Re: [PATCH v2 1/2] led: add oneshot trigger

[Fabio Baltieri]

On Wed, Jun 06, 2012 at 10:56:44AM +0800, Bryan Wu wrote:
> On Wed, Jun 6, 2012 at 8:51 AM, Shuah Khan <shuahkhan@xxxxxxxxx> wrote:
> > On Tue, 2012-06-05 at 23:38 +0200, Fabio Baltieri wrote:
> >> Add oneshot trigger to blink a led with configurable parameters via
> >> sysfs.
> >
> > Fabio,
> >
> > What are the use-cases for this trigger. Please see comments inline:
> >
> >
> >>
> >> Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
> >> Cc: Shuah Khan <shuahkhan@xxxxxxxxx>
> >> Cc: Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
> >> ---
> >> Hi all,
> >>
> >> that's my v2 of the ledtrig-oneshot trigger, with the correction suggested from
> >> Shuah in the original thread.  These include some unnecessary initialization
> >> and use of the new "activated" flag.
> >>
> >> I've kept the name to "oneshot" as I think it suits the role of the trigger as
> >> example/test for the led_blink_set_oneshot function but I have expanded a bit
> >> the Kconfig description to better identify the trigger's usage.
> >>
> >> About the namespace question, I think that naming the parameters delay_on and
> >> delay_off is ok as they have the same meaning as timer's ones (they also
> >> uses the same internal fields after all...).
> >>
> >> Also, I added a default set of delay_{on,off} to 100ms on activation, so that
> >> the trigger starts with a valid configuration, like ledtrig-timer does.
> >>
> >> Anything else that should be changed?
> >>
> >> Fabio
> >>
> >>  drivers/leds/Kconfig           |  14 +++
> >>  drivers/leds/Makefile          |   1 +
> >>  drivers/leds/ledtrig-oneshot.c | 198 +++++++++++++++++++++++++++++++++++++++++
> >>  3 files changed, 213 insertions(+)
> >>  create mode 100644 drivers/leds/ledtrig-oneshot.c
> >>
> >> 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..1aacdfe
> >> --- /dev/null
> >> +++ b/drivers/leds/ledtrig-oneshot.c
> >> @@ -0,0 +1,198 @@
> >> +/*
> >> + * 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>
> >> +
> >> +#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);
> >
> > Here when shot is set
> >
> > echo n > shot
> >
> > What are the values for blink_delay_on and blink_delay_off. Does user
> > need to set delay_on and delay_off first? If user doesn't set these then
> > what values are used?
> >
> > What about invert? Does user need to do echo 1 > invert and then
> > activate shot?
> >
> >
> 
> Exactly, Fabio, what about adding a document for the use case and
> sysfs interface?

Ok, I'll post a v3 with an additional document for the trigger then.

Fabio

> 
> -Bryan
> 
> >> +
> >> +     /* 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;
> >> +
> >> +     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");
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