From: thierry.reding@avionic-design.de (Thierry Reding)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V4 9/9] pwm_bl: Add mandatory backlight enable regulator
Date: Wed, 20 Mar 2013 23:19:27 +0100 [thread overview]
Message-ID: <20130320221927.GA6416@avionic-0098.mockup.avionic-design.de> (raw)
In-Reply-To: <5149F92A.3070004@wwwdotorg.org>
On Wed, Mar 20, 2013 at 12:00:10PM -0600, Stephen Warren wrote:
> On 03/19/2013 12:59 PM, Andrew Chew wrote:
> > Many backlights need to be explicitly enabled. Typically, this is done
> > with a GPIO. For flexibility, we generalize the enable mechanism to a
> > regulator.
> >
> > If an enable regulator is not needed, then a dummy regulator can be given
> > to the backlight driver. If a GPIO is used to enable the backlight,
> > then a fixed regulator can be instantiated to control the GPIO.
> >
> > The backlight enable regulator can be specified in the device tree node
> > for the backlight, or can be done with legacy board setup code in the
> > usual way.
>
> > diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> > index 1e4fc72..7e2e089 100644
> > --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> > +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> > @@ -10,6 +10,11 @@ Required properties:
> > last value in the array represents a 100% duty cycle (brightest).
> > - default-brightness-level: the default brightness level (index into the
> > array defined by the "brightness-levels" property)
> > + - enable-supply: A phandle to the regulator device tree node. This
> > + regulator will be turned on and off as the pwm is enabled and disabled.
> > + Many backlights are enabled via a GPIO. In this case, we instantiate
> > + a fixed regulator and give that to enable-supply. If a regulator
> > + is not needed, then provide a dummy fixed regulator.
>
> "enable" doesn't seem like the right name here; if this really is an
> "enable" input, then it's not a regulator. If you're calling it "enable"
> because the regulator is usually controlled by a GPIO that enables it,
> then what you really have is a regulator that provides power to the
> backlight, and the method that you enable that regulator is irrelevant.
>
> Put another way, wouldn't "power" be a better name, thus making the
> property "power-supply"? Although that property name migth be considered
> to have some negative correlation with other concepts, so if people
> object to that, perhaps e.g. "vdd-supply"?
"power" sounds like a reasonable name to me.
Thierry
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next prev parent reply other threads:[~2013-03-20 22:19 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 18:59 [PATCH V4 0/9] Add mandatory regulator for all users of pwm-backlight Andrew Chew
2013-03-19 18:59 ` [PATCH V4 1/9] ARM: OMAP: board-4430sdp: Provide regulator to pwm-backlight Andrew Chew
2013-03-19 18:59 ` [PATCH V4 2/9] ARM: S3C24XX: " Andrew Chew
2013-03-19 18:59 ` [PATCH V4 3/9] ARM: pxa: " Andrew Chew
2013-03-19 18:59 ` [PATCH V4 4/9] ARM: EXYNOS: " Andrew Chew
2013-03-19 18:59 ` [PATCH V4 5/9] unicore32: " Andrew Chew
2013-03-19 18:59 ` [PATCH V4 6/9] ARM: mxs: " Andrew Chew
2013-03-19 21:27 ` Marek Vasut
2013-03-19 21:31 ` Andrew Chew
2013-03-19 21:35 ` Marek Vasut
2013-03-19 22:10 ` Stephen Warren
2013-03-20 8:23 ` Mark Brown
2013-03-20 14:03 ` Marek Vasut
2013-03-20 3:13 ` Shawn Guo
2013-03-19 18:59 ` [PATCH V4 7/9] ARM: vt8500: " Andrew Chew
2013-03-20 18:18 ` [Bulk] " Tony Prisk
2013-03-19 18:59 ` [PATCH V4 8/9] ARM: tegra: " Andrew Chew
2013-03-21 20:01 ` Stephen Warren
2013-03-22 10:29 ` Thierry Reding
2013-03-19 18:59 ` [PATCH V4 9/9] pwm_bl: Add mandatory backlight enable regulator Andrew Chew
2013-03-20 18:00 ` Stephen Warren
2013-03-20 22:19 ` Thierry Reding [this message]
2013-03-20 2:14 ` [PATCH V4 0/9] Add mandatory regulator for all users of pwm-backlight Shawn Guo
2013-03-20 2:24 ` Alex Courbot
2013-03-20 3:08 ` Shawn Guo
2013-03-20 7:13 ` Tony Prisk
2013-03-22 1:57 ` Alex Courbot
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