From d706ee35bb2bbc9513ed2a2c999b5909f272c6b8 Mon Sep 17 00:00:00 2001
From: Algea Cao <algea.cao@rock-chips.com>
Date: Fri, 6 Aug 2021 09:58:38 +0800
Subject: [PATCH] drm/bridge: synopsys: dw-hdmi: Record hdmi clk previous
 status

Compare the status before and after to determine
whether to enable hdmi phy.

Signed-off-by: Algea Cao <algea.cao@rock-chips.com>
Change-Id: Ided938ab83d786d0003afad25a9a191d105d199e
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index fc39edc48877..2268db900232 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -164,9 +164,11 @@ static const u16 csc_coeff_rgb_full_to_rgb_limited[3][4] = {
 struct hdmi_vmode {
 	bool mdataenablepolarity;
 
+	unsigned int previous_pixelclock;
 	unsigned int mpixelclock;
 	unsigned int mpixelrepetitioninput;
 	unsigned int mpixelrepetitionoutput;
+	unsigned int previous_tmdsclock;
 	unsigned int mtmdsclock;
 };
 
@@ -2068,7 +2070,7 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi,
 	int hblank, vblank, h_de_hs, v_de_vs, hsync_len, vsync_len;
 	unsigned int vdisplay, hdisplay;
 
-
+	vmode->previous_pixelclock = vmode->mpixelclock;
 	vmode->mpixelclock = mode->crtc_clock * 1000;
 	if (hdmi_bus_fmt_is_yuv420(hdmi->hdmi_data.enc_out_bus_format))
 		vmode->mpixelclock /= 2;
@@ -2095,6 +2097,7 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi,
 		vmode->mtmdsclock /= 2;
 
 	dev_dbg(hdmi->dev, "final tmdsclock = %d\n", vmode->mtmdsclock);
+	vmode->previous_tmdsclock = vmode->mtmdsclock;
 
 	/* Set up HDMI_FC_INVIDCONF */
 	inv_val = (hdmi->hdmi_data.hdcp_enable ||
@@ -2423,12 +2426,18 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi,
 	hdmi_av_composer(hdmi, &connector->display_info, mode);
 
 	/* HDMI Initializateion Step B.2 */
-	ret = hdmi->phy.ops->init(hdmi, hdmi->phy.data,
-				  &connector->display_info,
-				  &hdmi->previous_mode);
-	if (ret)
-		return ret;
-	hdmi->phy.enabled = true;
+	if (!hdmi->phy.enabled ||
+	    hdmi->hdmi_data.video_mode.previous_pixelclock !=
+	    hdmi->hdmi_data.video_mode.mpixelclock ||
+	    hdmi->hdmi_data.video_mode.previous_tmdsclock !=
+	    hdmi->hdmi_data.video_mode.mtmdsclock) {
+		ret = hdmi->phy.ops->init(hdmi, hdmi->phy.data,
+					  &connector->display_info,
+					  &hdmi->previous_mode);
+		if (ret)
+			return ret;
+		hdmi->phy.enabled = true;
+	}
 
 	/* HDMI Initialization Step B.3 */
 	dw_hdmi_enable_video_path(hdmi);