[PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[Ben Whitten]

From: Ben Whitten <ben.whitten@gmail.com>

The patch was converted to led_blink_oneshot, in doing so we find that the
behaviour has changed. As I dont want to break 'userspace' led behaviour this
patch shouldn't be merged as is. Open to suggestions.

Given an interval of 50ms and heavy throughput, the previous implementation
produced a blink with 100ms period and 50% dutycycle. The led_blink_oneshot
version produces a blink with 140ms period and 57% dutycycle.
I assume a fudge factor on the oneshot delay to bring the period back to 100ms
would be device specific so not suitable.

Kind regards,
Ben Whitten (1):
  leds: trigger: Introduce a NETDEV trigger

 .../ABI/testing/sysfs-class-led-trigger-netdev     |  45 ++
 drivers/leds/trigger/Kconfig                       |   7 +
 drivers/leds/trigger/Makefile                      |   1 +
 drivers/leds/trigger/ledtrig-netdev.c              | 507 +++++++++++++++++++++
 4 files changed, 560 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-netdev
 create mode 100644 drivers/leds/trigger/ledtrig-netdev.c

-- 
2.7.4

[PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[Ben Whitten]

From: Ben Whitten <ben.whitten@gmail.com>

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

Signed-off-by: Ben Whitten <ben.whitten@gmail.com>

---
Changes in v2:
Sort includes and redate documentation
Correct licence
Remove macro and replace with generic function using enums
Convert blink logic in stats work to use led_blink_oneshot
Uses configured brightness instead of FULL
---
 .../ABI/testing/sysfs-class-led-trigger-netdev     |  45 ++
 drivers/leds/trigger/Kconfig                       |   7 +
 drivers/leds/trigger/Makefile                      |   1 +
 drivers/leds/trigger/ledtrig-netdev.c              | 507 +++++++++++++++++++++
 4 files changed, 560 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..451af6d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev
@@ -0,0 +1,45 @@
+What:		/sys/class/leds/<led>/device_name
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies the network device name to monitor.
+
+What:		/sys/class/leds/<led>/interval
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies the duration of the LED blink in milliseconds.
+		Defaults to 50 ms.
+
+What:		/sys/class/leds/<led>/link
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+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:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+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:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+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..3b6075d
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -0,0 +1,507 @@
+/*
+ * 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@gmail.com>
+ *
+ * Copyright 2007 Oliver Jowett <oliver@opencloud.com>
+ *
+ * Derived from ledtrig-timer.c which is:
+ *  Copyright 2005-2006 Openedhand Ltd.
+ *  Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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/atomic.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+#include <linux/timer.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 NETDEV_LED_LINK	0
+#define NETDEV_LED_TX	1
+#define NETDEV_LED_RX	2
+#define NETDEV_LED_MODE_LINKUP	3
+};
+
+enum netdev_led_attr {
+	NETDEV_ATTR_LINK,
+	NETDEV_ATTR_TX,
+	NETDEV_ATTR_RX
+};
+
+static void set_baseline_state(struct led_netdev_data *trigger_data)
+{
+	int current_brightness;
+	struct led_classdev *led_cdev = trigger_data->led_cdev;
+
+	current_brightness = led_cdev->brightness;
+	if (current_brightness)
+		led_cdev->blink_brightness = current_brightness;
+	if (!led_cdev->blink_brightness)
+		led_cdev->blink_brightness = led_cdev->max_brightness;
+
+	if (!test_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode))
+		led_set_brightness(led_cdev, LED_OFF);
+	else {
+		if (test_bit(NETDEV_LED_LINK, &trigger_data->mode))
+			led_set_brightness(led_cdev,
+					   led_cdev->blink_brightness);
+		else
+			led_set_brightness(led_cdev, LED_OFF);
+
+		/* If we are looking for RX/TX start periodically
+		 * checking stats
+		 */
+		if (test_bit(NETDEV_LED_TX, &trigger_data->mode) ||
+		    test_bit(NETDEV_LED_RX, &trigger_data->mode))
+			schedule_delayed_work(&trigger_data->work, 0);
+	}
+}
+
+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(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
