drm: Add a helper to forge HDMI vendor infoframes

This can then be used by DRM drivers to setup their vendor infoframes.

v2: Fix hmdi typo (Simon Farnsworth)
v3: Adapt to the hdmi_vendor_infoframe rename

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3aa653f..ed3505f 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3263,3 +3263,39 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 	return 0;
 }
 EXPORT_SYMBOL(drm_hdmi_avi_infoframe_from_display_mode);
+
+/**
+ * drm_hdmi_vendor_infoframe_from_display_mode() - fill an HDMI infoframe with
+ * data from a DRM display mode
+ * @frame: HDMI vendor infoframe
+ * @mode: DRM display mode
+ *
+ * Note that there's is a need to send HDMI vendor infoframes only when using a
+ * 4k or stereoscopic 3D mode. So when giving any other mode as input this
+ * function will return -EINVAL, error that can be safely ignored.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int
+drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,
+					    const struct drm_display_mode *mode)
+{
+	int err;
+	u8 vic;
+
+	if (!frame || !mode)
+		return -EINVAL;
+
+	vic = drm_match_hdmi_mode(mode);
+	if (!vic)
+		return -EINVAL;
+
+	err = hdmi_vendor_infoframe_init(frame);
+	if (err < 0)
+		return err;
+
+	frame->vic = vic;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_hdmi_vendor_infoframe_from_display_mode);