[PATCH 2/9] drm/dp: Add POST_LT_ADJ_REQ helpers

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Add small helpers (drm_dp_post_lt_adj_req_supported() and
drm_dp_post_lt_adj_req_in_progress()) to help with implementing
the POST_LT_ADJ_REQ sequence.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 8 ++++++++
 include/drm/display/drm_dp_helper.h     | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index f5c596234729..252f022f0837 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -122,6 +122,14 @@ bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 }
 EXPORT_SYMBOL(drm_dp_clock_recovery_ok);
 
+bool drm_dp_post_lt_adj_req_in_progress(const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+	u8 lane_align = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+
+	return lane_align & DP_POST_LT_ADJ_REQ_IN_PROGRESS;
+}
+EXPORT_SYMBOL(drm_dp_post_lt_adj_req_in_progress);
+
 u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],
 				     int lane)
 {
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index 89a34dff85a4..bec97d29bfa2 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -37,6 +37,7 @@ bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 			  int lane_count);
 bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 			      int lane_count);
+bool drm_dp_post_lt_adj_req_in_progress(const u8 link_status[DP_LINK_STATUS_SIZE]);
 u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],
 				     int lane);
 u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE],
@@ -155,6 +156,13 @@ drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 		(dpcd[DP_MAX_LANE_COUNT] & DP_ENHANCED_FRAME_CAP);
 }
 
+static inline bool
+drm_dp_post_lt_adj_req_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+	return dpcd[DP_DPCD_REV] >= 0x13 &&
+		(dpcd[DP_MAX_LANE_COUNT] & DP_POST_LT_ADJ_REQ_SUPPORTED);
+}
+
 static inline bool
 drm_dp_fast_training_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
-- 
2.45.3