net: phy: mscc: Add support for PHY LED control

Add support for the PHY LED controller in the MSCC VSC85xx driver. The
implementation provides LED brightness and hardware control through the
LED subsystem and integrates with the standard 'netdev' trigger.

Introduce new register definitions for the LED behavior register
(MSCC_PHY_LED_BEHAVIOR = 30) and the LED combine disable bits, which
control whether LEDs indicate link-only or combined link and activity
status. Implement a helper, vsc8541_led_combine_disable_set(), to update
these bits safely using phy_modify().

Add support for LED brightness control and hardware mode configuration.
The new callbacks implement the standard LED class operations, allowing
user control through sysfs. The brightness control maps to PHY LED force
on/off modes. The hardware control get and set functions translate
between the PHY-specific LED mode encodings and the LED subsystem
TRIGGER_NETDEV_* rules.

The combine feature is managed automatically based on the selected
rules. When both RX and TX activity are disabled, the combine feature is
turned off, causing LEDs to indicate link-only status. When either RX or
TX activity is enabled, the combine feature remains active and LEDs
indicate combined link and activity.

Register the LED callbacks for all VSC85xx PHY variants so that the LED
subsystem can manage their indicators consistently. Existing device tree
LED configuration and default behavior are preserved.

Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/mscc/mscc.h

···
 #define LED_MODE_SEL_MASK(x)		  (GENMASK(3, 0) << LED_MODE_SEL_POS(x))
 #define LED_MODE_SEL(x, mode)		  (((mode) << LED_MODE_SEL_POS(x)) & LED_MODE_SEL_MASK(x))
 
+#define MSCC_PHY_LED_BEHAVIOR		  30
+#define LED_COMBINE_DIS_MASK(x)		  BIT(x)
+#define LED_COMBINE_DIS(x, dis)		  (((dis) ? 1 : 0) << (x))
+
 #define MSCC_EXT_PAGE_CSR_CNTL_17	  17
 #define MSCC_EXT_PAGE_CSR_CNTL_18	  18
 

drivers/net/phy/mscc/mscc_main.c

···
 	return phy_modify(phydev, MSCC_PHY_LED_MODE_SEL, mask, val);
 }
 
+static int vsc85xx_led_combine_disable_set(struct phy_device *phydev,
+					   u8 led_num, bool combine_disable)
+{
+	u16 val = LED_COMBINE_DIS(led_num, combine_disable);
+	u16 mask = LED_COMBINE_DIS_MASK(led_num);
+
+	return phy_modify(phydev, MSCC_PHY_LED_BEHAVIOR, mask, val);
+}
+
 static int vsc85xx_mdix_get(struct phy_device *phydev, u8 *mdix)
 {
 	u16 reg_val;
···
 				const u32 *default_led_mode)
 {
 	struct vsc8531_private *vsc8531;
+	struct device_node *np;
 	int ret;
 
 	vsc8531 = devm_kzalloc(&phydev->mdio.dev, sizeof(*vsc8531), GFP_KERNEL);
···
 			return ret;
 	}
 
