lan78xx: Read LED states from Device Tree

Add support for DT property "microchip,led-modes", a vector of zero
to four cells (u32s) in the range 0-15, each of which sets the mode
for one of the LEDs. Some possible values are:

    0=link/activity          1=link1000/activity
    2=link100/activity       3=link10/activity
    4=link100/1000/activity  5=link10/1000/activity
    6=link10/100/activity    14=off    15=on

These values are given symbolic constants in a dt-bindings header.

Also use the presence of the DT property to indicate that the
LEDs should be enabled - necessary in the event that no valid OTP
or EEPROM is available.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -14572,6 +14572,7 @@ M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/usb/lan78xx.*
+F:	include/dt-bindings/net/microchip-lan78xx.h
 
 USB MASS STORAGE DRIVER
 M:	Alan Stern <stern@rowland.harvard.edu>

drivers/net/phy/microchip.c

@@ -20,6 +20,8 @@
 #include <linux/ethtool.h>
 #include <linux/phy.h>
 #include <linux/microchipphy.h>
+#include <linux/of.h>
+#include <dt-bindings/net/microchip-lan78xx.h>
 
 #define DRIVER_AUTHOR	"WOOJUNG HUH <woojung.huh@microchip.com>"
 #define DRIVER_DESC	"Microchip LAN88XX PHY driver"
@@ -70,13 +72,36 @@ static int lan88xx_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
 	struct lan88xx_priv *priv;
+	u32 led_modes[4];
+	int len;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
 	priv->wolopts = 0;
 
+	len = of_property_read_variable_u32_array(dev->of_node,
+						  "microchip,led-modes",
+						  led_modes,
+						  0,
+						  ARRAY_SIZE(led_modes));
+	if (len >= 0) {
+		u32 reg = 0;
+		int i;
+
+		for (i = 0; i < len; i++) {
+			if (led_modes[i] > 15)
+				return -EINVAL;
+			reg |= led_modes[i] << (i * 4);
+		}
+		for (; i < ARRAY_SIZE(led_modes); i++)
+			reg |= LAN78XX_FORCE_LED_OFF << (i * 4);
+		(void)phy_write(phydev, LAN78XX_PHY_LED_MODE_SELECT, reg);
+	} else if (len == -EOVERFLOW) {
+		return -EINVAL;
+	}
+
 	/* these values can be used to identify internal PHY */
 	priv->chip_id = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_ID);
 	priv->chip_rev = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_REV);

drivers/net/usb/lan78xx.c

@@ -37,6 +37,7 @@
 #include <linux/irqchip/chained_irq.h>
 #include <linux/microchipphy.h>
 #include <linux/phy.h>
+#include <linux/of_mdio.h>
 #include <linux/of_net.h>
 #include "lan78xx.h"
 
@@ -1760,6 +1761,7 @@ static int lan78xx_mdiobus_write(struct mii_bus *bus, int phy_id, int idx,
 
 static int lan78xx_mdio_init(struct lan78xx_net *dev)
 {
+	struct device_node *node;
 	int ret;
 
 	dev->mdiobus = mdiobus_alloc();
@@ -1788,7 +1790,13 @@ static int lan78xx_mdio_init(struct lan78xx_net *dev)
 		break;
 	}
 
-	ret = mdiobus_register(dev->mdiobus);
+	node = of_get_child_by_name(dev->udev->dev.of_node, "mdio");
+	if (node) {
+		ret = of_mdiobus_register(dev->mdiobus, node);
+		of_node_put(node);
+	} else {
+		ret = mdiobus_register(dev->mdiobus);
+	}
 	if (ret) {
 		netdev_err(dev->net, "can't register MDIO bus\n");
 		goto exit1;
@@ -2077,6 +2085,28 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
 	mii_adv = (u32)mii_advertise_flowctrl(dev->fc_request_control);
 	phydev->advertising |= mii_adv_to_ethtool_adv_t(mii_adv);
 
+	if (phydev->mdio.dev.of_node) {
+		u32 reg;
+		int len;
+
+		len = of_property_count_elems_of_size(phydev->mdio.dev.of_node,
+						      "microchip,led-modes",
+						      sizeof(u32));
+		if (len >= 0) {
+			/* Ensure the appropriate LEDs are enabled */
+			lan78xx_read_reg(dev, HW_CFG, &reg);
+			reg &= ~(HW_CFG_LED0_EN_ |
+				 HW_CFG_LED1_EN_ |
+				 HW_CFG_LED2_EN_ |
+				 HW_CFG_LED3_EN_);
+			reg |= (len > 0) * HW_CFG_LED0_EN_ |
+				(len > 1) * HW_CFG_LED1_EN_ |
+				(len > 2) * HW_CFG_LED2_EN_ |
+				(len > 3) * HW_CFG_LED3_EN_;
+			lan78xx_write_reg(dev, HW_CFG, reg);
+		}
+	}
+
 	genphy_config_aneg(phydev);
 
 	dev->fc_autoneg = phydev->autoneg;

include/dt-bindings/net/microchip-lan78xx.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _DT_BINDINGS_MICROCHIP_LAN78XX_H
+#define _DT_BINDINGS_MICROCHIP_LAN78XX_H
+
+/* LED modes for LAN7800/LAN7850 embedded PHY */
+
+#define LAN78XX_LINK_ACTIVITY           0
+#define LAN78XX_LINK_1000_ACTIVITY      1
+#define LAN78XX_LINK_100_ACTIVITY       2
+#define LAN78XX_LINK_10_ACTIVITY        3
+#define LAN78XX_LINK_100_1000_ACTIVITY  4
+#define LAN78XX_LINK_10_1000_ACTIVITY   5
+#define LAN78XX_LINK_10_100_ACTIVITY    6
+#define LAN78XX_DUPLEX_COLLISION        8
+#define LAN78XX_COLLISION               9
+#define LAN78XX_ACTIVITY                10
+#define LAN78XX_AUTONEG_FAULT           12
+#define LAN78XX_FORCE_LED_OFF           14
+#define LAN78XX_FORCE_LED_ON            15
+
+#endif

include/linux/microchipphy.h

@@ -70,4 +70,7 @@
 #define	LAN88XX_MMD3_CHIP_ID			(32877)
 #define	LAN88XX_MMD3_CHIP_REV			(32878)
 
+/* Registers specific to the LAN7800/LAN7850 embedded phy */
+#define LAN78XX_PHY_LED_MODE_SELECT		(0x1D)
+
 #endif /* _MICROCHIPPHY_H */