[RESEND net-next PATCH 2/3] net: dsa: qca8k: change only max_frame_size of mac_frame_size_reg

[Christian Marangi <ansuelsmth@gmail.com>]

Currently we overwrite the entire MAX_FRAME_SIZE reg instead of tweaking
just the MAX_FRAME_SIZE value. Change this and update only the relevant
bits.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.c | 8 ++++++--
 drivers/net/dsa/qca8k.h | 3 ++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 2727d3169c25..eaaf80f96fa9 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -2345,7 +2345,9 @@ qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 		return 0;
 
 	/* Include L2 header / FCS length */
-	return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
+	return regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
+				  QCA8K_MAX_FRAME_SIZE_MASK,
+				  new_mtu + ETH_HLEN + ETH_FCS_LEN);
 }
 
 static int
@@ -3015,7 +3017,9 @@ qca8k_setup(struct dsa_switch *ds)
 	}
 
 	/* Setup our port MTUs to match power on defaults */
-	ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, ETH_FRAME_LEN + ETH_FCS_LEN);
+	ret = regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
+				 QCA8K_MAX_FRAME_SIZE_MASK,
+				 ETH_FRAME_LEN + ETH_FCS_LEN);
 	if (ret)
 		dev_warn(priv->dev, "failed setting MTU settings");
 
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index ec58d0e80a70..1d0c383a95e7 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -87,7 +87,8 @@
 #define   QCA8K_MDIO_MASTER_MAX_REG			32
 #define QCA8K_GOL_MAC_ADDR0				0x60
 #define QCA8K_GOL_MAC_ADDR1				0x64
-#define QCA8K_MAX_FRAME_SIZE				0x78
+#define QCA8K_MAX_FRAME_SIZE_REG			0x78
+#define   QCA8K_MAX_FRAME_SIZE_MASK			GENMASK(13, 0)
 #define QCA8K_REG_PORT_STATUS(_i)			(0x07c + (_i) * 4)
 #define   QCA8K_PORT_STATUS_SPEED			GENMASK(1, 0)
 #define   QCA8K_PORT_STATUS_SPEED_10			0
-- 
2.36.1