On Wed 2018-10-24 21:17:25, Jacek Anaszewski wrote:
> On 10/24/2018 10:31 AM, Pavel Machek wrote:
> > Hi!
> > 
> >>> +
> >>> +         The gradual dimming format of the software pattern values 
> >>> should be:
> >>> +         "brightness_1 duration_1 brightness_2 duration_2 brightness_3
> >>> +         duration_3 ...". For example:
> >>> +
> >>> +         echo 0 1000 255 2000 > pattern
> >>> +
> >>> +         It will make the LED go gradually from zero-intensity to max 
> >>> (255)
> >>> +         intensity in 1000 milliseconds, then back to zero intensity in 
> >>> 2000
> >>> +         milliseconds:
> >>> +
> >>> +         LED brightness
> >>> +             ^
> >>> +         255-|       / \            / \            /
> >>> +             |      /    \         /    \         /
> >>> +             |     /       \      /       \      /
> >>> +             |    /          \   /          \   /
> >>> +           0-|   /             \/             \/
> >>> +             +---0----1----2----3----4----5----6------------> time (s)
> >>> +
> > 
> > Ok, so I got around to testing this.
> > 
> > echo "0 1000 10 2550 0 1000 0 100" > pattern
> > 
> > makes expected pattern [  .-xXx-.  ].
> > 
> > But when I do
> > 
> > echo "0 1000 10 2550 0 1000" > pattern
> > 
> > I only get expected pattern on the first iteration, then I get
> > [    Xx-.   ].
> 
> This is because the tuples are processed in a loop, without
> discerning between start and end of the sequence.
> 
> So this sequence ends up being squashed, because of the
> comparison:
> 
> if (data->curr->brightness == data->next->brightness) {
>       //step change od brightness
>       ...
>       /* Skip the tuple with zero duration */
> 
> Here we actually only assume that this is zero duration since it
> is not checked. Possibly needs fixing.
> 
>       pattern_trig_update_patterns(data);
>       /* Select next tuple */
>       pattern_trig_update_patterns(data);

I came up with this (untested).

diff --git a/drivers/leds/trigger/ledtrig-pattern.c 
b/drivers/leds/trigger/ledtrig-pattern.c
index ce7acd1..174a298 100644
--- a/drivers/leds/trigger/ledtrig-pattern.c
+++ b/drivers/leds/trigger/ledtrig-pattern.c
@@ -87,9 +87,10 @@ static void pattern_trig_timer_function(struct timer_list *t)
                                           data->curr->brightness);
                        mod_timer(&data->timer,
                                  jiffies + 
msecs_to_jiffies(data->curr->delta_t));
-
-                       /* Skip the tuple with zero duration */
-                       pattern_trig_update_patterns(data);
+                       if (!data->next->delta_t) {
+                               /* Skip the tuple with zero duration */
+                               pattern_trig_update_patterns(data);
+                       }
                        /* Select next tuple */
                        pattern_trig_update_patterns(data);
                } else {



> In effect we have:
> 
> 0 -> 10    // dimming
> 10 -> 0    // dimming
> 0 skipped  // step
> 10 -> 0    // dimming
> 0 skipped  // step
> 10 -> 0    // dimming
> ...
> 
> In order to get "rise - fall - rise - fall" sequence you need
> only two tuples:

Well, I wanted "rise - fall - delay - rise - fall - delay"
sequence. Let me test the patch...

Thanks,
                                                                        Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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