[PATCH v3 1/2] drm/sun4i: Add mode_set callback to the engine

[roman.stratiienko at globallogic.com]

From: Roman Stratiienko <roman.stratiienko at globallogic.com>

Create callback to update engine's registers on mode change.

Signed-off-by: Roman Stratiienko <roman.stratiienko at globallogic.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec at siol.net>
---
v2:
- Split commit in 2 parts.
- Add description to mode_set callback
- Dropped 1 line from sun4i_crtc_mode_set_nofb()
- Add struct drm_display_mode declaration (fix build warning)

v3:
- Pick reviewed-by line
- Add missing 'and' word to the mode_set callback description.
---
 drivers/gpu/drm/sun4i/sun4i_crtc.c   |  3 +++
 drivers/gpu/drm/sun4i/sunxi_engine.h | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun4i_crtc.c b/drivers/gpu/drm/sun4i/sun4i_crtc.c
index 3a153648b369..f9c627d601c3 100644
--- a/drivers/gpu/drm/sun4i/sun4i_crtc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_crtc.c
@@ -141,6 +141,9 @@ static void sun4i_crtc_mode_set_nofb(struct drm_crtc *crtc)
 	struct sun4i_crtc *scrtc = drm_crtc_to_sun4i_crtc(crtc);
 
 	sun4i_tcon_mode_set(scrtc->tcon, encoder, mode);
+
+	if (scrtc->engine->ops->mode_set)
+		scrtc->engine->ops->mode_set(scrtc->engine, mode);
 }
 
 static const struct drm_crtc_helper_funcs sun4i_crtc_helper_funcs = {
diff --git a/drivers/gpu/drm/sun4i/sunxi_engine.h b/drivers/gpu/drm/sun4i/sunxi_engine.h
index 548710a936d5..7faa844646ff 100644
--- a/drivers/gpu/drm/sun4i/sunxi_engine.h
+++ b/drivers/gpu/drm/sun4i/sunxi_engine.h
@@ -9,6 +9,7 @@
 struct drm_plane;
 struct drm_device;
 struct drm_crtc_state;
+struct drm_display_mode;
 
 struct sunxi_engine;
 
@@ -108,6 +109,17 @@ struct sunxi_engine_ops {
 	 * This function is optional.
 	 */
 	void (*vblank_quirk)(struct sunxi_engine *engine);
+
+	/**
+	 * @mode_set:
+	 *
+	 * This callback is used to update engine registers that
+	 * responsible for display frame size and other mode attributes.
+	 *
+	 * This function is optional.
+	 */
+	void (*mode_set)(struct sunxi_engine *engine,
+			 struct drm_display_mode *mode);
 };
 
 /**
-- 
2.17.1