drm/meson: add resume/suspend hooks

Add the suspend and resume hooks to:
- save and disable the entire DRM driver on suspend
- re-init the entire VPU subsystem on resume, to recover CRTC and pixel
generator functionnal usage after DDR suspend, then recover DRM driver
state

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190827095825.21015-3-narmstrong@baylibre.com

drivers/gpu/drm/meson/meson_drv.c

@@ -372,6 +372,33 @@ static const struct component_master_ops meson_drv_master_ops = {
 	.unbind	= meson_drv_unbind,
 };
 
+static int __maybe_unused meson_drv_pm_suspend(struct device *dev)
+{
+	struct meson_drm *priv = dev_get_drvdata(dev);
+
+	if (!priv)
+		return 0;
+
+	return drm_mode_config_helper_suspend(priv->drm);
+}
+
+static int __maybe_unused meson_drv_pm_resume(struct device *dev)
+{
+	struct meson_drm *priv = dev_get_drvdata(dev);
+
+	if (!priv)
+		return 0;
+
+	meson_vpu_init(priv);
+	meson_venc_init(priv);
+	meson_vpp_init(priv);
+	meson_viu_init(priv);
+
+	drm_mode_config_helper_resume(priv->drm);
+
+	return 0;
+}
+
 static int compare_of(struct device *dev, void *data)
 {
 	DRM_DEBUG_DRIVER("Comparing of node %pOF with %pOF\n",
@@ -467,11 +494,16 @@ static const struct of_device_id dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, dt_match);
 
+static const struct dev_pm_ops meson_drv_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(meson_drv_pm_suspend, meson_drv_pm_resume)
+};
+
 static struct platform_driver meson_drm_platform_driver = {
 	.probe      = meson_drv_probe,
 	.driver     = {
 		.name	= "meson-drm",
 		.of_match_table = dt_match,
+		.pm = &meson_drv_pm_ops,
 	},
 };