From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Mark Brown <broonie@kernel.org>
Cc: Todor Tomov <todor.tomov@linaro.org>,
robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com,
ijc+devicetree@hellion.org.uk, galak@codeaurora.org,
mchehab@osg.samsung.com, hverkuil@xs4all.nl,
geert@linux-m68k.org, matrandg@cisco.com, sakari.ailus@iki.fi,
linux-media@vger.kernel.org
Subject: Re: [PATCH v6 2/2] media: Add a driver for the ov5645 camera sensor.
Date: Mon, 14 Nov 2016 14:18:49 +0200 [thread overview]
Message-ID: <7012441.uVkdQjEznh@avalon> (raw)
In-Reply-To: <20161026115149.GD17252@sirena.org.uk>
Hi Mark,
On Wednesday 26 Oct 2016 12:51:49 Mark Brown wrote:
> On Wed, Oct 26, 2016 at 02:27:23PM +0300, Todor Tomov wrote:
> > And using Mark Brown's correct address...
>
> This is an *enormous* e-mail quoted to multiple levels with top posting
> and very little editing which makes it incredibly hard to find any
> relevant content.
>
> > >> I believe it should be an API guarantee, otherwise many drivers using
> > >> the bulk API would break. Mark, could you please comment on that ?
> > >
> > > Ok, let's wait for a response from Mark.
>
> Why would this be guaranteed by the API given that it's not documented
> and why would many drivers break? It's fairly rare for devices other
> than SoCs to have strict power on sequencing requirements as it is hard
> to achieve in practical systems.
I'm surprised, I've always considered the bulk regulator API as guaranteeing
sequencing, and have written quite a few drivers with that assumption. If
that's not correct then I'll have to switch them back to manual regulator
handling.
Is there a reason why the API shouldn't guarantee that regulators are powered
on in the order listed, and powered off in the reverse order ? Looking at the
implementation that's already the case for regulator_bulk_disable(), but
regulator_bulk_enable() uses async scheduling so doesn't guarantee ordering. I
wonder whether a synchronous version of regulator_bulk_enable() would be
useful.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2016-11-14 12:18 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-08 9:13 [PATCH v6 0/2] OV5645 camera sensor driver Todor Tomov
2016-09-08 9:13 ` [PATCH v6 1/2] media: i2c/ov5645: add the device tree binding document Todor Tomov
2016-09-08 12:22 ` Laurent Pinchart
2016-10-14 12:01 ` Todor Tomov
2016-10-19 8:49 ` Laurent Pinchart
2016-10-19 9:14 ` Todor Tomov
2016-10-19 9:21 ` Laurent Pinchart
2016-10-26 18:53 ` Rob Herring
2016-11-01 8:24 ` Todor Tomov
2016-11-03 0:06 ` Laurent Pinchart
2016-09-08 9:13 ` [PATCH v6 2/2] media: Add a driver for the ov5645 camera sensor Todor Tomov
2016-09-08 12:22 ` Laurent Pinchart
2016-10-14 11:57 ` Todor Tomov
2016-10-19 8:44 ` Laurent Pinchart
2016-10-26 11:15 ` Todor Tomov
2016-10-26 11:27 ` Todor Tomov
2016-10-26 11:51 ` Mark Brown
2016-11-14 12:18 ` Laurent Pinchart [this message]
2016-11-14 13:46 ` Mark Brown
2016-10-26 12:48 ` Ian Arkver
2016-10-26 14:07 ` Todor Tomov
2016-10-26 16:48 ` Ian Arkver
2016-10-27 7:50 ` Todor Tomov
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