevent to my patch, but feel free to test 30/35 and
> submit the changes back :)
>
This should be tested and optimized before pushing upstream.
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