Messages in this thread | | | Subject | Re: [PATCH 2/3] DT: EVM: add LEDs | From | "H. Nikolaus Schaller" <> | Date | Wed, 28 Sep 2016 08:49:30 +0200 |
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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.
BR, Nikolaus
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