Add Hardware Only Trigger for PHY Activity. This special trigger is used to
configure and expose the different HW trigger that are provided by the
PHY. Each blink mode can be configured by sysfs and on trigger
activation the hardware mode is enabled.

This currently implement these hw triggers:
  - blink_tx: Blink LED on tx packet receive
  - blink_rx: Blink LED on rx packet receive
  - keep_link_10m: Keep LED on with 10m link speed
  - keep_link_100m: Keep LED on with 100m link speed
  - kepp_link_1000m: Keep LED on with 1000m link speed
  - keep_half_duplex: Keep LED on with half duplex link
  - keep_full_duplex: Keep LED on with full duplex link
  - option_linkup_over: Ignore blink tx/rx with link keep not active
  - option_power_on_reset: Keep LED on with switch reset
  - option_blink_2hz: Set blink speed at 2hz for every blink event
  - option_blink_4hz: Set blink speed at 4hz for every blink event
  - option_blink_8hz: Set blink speed at 8hz for every blink event
  - option_blink_auto: Set blink speed at 2hz for 10m link speed,
      4hz for 100m and 8hz for 1000m

The trigger will check if the LED driver support the various blink modes
and will expose the blink modes in sysfs.
It will finally enable hw mode for the LED without configuring any rule.
This mean that the LED will blink/follow whatever offload trigger is
active by default and the user needs to manually configure the desired
offload triggers using sysfs.
A flag is passed to configure_offload with the related rule from this
trigger to active or disable.
It's in the led driver interest the detection and knowing how to
elaborate the passed flags and should report -EOPNOTSUPP otherwise.

The different hw triggers are exposed in the led sysfs dir under the
offload-phy-activity subdir.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
 drivers/leds/trigger/Kconfig                  |  28 +++
 drivers/leds/trigger/Makefile                 |   1 +
 .../trigger/ledtrig-hardware-phy-activity.c   | 171 ++++++++++++++++++
 include/linux/leds.h                          |  22 +++
 4 files changed, 222 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-hardware-phy-activity.c

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index dc6816d36d06..b947b238be3f 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig

@@ -154,4 +154,32 @@ config LEDS_TRIGGER_TTY
 
 	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_HARDWARE_PHY_ACTIVITY
+	tristate "LED Trigger for PHY Activity for Hardware Controlled LED"
+	depends on LEDS_HARDWARE_CONTROL
+	help
+	  This allows LEDs to be configured to run by hardware and offloaded
+	  based on some rules. The LED will blink or be on based on the PHY
+	  Activity for example on packet receive or based on the link speed.
+
+	  The current supported offload triggers are:
+	  - blink_tx: Blink LED on tx packet receive
+	  - blink_rx: Blink LED on rx packet receive
+	  - keep_link_10m: Keep LED on with 10m link speed
+	  - keep_link_100m: Keep LED on with 100m link speed
+	  - keep_link_1000m: Keep LED on with 1000m link speed
+	  - keep_half_duplex: Keep LED on with half duplex link
+	  - keep_full_duplex: Keep LED on with full duplex link
+	  - option_linkup_over: Blink rules are ignored with absent link
+	  - option_power_on_reset: Power ON Led on Switch/PHY reset
+	  - option_blink_2hz: Set blink speed at 2hz for every blink event
+	  - option_blink_4hz: Set blink speed at 4hz for every blink event
+	  - option_blink_8hz: Set blink speed at 8hz for every blink event
+
+	  These blink modes are present in the LED sysfs dir under
+	  hardware-phy-activity if supported by the LED driver.
+
+	  This trigger can be used only by LEDs that supports Hardware mode
+
+
 endif # LEDS_TRIGGERS

diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 25c4db97cdd4..f5d0d0057d2b 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile

@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_HARDWARE_PHY_ACTIVITY) += ledtrig-hardware-phy-activity.o

diff --git a/drivers/leds/trigger/ledtrig-hardware-phy-activity.c b/drivers/leds/trigger/ledtrig-hardware-phy-activity.c
new file mode 100644
index 000000000000..7fd0557fe878
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-hardware-phy-activity.c

@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/slab.h>
+
+#define PHY_ACTIVITY_MAX_TRIGGERS 12
+
+#define DEFINE_OFFLOAD_TRIGGER(trigger_name, trigger) \
+	static ssize_t trigger_name##_show(struct device *dev, \
+				struct device_attribute *attr, char *buf) \
+	{ \
+		struct led_classdev *led_cdev = led_trigger_get_led(dev); \
+		int val; \
+		val = led_cdev->hw_control_configure(led_cdev, trigger, BLINK_MODE_READ); \
+		return sprintf(buf, "%d\n", val ? 1 : 0); \
+	} \
+	static ssize_t trigger_name##_store(struct device *dev, \
+					struct device_attribute *attr, \
+					const char *buf, size_t size) \
+	{ \
+		struct led_classdev *led_cdev = led_trigger_get_led(dev); \
+		unsigned long state; \
+		int cmd, ret; \
+		ret = kstrtoul(buf, 0, &state); \
+		if (ret) \
+			return ret; \
+		cmd = !!state ? BLINK_MODE_ENABLE : BLINK_MODE_DISABLE; \
+		/* Update the configuration with every change */ \
+		led_cdev->hw_control_configure(led_cdev, trigger, cmd); \
+		return size; \
+	} \
+	DEVICE_ATTR_RW(trigger_name)
+
+/* Expose sysfs for every blink to be configurable from userspace */
+DEFINE_OFFLOAD_TRIGGER(blink_tx, BLINK_TX);
+DEFINE_OFFLOAD_TRIGGER(blink_rx, BLINK_RX);
+DEFINE_OFFLOAD_TRIGGER(keep_link_10m, KEEP_LINK_10M);
+DEFINE_OFFLOAD_TRIGGER(keep_link_100m, KEEP_LINK_100M);
+DEFINE_OFFLOAD_TRIGGER(keep_link_1000m, KEEP_LINK_1000M);
+DEFINE_OFFLOAD_TRIGGER(keep_half_duplex, KEEP_HALF_DUPLEX);
+DEFINE_OFFLOAD_TRIGGER(keep_full_duplex, KEEP_FULL_DUPLEX);
+DEFINE_OFFLOAD_TRIGGER(option_linkup_over, OPTION_LINKUP_OVER);
+DEFINE_OFFLOAD_TRIGGER(option_power_on_reset, OPTION_POWER_ON_RESET);
+DEFINE_OFFLOAD_TRIGGER(option_blink_2hz, OPTION_BLINK_2HZ);
+DEFINE_OFFLOAD_TRIGGER(option_blink_4hz, OPTION_BLINK_4HZ);
+DEFINE_OFFLOAD_TRIGGER(option_blink_8hz, OPTION_BLINK_8HZ);