drm: Add HDMI infoframe helpers

Add a generic helper to fill in an HDMI AVI infoframe with data
extracted from a DRM display mode.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

3 files changed, 40 insertions, 0 deletions

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index f8dae851130c..1e82882da9de 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -7,6 +7,7 @@
 menuconfig DRM
         tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)"
         depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && MMU
+        select HDMI
         select I2C
         select I2C_ALGOBIT
         select DMA_SHARED_BUFFER
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 6995d2fa46cf..c194f4e680ad 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -29,6 +29,7 @@
  */
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/hdmi.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <drm/drmP.h>
@@ -2856,3 +2857,35 @@ int drm_add_modes_noedid(struct drm_connector *connector,
         return num_modes;
 }
 EXPORT_SYMBOL(drm_add_modes_noedid);
+
+/**
+ * drm_hdmi_avi_infoframe_from_display_mode() - fill an HDMI AVI infoframe with
+ *                                              data from a DRM display mode
+ * @frame: HDMI AVI infoframe
+ * @mode: DRM display mode
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int
+drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
+                                         const struct drm_display_mode *mode)
+{
+        int err;
+
+        if (!frame || !mode)
+                return -EINVAL;
+
+        err = hdmi_avi_infoframe_init(frame);
+        if (err < 0)
+                return err;
+
+        frame->video_code = drm_match_cea_mode(mode);
+        if (!frame->video_code)
+                return 0;
+
+        frame->picture_aspect = HDMI_PICTURE_ASPECT_NONE;
+        frame->active_aspect = HDMI_ACTIVE_ASPECT_PICTURE;
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_hdmi_avi_infoframe_from_display_mode);
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 0cac551c5347..5da1b4ae7d84 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -247,6 +247,8 @@ struct edid {
 struct drm_encoder;
 struct drm_connector;
 struct drm_display_mode;
+struct hdmi_avi_infoframe;
+
 void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid);
 int drm_av_sync_delay(struct drm_connector *connector,
                       struct drm_display_mode *mode);
@@ -254,4 +256,8 @@ struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
                                      struct drm_display_mode *mode);
 int drm_load_edid_firmware(struct drm_connector *connector);
 
+int
+drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
+                                         const struct drm_display_mode *mode);
+
 #endif /* __DRM_EDID_H__ */