[PATCH v5 04/17] drm: add helper to validate ycbcr420 modes

[Shashank Sharma]

YCBCR420 modes are supported only on HDMI 2.0 capable sources.
This patch adds a drm helper to validate YCBCR420-only mode
on a particular connector. This function will help pruning
the YCBCR420-only modes from the connector's modelist.

V5: Introduced the patch in series.

Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
---
 drivers/gpu/drm/drm_edid.c         |  3 ++-
 drivers/gpu/drm/drm_modes.c        | 28 ++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_probe_helper.c |  4 ++++
 include/drm/drm_edid.h             |  1 +
 include/drm/drm_modes.h            |  5 +++++
 5 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index b879662..ad26c5e 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2947,10 +2947,11 @@ u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
 }
 EXPORT_SYMBOL(drm_match_cea_mode);
 
-static bool drm_valid_cea_vic(u8 vic)
+bool drm_valid_cea_vic(u8 vic)
 {
 	return vic > 0 && vic < ARRAY_SIZE(edid_cea_modes);
 }
+EXPORT_SYMBOL(drm_valid_cea_vic);
 
 /**
  * drm_get_cea_aspect_ratio - get the picture aspect ratio corresponding to
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index f2493b9..3b53c8e3 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1083,6 +1083,34 @@ drm_mode_validate_size(const struct drm_display_mode *mode,
 }
 EXPORT_SYMBOL(drm_mode_validate_size);
 
+/**
+ * drm_mode_ycbcr420_only - add 'ycbcr420-only' modes only when allowed
+ * @mode: mode to check
+ * @connector: drm connector under action
+ *
+ * This function is a helper which can be used to filter out any YCBCR420
+ * only mode, when the source doesn't support it.
+ *
+ * Returns:
+ * The mode status
+ */
+enum drm_mode_status
+drm_mode_validate_ycbcr420(const struct drm_display_mode *mode,
+			   struct drm_connector *connector)
+{
+	u8 vic = drm_match_cea_mode(mode);
+	enum drm_mode_status status = MODE_OK;
+	struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+
+	if (drm_valid_cea_vic(vic) && test_bit(vic, hdmi->y420_vdb_modes)) {
+		if (!connector->ycbcr_420_allowed)
+			status = MODE_NO_420;
+	}
+
+	return status;
+}
+EXPORT_SYMBOL(drm_mode_validate_ycbcr420);
+
 #define MODE_STATUS(status) [MODE_ ## status + 3] = #status
 
 static const char * const drm_mode_status_names[] = {
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 00e6832..904966c 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -528,6 +528,10 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_pipeline(mode,
 								  connector);
+
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_ycbcr420(mode,
+								  connector);
 	}
 
 prune:
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 89c0062..b55b2a7 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -477,4 +477,5 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name,
 struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
 					   int hsize, int vsize, int fresh,
 					   bool rb);
+bool drm_valid_cea_vic(u8 vic);
 #endif /* __DRM_EDID_H__ */
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
index 94ac771..f8a1268 100644
--- a/include/drm/drm_modes.h
+++ b/include/drm/drm_modes.h
@@ -80,6 +80,7 @@ struct videomode;
  * @MODE_ONE_SIZE: only one resolution is supported
  * @MODE_NO_REDUCED: monitor doesn't accept reduced blanking
  * @MODE_NO_STEREO: stereo modes not supported
+ * @MODE_NO_420: ycbcr 420 modes not supported
  * @MODE_STALE: mode has become stale
  * @MODE_BAD: unspecified reason
  * @MODE_ERROR: error condition
@@ -124,6 +125,7 @@ enum drm_mode_status {
 	MODE_ONE_SIZE,
 	MODE_NO_REDUCED,
 	MODE_NO_STEREO,
+	MODE_NO_420,
 	MODE_STALE = -3,
 	MODE_BAD = -2,
 	MODE_ERROR = -1
@@ -496,6 +498,9 @@ bool drm_mode_equal_no_clocks_no_stereo(const struct drm_display_mode *mode1,
 enum drm_mode_status drm_mode_validate_basic(const struct drm_display_mode *mode);
 enum drm_mode_status drm_mode_validate_size(const struct drm_display_mode *mode,
 					    int maxX, int maxY);
+enum drm_mode_status
+drm_mode_validate_ycbcr420(const struct drm_display_mode *mode,
+			   struct drm_connector *connector);
 void drm_mode_prune_invalid(struct drm_device *dev,
 			    struct list_head *mode_list, bool verbose);
 void drm_mode_sort(struct list_head *mode_list);
-- 
2.7.4