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From: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
To: Mike Dunn <mikedunn-kFrNdAxtuftBDgjK7y7TUQ@public.gmane.org>
Cc: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	Richard Purdie <rpurdie-Fm38FmjxZ/leoWH0uzbU5w@public.gmane.org>,
	Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Jean-Christophe Plagniol-Villard
	<plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>,
	Tomi Valkeinen <tomi.valkeinen-l0cyMroinI0@public.gmane.org>,
	Grant Likely
	<grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>,
	linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Robert Jarzmik <robert.jarzmik-GANU6spQydw@public.gmane.org>,
	Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
Subject: Re: [PATCH] pwm-backlight: allow for non-increasing brightness levels
Date: Tue, 17 Sep 2013 11:36:22 +0200	[thread overview]
Message-ID: <20130917093622.GB30088@pengutronix.de> (raw)
In-Reply-To: <1379010952-8928-1-git-send-email-mikedunn-kFrNdAxtuftBDgjK7y7TUQ@public.gmane.org>

Hi Mike,

On Thu, Sep 12, 2013 at 11:35:52AM -0700, Mike Dunn wrote:
> Currently the driver assumes that the values specified in the brightness-levels
> device tree property increase as they are parsed from left to right.  But boards
> that invert the signal between the PWM output and the backlight will need to
> specify decreasing brightness-levels.  This patch removes the assumption that
> the last element of the array is the max value, and instead searches the array
> for the max value and uses that as the normalizing value when determining the
> duty cycle.

Note there's also support for inverted PWMs in the PWM framework
provided your hardware supports this.

Sascha

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  parent reply	other threads:[~2013-09-17  9:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-12 18:35 [PATCH] pwm-backlight: allow for non-increasing brightness levels Mike Dunn
     [not found] ` <1379010952-8928-1-git-send-email-mikedunn-kFrNdAxtuftBDgjK7y7TUQ@public.gmane.org>
2013-09-17  9:36   ` Sascha Hauer [this message]
     [not found]     ` <20130917093622.GB30088-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2013-09-17 14:23       ` Mike Dunn
2013-09-19 11:56   ` Thierry Reding
2013-09-19 16:13     ` Mike Dunn

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