drm: panel: simple: Warn in case of incorrect bus format for LVDS panels

Only the MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,
MEDIA_BUS_FMT_RGB888_1X7X4_SPWG and MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA bus
formats are valid for LVDS panels. Warn at probe time to catch the
common mistake of using an incorrect format, as well as discrepancies
between the bus format and the reported bpc.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200629233320.8774-5-laurent.pinchart+renesas@ideasonboard.com

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index cd416376bf718ec23ecfc33cf33cfbeecd4d1c11..3a35f74d6cb76a400277f675a996614df844efb5 100644 (file)
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -549,13 +549,22 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
                        panel_simple_parse_panel_timing_node(dev, panel, &dt);
        }
 
-       if (desc->connector_type == DRM_MODE_CONNECTOR_LVDS)
+       if (desc->connector_type == DRM_MODE_CONNECTOR_LVDS) {
                /* Catch common mistakes for LVDS panels. */
                WARN_ON(desc->bus_flags &
                        ~(DRM_BUS_FLAG_DE_LOW |
                          DRM_BUS_FLAG_DE_HIGH |
                          DRM_BUS_FLAG_DATA_MSB_TO_LSB |
                          DRM_BUS_FLAG_DATA_LSB_TO_MSB));
+               WARN_ON(desc->bus_format != MEDIA_BUS_FMT_RGB666_1X7X3_SPWG &&
+                       desc->bus_format != MEDIA_BUS_FMT_RGB888_1X7X4_SPWG &&
+                       desc->bus_format != MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA);
+               WARN_ON(desc->bus_format == MEDIA_BUS_FMT_RGB666_1X7X3_SPWG &&
+                       desc->bpc != 6);
+               WARN_ON((desc->bus_format == MEDIA_BUS_FMT_RGB888_1X7X4_SPWG ||
+                        desc->bus_format == MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA) &&
+                       desc->bpc != 8);
+       }
 
        drm_panel_init(&panel->base, dev, &panel_simple_funcs,
                       desc->connector_type);