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Re: [PATCH 2/3] DT: EVM: add LEDs

From Tony Lindgren <tony@atomide.com>
Newsgroups linux.kernel
Subject Re: [PATCH 2/3] DT: EVM: add LEDs
Date 2016-09-28 17:20 +0200
Message-ID <smoOl-8oo-9@gated-at.bofh.it> (permalink)
References (1 earlier) <slT7V-5um-11@gated-at.bofh.it> <sm6y6-5bY-23@gated-at.bofh.it> <sm717-5DC-1@gated-at.bofh.it> <smdSV-1wB-3@gated-at.bofh.it> <smgQN-3jj-19@gated-at.bofh.it>
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* H. Nikolaus Schaller <hns@goldelico.com> [160927 23:50]:
> Hi,
> 
> > Am 28.09.2016 um 05:37 schrieb Tony Lindgren <tony@atomide.com>:
> > 
> > * H. Nikolaus Schaller <hns@goldelico.com> [160927 13:11]:
> >>> Am 27.09.2016 um 21:49 schrieb Tony Lindgren <tony@atomide.com>:
> >>> How about this for defaults:
> >>> 
> >>> - heartbeat for led3
> >>> - cpu0 for led4
> >>> - cpu1 for led5
> >> 
> >> Good idea. Will try.
> >> 
> >> What I don't exactly know is if these gpios based on an I2C-expander
> >> can handle cpu activity triggers or if they are locked up if this i2c
> >> processing triggers another cpu activity...
> > 
> > Oh right, if the GPIOs are on the i2c bus
> 
> yes, they are all gpio9 which is the tca6424 on i2c5.
> 
> > it's probably not a good
> > idea :) Or at least will be inaccurate if the bus can sleep.
> 
> I have tested a little by writing to /sys/class/leds/.../trigger.
> 
> If I make one LED trigger by "cpu0" it is always on and if I make
> a second one triggered by "cpu1" the heartbeat becomes irregular.
> 
> So indeed this does not work.

So should we just leave the default trigger unpopulated then?

Regards,

Tony

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Thread

[PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-27 07:30 +0200
  Re: [PATCH 2/3] DT: EVM: add LEDs Tony Lindgren <tony@atomide.com> - 2016-09-27 21:50 +0200
    Re: [PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-27 22:20 +0200
      Re: [PATCH 2/3] DT: EVM: add LEDs Tony Lindgren <tony@atomide.com> - 2016-09-28 05:40 +0200
        Re: [PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-28 08:50 +0200
          Re: [PATCH 2/3] DT: EVM: add LEDs Tony Lindgren <tony@atomide.com> - 2016-09-28 17:20 +0200
            Re: [PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-28 17:30 +0200
              Re: [PATCH 2/3] DT: EVM: add LEDs Tony Lindgren <tony@atomide.com> - 2016-09-28 18:20 +0200
  Re: [PATCH 2/3] DT: EVM: add LEDs Rob Herring <robh+dt@kernel.org> - 2016-09-29 07:20 +0200
    Re: [PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-29 07:20 +0200
    Re: [PATCH 2/3] DT: EVM: add LEDs "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-09-29 07:30 +0200

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