From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: David Cohen <david.a.cohen@linux.intel.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
linux-media@vger.kernel.org
Subject: Re: [PATCH v2 8/9] soc-camera: Add and use soc_camera_power_[on|off]() helper functions
Date: Tue, 17 Jul 2012 03:24:44 +0200 [thread overview]
Message-ID: <1785362.kzK4PIgmvB@avalon> (raw)
In-Reply-To: <50034F97.9060208@linux.intel.com>
Hi David,
Thanks for the review.
On Monday 16 July 2012 02:17:43 David Cohen wrote:
> On 07/05/2012 11:38 PM, Laurent Pinchart wrote:
> > Instead of forcing all soc-camera drivers to go through the mid-layer to
> > handle power management, create soc_camera_power_[on|off]() functions
> > that can be called from the subdev .s_power() operation to manage
> > regulators and platform-specific power handling. This allows non
> > soc-camera hosts to use soc-camera-aware clients.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> >
> > drivers/media/video/imx074.c | 9 +++
> > drivers/media/video/mt9m001.c | 9 +++
> > drivers/media/video/mt9m111.c | 52 +++++++++++++-----
> > drivers/media/video/mt9t031.c | 11 +++-
> > drivers/media/video/mt9t112.c | 9 +++
> > drivers/media/video/mt9v022.c | 9 +++
> > drivers/media/video/ov2640.c | 9 +++
> > drivers/media/video/ov5642.c | 10 +++-
> > drivers/media/video/ov6650.c | 9 +++
> > drivers/media/video/ov772x.c | 9 +++
> > drivers/media/video/ov9640.c | 10 +++-
> > drivers/media/video/ov9740.c | 15 +++++-
> > drivers/media/video/rj54n1cb0c.c | 9 +++
> > drivers/media/video/soc_camera.c | 83 ++++++++++++--------
> > drivers/media/video/soc_camera_platform.c | 11 ++++-
> > drivers/media/video/tw9910.c | 9 +++
> > include/media/soc_camera.h | 10 ++++
> > 17 files changed, 225 insertions(+), 58 deletions(-)
>
> [snip]
>
> > diff --git a/drivers/media/video/ov9740.c b/drivers/media/video/ov9740.c
> > index 3eb07c2..effd0f1 100644
> > --- a/drivers/media/video/ov9740.c
> > +++ b/drivers/media/video/ov9740.c
> > @@ -786,16 +786,29 @@ static int ov9740_g_chip_ident(struct v4l2_subdev
> > *sd,>
> > static int ov9740_s_power(struct v4l2_subdev *sd, int on)
> > {
> >
> > + struct i2c_client *client = v4l2_get_subdevdata(sd);
> > + struct soc_camera_link *icl = soc_camera_i2c_to_link(client);
> >
> > struct ov9740_priv *priv = to_ov9740(sd);
> >
> > + int ret;
> >
> > - if (!priv->current_enable)
> > + if (on) {
> > + ret = soc_camera_power_on(&client->dev, icl);
> > + if (ret < 0)
> > + return ret;
> > + }
> > +
> > + if (!priv->current_enable) {
> > + if (!on)
> > + soc_camera_power_off(&client->dev, icl);
>
> After your changes, this function has 3 if's (one nested) where all of
> them checks "on" variable due to you need to mix "on" and
> "priv->current_enable" checks. However, code's traceability is not so
> trivial.
> How about if you nest "priv->current_enable" into last "if" and keep
> only that one?
>
> See an incomplete code below:
> > return 0;
> >
> > + }
> >
> > if (on) {
>
> soc_camera_power_on();
> if (!priv->current_enable)
> return;
>
> > ov9740_s_fmt(sd, &priv->current_mf);
> > ov9740_s_stream(sd, priv->current_enable);
> >
> > } else {
> >
> > ov9740_s_stream(sd, 0);
>
> Execute ov9740_s_stream() conditionally:
> if (priv->current_enable) {
> ov9740_s_stream();
> priv->current_enable = true;
> }
>
> > + soc_camera_power_off(&client->dev, icl);
> >
> > priv->current_enable = true;
>
> priv->current_enable is set to false when ov9740_s_stream(0) is called
> then this function sets it back to true afterwards. So, in case you want
> to have no functional change, it seems to me you should call
> soc_camera_power_off() after that variable has its original value set
> back.
> In this case, even if you don't like my suggestion, you still need to
> swap those 2 lines above. :)
What do you think of
diff --git a/drivers/media/video/ov9740.c b/drivers/media/video/ov9740.c
index 3eb07c2..10c0ba9 100644
--- a/drivers/media/video/ov9740.c
+++ b/drivers/media/video/ov9740.c
@@ -786,17 +786,27 @@ static int ov9740_g_chip_ident(struct v4l2_subdev *sd,
static int ov9740_s_power(struct v4l2_subdev *sd, int on)
{
+ struct i2c_client *client = v4l2_get_subdevdata(sd);
+ struct soc_camera_link *icl = soc_camera_i2c_to_link(client);
struct ov9740_priv *priv = to_ov9740(sd);
-
- if (!priv->current_enable)
- return 0;
+ int ret;
if (on) {
- ov9740_s_fmt(sd, &priv->current_mf);
- ov9740_s_stream(sd, priv->current_enable);
+ ret = soc_camera_power_on(&client->dev, icl);
+ if (ret < 0)
+ return ret;
+
+ if (priv->current_enable) {
+ ov9740_s_fmt(sd, &priv->current_mf);
+ ov9740_s_stream(sd, 1);
+ }
} else {
- ov9740_s_stream(sd, 0);
- priv->current_enable = true;
+ if (priv->current_enable) {
+ ov9740_s_stream(sd, 0);
+ priv->current_enable = true;
+ }
+
+ soc_camera_power_off(&client->dev, icl);
}
return 0;
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2012-07-17 1:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-05 20:38 [PATCH v2 0/9] Miscellaneous soc-camera patches Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 1/9] soc-camera: Don't fail at module init time if no device is present Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 2/9] soc-camera: Pass the physical device to the power operation Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 3/9] ov2640: Don't access the device in the g_mbus_fmt operation Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 4/9] ov772x: " Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 5/9] tw9910: " Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 6/9] soc_camera: Don't call .s_power() during probe Laurent Pinchart
2012-07-05 20:38 ` [PATCH v2 7/9] soc-camera: Continue the power off sequence if one of the steps fails Laurent Pinchart
2012-07-15 22:24 ` David Cohen
2012-07-16 23:45 ` Laurent Pinchart
2012-07-17 11:03 ` David Cohen
2012-07-05 20:38 ` [PATCH v2 8/9] soc-camera: Add and use soc_camera_power_[on|off]() helper functions Laurent Pinchart
2012-07-15 23:17 ` David Cohen
2012-07-15 23:25 ` David Cohen
2012-07-17 1:24 ` Laurent Pinchart [this message]
2012-07-17 10:40 ` David Cohen
2012-07-05 20:38 ` [PATCH v2 9/9] soc-camera: Push probe-time power management to drivers Laurent Pinchart
2012-07-10 12:06 ` Guennadi Liakhovetski
2012-07-15 13:31 ` Laurent Pinchart
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