Re: [RFC patch net-next 3/3] net: dsa: ksz: moved ksz9477 port mirror to ksz_common.c

[Vladimir Oltean <olteanv@gmail.com>]

On Thu, Apr 28, 2022 at 03:09:50PM +0000, Arun.Ramadoss@microchip.com wrote:
> > > +#define
> > > P_MIRROR_CTRL                        REG_PORT_MRI_MIRROR_CTRL
> > > +
> > > +#define S_MIRROR_CTRL                        REG_SW_MRI_CTRL_0
> > 
> > Small comment: if P_MIRROR_CTRL and S_MIRROR_CTRL are expected to be
> > at
> > the same register offset for all switch families, why is there a
> > macro
> > behind a macro for their addresses?
> 
> ksz8795 and ksz9477 have different address/register for the
> Mirror_ctrl. To make it common for the both, P_MIRROR_CTRL is defined
> in ksz8795_reg.h and ksz9477_reg.h file.
> I just carried forward to ksz_reg.h.

So if P_MIRROR_CTRL has different values for ksz9477 and ksz8795, how
exactly do you plan to mask that difference away through the C preprocessor
at the level of ksz_reg.h included by ksz_common.c, depending on which
switch driver calls ksz_port_mirror_add()?

This can't work, you need to provide the offset of P_MIRROR_CTRL as
argument to the common function. What am I missing?