[PATCH v1 0/4] Apply DP helper APIs to do link train

[PATCH v1 0/4] Apply DP helper APIs to do link train

[Damon Ding]

Use the existing DP helper APIs instead of repeated self-defined
interfaces with the same functions. It can help make codes more
concise.

Damon Ding (4):
  drm/bridge: analogix_dp: Apply DP helper API
    drm_dp_dpcd_read_link_status()
  drm/bridge: analogix_dp: Apply DP helper API
    drm_dp_clock_recovery_ok()
  drm/bridge: analogix_dp: Apply DP helper API drm_dp_channel_eq_ok()
  drm/bridge: analogix_dp: Apply DP helper APIs to get adjusted voltages
    and pre-emphasises

 .../drm/bridge/analogix/analogix_dp_core.c    | 123 +++---------------
 1 file changed, 18 insertions(+), 105 deletions(-)

-- 
2.34.1

[PATCH v1 1/4] drm/bridge: analogix_dp: Apply DP helper API drm_dp_dpcd_read_link_status()

[Damon Ding]

Use existing DP helper API to read link status related DPCDs.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index ed35e567d117..6a3f3fb0ec0a 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -388,13 +388,13 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 {
 	int lane, lane_count, retval;
 	u8 voltage_swing, pre_emphasis, training_lane;
-	u8 link_status[2], adjust_request[2];
+	u8 link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
 
 	usleep_range(100, 101);
 
 	lane_count = dp->link_train.lane_count;
 
-	retval = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status, 2);
+	retval = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 	if (retval < 0)
 		return retval;
 
@@ -454,13 +454,13 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 {
 	int lane_count, retval;
 	u32 reg;
-	u8 link_align, link_status[2], adjust_request[2];
+	u8 link_align, link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
 
 	usleep_range(400, 401);
 
 	lane_count = dp->link_train.lane_count;
 
-	retval = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status, 2);
+	retval = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 	if (retval < 0)
 		return retval;
 
@@ -619,7 +619,7 @@ static int analogix_dp_full_link_train(struct analogix_dp_device *dp,
 static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 {
 	int ret;
-	u8 link_align, link_status[2];
+	u8 link_align, link_status[DP_LINK_STATUS_SIZE];
 
 	analogix_dp_set_link_bandwidth(dp, dp->link_train.link_rate);
 	ret = analogix_dp_wait_pll_locked(dp);
@@ -661,8 +661,7 @@ static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 			return ret;
 		}
 
-		ret = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status,
-				       2);
+		ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 		if (ret < 0) {
 			DRM_DEV_ERROR(dp->dev, "Read link status failed %d\n",
 				      ret);
-- 
2.34.1

[PATCH v1 2/4] drm/bridge: analogix_dp: Apply DP helper API drm_dp_clock_recovery_ok()

[Damon Ding]

Use existing DP helper API instead of analogix_dp_clock_recovery_ok()
with the same function.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 20 +++----------------
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 6a3f3fb0ec0a..fde190eac34e 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -301,19 +301,6 @@ static unsigned char analogix_dp_get_lane_status(u8 link_status[2], int lane)
 	return (link_value >> shift) & 0xf;
 }
 
-static int analogix_dp_clock_recovery_ok(u8 link_status[2], int lane_count)
-{
-	int lane;
-	u8 lane_status;
-
-	for (lane = 0; lane < lane_count; lane++) {
-		lane_status = analogix_dp_get_lane_status(link_status, lane);
-		if ((lane_status & DP_LANE_CR_DONE) == 0)
-			return -EINVAL;
-	}
-	return 0;
-}
-
 static int analogix_dp_channel_eq_ok(u8 link_status[2], u8 link_align,
 				     int lane_count)
 {
@@ -398,7 +385,7 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 	if (retval < 0)
 		return retval;
 
-	if (analogix_dp_clock_recovery_ok(link_status, lane_count) == 0) {
+	if (drm_dp_clock_recovery_ok(link_status, lane_count)) {
 		/* set training pattern 2 for EQ */
 		analogix_dp_set_training_pattern(dp, TRAINING_PTN2);
 
@@ -464,7 +451,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 	if (retval < 0)
 		return retval;
 
-	if (analogix_dp_clock_recovery_ok(link_status, lane_count)) {
+	if (!drm_dp_clock_recovery_ok(link_status, lane_count)) {
 		analogix_dp_reduce_link_rate(dp);
 		return -EIO;
 	}
@@ -668,8 +655,7 @@ static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 			return ret;
 		}
 
-		if (analogix_dp_clock_recovery_ok(link_status,
-						  dp->link_train.lane_count)) {
+		if (!drm_dp_clock_recovery_ok(link_status, dp->link_train.lane_count)) {
 			DRM_DEV_ERROR(dp->dev, "Clock recovery failed\n");
 			analogix_dp_reduce_link_rate(dp);
 			return -EIO;
-- 
2.34.1

[PATCH v1 3/4] drm/bridge: analogix_dp: Apply DP helper API drm_dp_channel_eq_ok()

[Damon Ding]

Use existing DP helper API instead of analogix_dp_channel_eq_ok()
with the same function.

