Merge branch 'ksz-switch-refclk'

Robert Hancock says:

====================
Allow disabling KSZ switch refclock

The reference clock output from the KSZ9477 and related Microchip
switch devices is not required on all board designs. Add a device
tree property to disable it for power and EMI reasons.

Changes since v3:
-rework some code for simplicity

Changes since v2:
-check for conflicting options in DT, added note in bindings doc

Changes since v1:
-added Acked-by on patch 1, rebase to net-next
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml

@@ -42,6 +42,12 @@ properties:
     description:
       Set if the output SYNCLKO frequency should be set to 125MHz instead of 25MHz.
 
+  microchip,synclko-disable:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Set if the output SYNCLKO clock should be disabled. Do not mix with
+      microchip,synclko-125.
+
 required:
   - compatible
   - reg

drivers/net/dsa/microchip/ksz9477.c

@@ -222,9 +222,12 @@ static int ksz9477_reset_switch(struct ksz_device *dev)
 			   (BROADCAST_STORM_VALUE *
 			   BROADCAST_STORM_PROT_RATE) / 100);
 
-	if (dev->synclko_125)
-		ksz_write8(dev, REG_SW_GLOBAL_OUTPUT_CTRL__1,
-			   SW_ENABLE_REFCLKO | SW_REFCLKO_IS_125MHZ);
+	data8 = SW_ENABLE_REFCLKO;
+	if (dev->synclko_disable)
+		data8 = 0;
+	else if (dev->synclko_125)
+		data8 = SW_ENABLE_REFCLKO | SW_REFCLKO_IS_125MHZ;
+	ksz_write8(dev, REG_SW_GLOBAL_OUTPUT_CTRL__1, data8);
 
 	return 0;
 }

drivers/net/dsa/microchip/ksz_common.c

@@ -434,6 +434,12 @@ int ksz_switch_register(struct ksz_device *dev,
 			}
 		dev->synclko_125 = of_property_read_bool(dev->dev->of_node,
 							 "microchip,synclko-125");
+		dev->synclko_disable = of_property_read_bool(dev->dev->of_node,
+							     "microchip,synclko-disable");
+		if (dev->synclko_125 && dev->synclko_disable) {
+			dev_err(dev->dev, "inconsistent synclko settings\n");
+			return -EINVAL;
+		}
 	}
 
 	ret = dsa_register_switch(dev->ds);

drivers/net/dsa/microchip/ksz_common.h

@@ -75,6 +75,7 @@ struct ksz_device {
 	u32 regs_size;
 	bool phy_errata_9477;
 	bool synclko_125;
+	bool synclko_disable;
 
 	struct vlan_table *vlan_cache;