From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
These functions return the chroma subsampling factors for the specified
pixel format.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_crtc_helper.c | 67 +++++++++++++++++++++++++++++++++++++
include/drm/drm_crtc_helper.h | 2 +
2 files changed, 69 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 7c5c516..1528068 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -1087,3 +1087,70 @@ int drm_format_plane_cpp(uint32_t format, int plane)
}
}
EXPORT_SYMBOL(drm_format_plane_cpp);
+
+/**
+ * drm_format_horz_chroma_subsampling - get the horizontal chroma subsampling factor
+ * @format: pixel format (V4L2_PIX_FMT_*)
+ *
+ * See linux/videodev2.h for valid values of @format.
+ *
+ * RETURNS:
+ * The horizontal chroma subsampling factor for the
+ * specified pixel format.
+ */
+int drm_format_horz_chroma_subsampling(uint32_t format)
+{
+ /* FIXME add all subsampled formats. */
+
+ switch (format) {
+ case V4L2_PIX_FMT_Y41P:
+ case V4L2_PIX_FMT_YUV411P:
+ case V4L2_PIX_FMT_YUV410:
+ case V4L2_PIX_FMT_YVU410:
+ return 4;
+ case V4L2_PIX_FMT_YUYV:
+ case V4L2_PIX_FMT_YVYU:
+ case V4L2_PIX_FMT_UYVY:
+ case V4L2_PIX_FMT_VYUY:
+ case V4L2_PIX_FMT_YUV422P:
+ case V4L2_PIX_FMT_YUV420:
+ case V4L2_PIX_FMT_YVU420:
+ case V4L2_PIX_FMT_NV12:
+ case V4L2_PIX_FMT_NV21:
+ case V4L2_PIX_FMT_NV16:
+ case V4L2_PIX_FMT_NV61:
+ return 2;
+ default:
+ return 1;
+ }
+}
+EXPORT_SYMBOL(drm_format_horz_chroma_subsampling);
+
+/**
+ * drm_format_vert_chroma_subsampling - get the vertical chroma subsampling factor
+ * @format: pixel format (V4L2_PIX_FMT_*)
+ *
+ * See linux/videodev2.h for valid values of @format.
+ *
+ * RETURNS:
+ * The vertical chroma subsampling factor for the
+ * specified pixel format.
+ */
+int drm_format_vert_chroma_subsampling(uint32_t format)
+{
+ /* FIXME add all subsampled formats. */
+
+ switch (format) {
+ case V4L2_PIX_FMT_YUV410:
+ case V4L2_PIX_FMT_YVU410:
+ return 4;
+ case V4L2_PIX_FMT_YUV420:
+ case V4L2_PIX_FMT_YVU420:
+ case V4L2_PIX_FMT_NV12:
+ case V4L2_PIX_FMT_NV21:
+ return 2;
+ default:
+ return 1;
+ }
+}
+EXPORT_SYMBOL(drm_format_vert_chroma_subsampling);
diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h
index 9996643..25d46b8 100644
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -149,5 +149,7 @@ 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);
+extern int drm_format_horz_chroma_subsampling(uint32_t format);
+extern int drm_format_vert_chroma_subsampling(uint32_t format);
#endif
--
1.7.3.4
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