Dear Wolfgang Denk
writel(AT91C_PA23_TXD2, AT91C_PIOA_OER);
is the most correct way.
"most correct way" are big words. No, this is not "correct" at all.
The whole set of address / offset definitions in include/asm-arm/arch-at91rm9200/AT91RM9200.h should be turned into a C struct.
I've got you misunderstood, what real pointer variable means.
If I understand you correctly now? The train goes in the opposite direction.
in the AT91RM9200.h
a port is defined as
typedef struct _AT91S_PIO { ... AT91_REG PIO_OER; /* Output Enable Register */ ... } AT91S_PIO, *AT91PS_PIO;
and
#define AT91C_BASE_PIOC ((AT91PS_PIO) 0xFFFFF800)
So the access should be
AT91PS_PIO pioa = AT91C_BASE_PIOA; ... writel(AT91C_PA23_TXD2, &pioa->PIO_OER);
or
writel(AT91C_PA23_TXD2, &AT91C_BASE_PIOA->PIO_OER);
instead of
writel(AT91C_PA23_TXD2, ((AT91PS_PIO) AT91C_BASE_PIOA)->PIO_OER)
or writel(AT91C_PA23_TXD2, AT91C_PIOA_OER)
The result, if all the board are adjusted, it can be removed individual register definitions like #define AT91C_PIOD_OWER ((AT91_REG *) 0xFFFFFAA0)
I'm right?
Best regards,
Jens Scharsig