In addtion, remove unused function analogix_dp_get_lane_status()

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 49 ++-----------------
 1 file changed, 4 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index fde190eac34e..1f1de45ca46f 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -293,33 +293,6 @@ static int analogix_dp_link_start(struct analogix_dp_device *dp)
 	return 0;
 }
 
-static unsigned char analogix_dp_get_lane_status(u8 link_status[2], int lane)
-{
-	int shift = (lane & 1) * 4;
-	u8 link_value = link_status[lane >> 1];
-
-	return (link_value >> shift) & 0xf;
-}
-
-static int analogix_dp_channel_eq_ok(u8 link_status[2], u8 link_align,
-				     int lane_count)
-{
-	int lane;
-	u8 lane_status;
-
-	if ((link_align & DP_INTERLANE_ALIGN_DONE) == 0)
-		return -EINVAL;
-
-	for (lane = 0; lane < lane_count; lane++) {
-		lane_status = analogix_dp_get_lane_status(link_status, lane);
-		lane_status &= DP_CHANNEL_EQ_BITS;
-		if (lane_status != DP_CHANNEL_EQ_BITS)
-			return -EINVAL;
-	}
-
-	return 0;
-}
-
 static unsigned char
 analogix_dp_get_adjust_request_voltage(u8 adjust_request[2], int lane)
 {
@@ -441,7 +414,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 {
 	int lane_count, retval;
 	u32 reg;
-	u8 link_align, link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
+	u8 link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
 
 	usleep_range(400, 401);
 
@@ -461,14 +434,9 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 	if (retval < 0)
 		return retval;
 
-	retval = drm_dp_dpcd_readb(&dp->aux, DP_LANE_ALIGN_STATUS_UPDATED,
-				   &link_align);
-	if (retval < 0)
-		return retval;
-
 	analogix_dp_get_adjust_training_lane(dp, adjust_request);
 
-	if (!analogix_dp_channel_eq_ok(link_status, link_align, lane_count)) {
+	if (drm_dp_channel_eq_ok(link_status, lane_count)) {
 		/* traing pattern Set to Normal */
 		retval = analogix_dp_training_pattern_dis(dp);
 		if (retval < 0)
@@ -606,7 +574,7 @@ static int analogix_dp_full_link_train(struct analogix_dp_device *dp,
 static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 {
 	int ret;
-	u8 link_align, link_status[DP_LINK_STATUS_SIZE];
+	u8 link_status[DP_LINK_STATUS_SIZE];
 
 	analogix_dp_set_link_bandwidth(dp, dp->link_train.link_rate);
 	ret = analogix_dp_wait_pll_locked(dp);
@@ -640,14 +608,6 @@ static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 	 * speed
 	 */
 	if (verify_fast_training) {
-		ret = drm_dp_dpcd_readb(&dp->aux, DP_LANE_ALIGN_STATUS_UPDATED,
-					&link_align);
-		if (ret < 0) {
-			DRM_DEV_ERROR(dp->dev, "Read align status failed %d\n",
-				      ret);
-			return ret;
-		}
-
 		ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
 		if (ret < 0) {
 			DRM_DEV_ERROR(dp->dev, "Read link status failed %d\n",
@@ -661,8 +621,7 @@ static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 			return -EIO;
 		}
 
-		if (analogix_dp_channel_eq_ok(link_status, link_align,
-					      dp->link_train.lane_count)) {
+		if (!drm_dp_channel_eq_ok(link_status, dp->link_train.lane_count)) {
 			DRM_DEV_ERROR(dp->dev, "Channel EQ failed\n");
 			analogix_dp_reduce_link_rate(dp);
 			return -EIO;
-- 
2.34.1

[PATCH v1 4/4] drm/bridge: analogix_dp: Apply DP helper APIs to get adjusted voltages and pre-emphasises

[Damon Ding]

Replace analogix_dp_get_adjust_request_voltage() and
analogix_dp_get_adjust_request_pre_emphasis() with existing DP helper
APIs with the same function.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 49 ++++---------------
 1 file changed, 9 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 1f1de45ca46f..a6d4935234c2 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -293,25 +293,6 @@ static int analogix_dp_link_start(struct analogix_dp_device *dp)
 	return 0;
 }
 
