drm/panel: lvds: Handle the optional regulator case properly

The devm_regulator_get_optional function, unlike it was assumed in the
commit a1c55bccf600 ("drm/panel: lvds: Add support for the power-supply
property"), is actually returning an error pointer with -ENODEV instead of
NULL when there's no regulator to find.

Make sure we handle that case properly.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Fixes: a1c55bccf600 ("drm/panel: lvds: Add support for the power-supply property")
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180110155941.16109-1-maxime.ripard@free-electrons.com

diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
index 57e38a9..b5e3994 100644 (file)
--- a/drivers/gpu/drm/panel/panel-lvds.c
+++ b/drivers/gpu/drm/panel/panel-lvds.c
@@ -215,8 +215,15 @@ static int panel_lvds_probe(struct platform_device *pdev)
        lvds->supply = devm_regulator_get_optional(lvds->dev, "power");
        if (IS_ERR(lvds->supply)) {
                ret = PTR_ERR(lvds->supply);
-               dev_err(lvds->dev, "failed to request regulator: %d\n", ret);
-               return ret;
+
+               if (ret != -ENODEV) {
+                       if (ret != -EPROBE_DEFER)
+                               dev_err(lvds->dev, "failed to request regulator: %d\n",
+                                       ret);
+                       return ret;
+               }
+
+               lvds->supply = NULL;
        }
 
        /* Get GPIOs and backlight controller. */