Message-ID: <20120531210117.GA2400@gmail.com>
Date:	Thu, 31 May 2012 23:01:17 +0200
From:	Fabio Baltieri <fabio.baltieri@...il.com>
To:	Shuah Khan <shuahkhan@...il.com>
Cc:	Bryan Wu <bryan.wu@...onical.com>, linux-leds@...r.kernel.org,
	linux-kernel@...r.kernel.org, Richard Purdie <rpurdie@...ys.net>
Subject: Re: [PATCH 3/3] led: add oneshot trigger

Hello Shuah,

On Sun, May 27, 2012 at 10:09:49AM -0600, Shuah Khan wrote:
> On Sun, 2012-05-27 at 01:19 +0200, Fabio Baltieri wrote:
> > Add oneshot trigger to blink a led with configurable parameters via
> > sysfs.
> > 
> > Signed-off-by: Fabio Baltieri <fabio.baltieri@...il.com>
> > Cc: Bryan Wu <bryan.wu@...onical.com>
> > Cc: Shuah Khan <shuahkhan@...il.com>
> > ---
> > 
> > That's (a cleaned up version of) what I used to test the first patch. Should
> > we also consider this one for integration?  Shuah Khan was working on
> > something similar, I'll add him in CC.
> 
> Fabio,
> 
> Thanks for including me in the review. If you haven't already looked at
> the the LEDS_TRIGGER_TRANSIENT I implemented, please take a look. It is
> in linux-next and is queued up for 3.5-rc1 inclusion. It is also a one
> shot timer, howver it holds the LED in a transient state (could be on or
> off depending on its permanent state) for a specified period of time and
> then goes back to the original state. Your use-case is different in that
> the trigger you are implementing it holds it in blink state. These two
> are distinct use-cases that address different needs and we will need
> both.
> 
> However, the in the interest of reducing confusion, I would recommend
> changing the name of the trigger you are adding to something that
> reflects that it holds the blink state. You could call it
> LED_TRIGGER_PULSEONCE or LED_TRIGGER_BLINKONCE.
> 
> Also could you please outline the use-cases. Might be a good idea to add
> a documentation file for this new trigger.
> 
> Did you look at LEDS_TRIGGER_TIMER to see if the name-space you are
> using conflicts with that triggers name-space. I think it does unless I
> am missing something.
> 
> Also you probably need to base your patch on linux-next so you can pick
> up one other infrastructure change I made to add a new activated flag to
> led_classdev structure. This new flag is used to keep track of trigger
> activated state and free memory and do cleanup.

Ok, anyway as your patch has been mainlined and this (totally?) overlaps
with it I think it's ok to just use this to test the API of first patch
of this set.

Fabio

> More comments in-line.
> 
> 
> > 
> > Fabio
> > 
> >  drivers/leds/Kconfig           |   9 ++
> >  drivers/leds/Makefile          |   1 +
> >  drivers/leds/ledtrig-oneshot.c | 190 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 200 insertions(+)
> >  create mode 100644 drivers/leds/ledtrig-oneshot.c
> > 
> > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> > index ff4b8cf..17c3cf2 100644
> > --- a/drivers/leds/Kconfig
> > +++ b/drivers/leds/Kconfig
> > @@ -422,6 +422,15 @@ config LEDS_TRIGGER_TIMER
> >  
> >  	  If unsure, say Y.
> >  
> > +config LEDS_TRIGGER_ONESHOT
> > +	tristate "One-Shot Trigger"
> > +	depends on LEDS_TRIGGERS
> > +	help
> > +	  This allows LEDs to blink in one-shot pulses with parameters
> > +	  controlled via sysfs.
> > +
> > +	  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 890481c..ec8ff79 100644
> > --- a/drivers/leds/Makefile
> > +++ b/drivers/leds/Makefile
> > @@ -51,6 +51,7 @@ 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..7d9a052
> > --- /dev/null
> > +++ b/drivers/leds/ledtrig-oneshot.c
> > @@ -0,0 +1,190 @@
> > +/*
> > + * One-Shot LED Trigger
> > + *
> > + * Copyright 2012, Fabio Baltieri <fabio.baltieri@...il.com>
> > + *
> > + * Based on ledtrig-timer.c by Richard Purdie <rpurdie@...nedhand.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/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>
> > +
> > +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 = -EINVAL;
> This initialization is not necessary.
> > +
> > +	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 = -EINVAL;
> This initialization is not necessary.
> > +
> > +	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 = -EINVAL;
> 
> This initialization is not necessary.
> > +
> > +	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);
> 
> Doesn't this conflict with LEDS_TRIGGER_TIMER namespace
> 
> > +static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
> 
> Doesn't this conflict with LEDS_TRIGGER_TIMER namespace
> > +static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
> 
> This probably conflict with 
> > +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;
> > +
> 
> This is where you can set activated flag to true and check the flag from
> your deactivate routine. Please check linux-next leds code. I also
> updated all led triggers to use this new flag.
> 
> 
> > +	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 (oneshot_data) {
> 
> You can check activated flag instead of onshot_data like the rest of the
> led triggers.
> 
> > +		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(led_cdev->trigger_data);
> > +	}
> > +
> > +	/* 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@...il.com>");
> > +MODULE_DESCRIPTION("One-Shot LED trigger");
> > +MODULE_LICENSE("GPL");
> 
> 
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