drm/exynos/hdmi: add core reset code

To ensure HDMI-PHY reprogramming will not affect
HDMI the latter should be reset.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 3f1eb07..f3a4ae5 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -1659,6 +1659,10 @@
 
 static void hdmiphy_conf_reset(struct hdmi_context *hdata)
 {
+	hdmi_reg_writemask(hdata, HDMI_CORE_RSTOUT, 0, 1);
+	usleep_range(10000, 12000);
+	hdmi_reg_writemask(hdata, HDMI_CORE_RSTOUT, ~0, 1);
+	usleep_range(10000, 12000);
 	hdmi_reg_writemask(hdata, HDMI_PHY_RSTOUT, ~0, HDMI_PHY_SW_RSTOUT);
 	usleep_range(10000, 12000);
 	hdmi_reg_writemask(hdata, HDMI_PHY_RSTOUT, 0, HDMI_PHY_SW_RSTOUT);