drm/crtc: Add property for aspect ratio

Added a property to enable user space to set aspect ratio.
This patch contains declaration of the property and code to create the
property.

v2: Thierry's review comments.
	- Made aspect ratio enum generic instead of HDMI/CEA specfic
	- Removed usage of temporary aspect_ratio variable

v3: Thierry's review comments.
	- Fixed indentation

v4: Thierry's review comments.
	- Return ENOMEM when property creation fails

Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 89bab66558ef..f0a777747907 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -182,6 +182,12 @@ static const struct drm_prop_enum_list drm_scaling_mode_enum_list[] =
 	{ DRM_MODE_SCALE_ASPECT, "Full aspect" },
 };
 
+static const struct drm_prop_enum_list drm_aspect_ratio_enum_list[] = {
+	{ DRM_MODE_PICTURE_ASPECT_NONE, "Automatic" },
+	{ DRM_MODE_PICTURE_ASPECT_4_3, "4:3" },
+	{ DRM_MODE_PICTURE_ASPECT_16_9, "16:9" },
+};
+
 /*
  * Non-global properties, but "required" for certain connectors.
  */
@@ -1391,6 +1397,33 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev)
 EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
 
 /**
+ * drm_mode_create_aspect_ratio_property - create aspect ratio property
+ * @dev: DRM device
+ *
+ * Called by a driver the first time it's needed, must be attached to desired
+ * connectors.
+ *
+ * Returns:
+ * Zero on success, errno on failure.
+ */
+int drm_mode_create_aspect_ratio_property(struct drm_device *dev)
+{
+	if (dev->mode_config.aspect_ratio_property)
+		return 0;
+
+	dev->mode_config.aspect_ratio_property =
+		drm_property_create_enum(dev, 0, "aspect ratio",
+				drm_aspect_ratio_enum_list,
+				ARRAY_SIZE(drm_aspect_ratio_enum_list));
+
+	if (dev->mode_config.aspect_ratio_property == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_aspect_ratio_property);
+
+/**
  * drm_mode_create_dirty_property - create dirty property
  * @dev: DRM device
  *