linux-kernel - Re: [PATCH v2 0/3] leds: blink resolution improvements

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Message-ID: <20150430173024.GB21211@amd>
Date:	Thu, 30 Apr 2015 19:30:25 +0200
From:	Pavel Machek <pavel@....cz>
To:	Stas Sergeev <stsp@...t.ru>
Cc:	linux-leds@...r.kernel.org,
	Linux kernel <linux-kernel@...r.kernel.org>,
	Stas Sergeev <stsp@...rs.sourceforge.net>
Subject: Re: [PATCH v2 0/3] leds: blink resolution improvements

Hi!

> >>The following patches improve the precision of led
> >>timer trigger and add the delay unit control.
> >>That allows to make PWM brightness control with timer
> >>trigger.
> >Are you sure that is good idea? Doing LED pwm with main cpu is quite harsh...
> Do you remember the pc-speaker driver? :)

Actually yes, I do, and that one has the same interface as "normal"
sound cards.

> For the timer trigger I would pretty much like my approach to stay.
> The reason is that the PWM I need to do, is not strictly a PWM -
> it needs the ON period in range of tens or hundreds of milliseconds,
> while the OFF period is in a couple of usecs (or vice-versa). No

That is a PWM, right? I see why you'd want to have short "on", but I
don't see why you'd want short "off"...

There's one thing you have to do: having two files, one specifiying
units and second one specifying timeout is not going to work.

What about simply "echo 0.001 > delay_on"?

Thanks,
									Pavel

-- 
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