phy: lynx-28g: optimize read-modify-write operation

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@nxp.com>
Link: https://patch.msgid.link/20260610151952.2141019-13-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/phy/freescale/phy-fsl-lynx-core.h b/drivers/phy/freescale/phy-fsl-lynx-core.h
index d82e529fa65a61f379734f3d677d6f3f01fc9785..3d9508dfb2c1c6e89b7f10a6f43147becad6c8c8 100644 (file)
--- 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)    \