v4l: rcar-fcp: Add an API to retrieve the FCP device

The new rcar_fcp_get_device() function retrieves the struct device
related to the FCP device. This is useful to handle DMA mapping through
the right device.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Acked-by: Mauro Cavalho Chehab <mchehab@s-opensource.com>
diff --git a/include/media/rcar-fcp.h b/include/media/rcar-fcp.h
index 8723f05..b60a7b1 100644
--- a/include/media/rcar-fcp.h
+++ b/include/media/rcar-fcp.h
@@ -19,6 +19,7 @@
 #if IS_ENABLED(CONFIG_VIDEO_RENESAS_FCP)
 struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np);
 void rcar_fcp_put(struct rcar_fcp_device *fcp);
+struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp);
 int rcar_fcp_enable(struct rcar_fcp_device *fcp);
 void rcar_fcp_disable(struct rcar_fcp_device *fcp);
 #else
@@ -27,6 +28,10 @@
 	return ERR_PTR(-ENOENT);
 }
 static inline void rcar_fcp_put(struct rcar_fcp_device *fcp) { }
+static inline struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
+{
+	return NULL;
+}
 static inline int rcar_fcp_enable(struct rcar_fcp_device *fcp)
 {
 	return 0;