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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Tomasz Figa <tfiga@chromium.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	linux-devicetree <devicetree@vger.kernel.org>,
	"Nicolas Boichat" <drinkcat@chromium.org>,
	srv_heupstream <srv_heupstream@mediatek.com>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Shengnan Wang (王圣男)" <shengnan.wang@mediatek.com>,
	"Louis Kuo" <louis.kuo@mediatek.com>,
	"Bartosz Golaszewski" <bgolaszewski@baylibre.com>,
	"Sj Huang" <sj.huang@mediatek.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>,
	"Dongchun Zhu" <dongchun.zhu@mediatek.com>,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Cao Bing Bu" <bingbu.cao@intel.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <linux-arm-kernel@lists.infradead.org>,
	"Linux Media Mailing List" <linux-media@vger.kernel.org>
Subject: Re: [PATCH V11 2/2] media: i2c: ov02a10: Add OV02A10 image sensor driver
Date: Tue, 30 Jun 2020 17:37:05 +0300
Message-ID: <20200630143705.GW3703480@smile.fi.intel.com> (raw)
In-Reply-To: <CAAFQd5B0GxPpGm750rVKfPJi-gtn7w9KouFhXZc4k5OEtiKqBg@mail.gmail.com>

On Tue, Jun 30, 2020 at 04:21:31PM +0200, Tomasz Figa wrote:
> On Tue, Jun 30, 2020 at 4:19 PM Tomasz Figa <tfiga@chromium.org> wrote:
> > On Tue, Jun 30, 2020 at 11:54 AM Sakari Ailus
> > <sakari.ailus@linux.intel.com> wrote:

...

> > > > +     ov02a10->rst_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> > >
> > >
> > > Shouldn't this be GPIOD_OUT_HIGH? That's the state it'll be after powering
> > > the sensor off the first time. Alternatively make reset signal high in
> > > runtime suspend callback.
> >
> > We might want to keep the signals low when the regulators are powered
> > down, to reduce the leakage.
> 
> Ah, I actually recall that the reset pin was physically active low, so
> we would indeed better keep it at HIGH. Sorry for the noise.

Here HIGH means "asserted", so in the code above it's LOW, means "deasserted",
i.o.w. non-reset state. I dunno what is better, it depends to the firmware /
driver expectations of the device configuration (from the power point of view,
HIGH makes sense here, and not LOW, i.o.w. asserted reset line).

And nice of the logical state that it doesn't depend to the active low / high
(the latter just transparent to the user).

-- 
With Best Regards,
Andy Shevchenko



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Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30  2:49 [PATCH V11 0/2] media: i2c: Add support for 0V02A10 sensor Dongchun Zhu
2020-06-30  2:49 ` [PATCH V11 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings Dongchun Zhu
2020-06-30 16:59   ` Tomasz Figa
2020-06-30  2:49 ` [PATCH V11 2/2] media: i2c: ov02a10: Add OV02A10 image sensor driver Dongchun Zhu
2020-06-30  9:54   ` Sakari Ailus
2020-06-30 14:19     ` Tomasz Figa
2020-06-30 14:21       ` Tomasz Figa
2020-06-30 14:37         ` Andy Shevchenko [this message]
2020-06-30 14:40           ` Tomasz Figa
2020-07-01  7:58             ` Dongchun Zhu
2020-06-30 17:07   ` Tomasz Figa
2020-06-30 18:47     ` Sakari Ailus
2020-07-01  8:47       ` Dongchun Zhu
2020-07-01  9:00         ` Sakari Ailus

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