linux-kernel - Re: [PATCH 4/7] [media] ir-rx51: add DT support to driver

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Message-ID: <20160510021826.GE1129@earth>
Date:	Tue, 10 May 2016 04:18:27 +0200
From:	Sebastian Reichel <sre@...nel.org>
To:	Rob Herring <robh@...nel.org>
Cc:	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Benoit Cousson <bcousson@...libre.com>,
	Tony Lindgren <tony@...mide.com>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux PWM List <linux-pwm@...r.kernel.org>,
	linux-omap <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	Pali Rohár <pali.rohar@...il.com>
Subject: Re: [PATCH 4/7] [media] ir-rx51: add DT support to driver

Hi,

On Mon, May 09, 2016 at 04:07:35PM -0500, Rob Herring wrote:
> There's already a pwm-led binding that can be used. Though there
> may be missing consumer IR to LED subsystem support in the kernel.
> You could list both compatibles, use the rx51 IR driver now, and
> then move to pwm-led driver in the future.

Well from a purely HW point of view it's a PWM connected led. The
usage is completely different though. Usually PWM is used to control
the LED's brightness via the duty cycle (basic concept: enabling led
only 50% of time reduces brightness to 50%).

In the IR led's case the aim is generating a specific serial pattern
instead. For this task it uses a dmtimer in PWM mode and a second
one to reconfigure the pwm timer.

I don't know about a good name, but rx51 should be replaced with
n900 in the compatible string. So maybe "nokia,n900-infrared-diode".

-- Sebastian

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