Re: [PATCH v5 09/11] media: v4l2-ctrls: Add helper to register properties

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Jacopo,

On Fri, Nov 08, 2019 at 04:59:42PM +0100, Jacopo Mondi wrote:
> Add an helper function to v4l2-ctrls to register controls associated
> with a device property.
> 
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  drivers/media/v4l2-core/v4l2-ctrls.c | 40 ++++++++++++++++++++++++++++
>  include/media/v4l2-ctrls.h           | 26 ++++++++++++++++++
>  2 files changed, 66 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 97e97c8069c9..ac1934558969 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -16,6 +16,7 @@
>  #include <media/v4l2-dev.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-event.h>
> +#include <media/v4l2-fwnode.h>
>  #include <media/v4l2-ioctl.h>
>  
>  #define dprintk(vdev, fmt, arg...) do {					\
> @@ -4587,3 +4588,42 @@ __poll_t v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait)
>  	return 0;
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_poll);
> +
> +int v4l2_ctrl_new_fwnode_properties(struct v4l2_ctrl_handler *hdl,
> +				    const struct v4l2_ctrl_ops *ctrl_ops,
> +				    const struct v4l2_fwnode_device_properties *p)
> +{
> +	if (p->location != V4L2_FWNODE_PROPERTY_UNSET) {
> +		u32 location_ctrl;
> +
> +		switch (p->location) {
> +		case V4L2_FWNODE_LOCATION_FRONT:
> +			location_ctrl = V4L2_LOCATION_FRONT;
> +			break;
> +		case V4L2_FWNODE_LOCATION_BACK:
> +			location_ctrl = V4L2_LOCATION_BACK;
> +			break;
> +		case V4L2_FWNODE_LOCATION_EXTERNAL:
> +			location_ctrl = V4L2_LOCATION_EXTERNAL;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		if (!v4l2_ctrl_new_std(hdl, ctrl_ops,
> +				       V4L2_CID_CAMERA_SENSOR_LOCATION,
> +				       location_ctrl, location_ctrl, 1,
> +				       location_ctrl))
> +			return hdl->error;
> +	}
> +
> +	if (p->rotation != V4L2_FWNODE_PROPERTY_UNSET) {
> +		if (!v4l2_ctrl_new_std(hdl, ctrl_ops,
> +				       V4L2_CID_CAMERA_SENSOR_ROTATION,
> +				       p->rotation, p->rotation, 1,
> +				       p->rotation))
> +			return hdl->error;
> +	}
> +
> +	return 0;

I think you should return hdl->error also here: calling this function on a
failed control handler should result in an error.

> +}
> +EXPORT_SYMBOL(v4l2_ctrl_new_fwnode_properties);
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index cf59abafb0d9..409c800ab1f5 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -30,6 +30,7 @@ struct v4l2_ctrl;
>  struct v4l2_ctrl_handler;
>  struct v4l2_ctrl_helper;
>  struct v4l2_fh;
> +struct v4l2_fwnode_device_properties;
>  struct v4l2_subdev;
>  struct v4l2_subscribed_event;
>  struct video_device;
> @@ -1417,4 +1418,29 @@ int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
>   */
>  int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);
>  
> +/**
> + * v4l2_ctrl_new_fwnode_properties() - Register controls for the device
> + *				       properties
> + *
> + * @hdl: pointer to &struct v4l2_ctrl_handler to register controls on
> + * @ctrl_ops: pointer to &struct v4l2_ctrl_ops to register controls with
> + * @p: pointer to &struct v4l2_fwnode_device_properties
> + *
> + * This function registers controls associated to device properties, using the
> + * property values contained in @p parameter, if the property has been set to
> + * a value.
> + *
> + * Currently the following v4l2 controls are parsed and registered:
> + * - V4L2_CID_CAMERA_SENSOR_LOCATION;
> + * - V4L2_CID_CAMERA_SENSOR_ROTATION;
> + *
> + * Controls already registered by the caller with the @hdl control handler are
> + * not overwritten. Callers should register the controls they want to handle
> + * themselves before calling this function.
> + *
> + * Return: 0 on success, a negative error code on failure.
> + */
> +int v4l2_ctrl_new_fwnode_properties(struct v4l2_ctrl_handler *hdl,
> +				    const struct v4l2_ctrl_ops *ctrl_ops,
> +				    const struct v4l2_fwnode_device_properties *p);
>  #endif

-- 
Regards,

Sakari Ailus