+	/*
+	 * Check for LED configuration in device tree if available
+	 * or fall back to default `vsc8531,led-x-mode` DT properties.
+	 */
+	np = of_get_child_by_name(phydev->mdio.dev.of_node, "leds");
+	if (np) {
+		of_node_put(np);
+
+		/* Force to defaults */
+		for (unsigned int i = 0; i < vsc8531->nleds; i++)
+			vsc8531->leds_mode[i] = default_led_mode[i];
+
+		return 0;
+	}
+
 	/* Parse LED modes from device tree */
 	return vsc85xx_dt_led_modes_get(phydev, default_led_mode);
+}
+
+static int vsc85xx_led_brightness_set(struct phy_device *phydev,
+				      u8 index, enum led_brightness value)
+{
+	struct vsc8531_private *vsc8531 = phydev->priv;
+
+	if (index >= vsc8531->nleds)
+		return -EINVAL;
+
+	return vsc85xx_led_cntl_set(phydev, index, value == LED_OFF ?
+				    VSC8531_FORCE_LED_OFF : VSC8531_FORCE_LED_ON);
+}
+
+static int vsc85xx_led_hw_is_supported(struct phy_device *phydev, u8 index,
+				       unsigned long rules)
+{
+	static const unsigned long supported = BIT(TRIGGER_NETDEV_LINK_1000) |
+					       BIT(TRIGGER_NETDEV_LINK_100) |
+					       BIT(TRIGGER_NETDEV_LINK_10) |
+					       BIT(TRIGGER_NETDEV_LINK) |
+					       BIT(TRIGGER_NETDEV_RX) |
+					       BIT(TRIGGER_NETDEV_TX);
+	struct vsc8531_private *vsc8531 = phydev->priv;
+
+	if (index >= vsc8531->nleds)
+		return -EINVAL;
+
+	if (rules & ~supported)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int vsc85xx_led_hw_control_get(struct phy_device *phydev, u8 index,
+				      unsigned long *rules)
+{
+	struct vsc8531_private *vsc8531 = phydev->priv;
+	u8 mode, behavior;
+	int rc;
+
+	if (index >= vsc8531->nleds)
+		return -EINVAL;
+
+	rc = phy_read(phydev, MSCC_PHY_LED_MODE_SEL);
+	if (rc < 0)
+		return rc;
+	mode = (rc & LED_MODE_SEL_MASK(index)) >> LED_MODE_SEL_POS(index);
+
+	rc = phy_read(phydev, MSCC_PHY_LED_BEHAVIOR);
+	if (rc < 0)
+		return rc;
+	behavior = (rc & LED_COMBINE_DIS_MASK(index)) >> index;
+
+	switch (mode) {
+	case VSC8531_LINK_ACTIVITY:
+	case VSC8531_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_1000_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_1000) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_100_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_100) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_10_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_10) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_100_1000_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_1000) |
+			 BIT(TRIGGER_NETDEV_LINK_100) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_10_1000_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_1000) |
+			 BIT(TRIGGER_NETDEV_LINK_10) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	case VSC8531_LINK_10_100_ACTIVITY:
+		*rules = BIT(TRIGGER_NETDEV_LINK_100) |
+			 BIT(TRIGGER_NETDEV_LINK_10) |
+			 BIT(TRIGGER_NETDEV_LINK);
+		break;
+
+	default:
+		*rules = 0;
+		break;
+	}
+
+	if (!behavior && *rules)
+		*rules |= BIT(TRIGGER_NETDEV_RX) | BIT(TRIGGER_NETDEV_TX);
+
+	return 0;
+}
+
+static int vsc85xx_led_hw_control_set(struct phy_device *phydev, u8 index,
+				      unsigned long rules)
+{
+	struct vsc8531_private *vsc8531 = phydev->priv;
+	u8 mode = VSC8531_FORCE_LED_ON;
+	bool combine_disable = false;
+	bool has_rx, has_tx;
+	int ret;
+
+	if (index >= vsc8531->nleds)
+		return -EINVAL;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK))
+		mode = VSC8531_LINK_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_10))
+		mode = VSC8531_LINK_10_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_100))
+		mode = VSC8531_LINK_100_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_1000))
+		mode = VSC8531_LINK_1000_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_100) &&
+	    rules & BIT(TRIGGER_NETDEV_LINK_1000))
+		mode = VSC8531_LINK_100_1000_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_10) &&
+	    rules & BIT(TRIGGER_NETDEV_LINK_1000))
+		mode = VSC8531_LINK_10_1000_ACTIVITY;
+
+	if (rules & BIT(TRIGGER_NETDEV_LINK_10) &&
+	    rules & BIT(TRIGGER_NETDEV_LINK_100))
+		mode = VSC8531_LINK_10_100_ACTIVITY;
+
+	/*
+	 * The VSC85xx PHYs provides an option to control LED behavior. By
+	 * default, the LEDx combine function is enabled, meaning the LED
+	 * will be on when there is link/activity or duplex/collision. If
+	 * the combine function is disabled, the LED will be on only for
+	 * link or duplex.
+	 *
+	 * To control this behavior, we check the selected rules. If both
+	 * RX and TX activity are not selected, the LED combine function
+	 * is disabled; otherwise, it remains enabled.
+	 */
+	has_rx = !!(rules & BIT(TRIGGER_NETDEV_RX));
+	has_tx = !!(rules & BIT(TRIGGER_NETDEV_TX));
+	if (!has_rx && !has_tx)
+		combine_disable = true;
+
+	ret = vsc85xx_led_combine_disable_set(phydev, index, combine_disable);
+	if (ret < 0)
+		return ret;
+
+	return vsc85xx_led_cntl_set(phydev, index, mode);
 }
 
 static int vsc8514_probe(struct phy_device *phydev)
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8502,
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8504,
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8514,
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8530,
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8531,
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8540,
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8541,
···
 	.get_sset_count = &vsc85xx_get_sset_count,
 	.get_strings    = &vsc85xx_get_strings,
 	.get_stats      = &vsc85xx_get_stats,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8552,
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	PHY_ID_MATCH_EXACT(PHY_ID_VSC856X),
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8572,
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	.phy_id		= PHY_ID_VSC8574,
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	PHY_ID_MATCH_EXACT(PHY_ID_VSC8575),
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	PHY_ID_MATCH_EXACT(PHY_ID_VSC8582),
···
 	.get_stats      = &vsc85xx_get_stats,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 },
 {
 	PHY_ID_MATCH_EXACT(PHY_ID_VSC8584),
···
 	.link_change_notify = &vsc85xx_link_change_notify,
 	.inband_caps    = vsc85xx_inband_caps,
 	.config_inband  = vsc85xx_config_inband,
+	.led_brightness_set = vsc85xx_led_brightness_set,
+	.led_hw_is_supported = vsc85xx_led_hw_is_supported,
+	.led_hw_control_get = vsc85xx_led_hw_control_get,
+	.led_hw_control_set = vsc85xx_led_hw_control_set,
 }
 
 };