disp: msm: dp: link training enhancements

Update the link training process along with the AUX
communications during link training as per hardware
recommendations.

Update the pre-emphasis and swing values for active
lanes only instead of all lanes.

During link training, update pre-emphasis and swing
values in hardware first and then update sink.

CRs-Fixed: 2458753
Change-Id: Ie05c9d6508b0c564b194032ae4ebb1bc5550e7b8
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>

msm/dp/dp_link.c

@@ -1426,6 +1426,10 @@ static int dp_link_adjust_levels(struct dp_link *dp_link, u8 *link_status)
 		&& (dp_link->phy_params.v_level == DP_LINK_VOLTAGE_LEVEL_2))
 		dp_link->phy_params.p_level = DP_LINK_PRE_EMPHASIS_LEVEL_1;
 
+	if ((dp_link->phy_params.p_level > DP_LINK_PRE_EMPHASIS_LEVEL_2)
+		&& (dp_link->phy_params.v_level == DP_LINK_VOLTAGE_LEVEL_1))
+		dp_link->phy_params.p_level = DP_LINK_PRE_EMPHASIS_LEVEL_2;
+
 	pr_debug("Set (VxPx): %x%x\n",
 		dp_link->phy_params.v_level, dp_link->phy_params.p_level);