phy: add common PHY properties support

Add a new PHY_COMMON_PROPS library that provides helper functions for
PHY drivers to read standardized polarity properties from the device
tree node:

  - phy_get_rx_polarity() / phy_get_tx_polarity()
  - phy_get_manual_rx_polarity() / phy_get_manual_tx_polarity()

The dt-bindings/phy/phy.h header with PHY_POL_NORMAL, PHY_POL_INVERT,
and PHY_POL_AUTO constants is provided via dts/upstream/include, which
is already in the build include path.

Ported from Merge tag 'phy-for-7.0':
  git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy

Link: https://git.kernel.org/linus/e7556b59ba65179612bce3fa56bb53d1b4fb20db
Signed-off-by: Lucien.Jheng <[email protected]>

1 files changed, 69 insertions, 0 deletions

diff --git a/include/linux/phy/phy-common-props.h b/include/linux/phy/phy-common-props.h
new file mode 100644
index 00000000000..9158851f2e1
--- /dev/null
+++ b/include/linux/phy/phy-common-props.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phy-common-props.h -- Common properties for generic PHYs
+ *
+ * Copyright 2025-2026 NXP
+ */
+
+#ifndef __PHY_COMMON_PROPS_H
+#define __PHY_COMMON_PROPS_H
+
+#include <dt-bindings/phy/phy.h>
+#include <dm/ofnode.h>
+
+/**
+ * phy_get_rx_polarity - Get RX polarity for PHY differential lane
+ * @node: Pointer to the PHY's device tree node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @supported: Bit mask of PHY_POL_NORMAL, PHY_POL_INVERT and PHY_POL_AUTO
+ * @default_val: Default polarity value if property is missing
+ * @val: Pointer to returned polarity.
+ *
+ * Return: zero on success, negative error on failure.
+ */
+int phy_get_rx_polarity(ofnode node, const char *mode_name,
+			unsigned int supported, unsigned int default_val,
+			unsigned int *val);
+
+/**
+ * phy_get_tx_polarity - Get TX polarity for PHY differential lane
+ * @node: Pointer to the PHY's device tree node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @supported: Bit mask of PHY_POL_NORMAL, PHY_POL_INVERT and PHY_POL_AUTO
+ * @default_val: Default polarity value if property is missing
+ * @val: Pointer to returned polarity.
+ *
+ * Return: zero on success, negative error on failure.
+ */
+int phy_get_tx_polarity(ofnode node, const char *mode_name,
+			unsigned int supported, unsigned int default_val,
+			unsigned int *val);
+
+/**
+ * phy_get_manual_rx_polarity - Get manual RX polarity for PHY differential lane
+ * @node: Pointer to the PHY's device tree node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @val: Pointer to returned polarity.
+ *
+ * Helper for PHYs which do not support protocols with automatic RX polarity
+ * detection and correction.
+ *
+ * Return: zero on success, negative error on failure.
+ */
+int phy_get_manual_rx_polarity(ofnode node, const char *mode_name,
+			       unsigned int *val);
+
+/**
+ * phy_get_manual_tx_polarity - Get manual TX polarity for PHY differential lane
+ * @node: Pointer to the PHY's device tree node.
+ * @mode_name: The name of the PHY mode to look up.
+ * @val: Pointer to returned polarity.
+ *
+ * Helper for PHYs without any custom default value for the TX polarity.
+ *
+ * Return: zero on success, negative error on failure.
+ */
+int phy_get_manual_tx_polarity(ofnode node, const char *mode_name,
+			       unsigned int *val);
+
+#endif /* __PHY_COMMON_PROPS_H */