From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi all,

This series adds support for configuring the active level of MIIC
PHY_LINK status signals on Renesas RZ/N1 and RZ/T2H/N2H platforms.

The MIIC block provides dedicated hardware PHY_LINK signals that indicate
EtherPHY link-up and link-down status independently of whether the MAC
(GMAC) or Ethernet switch (ETHSW) is used. While GMAC-based systems
typically obtain link state via MDIO and handle it in software, the
ETHSW relies on these PHY_LINK pins for both CPU-assisted operation and
switch-only forwarding paths that do not involve the host processor.

These hardware PHY_LINK signals are particularly important for use cases
requiring fast reaction to link-down events, such as redundancy protocols
including Device Level Ring (DLR). In such scenarios, relying solely on
software-based link detection introduces latency that can negatively
impact recovery time. The ETHSW therefore exposes PHY_LINK signals to
enable immediate hardware-level detection of cable or port failures.

Some systems require the PHY_LINK signal polarity to be configured as
active low rather than the default active high. This series introduces a
new DT property to describe the required polarity and adds corresponding
driver support to program the MIIC PHY_LINK register accordingly. The
configuration is accumulated during DT parsing and applied once hardware
initialization is complete, taking into account SoC-specific differences
between RZ/N1 and RZ/T2H/N2H.

Thanks for your review.

v2->v3:
- Updated commit message for patches 1 and 2 to improve clarity
- Renemaed DT property from renesas,miic-phylink-active-low to
  renesas,miic-phy-link-active-low.
- Updated references of PHYLINK to PHY_LINK and phylink to phy_link
  in code to avoid confusion with the Linux phylink subsystem.
- Simplified the PHY_LINK configuration parsing logic in the driver
  as suggested.

v1->v2:
- Updated commit message to elaborate the necessity of PHY link signals

Best regards,
Prabhakar

Lad Prabhakar (2):
  dt-bindings: net: pcs: renesas,rzn1-miic: Add phy_link property
  net: pcs: rzn1-miic: Add PHY_LINK active-level configuration support

 .../bindings/net/pcs/renesas,rzn1-miic.yaml   |   7 ++
 drivers/net/pcs/pcs-rzn1-miic.c               | 105 +++++++++++++++++-
 2 files changed, 109 insertions(+), 3 deletions(-)

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2.52.0