Hi Sakari,
On Mon, Nov 18, 2019 at 02:52:40PM +0200, Sakari Ailus wrote:
> Hi Jacopo,
>
> On Fri, Nov 08, 2019 at 04:59:39PM +0100, Jacopo Mondi wrote:
> > Add an helper function to parse common device properties in the same
> > way as v4l2_fwnode_endpoint_parse() parses common endpoint properties.
> >
> > Parse the 'rotation' and 'location' properties from the firmware
> > interface.
> >
> > Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
> > ---
> > drivers/media/v4l2-core/v4l2-fwnode.c | 42 +++++++++++++++++++++++
> > include/media/v4l2-fwnode.h | 48 +++++++++++++++++++++++++++
> > 2 files changed, 90 insertions(+)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > index 192cac076761..8af4174a2bbf 100644
> > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -596,6 +596,48 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> > }
> > EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
> >
> > +int v4l2_fwnode_device_parse(struct device *dev,
> > + struct v4l2_fwnode_device_properties *props)
> > +{
> > + struct fwnode_handle *fwnode = dev_fwnode(dev);
> > + u32 val;
> > + int ret;
> > +
> > + memset(props, 0, sizeof(*props));
> > +
> > + props->location = V4L2_FWNODE_PROPERTY_UNSET;
> > + ret = fwnode_property_read_u32(fwnode, "location", &val);
> > + if (!ret) {
> > + switch (val) {
> > + case V4L2_FWNODE_LOCATION_FRONT:
> > + case V4L2_FWNODE_LOCATION_BACK:
> > + case V4L2_FWNODE_LOCATION_EXTERNAL:
> > + break;
> > + default:
> > + dev_warn(dev, "Unsupported device location: %u\n", val);
> > + return -EINVAL;
> > + }
> > +
> > + props->location = val;
> > + dev_dbg(dev, "device location: %u\n", val);
> > + }
> > +
> > + props->rotation = V4L2_FWNODE_PROPERTY_UNSET;
> > + ret = fwnode_property_read_u32(fwnode, "rotation", &val);
> > + if (!ret) {
> > + if (val >= 360 || val % 90) {
> > + dev_warn(dev, "Unsupported device rotation: %u\n", val);
> > + return -EINVAL;
>
> In both cases, you return an error back to the user if there's a problem
> with the value of an optinoal property.
>
> It could prevent probing the driver if someone screwed up the firmware
> somehow, but also makes the matter more visible. I think it's good to start
> with this way, and hope we don't need to change it.
>
> > + }
> > +
> > + props->rotation = val;
> > + dev_dbg(dev, "device rotation: %u\n", val);
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_fwnode_device_parse);
> > +
> > static int
> > v4l2_async_notifier_fwnode_parse_endpoint(struct device *dev,
> > struct v4l2_async_notifier *notifier,
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index f6a7bcd13197..6d46d6fc3007 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -109,6 +109,36 @@ struct v4l2_fwnode_endpoint {
> > unsigned int nr_of_link_frequencies;
> > };
> >
> > +/**
> > + * v4l2_fwnode_location - identify a non initialized property.
> > + *
> > + * All properties in &struct v4l2_fwnode_device_properties are initialized
> > + * to this value.
> > + */
> > +#define V4L2_FWNODE_PROPERTY_UNSET (-1U)
>
> On the naming --- this is relevant for only one property at the moment, so
> I'd make it specific to that property, too. This also makes it fit for the
> enum below.
It is used also for rotation, not only for location. I need an
"UNSET" value as a 0 degree rotation is valid. To be hones I will keep
it generic, I do expect more properties to need it, as it will have to
be renamed later...
>
> > +
> > +/**
> > + * enum v4l2_fwnode_location - possible device locations
> > + * @V4L2_FWNODE_LOCATION_FRONT: device installed on the front side
> > + * @V4L2_FWNODE_LOCATION_BACK: device installed on the back side
> > + * @V4L2_FWNODE_LOCATION_EXTERNAL: device externally located
> > + */
> > +enum v4l2_fwnode_location {
> > + V4L2_FWNODE_LOCATION_FRONT,
> > + V4L2_FWNODE_LOCATION_BACK,
> > + V4L2_FWNODE_LOCATION_EXTERNAL
> > +};
> > +
> > +/**
> > + * struct v4l2_fwnode_device_properties - fwnode device properties
> > + * @location: device location. See &enum v4l2_fwnode_location
> > + * @rotation: device rotation
> > + */
> > +struct v4l2_fwnode_device_properties {
> > + enum v4l2_fwnode_location location;
> > + unsigned int rotation;
> > +};
> > +
> > /**
> > * struct v4l2_fwnode_link - a link between two endpoints
> > * @local_node: pointer to device_node of this endpoint
> > @@ -233,6 +263,24 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> > */
> > void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> >
> > +/**
> > + * v4l2_fwnode_device_parse() - parse fwnode device properties
> > + * @dev: pointer to &struct device
> > + * @props: pointer to &struct v4l2_fwnode_device_properties where to store the
> > + * parsed properties values
> > + *
> > + * This function parses and validates the V4L2 fwnode device properties from
> > + * the firmware interface. It is responsibility of the caller to allocate a
> > + * valid @struct v4l2_fwnode_device_properties structure and provide a pointer
> > + * to it in the @props parameter.
>
> I think the latter sentence (inserted before the leading comma of the
> previous sentence) could be phrased as:
>
> "and fills the @struct v4l2_fwnode_device_properties provided by the
> caller".
Yeah, thanks, better! I'll take it in!
Thanks
j
>
> > + *
> > + * Return:
> > + * % 0 on success
> > + * %-EINVAL if a parsed property value is not valid
> > + */
> > +int v4l2_fwnode_device_parse(struct device *dev,
> > + struct v4l2_fwnode_device_properties *props);
> > +
> > /**
> > * typedef parse_endpoint_func - Driver's callback function to be called on
> > * each V4L2 fwnode endpoint.
>
> --
> Regards,
>
> Sakari Ailus
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