[PATCH] leds: trigger: Introduce a NETDEV trigger

[Ben Whitten]

This commit introduces a NETDEV trigger for named device
activity. Available triggers are link, rx, and tx.

Signed-off-by: Ben Whitten <ben.whitten@xxxxxxxxx>
---
 .../ABI/testing/sysfs-class-led-trigger-netdev     |  45 +++
 drivers/leds/trigger/Kconfig                       |   7 +
 drivers/leds/trigger/Makefile                      |   1 +
 drivers/leds/trigger/ledtrig-netdev.c              | 428 +++++++++++++++++++++
 4 files changed, 481 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-netdev
 create mode 100644 drivers/leds/trigger/ledtrig-netdev.c

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-netdev b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev
new file mode 100644
index 0000000..2c917df
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev
@@ -0,0 +1,45 @@
+What:		/sys/class/leds/<led>/device_name
+Date:		Nov 2017
+KernelVersion:	4.15
+Contact:	linux-leds@xxxxxxxxxxxxxxx
+Description:
+		Specifies the network device name to monitor.
+
+What:		/sys/class/leds/<led>/interval
+Date:		Nov 2017
+KernelVersion:	4.15
+Contact:	linux-leds@xxxxxxxxxxxxxxx
+Description:
+		Specifies the duration of the LED blink in milliseconds.
+		Defaults to 50 ms.
+
+What:		/sys/class/leds/<led>/link
+Date:		Nov 2017
+KernelVersion:	4.15
+Contact:	linux-leds@xxxxxxxxxxxxxxx
+Description:
+		Signal the link state of the named network device.
+		If set to 0 (default), the LED's normal state is off.
+		If set to 1, the LED's normal state reflects the link state
+		of the named network device.
+		Setting this value also immediately changes the LED state.
+
+What:		/sys/class/leds/<led>/tx
+Date:		Nov 2017
+KernelVersion:	4.15
+Contact:	linux-leds@xxxxxxxxxxxxxxx
+Description:
+		Signal transmission of data on the named network device.
+		If set to 0 (default), the LED will not blink on transmission.
+		If set to 1, the LED will blink for the milliseconds specified
+		in interval to signal transmission.
+
+What:		/sys/class/leds/<led>/rx
+Date:		Nov 2017
+KernelVersion:	4.15
+Contact:	linux-leds@xxxxxxxxxxxxxxx
+Description:
+		Signal reception of data on the named network device.
+		If set to 0 (default), the LED will not blink on reception.
+		If set to 1, the LED will blink for the milliseconds specified
+		in interval to signal reception.
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 3f9ddb9..4ec1853 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -126,4 +126,11 @@ config LEDS_TRIGGER_PANIC
 	  a different trigger.
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_NETDEV
+	tristate "LED Netdev Trigger"
+	depends on NET && LEDS_TRIGGERS
+	help
+	  This allows LEDs to be controlled by network device activity.
+	  If unsure, say Y.
+
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 9f2e868..59e163d 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+= ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)	+= ledtrig-transient.o
 obj-$(CONFIG_LEDS_TRIGGER_CAMERA)	+= ledtrig-camera.o
 obj-$(CONFIG_LEDS_TRIGGER_PANIC)	+= ledtrig-panic.o
+obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
new file mode 100644
index 0000000..2953b41
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -0,0 +1,428 @@
+/*
+ * LED Kernel Netdev Trigger
+ *
+ * Toggles the LED to reflect the link and traffic state of a named net device
+ *
+ * Copyright 2017 Ben Whitten <ben.whitten@xxxxxxxxx>
+ *
+ * Copyright 2007 Oliver Jowett <oliver@xxxxxxxxxxxxx>
+ *
+ * Derived from ledtrig-timer.c which is:
+ *  Copyright 2005-2006 Openedhand Ltd.
