From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Tony Lindgren <tony@atomide.com>
Cc: "Benoît Cousson" <bcousson@baylibre.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Russell King" <linux@armlinux.org.uk>,
linux-omap@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org
Subject: Re: [PATCH 2/3] DT: EVM: add LEDs
Date: Wed, 28 Sep 2016 08:49:30 +0200 [thread overview]
Message-ID: <6004B143-F64B-4DA9-A054-3F2AB3FC2346@goldelico.com> (raw)
In-Reply-To: <20160928033703.erwozguik4rie3cn@atomide.com>
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
next prev parent reply other threads:[~2016-09-28 6:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-27 5:26 [PATCH 0/3] ARM: dts: omap5 uevm: add LEDs, USR1 button and EEPROM H. Nikolaus Schaller
2016-09-27 5:26 ` [PATCH 1/3] DT: EVM: add EEPROM H. Nikolaus Schaller
2016-09-27 5:26 ` [PATCH 2/3] DT: EVM: add LEDs H. Nikolaus Schaller
2016-09-27 19:49 ` Tony Lindgren
2016-09-27 20:10 ` H. Nikolaus Schaller
2016-09-28 3:37 ` Tony Lindgren
2016-09-28 6:49 ` H. Nikolaus Schaller [this message]
2016-09-28 15:12 ` Tony Lindgren
2016-09-28 15:28 ` H. Nikolaus Schaller
2016-09-28 16:12 ` Tony Lindgren
2016-09-29 5:14 ` Rob Herring
2016-09-29 5:18 ` H. Nikolaus Schaller
2016-09-29 5:20 ` H. Nikolaus Schaller
2016-09-27 5:26 ` [PATCH 3/3] DT: EVM: add USR1 button H. Nikolaus Schaller
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