[lkml]   [2012]   [Mar]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] LEDS-One-Shot-Timer-Trigger-implementation

    > In general I approve of this - thanks for your efforts.
    > However there are some details that need attention.

    > >
    > > This patch implements the one-shot-timer trigger support by enhancing the
    > > current led-class and ledtrig-timer drivers to support the following
    > > use-cases:
    > >
    > > use-case 1:
    > > echo one-shot-timer > /sys/class/leds/SOMELED/trigger
    > I don't like the name "one-shot-timer". This name describes how you expect
    > the functionality to be used, but not what the actual difference between
    > "timer" and "one-shot-timer" is.
    > That difference is simply that one-shot-timer does not start an initial
    > default blink, while "timer" does.
    > So a name like "timer-no-default" would be a more accurate description and so
    > should be preferred.

    Yes, timer-no-default describes the enhancement I am making, better than
    one-shot-timer does. I will generate patch v2 to address your concerns
    and will change the name to timer-no-default and update the relevant
    code and documentation that goes with the patch to reflect the change.
    > > echo 2000 > /sys/class/leds/SOMELED/delay_on
    > This command will call led_blink_set with an on time of '2000' and an off
    > time of '0'. This will cause led_set_software_blink to turn the LED on and
    > set no off timer. This is just as bad as starting a default blink - there is
    > no guarantee that the LED (or vibrator) will ever be turned off.
    > You need to set 'delay_off' to 'forever' first.

    Good point. Will update the documentation.
    > >
    > I think you should also mention here that:
    > - The 'forever' value is stored as 'ULONG_MAX'. Possibly a
    > #define FOREVER ULONG_MAX
    > in the code would be appropriate. This mapping is only used internally,
    > not in the interface.
    > - The led_blink_set function - which takes two pointers to times - has
    > been extended so that a NULL instead of a pointer means "forever".

    Will do.

    > > +
    > I think
    > return sprintf(buf, "forever\n");
    > if the more common usage.
    > Also in led_delay_off_show() below.


    > kstrtoul is currently preferred. It ensures uniform error codes.

    Yes. I noticed the warnings. This change is better made as
    a separate patch. Do you mind if I deferred it and volunteer to fix it
    in a separate patch shortly. :)

    > > +
    > Do you need to led_trigger_unregister(&timer_led_trigger) if the registration
    > of one_shot_timer_led_trigger fails?

    Yes, considered that while I was changing this routine, and thought
    might be better to leave the registered timer alone when the second
    registration fails. I can go either way.

    -- Shuah

     \ /
      Last update: 2012-03-28 18:11    [W:0.024 / U:2.616 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site