dm: video: Add a operation to display uclass

The current display class only allow to get timing from edid.
So add a operation to get timing directly from driver.
In driver, I will use fdtdec_decode_display_timing to get timing.

Signed-off-by: Jacob Chen <jacob-chen@iotwrt.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/video/display-uclass.c

@@ -36,6 +36,9 @@ int display_read_timing(struct udevice *dev, struct display_timing *timing)
 	u8 buf[EDID_EXT_SIZE];
 	int ret;
 
+	if (ops && ops->read_timing)
+		return ops->read_timing(dev, timing);
+
 	if (!ops || !ops->read_edid)
 		return -ENOSYS;
 	ret = ops->read_edid(dev, buf, sizeof(buf));

include/display.h

@@ -23,7 +23,7 @@ struct display_plat {
 };
 
 /**
- * display_read_timing() - Read timing information from EDID
+ * display_read_timing() - Read timing information
  *
  * @dev:	Device to read from
  * @return 0 if OK, -ve on error
@@ -42,6 +42,15 @@ int display_enable(struct udevice *dev, int panel_bpp,
 		   const struct display_timing *timing);
 
 struct dm_display_ops {
+	/**
+	 * read_timing() - Read information directly
+	 *
+	 * @dev:	Device to read from
+	 * @timing:	Display timings
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*read_timing)(struct udevice *dev, struct display_timing *timing);
+
 	/**
 	 * read_edid() - Read information from EDID
 	 *