-static unsigned char
-analogix_dp_get_adjust_request_voltage(u8 adjust_request[2], int lane)
-{
-	int shift = (lane & 1) * 4;
-	u8 link_value = adjust_request[lane >> 1];
-
-	return (link_value >> shift) & 0x3;
-}
-
-static unsigned char analogix_dp_get_adjust_request_pre_emphasis(
-					u8 adjust_request[2],
-					int lane)
-{
-	int shift = (lane & 1) * 4;
-	u8 link_value = adjust_request[lane >> 1];
-
-	return ((link_value >> shift) & 0xc) >> 2;
-}
-
 static void analogix_dp_reduce_link_rate(struct analogix_dp_device *dp)
 {
 	analogix_dp_training_pattern_dis(dp);
@@ -321,17 +302,15 @@ static void analogix_dp_reduce_link_rate(struct analogix_dp_device *dp)
 }
 
 static void analogix_dp_get_adjust_training_lane(struct analogix_dp_device *dp,
-						 u8 adjust_request[2])
+						 u8 link_status[DP_LINK_STATUS_SIZE])
 {
 	int lane, lane_count;
 	u8 voltage_swing, pre_emphasis, training_lane;
 
 	lane_count = dp->link_train.lane_count;
 	for (lane = 0; lane < lane_count; lane++) {
-		voltage_swing = analogix_dp_get_adjust_request_voltage(
-						adjust_request, lane);
-		pre_emphasis = analogix_dp_get_adjust_request_pre_emphasis(
-						adjust_request, lane);
+		voltage_swing = drm_dp_get_adjust_request_voltage(link_status, lane);
+		pre_emphasis = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
 		training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
 				DPCD_PRE_EMPHASIS_SET(pre_emphasis);
 
@@ -348,7 +327,7 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 {
 	int lane, lane_count, retval;
 	u8 voltage_swing, pre_emphasis, training_lane;
-	u8 link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
+	u8 link_status[DP_LINK_STATUS_SIZE];
 
 	usleep_range(100, 101);
 
@@ -374,15 +353,10 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 		return 0;
 	}
 
-	retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
-				  adjust_request, 2);
-	if (retval < 0)
-		return retval;
-
 	for (lane = 0; lane < lane_count; lane++) {
 		training_lane = analogix_dp_get_lane_link_training(dp, lane);
-		voltage_swing = analogix_dp_get_adjust_request_voltage(adjust_request, lane);
-		pre_emphasis = analogix_dp_get_adjust_request_pre_emphasis(adjust_request, lane);
+		voltage_swing = drm_dp_get_adjust_request_voltage(link_status, lane);
+		pre_emphasis = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
 
 		if (DPCD_VOLTAGE_SWING_GET(training_lane) == voltage_swing &&
 		    DPCD_PRE_EMPHASIS_GET(training_lane) == pre_emphasis)
@@ -399,7 +373,7 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 		}
 	}
 
-	analogix_dp_get_adjust_training_lane(dp, adjust_request);
+	analogix_dp_get_adjust_training_lane(dp, link_status);
 	analogix_dp_set_lane_link_training(dp);
 
 	retval = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET,
@@ -414,7 +388,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 {
 	int lane_count, retval;
 	u32 reg;
-	u8 link_status[DP_LINK_STATUS_SIZE], adjust_request[2];
+	u8 link_status[DP_LINK_STATUS_SIZE];
 
 	usleep_range(400, 401);
 
@@ -429,12 +403,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 		return -EIO;
 	}
 
-	retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
-				  adjust_request, 2);
-	if (retval < 0)
-		return retval;
-
-	analogix_dp_get_adjust_training_lane(dp, adjust_request);
+	analogix_dp_get_adjust_training_lane(dp, link_status);
 
 	if (drm_dp_channel_eq_ok(link_status, lane_count)) {
 		/* traing pattern Set to Normal */
-- 
2.34.1

Re: [PATCH v1 0/4] Apply DP helper APIs to do link train

[Marek Szyprowski]

On 24.08.2025 10:45, Damon Ding wrote:
> Use the existing DP helper APIs instead of repeated self-defined
> interfaces with the same functions. It can help make codes more
> concise.
>
> Damon Ding (4):
>    drm/bridge: analogix_dp: Apply DP helper API
>      drm_dp_dpcd_read_link_status()
>    drm/bridge: analogix_dp: Apply DP helper API
>      drm_dp_clock_recovery_ok()
>    drm/bridge: analogix_dp: Apply DP helper API drm_dp_channel_eq_ok()
>    drm/bridge: analogix_dp: Apply DP helper APIs to get adjusted voltages
>      and pre-emphasises
>
>   .../drm/bridge/analogix/analogix_dp_core.c    | 123 +++---------------
>   1 file changed, 18 insertions(+), 105 deletions(-)

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland