drm: add bus_formats and num_bus_formats fields to drm_display_info

Add bus_formats and num_bus_formats fields and
drm_display_info_set_bus_formats helper function to specify the bus
formats supported by a given display.

This information can be used by display controller drivers to configure
the output interface appropriately (i.e. RGB565, RGB666 or RGB888 on raw
RGB or LVDS busses).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/drm_crtc.c

@@ -761,6 +761,40 @@ static void drm_mode_remove(struct drm_connector *connector,
 	drm_mode_destroy(connector->dev, mode);
 }
 
+/**
+ * drm_display_info_set_bus_formats - set the supported bus formats
+ * @info: display info to store bus formats in
+ * @fmts: array containing the supported bus formats
+ * @nfmts: the number of entries in the fmts array
+ *
+ * Store the supported bus formats in display info structure.
+ * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
+ * a full list of available formats.
+ */
+int drm_display_info_set_bus_formats(struct drm_display_info *info,
+				     const u32 *formats,
+				     unsigned int num_formats)
+{
+	u32 *fmts = NULL;
+
+	if (!formats && num_formats)
+		return -EINVAL;
+
+	if (formats && num_formats) {
+		fmts = kmemdup(formats, sizeof(*formats) * num_formats,
+			       GFP_KERNEL);
+		if (!formats)
+			return -ENOMEM;
+	}
+
+	kfree(info->bus_formats);
+	info->bus_formats = fmts;
+	info->num_bus_formats = num_formats;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_display_info_set_bus_formats);
+
 /**
  * drm_connector_get_cmdline_mode - reads the user's cmdline mode
  * @connector: connector to quwery
@@ -923,6 +957,7 @@ void drm_connector_cleanup(struct drm_connector *connector)
 	ida_remove(&drm_connector_enum_list[connector->connector_type].ida,
 		   connector->connector_type_id);
 
+	kfree(connector->display_info.bus_formats);
 	drm_mode_object_put(dev, &connector->base);
 	kfree(connector->name);
 	connector->name = NULL;

include/drm/drm_crtc.h

@@ -31,6 +31,7 @@
 #include <linux/idr.h>
 #include <linux/fb.h>
 #include <linux/hdmi.h>
+#include <linux/media-bus-format.h>
 #include <uapi/drm/drm_mode.h>
 #include <uapi/drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
@@ -139,6 +140,9 @@ struct drm_display_info {
 	enum subpixel_order subpixel_order;
 	u32 color_formats;
 
+	const u32 *bus_formats;
+	unsigned int num_bus_formats;
+
 	/* Mask of supported hdmi deep color modes */
 	u8 edid_hdmi_dc_modes;
 
@@ -1282,6 +1286,10 @@ int drm_mode_connector_set_tile_property(struct drm_connector *connector);
 extern int drm_mode_connector_update_edid_property(struct drm_connector *connector,
 						   const struct edid *edid);
 
+extern int drm_display_info_set_bus_formats(struct drm_display_info *info,
+					    const u32 *formats,
+					    unsigned int num_formats);
+
 static inline bool drm_property_type_is(struct drm_property *property,
 		uint32_t type)
 {