drm/tegra: dp: Read alternate scrambler reset capability from sink

Parse from the sink capabilities whether or not the eDP alternate
scrambler reset value of 0xfffe is supported.
Signed-off-by: NThierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dp.c

@@ -14,6 +14,7 @@ static void drm_dp_link_caps_reset(struct drm_dp_link_caps *caps)
 	caps->tps3_supported = false;
 	caps->fast_training = false;
 	caps->channel_coding = false;
+	caps->alternate_scrambler_reset = false;
 }
 
 void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest,
@@ -23,6 +24,7 @@ void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest,
 	dest->tps3_supported = src->tps3_supported;
 	dest->fast_training = src->fast_training;
 	dest->channel_coding = src->channel_coding;
+	dest->alternate_scrambler_reset = src->alternate_scrambler_reset;
 }
 
 static void drm_dp_link_reset(struct drm_dp_link *link)
@@ -71,6 +73,9 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link)
 	link->caps.fast_training = drm_dp_fast_training_cap(dpcd);
 	link->caps.channel_coding = drm_dp_channel_coding_supported(dpcd);
 
+	if (drm_dp_alternate_scrambler_reset_cap(dpcd))
+		link->caps.alternate_scrambler_reset = true;
+
 	link->rate = link->max_rate;
 	link->lanes = link->max_lanes;
 

drivers/gpu/drm/tegra/dp.h

@@ -42,6 +42,13 @@ struct drm_dp_link_caps {
 	 * ANSI 8B/10B channel coding capability
 	 */
 	bool channel_coding;
+
+	/**
+	 * @alternate_scrambler_reset:
+	 *
+	 * eDP alternate scrambler reset capability
+	 */
+	bool alternate_scrambler_reset;
 };
 
 void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest,