Re: [PATCH v4 3/5] mfd: Add RTL8231 core device

From: Andrew Lunn
Date: Thu Jun 03 2021 - 10:04:15 EST

> I wanted to make the masking explicit, but since regmap-mdio currently requires
> a register address width of 5 bit, it could move there.
> Actually, can we safely assume that any MDIO driver implementing clause-22
> access (5-bit register address width) will just ignore higher bits? In that
> case, I could just drop these functions and not even modify regmap-mdio. It
> appears to work for bitbanged MDIO.

How are C45 addresses handled? The API to the MDIO bus driver uses a
register value which is 32 bits in width. Bit 30 indicates the address
is a C45 address, and then you have 21 bits of actual address.
regmap-mdio needs to be generic and support both C22 and C45.