Hi Anatolij
On Fri, 28 Sep 2012, Anatolij Gustschin wrote:
> With mpc52xx_csi interface I2C subdev streamon after vb2_streamon()
> doesn't work due to mpc52xx sensor interface glue-logic restrictions.
>
> Since mpc5200 doesn't have a camera sensor interface, the sensor on
> O2D cameras is connected to the LocalPlus bus by special glue-logic.
> While sensor read-out the sensor will be clocked with the bus chip-
> select signal as the sensor clock so that the read-out is synchronous
> with the data accesses on the bus. Therefore, I2C access can't be
> performed when the glue-logic is setup for sensor read-out.
>
> mpc52xx_csi driver for O2D cameras performs I2C subdev streamon in
> its start_streaming() operation and then disables the I2C bus access
> by configuring the interface glue-logic for sensor read-out.
> For above-mentioned reasons we disable this subdev call here.
>
> Signed-off-by: Anatolij Gustschin <agust@xxxxxxx>
> ---
> drivers/media/platform/soc_camera/soc_camera.c | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/media/platform/soc_camera/soc_camera.c b/drivers/media/platform/soc_camera/soc_camera.c
> index f6b1c1f..64e0abb 100644
> --- a/drivers/media/platform/soc_camera/soc_camera.c
> +++ b/drivers/media/platform/soc_camera/soc_camera.c
> @@ -809,7 +809,7 @@ static int soc_camera_streamon(struct file *file, void *priv,
> {
> struct soc_camera_device *icd = file->private_data;
> struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
> - struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> + struct v4l2_subdev __maybe_unused *sd = soc_camera_to_subdev(icd);
> int ret;
>
> WARN_ON(priv != file->private_data);
> @@ -826,8 +826,11 @@ static int soc_camera_streamon(struct file *file, void *priv,
> else
> ret = vb2_streamon(&icd->vb2_vidq, i);
>
> +#if !defined(CONFIG_VIDEO_MPC52xx_CSI) && \
> + !defined(CONFIG_VIDEO_MPC52xx_CSI_MODULE)
No, we're not adding any preprocessor or run-time hardware dependencies to
soc-camera or to any other generic code. I have no idea what those "IFM
O2D" cameras are. If it's their common feature, that they cannot take any
further I2C commands, while streaming, their drivers have to do that
themselves. And not only for stream-on, there are many operations, that
are allowed during streaming.
Thanks
Guennadi
> if (!ret)
> v4l2_subdev_call(sd, video, s_stream, 1);
> +#endif
>
> return ret;
> }
> --
> 1.7.1
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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