[RESEND 4/5] drm/mxsfb: Add PM_SLEEP support

[Leonard Crestez <leonard.crestez@nxp.com>]

Since power to the lcdif block can be lost on suspend implement
PM_SLEEP_OPS using drm_mode_config_helper_suspend/resume to save/restore
the current mode.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 68d79f5dc0d3..d797dfd40d98 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -416,17 +416,38 @@ static int mxsfb_remove(struct platform_device *pdev)
 	drm_dev_unref(drm);
 
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int mxsfb_suspend(struct device *dev)
+{
+       struct drm_device *drm = dev_get_drvdata(dev);
+
+       return drm_mode_config_helper_suspend(drm);
+}
+
+static int mxsfb_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 mxsfb_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(mxsfb_suspend, mxsfb_resume)
+};
+
 static struct platform_driver mxsfb_platform_driver = {
 	.probe		= mxsfb_probe,
 	.remove		= mxsfb_remove,
 	.id_table	= mxsfb_devtype,
 	.driver	= {
 		.name		= "mxsfb",
 		.of_match_table	= mxsfb_dt_ids,
+		.pm		= &mxsfb_pm_ops,
 	},
 };
 
 module_platform_driver(mxsfb_platform_driver);
 
-- 
2.17.1