From f3b0d8793c1619074d0ece2e1a7f64ea37eaf394 Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Wed, 5 Jun 2019 10:48:01 +0200
Subject: [PATCH] drm/tegra: dpaux: Make VDD supply optional

The VDD supply is only needed to supply power to eDP panels connected to
DPAUX. Technically that supply should be dealt with in the panel driver,
but for backwards-compatibility we need to keep this around anyway.

Also as a bit of background: the reason for why this supply is attached
to DPAUX is to make sure the panel is properly powered early on so that
it can generate a hotplug pulse at the appropriate time. This may no
longer be required given the support for deferred fbdev setup that was
"recently" introduced in DRM/KMS.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/drm/tegra/dpaux.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index ee4180d8db147..65c389d9c85da 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -485,11 +485,16 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	dpaux->vdd = devm_regulator_get(&pdev->dev, "vdd");
+	dpaux->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
 	if (IS_ERR(dpaux->vdd)) {
-		dev_err(&pdev->dev, "failed to get VDD supply: %ld\n",
-			PTR_ERR(dpaux->vdd));
-		return PTR_ERR(dpaux->vdd);
+		if (PTR_ERR(dpaux->vdd) != -ENODEV) {
+			if (PTR_ERR(dpaux->vdd) != -EPROBE_DEFER)
+				dev_err(&pdev->dev,
+					"failed to get VDD supply: %ld\n",
+					PTR_ERR(dpaux->vdd));
+
+			return PTR_ERR(dpaux->vdd);
+		}
 	}
 
 	platform_set_drvdata(pdev, dpaux);