+	if (trigger_data->net_dev != NULL)
+		if (netif_carrier_ok(trigger_data->net_dev))
+			set_bit(NETDEV_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);
+
+static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
+	enum netdev_led_attr attr)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+	int bit;
+
+	switch (attr) {
+	case NETDEV_ATTR_LINK:
+		bit = NETDEV_LED_LINK;
+		break;
+	case NETDEV_ATTR_TX:
+		bit = NETDEV_LED_TX;
+		break;
+	case NETDEV_ATTR_RX:
+		bit = NETDEV_LED_RX;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
+}
+
+static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
+	size_t size, enum netdev_led_attr attr)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+	unsigned long state;
+	int ret;
+	int bit;
+
+	ret = kstrtoul(buf, 0, &state);
+	if (ret)
+		return ret;
+
+	switch (attr) {
+	case NETDEV_ATTR_LINK:
+		bit = NETDEV_LED_LINK;
+		break;
+	case NETDEV_ATTR_TX:
+		bit = NETDEV_LED_TX;
+		break;
+	case NETDEV_ATTR_RX:
+		bit = NETDEV_LED_RX;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	cancel_delayed_work_sync(&trigger_data->work);
+
+	if (state)
+		set_bit(bit, &trigger_data->mode);
+	else
+		clear_bit(bit, &trigger_data->mode);
+
+	set_baseline_state(trigger_data);
+
+	return size;
+}
+
+static ssize_t link_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
+}
+
+static ssize_t link_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
+}
+
+static DEVICE_ATTR_RW(link);
+
+static ssize_t tx_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
+}
+
+static ssize_t tx_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
+}
+
+static DEVICE_ATTR_RW(tx);
+
+static ssize_t rx_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
+}
+
+static ssize_t rx_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
+}
+
+static DEVICE_ATTR_RW(rx);
+
+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(NETDEV_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(NETDEV_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;
+	unsigned long interval;
+	int invert;
+
+	/* If we dont have a device, insure we are off */
+	if (!trigger_data->net_dev) {
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+		return;
+	}
+
+	/* If we are not looking for RX/TX then return  */
+	if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
+	    !test_bit(NETDEV_LED_RX, &trigger_data->mode))
+		return;
+
+	/* If our previous blink is not done call again when expired */
+	if (timer_pending(&trigger_data->led_cdev->blink_timer)) {
+		schedule_delayed_work(&trigger_data->work,
+			jiffies-trigger_data->led_cdev->blink_timer.expires);
+		return;
+	}
+
+	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
+	new_activity =
+	    (test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
+		dev_stats->tx_packets : 0) +
+	    (test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
+		dev_stats->rx_packets : 0);
+
+	if (trigger_data->last_activity != new_activity) {
+		invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
+		interval = jiffies_to_msecs(
+				atomic_read(&trigger_data->interval));
+		/* base state is ON (link present) */
+		led_blink_set_oneshot(trigger_data->led_cdev,
+				      &interval,
+				      &interval,
+				      invert);
+		trigger_data->last_activity = new_activity;
+	}
+
+	schedule_delayed_work(&trigger_data->work,
+			(atomic_read(&trigger_data->interval)*2));
+}
+
+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@gmail.com>");
+MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
+MODULE_DESCRIPTION("Netdev LED trigger");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: [PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[Jacek Anaszewski]

Hi Ben,

On 12/05/2017 12:19 PM, Ben Whitten wrote:
> From: Ben Whitten <ben.whitten@gmail.com>
> 
> The patch was converted to led_blink_oneshot, in doing so we find that the
> behaviour has changed. As I dont want to break 'userspace' led behaviour this
> patch shouldn't be merged as is. Open to suggestions.
> 
> Given an interval of 50ms and heavy throughput, the previous implementation
> produced a blink with 100ms period and 50% dutycycle. The led_blink_oneshot
> version produces a blink with 140ms period and 57% dutycycle.

Please check if the LED class driver you're testing the trigger with
implements blink_set op. If yes it would be good to check if it doesn't
align the delay intervals to the hardware capabilities instead of
failing and relying on a LED core software blink fallback.


