drm: Add drm_format_plane_cpp() utility function

This function returns the bytes per pixel value based on the pixel
format and plane index.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Pauli Nieminen <pauli.nieminen@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 1ee08ae..5cc1d2d 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -1067,3 +1067,43 @@ int drm_format_num_planes(uint32_t format)
        }
 }
 EXPORT_SYMBOL(drm_format_num_planes);
+
+/**
+ * drm_format_plane_cpp - determine the bytes per pixel value
+ * @format: pixel format (DRM_FORMAT_*)
+ * @plane: plane index
+ *
+ * RETURNS:
+ * The bytes per pixel value for the specified plane.
+ */
+int drm_format_plane_cpp(uint32_t format, int plane)
+{
+       unsigned int depth;
+       int bpp;
+
+       if (plane >= drm_format_num_planes(format))
+               return 0;
+
+       switch (format) {
+       case DRM_FORMAT_YUYV:
+       case DRM_FORMAT_YVYU:
+       case DRM_FORMAT_UYVY:
+       case DRM_FORMAT_VYUY:
+               return 2;
+       case DRM_FORMAT_NV12:
+       case DRM_FORMAT_NV21:
+       case DRM_FORMAT_NV16:
+       case DRM_FORMAT_NV61:
+               return plane ? 2 : 1;
+       case DRM_FORMAT_YUV410:
+       case DRM_FORMAT_YUV411:
+       case DRM_FORMAT_YUV420:
+       case DRM_FORMAT_YUV422:
+       case DRM_FORMAT_YUV444:
+               return 1;
+       default:
+               drm_helper_get_fb_bpp_depth(format, &depth, &bpp);
+               return bpp >> 3;
+       }
+}
+EXPORT_SYMBOL(drm_format_plane_cpp);

diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h
index 20a43f7..9996643 100644 (file)
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -148,5 +148,6 @@ extern void drm_kms_helper_poll_disable(struct drm_device *dev);
 extern void drm_kms_helper_poll_enable(struct drm_device *dev);
 
 extern int drm_format_num_planes(uint32_t format);
+extern int drm_format_plane_cpp(uint32_t format, int plane);
 
 #endif