net: phy: fix circular LEDS_CLASS dependencies

The CONFIG_PHYLIB symbol is selected by a number of device drivers that
need PHY support, but it now has a dependency on CONFIG_LEDS_CLASS,
which may not be enabled, causing build failures.

Avoid the risk of missing and circular dependencies by guarding the
phylib LED support itself in another Kconfig symbol that can only be
enabled if the dependency is met.

This could be made a hidden symbol and always enabled when both CONFIG_OF
and CONFIG_LEDS_CLASS are reachable from the phylib, but there may be an
advantage in having users see this option when they have a misconfigured
kernel without built-in LED support.

Fixes: 01e5b72 ("net: phy: Add a binding for PHY LEDs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20230420084624.3005701-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/Kconfig

@@ -18,7 +18,6 @@ menuconfig PHYLIB
 	depends on NETDEVICES
 	select MDIO_DEVICE
 	select MDIO_DEVRES
-	depends on LEDS_CLASS || LEDS_CLASS=n
 	help
 	  Ethernet controllers are usually attached to PHY
 	  devices.  This option provides infrastructure for
@@ -45,6 +44,14 @@ config LED_TRIGGER_PHY
 		<Speed in megabits>Mbps OR <Speed in gigabits>Gbps OR link
 		for any speed known to the PHY.
 
+config PHYLIB_LEDS
+	bool "Support probing LEDs from device tree"
+	depends on LEDS_CLASS=y || LEDS_CLASS=PHYLIB
+	depends on OF
+	default y
+	help
+	  When LED class support is enabled, phylib can automatically
+	  probe LED setting from device tree.
 
 config FIXED_PHY
 	tristate "MDIO Bus/PHY emulation with fixed speed/link PHYs"

drivers/net/phy/phy_device.c

@@ -3284,7 +3284,8 @@ static int phy_probe(struct device *dev)
 	/* Get the LEDs from the device tree, and instantiate standard
 	 * LEDs for them.
 	 */
-	err = of_phy_leds(phydev);
+	if (IS_ENABLED(CONFIG_PHYLIB_LEDS))
+		err = of_phy_leds(phydev);
 
 out:
 	/* Re-assert the reset signal on error */