drm/exynos: Add display-timing node parsing using video helper function

Add support for parsing the display-timing node using video helper
function.

The DT node parsing is done only if 'dev.of_node'
exists and the NON-DT logic is still maintained under the 'else' part.

Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Acked-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -20,6 +20,7 @@
 #include <linux/of_device.h>
 #include <linux/pm_runtime.h>
 
+#include <video/of_display_timing.h>
 #include <video/samsung_fimd.h>
 #include <drm/exynos_drm.h>
 
@@ -884,10 +885,25 @@ static int fimd_probe(struct platform_device *pdev)
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
-	pdata = pdev->dev.platform_data;
-	if (!pdata) {
-		dev_err(dev, "no platform data specified\n");
-		return -EINVAL;
+	if (pdev->dev.of_node) {
+		pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+		if (!pdata) {
+			DRM_ERROR("memory allocation for pdata failed\n");
+			return -ENOMEM;
+		}
+
+		ret = of_get_fb_videomode(dev->of_node, &pdata->panel.timing,
+					OF_USE_NATIVE_MODE);
+		if (ret) {
+			DRM_ERROR("failed: of_get_fb_videomode() : %d\n", ret);
+			return ret;
+		}
+	} else {
+		pdata = pdev->dev.platform_data;
+		if (!pdata) {
+			DRM_ERROR("no platform data specified\n");
+			return -EINVAL;
+		}
 	}
 
 	panel = &pdata->panel;