+ *  Author: Richard Purdie <rpurdie@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/ctype.h>
+#include <linux/atomic.h>
+#include <linux/leds.h>
+
+/*
+ * Configurable sysfs attributes:
+ *
+ * device_name - network device name to monitor
+ *
+ * interval - duration of LED blink, in milliseconds
+ *
+ * link -  LED's normal state reflects whether the link is up
+ *         (has carrier) or not
+ * tx -  LED blinks on transmitted data
+ * rx -  LED blinks on receive data
+ *
+ */
+
+struct led_netdev_data {
+	spinlock_t lock;
+
+	struct delayed_work work;
+	struct notifier_block notifier;
+
+	struct led_classdev *led_cdev;
+	struct net_device *net_dev;
+
+	char device_name[IFNAMSIZ];
+	atomic_t interval;
+	unsigned int last_activity;
+
+	unsigned long mode;
+#define LED_BLINK_link	0
+#define LED_BLINK_tx	1
+#define LED_BLINK_rx	2
+#define LED_MODE_LINKUP	3
+};
+
+static void set_baseline_state(struct led_netdev_data *trigger_data)
+{
+	if (!test_bit(LED_MODE_LINKUP, &trigger_data->mode))
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+	else {
+		if (test_bit(LED_BLINK_link, &trigger_data->mode))
+			led_set_brightness(trigger_data->led_cdev, LED_FULL);
+
+		if (test_bit(LED_BLINK_tx, &trigger_data->mode) ||
+		    test_bit(LED_BLINK_rx, &trigger_data->mode))
+			schedule_delayed_work(&trigger_data->work,
+				atomic_read(&trigger_data->interval));
+	}
+}
+
+static ssize_t device_name_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+	ssize_t len;
+
+	spin_lock_bh(&trigger_data->lock);
+	len = sprintf(buf, "%s\n", trigger_data->device_name);
+	spin_unlock_bh(&trigger_data->lock);
+
+	return len;
+}
+
+static ssize_t device_name_store(struct device *dev,
+				 struct device_attribute *attr, const char *buf,
+				 size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+	if (size >= IFNAMSIZ)
+		return -EINVAL;
+
+	cancel_delayed_work_sync(&trigger_data->work);
+
+	spin_lock_bh(&trigger_data->lock);
+
+	if (trigger_data->net_dev) {
+		dev_put(trigger_data->net_dev);
+		trigger_data->net_dev = NULL;
+	}
+
+	strncpy(trigger_data->device_name, buf, size);
+	if (size > 0 && trigger_data->device_name[size - 1] == '\n')
+		trigger_data->device_name[size - 1] = 0;
+
+	if (trigger_data->device_name[0] != 0)
+		trigger_data->net_dev =
+		    dev_get_by_name(&init_net, trigger_data->device_name);
+
+	clear_bit(LED_MODE_LINKUP, &trigger_data->mode);
+	if (trigger_data->net_dev != NULL)
+		if (netif_carrier_ok(trigger_data->net_dev))
+			set_bit(LED_MODE_LINKUP, &trigger_data->mode);
+
+	trigger_data->last_activity = 0;
+
+	set_baseline_state(trigger_data);
+	spin_unlock_bh(&trigger_data->lock);
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(device_name);
+
+#define led_mode_flags_attr(field)					\
+static ssize_t field##_show(struct device *dev,				\
+	struct device_attribute *attr, char *buf)			\
+{									\
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);		\
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;	\
+									\
+	return sprintf(buf, "%u\n", test_bit(LED_BLINK_##field,		\
+					&trigger_data->mode));		\
+}									\
+static ssize_t field##_store(struct device *dev,			\
+	struct device_attribute *attr, const char *buf, size_t size)	\
+{									\
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);		\
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;	\
+	unsigned long state;						\
+	int ret;							\
+									\
+	ret = kstrtoul(buf, 0, &state);					\
+	if (ret)							\
+		return ret;						\
+									\