> I assume a fudge factor on the oneshot delay to bring the period back to 100ms
> would be device specific so not suitable.
> 
> Kind regards,
> Ben Whitten (1):
>   leds: trigger: Introduce a NETDEV trigger
> 
>  .../ABI/testing/sysfs-class-led-trigger-netdev     |  45 ++
>  drivers/leds/trigger/Kconfig                       |   7 +
>  drivers/leds/trigger/Makefile                      |   1 +
>  drivers/leds/trigger/ledtrig-netdev.c              | 507 +++++++++++++++++++++
>  4 files changed, 560 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-netdev
>  create mode 100644 drivers/leds/trigger/ledtrig-netdev.c
> 

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[Ben Whitten]

Hi Jacek,

On 5 December 2017 at 20:38, Jacek Anaszewski
<jacek.anaszewski@gmail.com> wrote:
> Hi Ben,
>
> On 12/05/2017 12:19 PM, Ben Whitten wrote:
>> From: Ben Whitten <ben.whitten@gmail.com>
>>
>> The patch was converted to led_blink_oneshot, in doing so we find that the
>> behaviour has changed. As I dont want to break 'userspace' led behaviour this
>> patch shouldn't be merged as is. Open to suggestions.
>>
>> Given an interval of 50ms and heavy throughput, the previous implementation
>> produced a blink with 100ms period and 50% dutycycle. The led_blink_oneshot
>> version produces a blink with 140ms period and 57% dutycycle.
>
> Please check if the LED class driver you're testing the trigger with
> implements blink_set op. If yes it would be good to check if it doesn't
> align the delay intervals to the hardware capabilities instead of
> failing and relying on a LED core software blink fallback.

The led are using gpio-led set from device tree on an embedded system, sama5
based. So as far as I can tell blink_op is NULL in this case and it
then relies on
software for the blink in the form of timers.
I assume its the jiffies playing a part here, taking a jiffy or two to
queue up a flash
may add 10ms to the desired 50ms delay_on/delay_off that I am seeing. Then the
extra time may be due to the stats workqueue not aligning with the
blink timer to
kick it off again.

Best regards,
Ben

Re: [PATCH/RFC v2] leds: trigger: Introduce a NETDEV trigger

[Ben Whitten]

On 6 December 2017 at 20:07, Ben Whitten <ben.whitten@gmail.com> wrote:
> Hi Jacek,
>
> On 5 December 2017 at 20:38, Jacek Anaszewski
> <jacek.anaszewski@gmail.com> wrote:
>> Hi Ben,
>>
>> On 12/05/2017 12:19 PM, Ben Whitten wrote:
>>> From: Ben Whitten <ben.whitten@gmail.com>
>>>
>>> The patch was converted to led_blink_oneshot, in doing so we find that the
>>> behaviour has changed. As I dont want to break 'userspace' led behaviour this
>>> patch shouldn't be merged as is. Open to suggestions.
>>>
>>> Given an interval of 50ms and heavy throughput, the previous implementation
>>> produced a blink with 100ms period and 50% dutycycle. The led_blink_oneshot
>>> version produces a blink with 140ms period and 57% dutycycle.
>>
>> Please check if the LED class driver you're testing the trigger with
>> implements blink_set op. If yes it would be good to check if it doesn't
>> align the delay intervals to the hardware capabilities instead of
>> failing and relying on a LED core software blink fallback.
>
> The led are using gpio-led set from device tree on an embedded system, sama5
> based. So as far as I can tell blink_op is NULL in this case and it
> then relies on
> software for the blink in the form of timers.
> I assume its the jiffies playing a part here, taking a jiffy or two to
> queue up a flash
> may add 10ms to the desired 50ms delay_on/delay_off that I am seeing. Then the
> extra time may be due to the stats workqueue not aligning with the
> blink timer to
> kick it off again.

I have found a solution. As oneshot appears run in software regardless
based on the
check in led_blink_setup, cancelling the software timer in the stats
worker allows for
an immidiate requeue. This brings the period back down to 110ms and looks
identical to the previous implementation.

Best regards,
Ben