net: dsa: ks8: configure 1.8V ldo from oftree

Signed-off-by: Jan Sondhauss <jan.sondhauss@wago.com>

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

@@ -49,6 +49,11 @@ properties:
       Set if the output SYNCLKO clock should be disabled. Do not mix with
       microchip,synclko-125.
 
+  microchip,disable-internal-ldo:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Set if the internal 1.8V LDO should be disabled.
+
   interrupts:
     maxItems: 1
 

drivers/net/dsa/microchip/ksz8795.c

@@ -1390,11 +1390,25 @@ int ksz8_enable_stp_addr(struct ksz_device *dev)
 	return ksz8_w_sta_mac_table(dev, 0, &alu);
 }
 
+static void ksz8_set_internal_ldo(struct ksz_device *dev)
+{
+#define REG_INTERNAL_1V8_LDO_CTRL	0xC1
+#define REG_INTERNAL_1V8_LDO_CTRL_DISABLE	BIT(6)
+
+	ksz_cfg(dev, REG_INTERNAL_1V8_LDO_CTRL, REG_INTERNAL_1V8_LDO_CTRL_DISABLE,
+		dev->disable_internal_ldo);
+
+	if (dev->disable_internal_ldo)
+		dev_info(dev->dev, "1.8V LDO disabled\n");
+}
+
 int ksz8_setup(struct dsa_switch *ds)
 {
 	struct ksz_device *dev = ds->priv;
 	int i;
 
+	ksz8_set_internal_ldo(dev);
+
 	ds->mtu_enforcement_ingress = true;
 
 	/* We rely on software untagging on the CPU port, so that we

drivers/net/dsa/microchip/ksz_common.c

@@ -3651,6 +3651,9 @@ int ksz_switch_register(struct ksz_device *dev)
 			dev_err(dev->dev, "inconsistent synclko settings\n");
 			return -EINVAL;
 		}
+
+		dev->disable_internal_ldo = of_property_read_bool(dev->dev->of_node,
+								  "microchip,disable-internal-ldo");
 	}
 
 	ret = dsa_register_switch(dev->ds);

drivers/net/dsa/microchip/ksz_common.h

@@ -148,6 +148,7 @@ struct ksz_device {
 	int irq;
 
 	struct gpio_desc *reset_gpio;	/* Optional reset GPIO */
+	bool disable_internal_ldo;	/* Disable internal 1.8V LDO */
 
 	/* chip specific data */
 	u32 chip_id;