Re: [PATCH v2 7/9] media: i2c: ov772x: Remove soc_camera dependencies

Laurent Pinchart
2018-01-03T15:49:37Z

Hi Jacopo,

On Wednesday, 3 January 2018 17:44:58 EET jacopo mondi wrote:
> On Tue, Jan 02, 2018 at 05:44:03PM +0200, Laurent Pinchart wrote:
> > On Thursday, 28 December 2017 16:01:19 EET Jacopo Mondi wrote:
> >> Remove soc_camera framework dependencies from ov772x sensor driver.
> >> - Handle clock and gpios
> >> - Register async subdevice
> >> - Remove soc_camera specific g/s_mbus_config operations
> >> - Change image format colorspace to SRGB
> >
> > Could you explain the rationale for this ?
>
> Hans suggested this, and I assume it is beacause COLORSPACE_JPEG ==
> (COLORSPACE_SRGB + assumptions on quantization ranges) which does not
> apply to the sensor.

Could you capture it in the commit message ? :-)

> >> - Remove sizes crop from get_selection as driver can't scale
> >> - Add kernel doc to driver interface header file
> >> - Adjust build system
> >
> > That's a lot for a single patch. On the other hand I don't think splitting
> > this in 7 patches would be a good idea either. If you can find a better
> > granularity, go for it, otherwise keep it as-is. Same comment for the
> > tw9910 driver.
>
> I know.
> I would have kept changes down to the minimum required to remove
> soc_camera dependencies, but I received comments on other parts of the
> driver not directly soc_camera specific. I understand this, since I'm
> touching the driver it is maybe worth changing some parts of it that
> needs updates..
>
> >> This commit does not remove the original soc_camera based driver as long
> >> as other platforms depends on soc_camera-based CEU driver.
> >>
> >> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> >> ---
> >>
> >> drivers/media/i2c/Kconfig | 11 +++
> >> drivers/media/i2c/Makefile | 1 +
> >> drivers/media/i2c/ov772x.c | 169 +++++++++++++++++++++++++-------------
> >> include/media/i2c/ov772x.h | 8 ++-
> >> 4 files changed, 130 insertions(+), 59 deletions(-)
> >>
> >> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> >> index cb5d7ff..a61d7f4 100644
> >> --- a/drivers/media/i2c/Kconfig
> >> +++ b/drivers/media/i2c/Kconfig
> >
> > [snip]
> >
> >> diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> >> index 8063835..f7b293f 100644
> >> --- a/drivers/media/i2c/ov772x.c
> >> +++ b/drivers/media/i2c/ov772x.c
> >> @@ -1,6 +1,9 @@
> >
> > [snip]
> >
> >> @@ -25,8 +26,8 @@
> >>
> >> #include <linux/videodev2.h>
> >>
> >> #include <media/i2c/ov772x.h>
> > >
> > > -#include <media/soc_camera.h>
> > > -#include <media/v4l2-clk.h>
> > > +
> > > +#include <media/v4l2-device.h>
> > >
> > > #include <media/v4l2-ctrls.h>
> >
> > I think C comes before D.
> >
> > > #include <media/v4l2-subdev.h>
> > > #include <media/v4l2-image-sizes.h>
> >
> > [snip]
> >
> >> @@ -650,13 +653,63 @@ static int ov772x_s_register(struct v4l2_subdev
> >> *sd,
> >> }
> >> #endif
> >>
> >> +static int ov772x_power_on(struct ov772x_priv *priv)
> >> +{
> >> + struct i2c_client *client = v4l2_get_subdevdata(&priv->subdev);
> >> + int ret;
> >> +
> >> + if (priv->info->xclk_rate)
> >> + ret = clk_set_rate(priv->clk, priv->info->xclk_rate);
> >
> > The return value is then ignored.
> >
> > I wonder whether the clk_set_rate() call shouldn't be kept in board code
> > as it's a board-specific frequency. DT platforms would use the
> > assigned-clock-rates property that doesn't require any explicit handling
> > in the driver.
>
> DT based platforms won't have any info->xlkc_rate, so they should be
> fine. I wonder how could I set rate in board code, as I'm just
> registering an alias for the clock there...

Exactly as done by the current code, get the clock and set the rate :) You can
do that at initialization time, when you register the alias. Don't forget to
put the clock too.

> >> + if (priv->clk) {
> >> + ret = clk_prepare_enable(priv->clk);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> +
> >> + if (priv->pwdn_gpio) {
> >> + gpiod_set_value(priv->pwdn_gpio, 1);
> >> + usleep_range(500, 1000);
> >> + }
> >> +
> >> + /* Reset GPIOs are shared in some platforms. */
> >
> > I'd make this a FIXME comment as this is really a hack.
> >
> > /*
> > * FIXME: The reset signal is connected to a shared GPIO on some
> > * platforms (namely the SuperH Migo-R). Until a framework becomes
> > * available to handle this cleanly, request the GPIO temporarily
> > * only to avoid conflicts.
> > */
> >
> > Same for the tw9910 driver.
>
> Ack.

--
Regards,

Laurent Pinchart