Many PHYs support various HW control modes for LEDs connected directly
to them.

This code adds a new private LED trigger called phydev-hw-mode. When
this trigger is enabled for a LED, the various HW control modes which
the PHY supports for given LED can be get/set via hw_mode sysfs file.

A PHY driver wishing to utilize this API needs to register the LEDs on
its own and set the .trigger_type member of LED classdev to
&phy_hw_led_trig_type. It also needs to implement the methods
.led_iter_hw_mode, .led_set_hw_mode and .led_get_hw_mode in struct
phydev.

Signed-off-by: Marek Behún <redacted>
---
 drivers/net/phy/Kconfig           |  9 +++
 drivers/net/phy/Makefile          |  1 +
 drivers/net/phy/phy_hw_led_mode.c | 96 +++++++++++++++++++++++++++++++
 include/linux/phy.h               | 15 +++++
 4 files changed, 121 insertions(+)
 create mode 100644 drivers/net/phy/phy_hw_led_mode.c

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index dd20c2c27c2f..ffea11f73acd 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig

@@ -283,6 +283,15 @@ config LED_TRIGGER_PHY
 		<Speed in megabits>Mbps OR <Speed in gigabits>Gbps OR link
 		for any speed known to the PHY.
 
+config LED_TRIGGER_PHY_HW
+	bool "Support HW LED control modes"
+	depends on LEDS_TRIGGERS
+	help
+	  Many PHYs can control blinking of LEDs connected directly to them.
+	  This adds a special LED trigger called phydev-hw-mode. When enabled,
+	  the various control modes supported by the PHY on given LED can be
+	  chosen via hw_mode sysfs file.
+
 
 comment "MII PHY device drivers"
 

diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index d84bab489a53..fd0253ab8097 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile

@@ -20,6 +20,7 @@ endif
 obj-$(CONFIG_MDIO_DEVRES)	+= mdio_devres.o
 libphy-$(CONFIG_SWPHY)		+= swphy.o
 libphy-$(CONFIG_LED_TRIGGER_PHY)	+= phy_led_triggers.o
+libphy-$(CONFIG_LED_TRIGGER_PHY_HW)	+= phy_hw_led_mode.o
 
 obj-$(CONFIG_PHYLINK)		+= phylink.o
 obj-$(CONFIG_PHYLIB)		+= libphy.o

diff --git a/drivers/net/phy/phy_hw_led_mode.c b/drivers/net/phy/phy_hw_led_mode.c
new file mode 100644
index 000000000000..b4c2f25266a5
--- /dev/null
+++ b/drivers/net/phy/phy_hw_led_mode.c

@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * drivers/net/phy/phy_hw_led_mode.c
+ *
+ * PHY HW LED mode trigger
+ *
+ * Copyright (C) 2020 Marek Behun <marek.behun@nic.cz>
+ */
+#include <linux/leds.h>
+#include <linux/phy.h>
+
+static void phy_hw_led_trig_deactivate(struct led_classdev *cdev)
+{
+	struct phy_device *phydev = to_phy_device(cdev->dev->parent);
+	int ret;
+
+	ret = phydev->drv->led_set_hw_mode(phydev, cdev, NULL);
+	if (ret < 0) {
+		phydev_err(phydev, "failed deactivating HW mode on LED %s\n", cdev->name);
+		return;
+	}