net: phy: Add phy_modify_mmd() and phy_modify_mmd_changed() from Linux

Add phy_modify_mmd()/phy_modify_mmd_changed() from Linux 5.1.y as of commit
b8554d4f7288f ("net: phy: add register modifying helpers returning 1 on change")
This is used by the upcoming Marvell 10G PHY driver.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index f720d0a792..0eeb0cb3a8 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -1158,6 +1158,60 @@ int phy_clear_bits_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val
 	return 0;
 }
 
+/**
+ * phy_modify_mmd_changed - Function for modifying a register on MMD
+ * @phydev: the phy_device struct
+ * @devad: the MMD containing register to modify
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: new value of bits set in mask to write to @regnum
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ *
+ * Returns negative errno, 0 if there was no change, and 1 in case of change
+ */
+int phy_modify_mmd_changed(struct phy_device *phydev, int devad, u32 regnum,
+			   u16 mask, u16 set)
+{
+	int new, ret;
+
+	ret = phy_read_mmd(phydev, devad, regnum);
+	if (ret < 0)
+		return ret;
+
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
+
+	ret = phy_write_mmd(phydev, devad, regnum, new);
+
+	return ret < 0 ? ret : 1;
+}
+
+/**
+ * phy_modify_mmd - Convenience function for modifying a register on MMD
+ * @phydev: the phy_device struct
+ * @devad: the MMD containing register to modify
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: new value of bits set in mask to write to @regnum
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int phy_modify_mmd(struct phy_device *phydev, int devad, u32 regnum,
+		   u16 mask, u16 set)
+{
+	int ret;
+
+	ret = phy_modify_mmd_changed(phydev, devad, regnum, mask, set);
+
+	return ret < 0 ? ret : 0;
+}
+
 bool phy_interface_is_ncsi(void)
 {
 #ifdef CONFIG_PHY_NCSI