[PATCH net-next] net: phy: add helpers for comparing phy IDs

[Russell King <rmk+kernel@armlinux.org.uk>]

There are several places which open code comparing PHY IDs. Provide a
couple of helpers to assist with this, using a slightly simpler test
than the original:

- phy_id_compare() compares two arbitary PHY IDs and a mask of the
  significant bits in the ID.
- phydev_id_compare() compares the bound phydev with the specified
  PHY ID, using the bound driver's mask.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/micrel.c     |  6 +++---
 drivers/net/phy/phy_device.c | 16 +++++++---------
 drivers/net/phy/phylink.c    |  4 ++--
 include/linux/phy.h          | 28 ++++++++++++++++++++++++++++
 4 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 3f81bb8dac44..2094d49025a7 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -637,7 +637,7 @@ static int ksz8051_ksz8795_match_phy_device(struct phy_device *phydev,
 {
 	int ret;
 
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) != PHY_ID_KSZ8051)
+	if (!phy_id_compare(phydev->phy_id, PHY_ID_KSZ8051, MICREL_PHY_ID_MASK))
 		return 0;
 
 	ret = phy_read(phydev, MII_BMSR);
@@ -1566,7 +1566,7 @@ static int ksz9x31_cable_test_fault_length(struct phy_device *phydev, u16 stat)
 	 *
 	 * distance to fault = (VCT_DATA - 22) * 4 / cable propagation velocity
 	 */
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) == PHY_ID_KSZ9131)
+	if (phydev_id_compare(phydev, PHY_ID_KSZ9131))
 		dt = clamp(dt - 22, 0, 255);
 
 	return (dt * 400) / 10;
@@ -1998,7 +1998,7 @@ static __always_inline int ksz886x_cable_test_fault_length(struct phy_device *ph
 	 */
 	dt = FIELD_GET(data_mask, status);
 
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) == PHY_ID_LAN8814)
+	if (phydev_id_compare(phydev, PHY_ID_LAN8814))
 		return ((dt - 22) * 800) / 10;
 	else
 		return (dt * 400) / 10;
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8852b0c53114..2cad9cc3f6b8 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -454,8 +454,7 @@ int phy_unregister_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask)
 		fixup = list_entry(pos, struct phy_fixup, list);
 
 		if ((!strcmp(fixup->bus_id, bus_id)) &&
-		    ((fixup->phy_uid & phy_uid_mask) ==
-		     (phy_uid & phy_uid_mask))) {
+		    phy_id_compare(fixup->phy_uid, phy_uid, phy_uid_mask)) {
 			list_del(&fixup->list);
 			kfree(fixup);
 			ret = 0;
@@ -491,8 +490,8 @@ static int phy_needs_fixup(struct phy_device *phydev, struct phy_fixup *fixup)
 		if (strcmp(fixup->bus_id, PHY_ANY_ID) != 0)
 			return 0;
 
-	if ((fixup->phy_uid & fixup->phy_uid_mask) !=
-	    (phydev->phy_id & fixup->phy_uid_mask))
+	if (!phy_id_compare(phydev->phy_id, fixup->phy_uid,
+			    fixup->phy_uid_mask))
 		if (fixup->phy_uid != PHY_ANY_UID)
 			return 0;
 
@@ -539,15 +538,14 @@ static int phy_bus_match(struct device *dev, struct device_driver *drv)
 			if (phydev->c45_ids.device_ids[i] == 0xffffffff)
 				continue;
 
-			if ((phydrv->phy_id & phydrv->phy_id_mask) ==
-			    (phydev->c45_ids.device_ids[i] &
-			     phydrv->phy_id_mask))
+			if (phy_id_compare(phydev->c45_ids.device_ids[i],
+					   phydrv->phy_id, phydrv->phy_id_mask))
 				return 1;
 		}
 		return 0;
 	} else {
-		return (phydrv->phy_id & phydrv->phy_id_mask) ==
-			(phydev->phy_id & phydrv->phy_id_mask);
+		return phy_id_compare(phydev->phy_id, phydrv->phy_id,
+				      phydrv->phy_id_mask);
 	}
 }
 
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index ee7e06718983..095c601985e7 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -3179,8 +3179,8 @@ static void phylink_sfp_link_up(void *upstream)
  */
 static bool phylink_phy_no_inband(struct phy_device *phy)
 {
-	return phy->is_c45 &&
-		(phy->c45_ids.device_ids[1] & 0xfffffff0) == 0xae025150;
+	return phy->is_c45 && phy_id_compare(phy->c45_ids.device_ids[1],
+					     0xae025150, 0xfffffff0);
 }
 
 static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
diff --git a/include/linux/phy.h b/include/linux/phy.h
index d8cd7115c773..2da87a36200d 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1112,6 +1112,34 @@ struct phy_driver {
 #define PHY_ID_MATCH_MODEL(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 4)
 #define PHY_ID_MATCH_VENDOR(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 10)
 
+/**
+ * phy_id_compare - compare @id1 with @id2 taking account of @mask
+ * @id1: first PHY ID
+ * @id2: second PHY ID
+ * @mask: the PHY ID mask, set bits are significant in matching
+ *
+ * Return true if the bits from @id1 and @id2 specified by @mask match.
+ * This uses an equivalent test to (@id & @mask) == (@phy_id & @mask).
+ */
+static inline bool phy_id_compare(u32 id1, u32 id2, u32 mask)
+{
+	return !((id1 ^ id2) & mask);
+}
+
+/**
+ * phydev_id_compare - compare @id with the PHY's Clause 22 ID
+ * @phydev: the PHY device
+ * @id: the PHY ID to be matched
+ *
+ * Compare the @phydev clause 22 ID with the provided @id and return true or
+ * false depending whether it matches, using the bound driver mask. The
+ * @phydev must be bound to a driver.
+ */
+static inline bool phydev_id_compare(struct phy_device *phydev, u32 id)
+{
+	return phy_id_compare(id, phydev->phy_id, phydev->drv->phy_id_mask);
+}
+
 /* A Structure for boards to register fixups with the PHY Lib */
 struct phy_fixup {
 	struct list_head list;
-- 
2.30.2