Add PCS core support

This series adds support for creating PCSs as devices on a bus with a
driver (patch 3). As initial users,

- The Lynx PCS (and all of its users) is converted to this system (patch 5)
- The Xilinx PCS is broken out from the AXI Ethernet driver (patches 6-8)
- The Cadence MACB driver is converted to support external PCSs (namely
  the Xilinx PCS) (patches 9-10).

To build documentation without errors, this series requires commit
de258fa8ca8d ("scripts: kernel-doc: fix parsing function-like typedefs
(again)"), currently applied to docs-next [1].

Care has been taken to ensure backwards-compatibility. The main source
of this is that many PCS devices lack compatibles and get detected as
PHYs. To address this, pcs_get_by_fwnode_compat allows drivers to edit
the devicetree to add appropriate compatibles.

There is another series [2] with the same goal by Christian Marangi. In
comparison, I believe this series

- Implements a simpler and more-robust method of PCS access.
- Provides a more-direct upgrade path for existing MAC and PCS drivers.

[1] https://lore.kernel.org/all/e0abb103c73a96d76602d909f60ab...
[2] https://lore.kernel.org/netdev/20250406221423.9723-1-ansu...

Changes in v4:
- Add a note about the license
- Adjust variable ordering in pcs_find_fwnode
- Annotate pcs_wrapper.wrapped with __rcu
- Fix PCS lookup functions missing ERR_PTR casts
- Fix documentation for devm_pcs_register_full
- Fix incorrect condition in pcs_post_config
- Fix linking when PCS && !OF_DYNAMIC
- Fix linking when PCS && OF_DYNAMIC && PHYLIB=m
- Re-add documentation for axienet_xilinx_pcs_get that was accidentally
  removed
- Reduce line lengths to under 80 characters
- Remove unused dev parameter to pcs_put
- Use a spinlock instead of a mutex to protect pcs_wrappers

Changes in v3:
- Add '>' modifier for paragraph to description
- Adjust axienet_xilinx_pcs_get for changes to pcs_find_fwnode API
- Drop patches destined for other trees, as they have either already
  been applied or are no longer necessary.
- Edit description to reference clocks instead of resets
- Remove support for #pcs-cells. Upon further investigation, the
  requested functionality can be accomplished by specifying the PCS's
  fwnode manually.
- Select PCS_XILINX unconditionally

Changes in v2:
- Add fallbacks for pcs_get* and pcs_put
- Add support for #pcs-cells
- Change base compatible to just xlnx,pcs
- Change compatible to just xlnx,pcs
- Defer devicetree updates for another series
- Drop #clock-cells description
- Drop PCS_ALTERA_TSE which was accidentally added while rebasing
- Move #clock-cells after compatible
- Move update to macb_pcs_get_state to previous patch
- Remove outdated comment
- Remove second example
- Remove unused variable
- Remove unused variable lynx_properties
- Rename pcs-modes to xlnx,pcs-modes
- Reorder pcs_handle to come before suffix props
- Reword commit message
- Rework xilinx_pcs_validate to just clear out half-duplex modes instead
  of constraining modes based on the interface.

Sean Anderson (10):
  dt-bindings: net: Add Xilinx PCS
  net: phylink: Support setting PCS link change callbacks
  net: pcs: Add subsystem
  net: pcs: lynx: Convert to an MDIO driver
  net: phy: Export some functions
  net: pcs: Add Xilinx PCS driver
  net: axienet: Convert to use PCS subsystem
  net: macb: Move most of mac_config to mac_prepare
  net: macb: Support external PCSs
  of: property: Add device link support for PCS

Vladimir Oltean (1):
  net: dsa: ocelot: suppress PHY device scanning on the internal MDIO
    bus

 .../devicetree/bindings/net/xilinx,pcs.yaml   | 114 +++
 Documentation/networking/index.rst            |   1 +
 Documentation/networking/kapi.rst             |   4 +
 Documentation/networking/pcs.rst              | 102 +++
 MAINTAINERS                                   |   8 +
 drivers/net/dsa/ocelot/Kconfig                |   4 +
 drivers/net/dsa/ocelot/felix_vsc9959.c        |  15 +-
 drivers/net/dsa/ocelot/seville_vsc9953.c      |  16 +-
 drivers/net/ethernet/altera/Kconfig           |   2 +
 drivers/net/ethernet/altera/altera_tse_main.c |   7 +-
 drivers/net/ethernet/cadence/macb.h           |   1 +
 drivers/net/ethernet/cadence/macb_main.c      | 229 ++++--
 drivers/net/ethernet/freescale/dpaa/Kconfig   |   2 +-
 drivers/net/ethernet/freescale/dpaa2/Kconfig  |   3 +
 .../net/ethernet/freescale/dpaa2/dpaa2-mac.c  |  11 +-
 drivers/net/ethernet/freescale/enetc/Kconfig  |   2 +
 .../net/ethernet/freescale/enetc/enetc_pf.c   |   8 +-
 .../net/ethernet/freescale/enetc/enetc_pf.h   |   1 -
 .../freescale/enetc/enetc_pf_common.c         |   4 +-
 drivers/net/ethernet/freescale/fman/Kconfig   |   4 +-
 .../net/ethernet/freescale/fman/fman_memac.c  |  25 +-
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |   3 +
 .../ethernet/stmicro/stmmac/dwmac-socfpga.c   |   6 +-
 drivers/net/ethernet/xilinx/Kconfig           |   7 +
 drivers/net/ethernet/xilinx/xilinx_axienet.h  |   4 +-
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 104 +--
 drivers/net/pcs/Kconfig                       |  45 +-
 drivers/net/pcs/Makefile                      |   4 +
 drivers/net/pcs/core.c                        | 686 ++++++++++++++++++
 drivers/net/pcs/pcs-lynx.c                    | 110 +--
 drivers/net/pcs/pcs-xilinx.c                  | 485 +++++++++++++
 drivers/net/phy/mdio_device.c                 |   1 +
 drivers/net/phy/phy_device.c                  |   3 +-
 drivers/net/phy/phylink.c                     |  24 +-
 drivers/of/property.c                         |   2 +
 include/linux/pcs-lynx.h                      |  13 +-
 include/linux/pcs-xilinx.h                    |  15 +
 include/linux/pcs.h                           | 205 ++++++
 include/linux/phy.h                           |   1 +
 include/linux/phylink.h                       |  27 +-
 40 files changed, 2012 insertions(+), 296 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/net/xilinx,pcs.yaml
 create mode 100644 Documentation/networking/pcs.rst
 create mode 100644 drivers/net/pcs/core.c
 create mode 100644 drivers/net/pcs/pcs-xilinx.c
 create mode 100644 include/linux/pcs-xilinx.h
 create mode 100644 include/linux/pcs.h

-- 
2.35.1.1320.gc452695387.dirty