Re: [PATCH net-next v2 1/2] net: axienet: use device_property and fwnode APIs for probe-time config

On Mon, Sep 28, 2026 at 10:42:55AM +0300, Sagi Maimon wrote:

axienet_probe() reads its configuration exclusively through the of_*
API, so the driver can only be instantiated from a device tree node.

The ADVA TimeCard X2 is a PCIe timing card, driven by ptp_ocp, whose
FPGA contains an AXI Ethernet MAC with an AXI DMA engine.  ptp_ocp is
going to register the MAC as a child platform device described by a
software node, so that this driver runs it rather than a copy in
ptp_ocp.  That needs the probe-time configuration to be readable from a
software node.

Convert only the lookups such a caller needs: "xlnx,rxmem", which probe
requires; "phy-mode"; the MAC address; and the PHY connection, which is
where phylink finds a "fixed-link" child.  On a device tree this is a
no-op: device_property_read_u32() dispatches to the of_* implementation
when dev->fwnode is an OF node, phylink_of_phy_connect() is a wrapper
around phylink_fwnode_phy_connect(), and device_get_phy_mode() and
device_get_mac_address() are thin fwnode wrappers around the same
lookups.  device_get_mac_address() also keeps the "mac-address" nvmem
cell fallback that of_get_mac_address() has.

Note that device_get_phy_mode() returns the mode as a positive value
rather than through an out parameter, so the error test changes from
"if (ret)" to "if (ret < 0)".

Everything else stays on the OF API.  "xlnx,txcsum", "xlnx,rxcsum" and
"xlnx,switch-x-sgmii" are optional, and "xlnx,phy-type" is deprecated in
favour of "phy-mode".  Without an OF node each of those lookups finds
nothing, exactly as for a device tree node that leaves them out: no
checksum offload, no runtime SGMII/1000BASE-X switching and a
fall-through to "phy-mode".  The "dmas" test likewise selects the
built-in AXI DMA engine.  The "axistream-connected", "pcs-handle" and
"phy-handle" phandle lookups stay too: a caller without an OF node takes
neither branch, getting its DMA registers from its own platform
resources, and it cannot use the SGMII and 1000BASE-X modes, which need
a PCS.

No functional change intended.

Tested on the X2 with a local ptp_ocp change, with CONFIG_OF disabled
and enabled: the interface probes with its configuration read from the
software node and passes traffic.  No device tree board was available,
so the claim that this is a no-op for device tree users rests on the
dispatch described above.

Assisted-by: LLM sparse
Signed-off-by: Sagi Maimon <redacted>

Lets see what the AI reviewer says about this, but it looks O.K. to me:

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew