Re: [PATCH 4/4] leds: trigger: Add pattern initialization from Device Tree

[Jacek Anaszewski]

On 12/8/18 7:44 PM, Jacek Anaszewski wrote:
> Hi Krzysztof,
>
> Thank you for the patch set.
>
> Applied 1/4 and 2/4.
>
> I'll hold on merging 3/4 until we sort out the issues
> I have with this one. Please refer to my comment below.
>
> On 12/7/18 1:32 PM, Krzysztof Kozlowski wrote:
> > Allow initialization of pattern used in pattern trigger from Device Tree
> > property.
> >
> > This is especially useful for embedded systems where the pattern trigger
> > would be used to indicate the process of boot status in a nice,
> > user-friendly blinking way. This initialization pattern will be used
> > till user-space is brought up and sets its own pattern, indicating the
> > boot status is for example finished.
> >
> > Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > ---
> > Â drivers/leds/trigger/ledtrig-pattern.c | 18 ++++++++++++++++++
> > Â 1 file changed, 18 insertions(+)
> >
> > diff --git a/drivers/leds/trigger/ledtrig-pattern.c 
> > b/drivers/leds/trigger/ledtrig-pattern.c
> > index 1870cf87afe1..96309d3bc43c 100644
> > --- a/drivers/leds/trigger/ledtrig-pattern.c
> > +++ b/drivers/leds/trigger/ledtrig-pattern.c
> > @@ -11,6 +11,7 @@
> > Â #include <linux/leds.h>
> > Â #include <linux/module.h>
> > Â #include <linux/mutex.h>
> > +#include <linux/of.h>
> > Â #include <linux/slab.h>
> > Â #include <linux/timer.h>
> > @@ -331,6 +332,21 @@ static const struct attribute_group 
> > *pattern_trig_groups[] = {
> > ÂÂÂÂÂ NULL,
> > Â };
> > +static void pattern_init(struct led_classdev *led_cdev)
> > +{
> > +ÂÂÂ struct device_node *np = dev_of_node(led_cdev->dev);
> > +ÂÂÂ const char *pattern;
> > +
> > +ÂÂÂ if (!np)
> > +ÂÂÂÂÂÂÂ return;
> > +
> > +ÂÂÂ if (!of_property_read_string(np, "linux,trigger-pattern", 
> > &pattern)) {
> > +ÂÂÂÂÂÂÂ if (strlen(pattern))
> > +ÂÂÂÂÂÂÂÂÂÂÂ pattern_trig_store_patterns(led_cdev, pattern,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ strlen(pattern), false);
> > +ÂÂÂ }
> > +}
> > +
> > Â static int pattern_trig_activate(struct led_classdev *led_cdev)
> > Â {
> > ÂÂÂÂÂ struct pattern_trig_data *data;
> > @@ -354,6 +370,8 @@ static int pattern_trig_activate(struct 
> > led_classdev *led_cdev)
> > ÂÂÂÂÂ timer_setup(&data->timer, pattern_trig_timer_function, 0);
> > ÂÂÂÂÂ led_cdev->activated = true;
> > +ÂÂÂ pattern_init(led_cdev);

With my recent patches it would suffice to replace above line with:

if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
	pattern_init(led_cdev);
	led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
}

> It means that the pattern defined in DT would be applied
> whenever the pattern trigger is set for a LED class device,
> whereas it should happen only on LED class device initialization,
> if linux,default-trigger is set to "pattern".
>
> What we would need for making that work is a generic support for
> parsing trigger specific initialization data in the
> of_led_classdev_register().
>
> > +
> > ÂÂÂÂÂ return 0;
> > Â }

--
Best regards,
Jacek Anaszewski