linux-kernel - [PATCH v5 23/36] drm/bridge: analogix_dp: Move fast link training detect to set

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Date:   Fri,  9 Mar 2018 23:23:14 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     architt@...eaurora.org, inki.dae@...sung.com,
        thierry.reding@...il.com, hjc@...k-chips.com,
        seanpaul@...omium.org, airlied@...ux.ie, tfiga@...omium.org,
        heiko@...ech.de
Cc:     dri-devel@...ts.freedesktop.org, dianders@...omium.org,
        a.hajda@...sung.com, ykk@...k-chips.com, kernel@...labora.com,
        m.szyprowski@...sung.com, linux-samsung-soc@...r.kernel.org,
        jy0922.shim@...sung.com, rydberg@...math.org, krzk@...nel.org,
        linux-rockchip@...ts.infradead.org, kgene@...nel.org,
        linux-input@...r.kernel.org, orjan.eide@....com,
        wxt@...k-chips.com, jeffy.chen@...k-chips.com,
        linux-arm-kernel@...ts.infradead.org, mark.yao@...k-chips.com,
        wzz@...k-chips.com, hl@...k-chips.com, jingoohan1@...il.com,
        sw0312.kim@...sung.com, linux-kernel@...r.kernel.org,
        kyungmin.park@...sung.com, Laurent.pinchart@...asonboard.com,
        kuankuan.y@...il.com, hshi@...omium.org,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>
Subject: [PATCH v5 23/36] drm/bridge: analogix_dp: Move fast link training detect to set_bridge

From: zain wang <wzz@...k-chips.com>

It's too early to detect fast link training, if other step after it
failed, we will set fast_link flag to 1, and retry set_bridge again. In
this case we will power down and power up panel power supply, and we
will do fast link training since we have set fast_link flag to 1. In
fact, we should do full link training now, not the fast link training.
So we should move the fast link detection at the end of set_bridge.

Cc: Tomasz Figa <tfiga@...omium.org>
Signed-off-by: zain wang <wzz@...k-chips.com>
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Sean Paul <seanpaul@...omium.org>
Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
Reviewed-by: Andrzej Hajda <a.hajda@...sung.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
---

 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 42 +++++++++++++---------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index d76e1652b1fd..37b16643f14c 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -601,7 +601,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 {
 	int lane, lane_count, retval;
 	u32 reg;
-	u8 link_align, link_status[2], adjust_request[2], spread;
+	u8 link_align, link_status[2], adjust_request[2];
 
 	usleep_range(400, 401);
 
@@ -645,20 +645,6 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 		dev_dbg(dp->dev, "final lane count = %.2x\n",
 			dp->link_train.lane_count);
 
-		retval = drm_dp_dpcd_readb(&dp->aux, DP_MAX_DOWNSPREAD,
-					   &spread);
-		if (retval != 1) {
-			dev_err(dp->dev, "failed to read downspread %d\n",
-				retval);
-			dp->fast_train_enable = false;
-		} else {
-			dp->fast_train_enable =
-				(spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING) ?
-					true : false;
-		}
-		dev_dbg(dp->dev, "fast link training %s\n",
-			dp->fast_train_enable ? "supported" : "unsupported");
-
 		dp->link_train.lt_state = FINISHED;
 
 		return 0;
@@ -996,6 +982,22 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static int analogix_dp_fast_link_train_detection(struct analogix_dp_device *dp)
+{
+	int ret;
+	u8 spread;
+
+	ret = drm_dp_dpcd_readb(&dp->aux, DP_MAX_DOWNSPREAD, &spread);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to read downspread %d\n", ret);
+		return ret;
+	}
+	dp->fast_train_enable = !!(spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING);
+	dev_dbg(dp->dev, "fast link training %s\n",
+		dp->fast_train_enable ? "supported" : "unsupported");
+	return 0;
+}
+
 static int analogix_dp_commit(struct analogix_dp_device *dp)
 {
 	int ret;
@@ -1038,8 +1040,16 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
 	if (ret)
 		return ret;
 
-	if (dp->psr_enable)
+	if (dp->psr_enable) {
 		ret = analogix_dp_enable_sink_psr(dp);
+		if (ret)
+			return ret;
+	}
+
+	/* Check whether panel supports fast training */
+	ret =  analogix_dp_fast_link_train_detection(dp);
+	if (ret)
+		dp->psr_enable = false;
 
 	return ret;
 }
-- 
2.16.1