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 <jac...@jmondi.org>
---
 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;
+               }
+
+               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)
+
+/**
+ * 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.
+ *
+ * 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.
-- 
2.23.0

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