Dear Graeme Russ,
In message BANLkTik3cXeMzU0qpxDLSQMtK-AbEoDCPQ@mail.gmail.com you wrote:
Now, that being said, I see no reason not to do the following if I had, for example, multiple serial port configuration registers which are all identical:
/* num data bits is stored in bits 2-4 of the serial config register */ #define DATA_BITS_MASK 0x001c #define DATA_BITS_OFFSET 2
u32 set_serial_data_bits(u32 ser_cfg, u8 data_bits) { ser_cfg &= ~DATA_BITS_MASK; ser_cfg |= ((u32)ser_cfg << DATA_BITS_OFFSET) & DATA_BITS_MASK;
return ser_cfg; }
void serial_init(void) { u32 ser_cfg;
for (i=0; i<NUM_SERIAL_PORTS; i++) { ser_cfg = read_serial_cfg(i); ser_cfg = set_serial_data_bits(ser_cfg, 7); write_serial_cfg(i, ser_cfg); } }
One reason for not doing this is that we should not reinvent the wheel again and again, and instead use standard APIs.
I cannot find any such code in U-Boot, so I cannot check, but to me it smells a lot as if this code should rather use clrsetbits_*() and other proper I/O accessors.
Best regards,
Wolfgang Denk