Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation

From	Sakari Ailus <sakari.ailus@iki.fi>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation
Date	2017-09-18 15:30 +0200
Message-ID	<ur4hA-6QH-19@gated-at.bofh.it> (permalink)
References	<uqY2t-2oA-3@gated-at.bofh.it> <uqY2t-2oA-5@gated-at.bofh.it> <uqYOS-36l-21@gated-at.bofh.it> <ur0xj-4fK-9@gated-at.bofh.it>
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Hi Wenyou,

On Mon, Sep 18, 2017 at 05:26:16PM +0800, Yang, Wenyou wrote:
> Hi Sakari,
> 
> 
> On 2017/9/18 15:35, Sakari Ailus wrote:
> > Hi Wenyou,
> > 
> > Thanks for the update.
> > 
> > The driver exposes controls that are accessible through the sub-device node
> > even if the device hasn't been powered on.
> > 
> > Many ISP and bridge drivers will also power the sensor down once the last
> > user of the user space device nodes disappears. You could keep the device
> > powered at all times or change the behaviour so that controls can be
> > accessed when the power is off.
> > 
> > The best option would be to convert the driver to use runtime PM.
> Yes, I agree with you.
> I also noticed there are a lot of things needed to improve except for it,
> such as the platform data via device tree.
> I would like do it in another patch set. I will continue to work on it.

Adding runtime PM support later on sound good to me.

> > An example of this can be found in drivers/media/i2c/ov13858.c .
> A good example, thank you for your providing.

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi

Thread

[PATCH v4 0/3] media: ov7670: Add entity init and power operation Wenyou Yang <wenyou.yang@microchip.com> - 2017-09-18 08:50 +0200
  [PATCH v4 1/3] media: ov7670: Add entity pads initialization Wenyou Yang <wenyou.yang@microchip.com> - 2017-09-18 08:50 +0200
  [PATCH v4 3/3] media: ov7670: Add the s_power operation Wenyou Yang <wenyou.yang@microchip.com> - 2017-09-18 08:50 +0200
    Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation Sakari Ailus <sakari.ailus@iki.fi> - 2017-09-18 09:40 +0200
      Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation "Yang, Wenyou" <Wenyou.Yang@Microchip.com> - 2017-09-18 11:30 +0200
        Re: [PATCH v4 3/3] media: ov7670: Add the s_power operation Sakari Ailus <sakari.ailus@iki.fi> - 2017-09-18 15:30 +0200
  [PATCH v4 2/3] media: ov7670: Add the get_fmt callback Wenyou Yang <wenyou.yang@microchip.com> - 2017-09-18 08:50 +0200
    Re: [PATCH v4 2/3] media: ov7670: Add the get_fmt callback Sakari Ailus <sakari.ailus@iki.fi> - 2017-09-18 09:40 +0200
      Re: [PATCH v4 2/3] media: ov7670: Add the get_fmt callback "Yang, Wenyou" <Wenyou.Yang@Microchip.com> - 2017-09-18 11:30 +0200

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