Dear Graeme Russ,
In message <banlktik3cxemzu0qpxdlsqmtk-abeod...@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
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
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- Terry Pratchett, _Going_Postal_
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