drm/omap: Do dss_device (display) ordering in omap_drv.c

Sort the dssdev array based on DT aliases.

With this change we can remove the panel ordering from dss/display.c and
have all sorting related to dssdevs in one place.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/dss/display.c

@@ -52,6 +52,8 @@ int omapdss_register_display(struct omap_dss_device *dssdev)
 	if (id < 0)
 		id = disp_num_counter++;
 
+	dssdev->alias_id = id;
+
 	snprintf(dssdev->alias, sizeof(dssdev->alias), "display%d", id);
 
 	/* Use 'label' property for name, if it exists */

drivers/gpu/drm/omapdrm/dss/omapdss.h

@@ -467,6 +467,7 @@ struct omap_dss_device {
 
 	/* alias in the form of "display%d" */
 	char alias[16];
+	unsigned int alias_id;
 
 	enum omap_display_type type;
 	enum omap_display_type output_type;

drivers/gpu/drm/omapdrm/omap_drv.c

@@ -15,6 +15,8 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/of.h>
+#include <linux/sort.h>
 #include <linux/sys_soc.h>
 
 #include <drm/drm_atomic.h>
@@ -165,6 +167,18 @@ static void omap_disconnect_dssdevs(struct drm_device *ddev)
 	priv->num_dssdevs = 0;
 }
 
+static int omap_compare_dssdevs(const void *a, const void *b)
+{
+	const struct omap_dss_device *dssdev1 = *(struct omap_dss_device **)a;
+	const struct omap_dss_device *dssdev2 = *(struct omap_dss_device **)b;
+
+	if (dssdev1->alias_id > dssdev2->alias_id)
+		return 1;
+	else if (dssdev1->alias_id < dssdev2->alias_id)
+		return -1;
+	return 0;
+}
+
 static int omap_connect_dssdevs(struct drm_device *ddev)
 {
 	struct omap_drm_private *priv = ddev->dev_private;
@@ -193,6 +207,10 @@ static int omap_connect_dssdevs(struct drm_device *ddev)
 		}
 	}
 
+	/* Sort the list by DT aliases */
+	sort(priv->dssdevs, priv->num_dssdevs, sizeof(priv->dssdevs[0]),
+	     omap_compare_dssdevs, NULL);
+
 	return 0;
 
 cleanup: