[PATCH v4 06/18] drm: Add drm_format_plane_width() and drm_format_plane_height()

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Add a few helpers to get the dimensions of the chroma plane(s).

v2: Add kernel-doc (Daniel)
v3: Fix kerneldoc "Returns:" style (Daniel)
    Uninline the functions and check for num_planes (Daniel)
v4: Add the required EXPORT_SYMBOL()s

Cc: dri-devel at lists.freedesktop.org
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_crtc.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_crtc.h     |  2 ++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 6e6514ef9968..1685eb33b4f3 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5715,6 +5715,48 @@ int drm_format_vert_chroma_subsampling(uint32_t format)
 EXPORT_SYMBOL(drm_format_vert_chroma_subsampling);
 
 /**
+ * drm_format_plane_width - width of the plane given the first plane
+ * @width: width of the first plane
+ * @format: pixel format
+ * @plane: plane index
+ *
+ * Returns:
+ * The width of @plane, given that the width of the first plane is @width.
+ */
+int drm_format_plane_width(int width, uint32_t format, int plane)
+{
+	if (plane >= drm_format_num_planes(format))
+		return 0;
+
+	if (plane == 0)
+		return width;
+
+	return width / drm_format_horz_chroma_subsampling(format);
+}
+EXPORT_SYMBOL(drm_format_plane_width);
+
+/**
+ * drm_format_plane_height - height of the plane given the first plane
+ * @height: height of the first plane
+ * @format: pixel format
+ * @plane: plane index
+ *
+ * Returns:
+ * The height of @plane, given that the height of the first plane is @height.
+ */
+int drm_format_plane_height(int height, uint32_t format, int plane)
+{
+	if (plane >= drm_format_num_planes(format))
+		return 0;
+
+	if (plane == 0)
+		return height;
+
+	return height / drm_format_vert_chroma_subsampling(format);
+}
+EXPORT_SYMBOL(drm_format_plane_height);
+
+/**
  * drm_rotation_simplify() - Try to simplify the rotation
  * @rotation: Rotation to be simplified
  * @supported_rotations: Supported rotations
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c65a212db77e..3a4b53ecd121 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -2482,6 +2482,8 @@ extern int drm_format_num_planes(uint32_t format);
 extern int drm_format_plane_cpp(uint32_t format, int plane);
 extern int drm_format_horz_chroma_subsampling(uint32_t format);
 extern int drm_format_vert_chroma_subsampling(uint32_t format);
+extern int drm_format_plane_width(int width, uint32_t format, int plane);
+extern int drm_format_plane_height(int height, uint32_t format, int plane);
 extern const char *drm_get_format_name(uint32_t format);
 extern struct drm_property *drm_mode_create_rotation_property(struct drm_device *dev,
 							      unsigned int supported_rotations);
-- 
2.4.10