drm: sun4i: Add support for suspending the display driver

Shut down the display engine during suspend.
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029112846.3604925-1-megous@megous.com

drivers/gpu/drm/sun4i/sun4i_drv.c

@@ -346,6 +346,27 @@ static int sun4i_drv_add_endpoints(struct device *dev,
 	return count;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int sun4i_drv_drm_sys_suspend(struct device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(dev);
+
+	return drm_mode_config_helper_suspend(drm);
+}
+
+static int sun4i_drv_drm_sys_resume(struct device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(dev);
+
+	return drm_mode_config_helper_resume(drm);
+}
+#endif
+
+static const struct dev_pm_ops sun4i_drv_drm_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sun4i_drv_drm_sys_suspend,
+				sun4i_drv_drm_sys_resume)
+};
+
 static int sun4i_drv_probe(struct platform_device *pdev)
 {
 	struct component_match *match = NULL;
@@ -418,6 +439,7 @@ static struct platform_driver sun4i_drv_platform_driver = {
 	.driver		= {
 		.name		= "sun4i-drm",
 		.of_match_table	= sun4i_drv_of_table,
+		.pm = &sun4i_drv_drm_pm_ops,
 	},
 };
 module_platform_driver(sun4i_drv_platform_driver);