[PATCH] drm/tegra: dpaux: Make VDD supply optional

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

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 at 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 ee4180d8db14..65c389d9c85d 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);
-- 
2.21.0