Re: [PATCH net-next v13 3/4] net: dsa: microchip: Support Microchip KSZ8995XA / KS8995XA

[Nicolai Buchwitz <nb@tipi-net.de>]

On 13.9.2026 21:56, Linus Walleij wrote:
> This adds support for the Microchip KSZ8995XA also known as the
> Micrel KS8995XA switch to the KSZ driver.
> 
> The KSZ8995XA shares family ID 0x95 and chip-ID nibble 0x0 with
> the KS8995MA, so hardware detection cannot distinguish them. The
> legacy "micrel,ks8995" compatible is therefore treated as KSZ8995XA.
> No KS8995MA users are known, and KS8995E has no documented SPI
> management interface. Neither MA nor E has been verified with this
> driver.
> 
> The helper macros are named ksz_is_ksz8995xa() to make it
> possible to add E and MA support in the future.
> 
> Wait for the self-clearing per-port PHY reset bits before continuing
> with switch setup. Poll each port for up to 600 ms and allow an
> additional millisecond for the PHYs to settle.
> 
> The KSZ8995XA has eight global TOS priority registers with one
> bit per DSCP code point, providing two internal priority levels.
> The registers are ordered in the opposite direction from the
> other KSZ8 switches. Describe the two priorities in the chip
> data, then augment the DCB helpers for this.
> 
> Practical testing also shows that its packet-size control bits use
> the same semantics as the other KSZ8 switches. The polarity in the
> manual appears to be wrong and makes the switch hang on big packets.
> 
> The legacy KS8995 driver also matches the Micrel compatibles for
> KSZ8864 and KSZ8795. Add these to the KSZ SPI driver here and use
> an exact tristate dependency to make the drivers mutually exclusive.
> This transfers ownership atomically, avoiding module probe races and
> gaps in driver coverage between patches.
> 
> Assisted-by: LLM
> Signed-off-by: Linus Walleij <linusw@kernel.org>
> ---

> [...]

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks,
Nicolai