linux-kernel - Re: [PATCH v1] pwm: add sysfs interface

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Message-Id: <201304091121.20510.poeschel@lemonage.de>
Date:	Tue, 9 Apr 2013 11:21:20 +0200
From:	Lars Poeschel <poeschel@...onage.de>
To:	Thierry Reding <thierry.reding@...onic-design.de>
Cc:	Lars Poeschel <larsi@....tu-dresden.de>, rob@...dley.net,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v1] pwm: add sysfs interface

On Monday 08 April 2013 at 13:34:58, Thierry Reding wrote:
> By the way, would you mind elaborating a bit on the various use-cases
> that you have? I'm interested in what people use the PWM subsystem for
> and you seem to be the only one currently using it from userspace. I'm
> hoping I can get a better understanding of what the PWM subsystem nedes
> to provide if I know what people use it for.

Sure, but there is not much about it: 
The PWM output is connected to an electronic circuit that converts the 
signal to a voltage. The higher the duty cycle is the higher the voltage 
gets. In fact this is a simple DAC converter. This voltage limits the 
electric current a battery recharger uses to charge a battery. We think 
controlling the PWM from userspace is a simple way for our application to 
control the voltage.
If you have further questions feel free to ask.

Lars
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