drm/mediatek: Add return value check when reading DPCD

[ Upstream commit 522908140645865dc3e2fac70fd3b28834dfa7be ]

Check the return value of drm_dp_dpcd_readb() to confirm that
AUX communication is successful. To simplify the code, replace
drm_dp_dpcd_readb() and DP_GET_SINK_COUNT() with drm_dp_read_sink_count().

Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
Signed-off-by: Liankun Yang <liankun.yang@mediatek.com>
Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20241218113448.2992-1-liankun.yang@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 09a496588b50f2daaa43455d0a321e22639c04c4..6bf50a15c9b4e5b2bbfc4e82dfe81f160bd3e68f 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -1952,7 +1952,6 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge)
        struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
        enum drm_connector_status ret = connector_status_disconnected;
        bool enabled = mtk_dp->enabled;
-       u8 sink_count = 0;
 
        if (!mtk_dp->train_info.cable_plugged_in)
                return ret;
@@ -1974,8 +1973,8 @@ static enum drm_connector_status mtk_dp_bdg_detect(struct drm_bridge *bridge)
         * function, we just need to check the HPD connection to check
         * whether we connect to a sink device.
         */
-       drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT, &sink_count);
-       if (DP_GET_SINK_COUNT(sink_count))
+
+       if (drm_dp_read_sink_count(&mtk_dp->aux) > 0)
                ret = connector_status_connected;
 
        if (!enabled) {