[PATCH v2] drm/bridge: it66121: Select HDMI or DVI mode based on sink type

[Javier Martinez Canillas]

Currently, the driver assumes that the connector sink type is always HDMI,
so it configures the bridge in this mode and enables the transmission of
AVI infoframe packets.

But this can cause problems on DVI monitors that can fail to interpret the
video signal and lead to not having display output.

Check the connector display information sink type to decide whether DVI or
HDMI mode should be set and if the AVI infoframes packets should be sent.

Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---

Changes in v2:
- Don't store the sink type in a per-commit bridge state (Maxime).

 drivers/gpu/drm/bridge/ite-it66121.c | 67 +++++++++++++++++-----------
 1 file changed, 41 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index 19a027d75b61..a9c5bab665af 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -182,6 +182,7 @@
 
 #define IT66121_HDMI_MODE_REG			0xC0
 #define IT66121_HDMI_MODE_HDMI			BIT(0)
+#define IT66121_HDMI_MODE_DVI			0
 
 #define IT66121_SYS_STATUS_REG			0x0E
 #define IT66121_SYS_STATUS_ACTIVE_IRQ		BIT(7)
@@ -766,41 +767,55 @@ void it66121_bridge_mode_set(struct drm_bridge *bridge,
 {
 	u8 buf[HDMI_INFOFRAME_SIZE(AVI)];
 	struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
+	struct drm_connector *connector = ctx->connector;
 	int ret;
 
 	mutex_lock(&ctx->lock);
 
-	ret = drm_hdmi_avi_infoframe_from_display_mode(&ctx->hdmi_avi_infoframe, ctx->connector,
-						       adjusted_mode);
-	if (ret) {
-		DRM_ERROR("Failed to setup AVI infoframe: %d\n", ret);
-		goto unlock;
-	}
+	if (!connector || connector->display_info.is_hdmi) {
+		ret = drm_hdmi_avi_infoframe_from_display_mode(&ctx->hdmi_avi_infoframe,
+							       connector,
+							       adjusted_mode);
+		if (ret) {
+			DRM_ERROR("Failed to setup AVI infoframe: %d\n", ret);
+			goto unlock;
+		}
 
-	ret = hdmi_avi_infoframe_pack(&ctx->hdmi_avi_infoframe, buf, sizeof(buf));
-	if (ret < 0) {
-		DRM_ERROR("Failed to pack infoframe: %d\n", ret);
-		goto unlock;
-	}
+		ret = hdmi_avi_infoframe_pack(&ctx->hdmi_avi_infoframe, buf, sizeof(buf));
+		if (ret < 0) {
+			DRM_ERROR("Failed to pack infoframe: %d\n", ret);
+			goto unlock;
+		}
 
-	/* Write new AVI infoframe packet */
-	ret = regmap_bulk_write(ctx->regmap, IT66121_AVIINFO_DB1_REG,
-				&buf[HDMI_INFOFRAME_HEADER_SIZE],
-				HDMI_AVI_INFOFRAME_SIZE);
-	if (ret)
-		goto unlock;
+		/* Write new AVI infoframe packet */
+		ret = regmap_bulk_write(ctx->regmap, IT66121_AVIINFO_DB1_REG,
+					&buf[HDMI_INFOFRAME_HEADER_SIZE],
+					HDMI_AVI_INFOFRAME_SIZE);
+		if (ret)
+			goto unlock;
 
-	if (regmap_write(ctx->regmap, IT66121_AVIINFO_CSUM_REG, buf[3]))
-		goto unlock;
+		if (regmap_write(ctx->regmap, IT66121_AVIINFO_CSUM_REG, buf[3]))
+			goto unlock;
 
-	/* Enable AVI infoframe */
-	if (regmap_write(ctx->regmap, IT66121_AVI_INFO_PKT_REG,
-			 IT66121_AVI_INFO_PKT_ON | IT66121_AVI_INFO_PKT_RPT))
-		goto unlock;
+		/* Enable AVI infoframe */
+		if (regmap_write(ctx->regmap, IT66121_AVI_INFO_PKT_REG,
+				 IT66121_AVI_INFO_PKT_ON | IT66121_AVI_INFO_PKT_RPT))
+			goto unlock;
 
-	/* Set TX mode to HDMI */
-	if (regmap_write(ctx->regmap, IT66121_HDMI_MODE_REG, IT66121_HDMI_MODE_HDMI))
-		goto unlock;
+		/* Set TX mode to HDMI */
+		if (regmap_write(ctx->regmap, IT66121_HDMI_MODE_REG,
+				 IT66121_HDMI_MODE_HDMI))
+			goto unlock;
+	} else {
+		/* Disable AVI infoframe */
+		if (regmap_write(ctx->regmap, IT66121_AVI_INFO_PKT_REG, 0))
+			goto unlock;
+
+		/* Set TX mode to DVI */
+		if (regmap_write(ctx->regmap, IT66121_HDMI_MODE_REG,
+				 IT66121_HDMI_MODE_DVI))
+			goto unlock;
+	}
 
 	if ((ctx->id == ID_IT66121 || ctx->id == ID_IT66122) &&
 	    regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
-- 
2.54.0

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat