From: swarren@wwwdotorg.org (Stephen Warren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V4 9/9] pwm_bl: Add mandatory backlight enable regulator
Date: Wed, 20 Mar 2013 12:00:10 -0600 [thread overview]
Message-ID: <5149F92A.3070004@wwwdotorg.org> (raw)
In-Reply-To: <1363719573-20926-10-git-send-email-achew@nvidia.com>
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"?
next prev parent reply other threads:[~2013-03-20 18:00 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 [this message]
2013-03-20 22:19 ` Thierry Reding
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5149F92A.3070004@wwwdotorg.org \
--to=swarren@wwwdotorg.org \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).