[PATCH v2 phy-next 11/15] phy: lynx-28g: optimize read-modify-write operation

[Vladimir Oltean]

It is unnecessary to rewrite a register if the masked field already
contains the desired value upon reading. The hardware behaviour does not
depend upon register writes with identical values.

Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
v1->v2: none
---
 drivers/phy/freescale/phy-fsl-lynx-core.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/freescale/phy-fsl-lynx-core.h b/drivers/phy/freescale/phy-fsl-lynx-core.h
index d82e529fa65a..3d9508dfb2c1 100644
--- a/drivers/phy/freescale/phy-fsl-lynx-core.h
+++ b/drivers/phy/freescale/phy-fsl-lynx-core.h
@@ -93,7 +93,8 @@ static inline void lynx_rmw(struct lynx_priv *priv, unsigned long off, u32 val,
 	orig = lynx_read(priv, off);
 	tmp = orig & ~mask;
 	tmp |= val;
-	lynx_write(priv, off, tmp);
+	if (orig != tmp)
+		lynx_write(priv, off, tmp);
 }
 
 #define lynx_lane_rmw(lane, reg, val, mask)	\
-- 
2.34.1