[PATCH v4 0/3] phy: add common PHY polarity properties support

[Lucien.Jheng]

This series ports PHY polarity inversion support via generic device tree
properties from Linux kernel, synchronizing with Merge tag 'phy-for-7.0'
of git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy.

Patch 1 introduces a new PHY_COMMON_PROPS library providing helper
functions (phy_get_rx_polarity, phy_get_tx_polarity, and their
"manual" variants) for PHY drivers to read standard polarity properties
from the device tree. The PHY_POL_NORMAL, PHY_POL_INVERT, and
PHY_POL_AUTO constants are consumed from dts/upstream/include, which is
already on the compiler include path.

Patch 2 updates the Airoha EN8811H PHY driver to use the new standard
rx-polarity and tx-polarity properties, with backward compatibility
fallback to the now-deprecated airoha,pnswap-rx and airoha,pnswap-tx
boolean properties.

Patch 3 adds sandbox DM unit tests for the new library, ported from
the Linux KUnit test (linux/drivers/phy/phy-common-props-test.c), along
with the 8 sandbox DT test nodes in arch/sandbox/dts/test.dts and the
CONFIG_PHY_COMMON_PROPS=y entry in configs/sandbox_defconfig. 16 unit
test cases (8 for rx, 8 for tx) cover: missing property, single value
with no names array, count mismatches, name-based lookup, missing
default fallback, default fallback, and unsupported polarity value.

Changes in v4:
- Squash former patches 3 and 4 into a single patch to fix bisectability
  (the test code referenced DT nodes that were only added in the
  following patch)
- Add CONFIG_PHY_COMMON_PROPS=y to configs/sandbox_defconfig
- patch 1: replace printf with pr_err for error-condition messages in
  phy-common-props.c
- patch 2: use phy_string_for_interface() instead of direct array access
  phy_interface_strings[] in en8811h_config_serdes_polarity()
- patch 2: remove unused local variables ofnode node and u32 pbus_value
  from en8811h_config()

Changes in v3:
- patch 1: fix ofnode_get_u32_prop_for_name() to apply default_val and
  return 0 when the polarity property is absent, instead of returning
  -ENOENT; update @node and @default_val kdoc accordingly — this aligns
  the "missing property" path with the behaviour expected by
  phy_get_manual_rx/tx_polarity() and is validated by the new unit tests
- Add unit tests for the PHY_COMMON_PROPS library (patches 3-4), ported
  from Linux KUnit test linux/drivers/phy/phy-common-props-test.c
- Add test/dm/Makefile build entry gated on CONFIG_PHY_COMMON_PROPS
- Add 8 sandbox DT nodes to arch/sandbox/dts/test.dts covering all test
  scenarios; include <dt-bindings/phy/phy.h> in test.dts

Changes in v2:
- Drop DT binding patches (v1 patches 1 and 3): already merged via
  the DTS upstream subtree merge (tag 'v7.0-rc2-dts')
- Drop creation of include/dt-bindings/phy/phy.h: the header is now
  provided by dts/upstream/include/dt-bindings/phy/phy.h, which is
  already in the build's include search path

Lucien.Jheng (3):
  phy: add common PHY properties support
  net: phy: airoha: air_en8811: use standard rx-polarity/tx-polarity properties
  test: dm: add PHY common props unit tests and sandbox DT nodes

 arch/sandbox/dts/test.dts            |  60 +++++
 configs/sandbox_defconfig            |   1 +
 drivers/net/phy/airoha/Kconfig       |   1 +
 drivers/net/phy/airoha/air_en8811.c  |  60 +++--
 drivers/phy/Kconfig                  |   8 +
 drivers/phy/Makefile                 |   1 +
 drivers/phy/phy-common-props.c       | 286 ++++++++++++++++++++++++
 include/linux/phy/phy-common-props.h |  69 ++++++
 test/dm/Makefile                     |   1 +
 test/dm/phy_common_props.c           | 319 +++++++++++++++++++++++++++
 10 files changed, 790 insertions(+), 16 deletions(-)
 create mode 100644 drivers/phy/phy-common-props.c
 create mode 100644 include/linux/phy/phy-common-props.h
 create mode 100644 test/dm/phy_common_props.c

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2.34.1