net: phy: Introduce generic SFP handling for PHY drivers

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There are currently 4 PHY drivers that can drive downstream SFPs:
marvell.c, marvell10g.c, at803x.c and marvell-88x2222.c. Most of the
logic is boilerplate, either calling into generic phylib helpers (for
SFP PHY attach, bus attach, etc.) or performing the same tasks with a
bit of validation :
 - Getting the module's expected interface mode
 - Making sure the PHY supports it
 - Optionaly perform some configuration to make sure the PHY outputs
   the right mode

This can be made more generic by leveraging the phy_port, and its
configure_mii() callback which allows setting a port's interfaces when
the port is a serdes.

Introduce a generic PHY SFP support. If a driver doesn't probe the SFP
bus itself, but an SFP phandle is found in devicetree/firmware, then the
generic PHY SFP support will be used, relying on port ops.

PHY driver need to :
 - Register a .attach_port() callback
 - When a serdes port is registered to the PHY, drivers must set
   port->interfaces to the set of PHY_INTERFACE_MODE the port can output
 - If the port has limitations regarding speed, duplex and aneg, the
   port can also fine-tune the final linkmodes that can be supported
 - The port may register a set of ops, including .configure_mii(), that
   will be called at module_insert time to adjust the interface based on
   the module detected.

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260108080041.553250-8-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

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Maxime Chevallier 2026-01-08 09:00:32 +01:00 • committed by Jakub Kicinski

parent 07f3ca9e09

commit d7c6082f7e

3 changed files with 111 additions and 0 deletions

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107

drivers/net/phy/phy_device.c

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2

include/linux/phy.h

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2

include/linux/phy_port.h

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