[RFC][PATCH 2/3] drm/modes: Make width-mm/height-mm mandatory in of_get_drm_panel_display_mode()

[Marek Vasut <marex@denx.de>]

Make the width-mm/height-mm panel properties mandatory in
of_get_drm_panel_display_mode(), print error message and
return -ve in case these DT properties are not present.
This is needed to correctly report panel dimensions.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dmitry Osipenko <digetx@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: devicetree@vger.kernel.org
To: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/drm_modes.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 3f819c7a021b..45dc2d5c3ea6 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -761,12 +761,16 @@ int of_get_drm_panel_display_mode(struct device_node *np,
 		drm_bus_flags_from_videomode(&vm, bus_flags);
 
 	ret = of_property_read_u32(np, "width-mm", &width_mm);
-	if (ret && ret != -EINVAL)
+	if (ret < 0) {
+		pr_err("%pOF: invalid or missing width-mm DT property\n", np);
 		return ret;
+	}
 
 	ret = of_property_read_u32(np, "height-mm", &height_mm);
-	if (ret && ret != -EINVAL)
+	if (ret < 0) {
+		pr_err("%pOF: invalid or missing height-mm DT property\n", np);
 		return ret;
+	}
 
 	dmode->width_mm = width_mm;
 	dmode->height_mm = height_mm;
-- 
2.35.1