Re: [PATCH v3] led: add oneshot trigger
From: Bryan Wu
Date: Thu Jun 07 2012 - 08:59:08 EST
On Thu, Jun 7, 2012 at 6:11 AM, Fabio Baltieri <fabio.baltieri@xxxxxxxxx> wrote:
> Add oneshot trigger to blink a led with configurale parameters via
> sysfs.
>
> Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
> Cc: Shuah Khan <shuahkhan@xxxxxxxxx>
> Cc: Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
> ---
>
> Here is the v3, with added documentation file with short description, sysfs
> description, use case example (the one I developed ths for, actually) and
> default values.
>
> Also, while trying the use case, I added instantaneous setting of led state when
> setting the "invert" attribute.
>
> Let me know what you think of this!
>
I'm fine this patch now, and added to my for-next and devel branches.
-Bryan
> Fabio
>
> Documentation/leds/ledtrig-oneshot.txt | 59 ++++++++++
> drivers/leds/Kconfig | 14 +++
> drivers/leds/Makefile | 1 +
> drivers/leds/ledtrig-oneshot.c | 204 +++++++++++++++++++++++++++++++++
> 4 files changed, 278 insertions(+)
> create mode 100644 Documentation/leds/ledtrig-oneshot.txt
> create mode 100644 drivers/leds/ledtrig-oneshot.c
>
> diff --git a/Documentation/leds/ledtrig-oneshot.txt b/Documentation/leds/ledtrig-oneshot.txt
> new file mode 100644
> index 0000000..07cd1fa
> --- /dev/null
> +++ b/Documentation/leds/ledtrig-oneshot.txt
> @@ -0,0 +1,59 @@
> +One-shot LED Trigger
> +====================
> +
> +This is a LED trigger useful for signaling the user of an event where there are
> +no clear trap points to put standard led-on and led-off settings. Using this
> +trigger, the application needs only to signal the trigger when an event has
> +happened, than the trigger turns the LED on and than keeps it off for a
> +specified amount of time.
> +
> +This trigger is meant to be usable both for sporadic and dense events. In the
> +first case, the trigger produces a clear single controlled blink for each
> +event, while in the latter it keeps blinking at constant rate, as to signal
> +that the events are arriving continuously.
> +
> +A one-shot LED only stays in a constant state when there are no events. An
> +additional "invert" property specifies if the LED has to stay off (normal) or
> +on (inverted) when not rearmed.
> +
> +The trigger can be activated from user space on led class devices as shown
> +below:
> +
> + echo oneshot > trigger
> +
> +This adds the following sysfs attributes to the LED:
> +
> + delay_on - specifies for how many milliseconds the LED has to stay at
> + LED_FULL brightness after it has been armed.
> + Default to 100 ms.
> +
> + delay_off - specifies for how many milliseconds the LED has to stay at
> + LED_OFF brightness after it has been armed.
> + Default to 100 ms.
> +
> + invert - reverse the blink logic. If set to 0 (default) blink on for delay_on
> + ms, then blink off for delay_off ms, leaving the LED normally off. If
> + set to 1, blink off for delay_off ms, then blink on for delay_on ms,
> + leaving the LED normally on.
> + Setting this value also immediately change the LED state.
> +
> + shot - write any non-empty string to signal an events, this starts a blink
> + sequence if not already running.
> +
> +Example use-case: network devices, initialization:
> +
> + echo oneshot > trigger # set trigger for this led
> + echo 33 > delay_on # blink at 1 / (33 + 33) Hz on continuous traffic
> + echo 33 > delay_off
> +
> +interface goes up:
> +
> + echo 1 > invert # set led as normally-on, turn the led on
> +
> +packet received/transmitted:
> +
> + echo 1 > shot # led starts blinking, ignored if already blinking
> +
> +interface goes down
> +
> + echo 0 > invert # set led as normally-off, turn the led off
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 04cb8c8..1f151fb 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -443,6 +443,20 @@ config LEDS_TRIGGER_TIMER
>
> If unsure, say Y.
>
> +config LEDS_TRIGGER_ONESHOT
> + tristate "LED One-shot Trigger"
> + depends on LEDS_TRIGGERS
> + help
> + This allows LEDs to blink in one-shot pulses with parameters
> + controlled via sysfs. It's useful to notify the user on
> + sporadic events, when there are no clear begin and end trap points,
> + or on dense events, where this blinks the LED at constant rate if
> + rearmed continuously.
> +
> + It also shows how to use the led_blink_set_oneshot() function.
> +
> + If unsure, say Y.
