Re: [PATCH net-next] net: pcs: tse: port to pcs-lynx

[Vladimir Oltean]

On Fri, Feb 10, 2023 at 09:02:39PM +0100, Andrew Lunn wrote:
> I was wondering if the glue could actually be made generic. The kernel
> has a number of reasonably generic MMIO device drivers, which are just
> given an address range and assume a logical mapping.
> 
> Could this be made into a generic MDIO MMIO bus driver, which just
> gets configured with a base address, and maybe a stride between
> registers?

This sounds interesting to me because I also have at least one other
potential use for it. The "nxp,sja1110-base-tx-mdio" driver does basically
just that, except it's SPI instead of MMIO. So if the generic driver was a
platform device driver and it was aware of dev_get_regmap(), it could
get reused.

What I'm not sure of is the spacing between MDIO registers. For the
SJA1110 CBTX PHY, the registers are 32-bit wide (but contain 16-bit
values). So MII_BMCR is at offset 0x0, MII_BMSR at 0x4 etc. I'd imagine
that other MDIO buses might have MII_BMSR at 0x2.