From: Tony Makkiel <tony.makkiel@daqri.com>
To: linux-leds@vger.kernel.org
Cc: Tony Makkiel <tony.makkiel@daqri.com>
Subject: Re: Hardware blink and brightness
Date: Thu, 26 May 2016 15:48:47 +0100 [thread overview]
Message-ID: <57470CCF.8050808@daqri.com> (raw)
In-Reply-To: <573EBBCE.2030709@samsung.com>
On 20/05/16 08:25, Jacek Anaszewski wrote:
> Hi Tony,
>
> On 05/19/2016 05:57 PM, Tony Makkiel wrote:
>> Hi,
>> Is there any particular reason to stipulate, (hardware) blink should be turned off, when brightness is set to 0? Following is copied from "Documentation/leds/leds-class.txt"
>>
>> "Setting the brightness to zero with brightness_set() callback function
>> should completely turn off the LED and cancel the previously programmed
>> hardware blinking function, if any."
>>
>> The chip driver could also use other methods for the same, keeping brightness independent of blink.
>>
>> For example, delay_on/off
>> delay_off=0 ==> blink off, led on.
>> delay_on=0 ==> blink off, led off.
>>
>> Or am I overlooking something?
>
> Setting brightness to zero not only disables blinking but also
> any other active trigger. Besides, would it make sense to have
> blinking enabled with brightness set to 0?
I agree brightness set to 0, should turn off led. I was thinking of
case when user turns led back ON with a brightness value. Ideally
led comes back on blinking as was configured previously(making,
brightness and blink independent). At present, once the brightness
is set, blink also needs to be reconfigured.
>
> Anyway, we have to keep this interface as-is so as not to break
> existing users of the LED API.
I see your point now, Thank you. I was under the wrong impression, this
could be achieved without code change.
Initially, I thought of using delay_on/delay_off, to turn
off blink. But with this approach, even if it will save a step
initially (no need to reconfigure blink), will add additional
step (re-enable trigger) to disable blink.
>
prev parent reply other threads:[~2016-05-26 14:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-19 15:57 Hardware blink and brightness Tony Makkiel
2016-05-20 7:25 ` Jacek Anaszewski
2016-05-26 14:48 ` Tony Makkiel [this message]
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