Hi Sakari,
On Tue, Sep 08, 2020 at 11:51:21AM +0300, Sakari Ailus wrote:
> Document that it is possible to provide defaults for multiple bus types to
> v4l2_fwnode_endpoint_parse and v4l2_fwnode_endpoint_alloc_parse. Also
> underline the fact that detecting the bus type without bus-type property
> is only for the old drivers.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> include/media/v4l2-fwnode.h | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index d04f39b60096..ccaa5693df14 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -226,11 +226,10 @@ struct v4l2_fwnode_connector {
> * call this function once the correct type is found --- with a default
> * configuration valid for that type.
> *
> - * As a compatibility means guessing the bus type is also supported by setting
> - * @vep.bus_type to V4L2_MBUS_UNKNOWN. The caller may not provide a default
> - * configuration in this case as the defaults are specific to a given bus type.
> - * This functionality is deprecated and should not be used in new drivers and it
> - * is only supported for CSI-2 D-PHY, parallel and Bt.656 buses.
> + * It is also allowed to set @vep.bus_type to V4L2_MBUS_UNKNOWN. USING THIS
> + * FEATURE REQUIRES "bus-type" PROPERTY IN DT BINDINGS. For old drivers,
> + * guessing @vep.bus_type between CSI-2 D-PHY, parallel and Bt.656 busses is
> + * supported. NEVER RELY ON GUESSING @vep.bus_type IN NEW DRIVERS!
As per the discussion in:
[PATCH v4 1/3] media: i2c: ov772x: Parse endpoint properties
this leaves a bit of gray area on how to address cases where older dts
do not report any "bus-type" property, as in the case of PARALLEL vs
BT.656 Prabhakar has, it gets impossible to detect mis-configurations.
I have suggested him two different behaviours, depending if 'bus-type'
is present in the fwnode or not, but I'm not sure that's the best way
forward. What do you think ?
> *
> * The function does not change the V4L2 fwnode endpoint state if it fails.
> *
> @@ -269,11 +268,10 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
> * call this function once the correct type is found --- with a default
> * configuration valid for that type.
> *
> - * As a compatibility means guessing the bus type is also supported by setting
> - * @vep.bus_type to V4L2_MBUS_UNKNOWN. The caller may not provide a default
> - * configuration in this case as the defaults are specific to a given bus type.
> - * This functionality is deprecated and should not be used in new drivers and it
> - * is only supported for CSI-2 D-PHY, parallel and Bt.656 buses.
> + * It is also allowed to set @vep.bus_type to V4L2_MBUS_UNKNOWN. USING THIS
> + * FEATURE REQUIRES "bus-type" PROPERTY IN DT BINDINGS. For old drivers,
> + * guessing @vep.bus_type between CSI-2 D-PHY, parallel and Bt.656 busses is
> + * supported. NEVER RELY ON GUESSING @vep.bus_type IN NEW DRIVERS!
> *
> * The function does not change the V4L2 fwnode endpoint state if it fails.
> *
> --
> 2.27.0
>