+	cancel_delayed_work_sync(&trigger_data->work);			\
+									\
+	if (state)							\
+		set_bit(LED_BLINK_##field, &trigger_data->mode);	\
+	else								\
+		clear_bit(LED_BLINK_##field, &trigger_data->mode);	\
+									\
+	set_baseline_state(trigger_data);				\
+									\
+	return size;							\
+}									\
+static DEVICE_ATTR_RW(field);
+
+led_mode_flags_attr(link);
+led_mode_flags_attr(rx);
+led_mode_flags_attr(tx);
+
+static ssize_t interval_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%u\n",
+		       jiffies_to_msecs(atomic_read(&trigger_data->interval)));
+}
+
+static ssize_t interval_store(struct device *dev,
+			      struct device_attribute *attr, const char *buf,
+			      size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+	unsigned long value;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &value);
+	if (ret)
+		return ret;
+
+	/* impose some basic bounds on the timer interval */
+	if (value >= 5 && value <= 10000) {
+		cancel_delayed_work_sync(&trigger_data->work);
+
+		atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
+		set_baseline_state(trigger_data);	/* resets timer */
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(interval);
+
+static int netdev_trig_notify(struct notifier_block *nb,
+			      unsigned long evt, void *dv)
+{
+	struct net_device *dev =
+		netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
+	struct led_netdev_data *trigger_data = container_of(nb,
+							    struct
+							    led_netdev_data,
+							    notifier);
+
+	if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
+	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
+	    && evt != NETDEV_CHANGENAME)
+		return NOTIFY_DONE;
+
+	if (strcmp(dev->name, trigger_data->device_name))
+		return NOTIFY_DONE;
+
+	cancel_delayed_work_sync(&trigger_data->work);
+
+	spin_lock_bh(&trigger_data->lock);
+
+	clear_bit(LED_MODE_LINKUP, &trigger_data->mode);
+	switch (evt) {
+	case NETDEV_REGISTER:
+		if (trigger_data->net_dev)
+			dev_put(trigger_data->net_dev);
+		dev_hold(dev);
+		trigger_data->net_dev = dev;
+		break;
+	case NETDEV_CHANGENAME:
+	case NETDEV_UNREGISTER:
+		if (trigger_data->net_dev) {
+			dev_put(trigger_data->net_dev);
+			trigger_data->net_dev = NULL;
+		}
+		break;
+	case NETDEV_UP:
+	case NETDEV_CHANGE:
+		if (netif_carrier_ok(dev))
+			set_bit(LED_MODE_LINKUP, &trigger_data->mode);
+		break;
+	}
+
+	set_baseline_state(trigger_data);
+
+	spin_unlock_bh(&trigger_data->lock);
+
+	return NOTIFY_DONE;
+}
+
+/* here's the real work! */
+static void netdev_trig_work(struct work_struct *work)
+{
+	struct led_netdev_data *trigger_data = container_of(work,
+							    struct
+							    led_netdev_data,
+							    work.work);
+	struct rtnl_link_stats64 *dev_stats;
+	unsigned int new_activity;
+	struct rtnl_link_stats64 temp;
+
+	if (!test_bit(LED_MODE_LINKUP, &trigger_data->mode) ||
+	    !trigger_data->net_dev ||
+	    (!test_bit(LED_BLINK_tx, &trigger_data->mode) &&
+	     !test_bit(LED_BLINK_rx, &trigger_data->mode))) {
+		/* we don't need to do timer work, just reflect link state. */
+		led_set_brightness(trigger_data->led_cdev,
+				   (test_bit
+				    (LED_BLINK_link, &trigger_data->mode)
+				    && test_bit(LED_MODE_LINKUP,
+						&trigger_data->mode
+						) ? LED_FULL : LED_OFF));
+		return;
+	}
+
+	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
+	new_activity =
+	    (test_bit(LED_BLINK_tx, &trigger_data->mode) ?
+		dev_stats->tx_packets : 0) +
+	    (test_bit(LED_BLINK_rx, &trigger_data->mode) ?
