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Message-ID: <1291231412.3066.11.camel@realization>
Date: Wed, 01 Dec 2010 20:23:32 +0100
From: Alberto Panizzo <maramaopercheseimorto@...il.com>
To: Guennadi Liakhovetski <g.liakhovetski@....de>
Cc: Mauro Carvalho Chehab <mchehab@...radead.org>,
linux-media@...r.kernel.org,
linux-kernel <linux-kernel@...r.kernel.org>,
Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: Re: [PATCH v2] soc_camera: Add the ability to bind regulators to
soc_camedra devices
On mer, 2010-12-01 at 18:26 +0100, Guennadi Liakhovetski wrote:
> On Tue, 30 Nov 2010, Alberto Panizzo wrote:
>
> > In certain machines, camera devices are supplied directly
> > by a number of regulators. This patch add the ability to drive
> > these regulators directly by the soc_camera driver.
> >
> > Signed-off-by: Alberto Panizzo <maramaopercheseimorto@...il.com>
> > ---
> >
> > v2 changes:
> > It is used the more standard regulator_bulk API, thanks to
> > Mark Brown for pointing this.
> >
> > drivers/media/video/soc_camera.c | 73 +++++++++++++++++++++++++++-----------
> > include/media/soc_camera.h | 5 +++
> > 2 files changed, 57 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c
> > index 43848a7..f1c2094 100644
> > --- a/drivers/media/video/soc_camera.c
> > +++ b/drivers/media/video/soc_camera.c
>
> Have to
>
> #include <linux/regulator/consumer.h>
>
> here
>
> > @@ -43,6 +43,41 @@ static LIST_HEAD(hosts);
> > static LIST_HEAD(devices);
> > static DEFINE_MUTEX(list_lock); /* Protects the list of hosts */
> >
> > +static int soc_camera_power_set(struct soc_camera_device *icd,
> > + struct soc_camera_link *icl,
> > + int power_on)
> > +{
> > + int ret = 0;
>
> "= 0" unneeded.
>
> > +
> > + if (power_on) {
> > + ret = regulator_bulk_enable(icl->num_regulators,
> > + icl->regulators);
> > + } else {
> > + ret = regulator_bulk_disable(icl->num_regulators,
> > + icl->regulators);
> > + }
>
> superfluous braces
>
> > + if (ret < 0) {
> > + dev_err(icd->pdev, "Cannot %s regulators",
> > + power_on ? "ENABLE" : "DISABLE");
>
> why capitals?
To distinguish between hardcoded words and produced ones.
Otherwise I prefer to separate the two messages and put them in the
two branches of the if.
What do you think about?
>
> > + goto err;
>
> just return ret
>
> > + }
> > +
> > + if (icl->power) {
> > + ret = icl->power(icd->pdev, power_on);
> > + if (ret < 0) {
> > + dev_err(icd->pdev,
> > + "Platform failed to power %s the camera.\n",
> > + power_on ? "ON" : "OFF");
>
> why capitals?
>
> > + goto err;
>
> just return ret, although, if switching on failed, and the platform us
> also using regulators, don't you want to turn them off? Still I would do
> this here inline without a goto, but that's already a matter of taste, so,
> if you prefer, in this case a goto would be justified.
regulator_bulk is an all or none API, so if an error happen enabling
some regulators, it automatically disable the previous enabled ones.
>
> > + }
> > + }
> > +
> > + return 0;
> > +
> > +err:
> > + return ret;
>
> with the above, this might go.
>
> > +}
> > +
> > const struct soc_camera_format_xlate *soc_camera_xlate_by_fourcc(
> > struct soc_camera_device *icd, unsigned int fourcc)
> > {
> > @@ -375,11 +410,9 @@ static int soc_camera_open(struct file *file)
> > },
> > };
> >
> > - if (icl->power) {
> > - ret = icl->power(icd->pdev, 1);
> > - if (ret < 0)
> > - goto epower;
> > - }
> > + ret = soc_camera_power_set(icd, icl, 1);
> > + if (ret < 0)
> > + goto epower;
> >
> > /* The camera could have been already on, try to reset */
> > if (icl->reset)
> > @@ -425,8 +458,7 @@ esfmt:
> > eresume:
> > ici->ops->remove(icd);
> > eiciadd:
> > - if (icl->power)
> > - icl->power(icd->pdev, 0);
> > + soc_camera_power_set(icd, icl, 0);
> > epower:
> > icd->use_count--;
> > mutex_unlock(&icd->video_lock);
> > @@ -450,8 +482,7 @@ static int soc_camera_close(struct file *file)
> >
> > ici->ops->remove(icd);
> >
> > - if (icl->power)
> > - icl->power(icd->pdev, 0);
> > + soc_camera_power_set(icd, icl, 0);
> > }
> >
> > if (icd->streamer == file)
> > @@ -941,14 +972,14 @@ static int soc_camera_probe(struct device *dev)
> >
> > dev_info(dev, "Probing %s\n", dev_name(dev));
> >
> > - if (icl->power) {
> > - ret = icl->power(icd->pdev, 1);
> > - if (ret < 0) {
> > - dev_err(dev,
> > - "Platform failed to power-on the camera.\n");
> > - goto epower;
> > - }
> > - }
> > + ret = regulator_bulk_get(icd->pdev, icl->num_regulators,
> > + icl->regulators);
> > + if (ret)
>
> "if (ret < 0)" for consistency, please
regulator_bulk_get return 0 on success..
>
> > + goto epower;
> > +
> > + ret = soc_camera_power_set(icd, icl, 1);
> > + if (ret < 0)
> > + goto epower;
>
> You need a new label for this error - you also have to free regulators, if
> this fails.
The same as before regulator_bulk_get is an all or none call that free
regulators itself on error.
Maybe return ret instead of goto epower?
>
> >
> > /* The camera could have been already on, try to reset */
> > if (icl->reset)
> > @@ -1021,8 +1052,7 @@ static int soc_camera_probe(struct device *dev)
> >
> > ici->ops->remove(icd);
> >
> > - if (icl->power)
> > - icl->power(icd->pdev, 0);
> > + soc_camera_power_set(icd, icl, 0);
> >
> > mutex_unlock(&icd->video_lock);
> >
> > @@ -1044,8 +1074,7 @@ eadddev:
> > evdc:
> > ici->ops->remove(icd);
> > eadd:
> > - if (icl->power)
> > - icl->power(icd->pdev, 0);
> > + soc_camera_power_set(icd, icl, 0);
> > epower:
> > return ret;
> > }
> > @@ -1081,6 +1110,8 @@ static int soc_camera_remove(struct device *dev)
> > }
> > soc_camera_free_user_formats(icd);
> >
> > + regulator_bulk_free(icl->num_regulators, icl->regulators);
> > +
> > return 0;
> > }
> >
> > diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
> > index 86e3631..3e6b903 100644
> > --- a/include/media/soc_camera.h
> > +++ b/include/media/soc_camera.h
> > @@ -15,6 +15,7 @@
> > #include <linux/device.h>
> > #include <linux/mutex.h>
> > #include <linux/pm.h>
> > +#include <linux/regulator/consumer.h>
>
> No need to include the header here, just declare
>
> struct regulator_bulk_data;
Ok, this is a coding style tip that I didn't know.
Thanks to you Guennadi!
--
Alberto!
Be Persistent!
- Greg Kroah-Hartman (FOSDEM 2010)
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