> +
> config LEDS_TRIGGER_IDE_DISK
> bool "LED IDE Disk Trigger"
> depends on IDE_GD_ATA
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index f8958cd..9112d51 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -53,6 +53,7 @@ obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
>
> # LED Triggers
> obj-$(CONFIG_LEDS_TRIGGER_TIMER) += ledtrig-timer.o
> +obj-$(CONFIG_LEDS_TRIGGER_ONESHOT) += ledtrig-oneshot.o
> obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK) += ledtrig-ide-disk.o
> obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT) += ledtrig-heartbeat.o
> obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT) += ledtrig-backlight.o
> diff --git a/drivers/leds/ledtrig-oneshot.c b/drivers/leds/ledtrig-oneshot.c
> new file mode 100644
> index 0000000..5c9edf7
> --- /dev/null
> +++ b/drivers/leds/ledtrig-oneshot.c
> @@ -0,0 +1,204 @@
> +/*
> + * One-shot LED Trigger
> + *
> + * Copyright 2012, Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
> + *
> + * Based on ledtrig-timer.c by 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/kernel.h>
> +#include <linux/init.h>
> +#include <linux/device.h>
> +#include <linux/ctype.h>
> +#include <linux/slab.h>
> +#include <linux/leds.h>
> +#include "leds.h"
> +
> +#define DEFAULT_DELAY 100
> +
> +struct oneshot_trig_data {
> + unsigned int invert;
> +};
> +
> +static ssize_t led_shot(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> + struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
> +
> + led_blink_set_oneshot(led_cdev,
> + &led_cdev->blink_delay_on, &led_cdev->blink_delay_off,
> + oneshot_data->invert);
> +
> + /* content is ignored */
> + return size;
> +}
> +static ssize_t led_invert_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> + struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
> +
> + return sprintf(buf, "%u\n", oneshot_data->invert);
> +}
> +
> +static ssize_t led_invert_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> + struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
> + unsigned long state;
> + int ret;
> +
> + ret = kstrtoul(buf, 0, &state);
> + if (ret)
> + return ret;
> +
> + oneshot_data->invert = !!state;
> +
> + if (oneshot_data->invert)
> + led_set_brightness(led_cdev, LED_FULL);
> + else
> + led_set_brightness(led_cdev, LED_OFF);
> +
> + return size;
> +}
> +
> +static ssize_t led_delay_on_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%lu\n", led_cdev->blink_delay_on);
> +}
> +
> +static ssize_t led_delay_on_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> + unsigned long state;
> + int ret;
> +
> + ret = kstrtoul(buf, 0, &state);
> + if (ret)
> + return ret;
> +
> + led_cdev->blink_delay_on = state;
> +
> + return size;
> +}
> +static ssize_t led_delay_off_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%lu\n", led_cdev->blink_delay_off);
> +}
> +
> +static ssize_t led_delay_off_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct led_classdev *led_cdev = dev_get_drvdata(dev);
> + unsigned long state;
> + int ret;
> +
> + ret = kstrtoul(buf, 0, &state);
> + if (ret)
> + return ret;
> +
> + led_cdev->blink_delay_off = state;
> +
> + return size;
> +}
> +
> +static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
> +static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
> +static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
> +static DEVICE_ATTR(shot, 0200, NULL, led_shot);
> +
> +static void oneshot_trig_activate(struct led_classdev *led_cdev)
> +{
> + struct oneshot_trig_data *oneshot_data;
> + int rc;
> +
> + oneshot_data = kzalloc(sizeof(*oneshot_data), GFP_KERNEL);
> + if (!oneshot_data)
> + return;
> +
> + led_cdev->trigger_data = oneshot_data;
> +
> + rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
> + if (rc)
> + goto err_out_trig_data;
> + rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
> + if (rc)
> + goto err_out_delayon;
> + rc = device_create_file(led_cdev->dev, &dev_attr_invert);
> + if (rc)
> + goto err_out_delayoff;
> + rc = device_create_file(led_cdev->dev, &dev_attr_shot);
> + if (rc)
> + goto err_out_invert;
> +
> + led_cdev->blink_delay_on = DEFAULT_DELAY;
> + led_cdev->blink_delay_off = DEFAULT_DELAY;
> +
> + led_cdev->activated = true;
> +
> + return;
> +
> +err_out_invert:
> + device_remove_file(led_cdev->dev, &dev_attr_invert);
> +err_out_delayoff:
> + device_remove_file(led_cdev->dev, &dev_attr_delay_off);
> +err_out_delayon:
> + device_remove_file(led_cdev->dev, &dev_attr_delay_on);
> +err_out_trig_data:
> + kfree(led_cdev->trigger_data);
> +}
> +
> +static void oneshot_trig_deactivate(struct led_classdev *led_cdev)
> +{
> + struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
> +
> + if (led_cdev->activated) {
> + device_remove_file(led_cdev->dev, &dev_attr_delay_on);
> + device_remove_file(led_cdev->dev, &dev_attr_delay_off);
> + device_remove_file(led_cdev->dev, &dev_attr_invert);
> + device_remove_file(led_cdev->dev, &dev_attr_shot);
> + kfree(oneshot_data);
> + led_cdev->activated = false;
> + }
> +
> + /* Stop blinking */
> + led_brightness_set(led_cdev, LED_OFF);
> +}
> +
> +static struct led_trigger oneshot_led_trigger = {
> + .name = "oneshot",
> + .activate = oneshot_trig_activate,
> + .deactivate = oneshot_trig_deactivate,
> +};
> +
> +static int __init oneshot_trig_init(void)
> +{
> + return led_trigger_register(&oneshot_led_trigger);
> +}
> +
> +static void __exit oneshot_trig_exit(void)
> +{
> + led_trigger_unregister(&oneshot_led_trigger);
> +}
> +
> +module_init(oneshot_trig_init);
> +module_exit(oneshot_trig_exit);
> +
> +MODULE_AUTHOR("Fabio Baltieri <fabio.baltieri@xxxxxxxxx>");
> +MODULE_DESCRIPTION("One-shot LED trigger");
> +MODULE_LICENSE("GPL");
> --
> 1.7.11.rc1.9.gf623ca1.dirty
>
--
Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
Kernel Developer +86.186-168-78255 Mobile
Canonical Ltd. www.canonical.com
Ubuntu - Linux for human beings | www.ubuntu.com
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