+		dev_stats->rx_packets : 0);
+
+	if (test_bit(LED_BLINK_link, &trigger_data->mode)) {
+		/* base state is ON (link present) */
+		/* if there's no link, we don't get this far and
+		 * the LED is off
+		 */
+
+		/* OFF -> ON always */
+		/* ON -> OFF on activity */
+		if (trigger_data->led_cdev->brightness == LED_OFF)
+			led_set_brightness(trigger_data->led_cdev, LED_FULL);
+		else if (trigger_data->last_activity != new_activity)
+			led_set_brightness(trigger_data->led_cdev, LED_OFF);
+	} else {
+		/* base state is OFF */
+		/* ON -> OFF always */
+		/* OFF -> ON on activity */
+		if (trigger_data->led_cdev->brightness == LED_FULL)
+			led_set_brightness(trigger_data->led_cdev, LED_OFF);
+		else if (trigger_data->last_activity != new_activity)
+			led_set_brightness(trigger_data->led_cdev, LED_FULL);
+	}
+
+	trigger_data->last_activity = new_activity;
+	schedule_delayed_work(&trigger_data->work,
+			      atomic_read(&trigger_data->interval));
+}
+
+static void netdev_trig_activate(struct led_classdev *led_cdev)
+{
+	struct led_netdev_data *trigger_data;
+	int rc;
+
+	trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
+	if (!trigger_data)
+		return;
+
+	spin_lock_init(&trigger_data->lock);
+
+	trigger_data->notifier.notifier_call = netdev_trig_notify;
+	trigger_data->notifier.priority = 10;
+
+	INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
+
+	trigger_data->led_cdev = led_cdev;
+	trigger_data->net_dev = NULL;
+	trigger_data->device_name[0] = 0;
+
+	trigger_data->mode = 0;
+	atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
+	trigger_data->last_activity = 0;
+
+	led_cdev->trigger_data = trigger_data;
+
+	rc = device_create_file(led_cdev->dev, &dev_attr_device_name);
+	if (rc)
+		goto err_out;
+	rc = device_create_file(led_cdev->dev, &dev_attr_link);
+	if (rc)
+		goto err_out_device_name;
+	rc = device_create_file(led_cdev->dev, &dev_attr_rx);
+	if (rc)
+		goto err_out_link;
+	rc = device_create_file(led_cdev->dev, &dev_attr_tx);
+	if (rc)
+		goto err_out_rx;
+	rc = device_create_file(led_cdev->dev, &dev_attr_interval);
+	if (rc)
+		goto err_out_tx;
+	rc = register_netdevice_notifier(&trigger_data->notifier);
+	if (rc)
+		goto err_out_interval;
+	return;
+
+err_out_interval:
+	device_remove_file(led_cdev->dev, &dev_attr_interval);
+err_out_tx:
+	device_remove_file(led_cdev->dev, &dev_attr_tx);
+err_out_rx:
+	device_remove_file(led_cdev->dev, &dev_attr_rx);
+err_out_link:
+	device_remove_file(led_cdev->dev, &dev_attr_link);
+err_out_device_name:
+	device_remove_file(led_cdev->dev, &dev_attr_device_name);
+err_out:
+	led_cdev->trigger_data = NULL;
+	kfree(trigger_data);
+}
+
+static void netdev_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+	if (trigger_data) {
+		unregister_netdevice_notifier(&trigger_data->notifier);
+
+		device_remove_file(led_cdev->dev, &dev_attr_device_name);
+		device_remove_file(led_cdev->dev, &dev_attr_link);
+		device_remove_file(led_cdev->dev, &dev_attr_rx);
+		device_remove_file(led_cdev->dev, &dev_attr_tx);
+		device_remove_file(led_cdev->dev, &dev_attr_interval);
+
+		cancel_delayed_work_sync(&trigger_data->work);
+
+		if (trigger_data->net_dev)
+			dev_put(trigger_data->net_dev);
+
+		kfree(trigger_data);
+	}
+}
+
+static struct led_trigger netdev_led_trigger = {
+	.name = "netdev",
+	.activate = netdev_trig_activate,
+	.deactivate = netdev_trig_deactivate,
+};
+
+static int __init netdev_trig_init(void)
+{
+	return led_trigger_register(&netdev_led_trigger);
+}
+
+static void __exit netdev_trig_exit(void)
+{
+	led_trigger_unregister(&netdev_led_trigger);
+}
+
+module_init(netdev_trig_init);
+module_exit(netdev_trig_exit);
+
+MODULE_AUTHOR("Ben Whitten <ben.whitten@xxxxxxxxx>");
+MODULE_AUTHOR("Oliver Jowett <oliver@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Netdev LED trigger");
+MODULE_LICENSE("GPL");
-- 
2.7.4