Re: [PATCH net-next v11 0/9] net: dsa: add DSA support for the LAN9645x switch chip family

[Jens Emil Schulz Ostergaard]

On Tue, 2026-08-11 at 12:35 +0200, Paolo Abeni wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 8/5/26 4:34 PM, Jens Emil Schulz Østergaard wrote:
> > This series provides the Microchip LAN9645X Switch driver.
> > 
> > The LAN9645x is a family of chips with ethernet switch functionality and
> > multiple peripheral functions. The switch delivers up to 9 ethernet
> > ports and 12 Gbps switching bandwidth.
> > 
> > The switch chip has 5 integrated copper PHYs, support for 2x RGMII
> > interfaces, 2x SGMII and one QSGMII interface.
> > 
> > The switch chip is from the same design architecture family as ocelot
> > and lan966x, and the driver reflects this similarity. However, LAN9645x
> > does not have an internal CPU in any package, and must be driven
> > externally. For register IO it supports interfaces such as SPI, I2C and
> > MDIO.
> > 
> > The chip supports a variety of network features such as
> > 
> > * Mactable for MDB/FDB functionality
> > * Bridge forwarding offload
> > * VLAN-aware bridging
> > * IGMP/MLD snooping
> > * Link aggregation
> > * PTP timestamping
> > * FRER (802.1CB)
> > * Media Redundancy Protocol
> > * Parallel Redundancy and High-Availability Seamless Redundancy
> >   (HSR/PRP) in DANH/DANP mode
> > * Per stream filtering and policing
> > * Shapers such as Credit Based Shaping and Time Aware Shaing
> > * Frame preemption
> > * A TCAM (VCAP) for line-rate frame processing
> > 
> > The LAN9645x family consists of the following SKUs:
> > 
> > LAN96455F
> > LAN96457F
> > LAN96459F
> > LAN96455S
> > LAN96457S
> > LAN96459S
> > 
> > The difference between the SKUs is the number of supported ports (5, 7
> > or 9) and features supported. The F subfamily supports HSR/PRP and TSN,
> > while the S subfamily does not.
> > 
> > The intended way to bind this driver is using a parent MFD driver,
> > responsible for the register IO protocol, and distributing regmaps to
> > child devices. The goal is to use the same approach as the MFD driver in
> > drivers/mfd/ocelot-spi.c.
> > 
> > This driver expects to request named regmaps from a parent device. This
> > approach is similar to the DSA driver
> > 
> > drivers/net/dsa/ocelot/ocelot_ext.c
> > 
> > which supports being driven by an external CPU via SPI with parent
> > device drivers/mfd/ocelot-spi.c.
> > 
> > The MFD driver will come in a later series, because there are
> > requirements on the number of child devices before a driver qualifies as
> > a MFD device.
> > 
> > Development is done using the LAN966x as a host CPU, running the lan966x
> > swichdev driver, using the EVB-LAN9668 EDS2 board.
> > 
> > The datasheet is available here:
> > https://ww1.microchip.com/downloads/aemDocuments/documents/UNG/ProductDocuments/DataSheets/LAN9645xF-Data-Sheet-DS00006065.pdf
> > 
> > This series will deliver the following features:
> > 
> > * Standalone ports
> > * Bridge forwarding and FDB offloading
> > * VLAN-aware bridge
> > * Stats integration
> > 
> > More support will be added at a later stage. Here is a tentative plan of
> > future patches for this DSA driver:
> > 
> > * Add LAG support.
> > * Add MDB support.
> > * Add TC matchall mirror support.
> > * Add TC matchall police support.
> > * Add DCB/qos support.
> > * Add simple TC support: mqprio, cbs, tbf, ebf.
> > * Add TC flower filter support.
> > * Add HSR/PRP offloading support.
> > * Add PTP support.
> > * Add TC taprio support.
> > 
> > For completeness I include tentative plan of planned patches for
> > LAN9645x peripherals:
> > 
> > * Extend pinctrl-ocelot for LAN9645x:
> >   https://lore.kernel.org/linux-gpio/20260119-pinctrl_ocelot_extend_support_for_lan9645x-v1-0-1228155ed0ee@xxxxxxxxxxxxx/
> > * Add driver for internal PHY:
> >   https://lore.kernel.org/netdev/20260123-phy_micrel_add_support_for_lan9645x_internal_phy-v1-1-8484b1a5a7fd@xxxxxxxxxxxxx/
> > * MFD driver for managing register IO protocol and child device
> >   initialization.
> > * Extend pinctrl-microchip-sgpio for LAN9645x support.
> > * Extend i2c_designware for LAN9645x support.
> > * Add driver for outbound interrupt controller.
> > * Add serdes driver for lan9645x.
> > 
> > Signed-off-by: Jens Emil Schulz Østergaard <jensemil.schulzostergaard@xxxxxxxxxxxxx>
> I forwarded the feedback from sashiko/nipa, but sashiko gemini has more
> comments:
> 
> https://sashiko.dev/#/patchset/20260805-dsa_lan9645x_switch_driver_base-v11-0-007ebc983a0a%40microchip.com
> 
> please have a look and also to net-next commit c82ff94592fb
> 
> /P
> 
I will go through the comments from the sashiko brothers.

Thanks
Emil