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From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Thomas Abraham <thomas.abraham@linaro.org>
Cc: Kyungmin Park <kmpark@infradead.org>,
	rpurdie@rpsys.net, ben-linux@fluff.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	kgene.kim@samsung.com, patches@linaro.org,
	Linus Walleij <linus.walleij@linaro.org>,
	Rajendra Nayak <rnayak@ti.com>
Subject: Re: [PATCH] backlight: add regulator support for platform_lcd driver
Date: Mon, 5 Dec 2011 10:52:02 +0000	[thread overview]
Message-ID: <20111205105201.GD11150@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <CAJuYYwTT2jbbquZM=ZwK=Gh39ss=iG0WDCc3TYjzHLEgfeC1gA@mail.gmail.com>

On Mon, Dec 05, 2011 at 04:06:17PM +0530, Thomas Abraham wrote:
> On 5 December 2011 15:40, Kyungmin Park <kmpark@infradead.org> wrote:

> > Recent regulator discussion. it should be failed instead fall through
> > gracefully.

> Ok. But in this case, there could be boards that do not use a
> regulator for the lcd/display interface. Is it mandatory for fail if
> regulator is not found. Sorry, I have not read through the regulator
> discussion.

The boards should supply a fixed voltage regulator representing the
supply (or use CONFIG_REGULATOR_DUMMY to substitute in a dummy regulator
when not needed).  Sascha Hauer had some patches to add a flag that
could be set to enable this mode on init rather than through Kconfig but
they needed a bit of cleanup, not sure what the status is there.

> The constraint 'apply_uV' cannot be expressed with a device tree. So
> there has be a mechanism to set the required output voltage for a
> regulator.

It's not an option to not have it with device tree - if there's a single
voltage specified apply_uV is assumed.

WARNING: multiple messages have this Message-ID (diff)
From: broonie@opensource.wolfsonmicro.com (Mark Brown)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] backlight: add regulator support for platform_lcd driver
Date: Mon, 5 Dec 2011 10:52:02 +0000	[thread overview]
Message-ID: <20111205105201.GD11150@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <CAJuYYwTT2jbbquZM=ZwK=Gh39ss=iG0WDCc3TYjzHLEgfeC1gA@mail.gmail.com>

On Mon, Dec 05, 2011 at 04:06:17PM +0530, Thomas Abraham wrote:
> On 5 December 2011 15:40, Kyungmin Park <kmpark@infradead.org> wrote:

> > Recent regulator discussion. it should be failed instead fall through
> > gracefully.

> Ok. But in this case, there could be boards that do not use a
> regulator for the lcd/display interface. Is it mandatory for fail if
> regulator is not found. Sorry, I have not read through the regulator
> discussion.

The boards should supply a fixed voltage regulator representing the
supply (or use CONFIG_REGULATOR_DUMMY to substitute in a dummy regulator
when not needed).  Sascha Hauer had some patches to add a flag that
could be set to enable this mode on init rather than through Kconfig but
they needed a bit of cleanup, not sure what the status is there.

> The constraint 'apply_uV' cannot be expressed with a device tree. So
> there has be a mechanism to set the required output voltage for a
> regulator.

It's not an option to not have it with device tree - if there's a single
voltage specified apply_uV is assumed.

  reply	other threads:[~2011-12-05 10:52 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-05  8:48 [PATCH] backlight: add regulator support for platform_lcd driver Thomas Abraham
2011-12-05  8:48 ` Thomas Abraham
2011-12-05  8:52 ` Felipe Balbi
2011-12-05  8:52   ` Felipe Balbi
2011-12-05  9:14   ` Thomas Abraham
2011-12-05  9:14     ` Thomas Abraham
2011-12-05 10:10 ` Kyungmin Park
2011-12-05 10:10   ` Kyungmin Park
2011-12-05 10:33   ` Mark Brown
2011-12-05 10:33     ` Mark Brown
2011-12-05 10:36   ` Thomas Abraham
2011-12-05 10:36     ` Thomas Abraham
2011-12-05 10:52     ` Mark Brown [this message]
2011-12-05 10:52       ` Mark Brown

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