[PATCH 1/6] drm/display: hdmi: add generic mode_valid helper

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

Add drm_hdmi_connector_mode_valid(), generic helper for HDMI connectors.
It can be either used directly or as a part of the .mode_valid callback.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 drivers/gpu/drm/display/drm_hdmi_helper.c | 25 +++++++++++++++++++++++++
 include/drm/display/drm_hdmi_helper.h     |  4 ++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_hdmi_helper.c b/drivers/gpu/drm/display/drm_hdmi_helper.c
index 74dd4d01dd9b..0ac5cb000ee2 100644
--- a/drivers/gpu/drm/display/drm_hdmi_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_helper.c
@@ -256,3 +256,28 @@ drm_hdmi_compute_mode_clock(const struct drm_display_mode *mode,
 	return DIV_ROUND_CLOSEST_ULL(clock * bpc, 8);
 }
 EXPORT_SYMBOL(drm_hdmi_compute_mode_clock);
+
+/**
+ * drm_hdmi_connector_mode_valid() - Check if mode is valid for HDMI connector
+ * @connector: DRM connector to validate the mode
+ * @mode: Display mode to validate
+ *
+ * Generic .mode_valid implementation for HDMI connectors.
+ */
+enum drm_mode_status
+drm_hdmi_connector_mode_valid(const struct drm_connector *connector,
+			      const struct drm_display_mode *mode)
+{
+	const struct drm_connector_hdmi_funcs *funcs = connector->hdmi.funcs;
+	unsigned long long rate;
+
+	rate = drm_hdmi_compute_mode_clock(mode, 8, HDMI_COLORSPACE_RGB);
+	if (!rate)
+		return MODE_ERROR;
+
+	if (!funcs || !funcs->tmds_char_rate_valid)
+		return MODE_OK;
+
+	return funcs->tmds_char_rate_valid(connector, mode, rate);
+}
+EXPORT_SYMBOL(drm_hdmi_connector_mode_valid);
diff --git a/include/drm/display/drm_hdmi_helper.h b/include/drm/display/drm_hdmi_helper.h
index 57e3b18c15ec..e38b62df59f3 100644
--- a/include/drm/display/drm_hdmi_helper.h
+++ b/include/drm/display/drm_hdmi_helper.h
@@ -28,4 +28,8 @@ unsigned long long
 drm_hdmi_compute_mode_clock(const struct drm_display_mode *mode,
 			    unsigned int bpc, enum hdmi_colorspace fmt);
 
+enum drm_mode_status
+drm_hdmi_connector_mode_valid(const struct drm_connector *connector,
+			      const struct drm_display_mode *mode);
+
 #endif

-- 
2.39.5