drm/sun4i: Rework enabling plane in DE2 driver

If we want to support multiple planes in the future, code which enables
pipe has to be moved to appropriate place and it must depend on channel
id instead of being hardcoded.

Side effect of that rework is definition of default Z position. For now,
put first channel at the bottom, second above it and so on.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171201060550.10392-10-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun8i_mixer.c

@@ -55,6 +55,15 @@ void sun8i_mixer_layer_enable(struct sun8i_mixer *mixer,
 	regmap_update_bits(mixer->engine.regs,
 			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(chan, layer),
 			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN, val);
+
+	if (enable)
+		val = SUN8I_MIXER_BLEND_PIPE_CTL_EN(chan);
+	else
+		val = 0;
+
+	regmap_update_bits(mixer->engine.regs,
+			   SUN8I_MIXER_BLEND_PIPE_CTL,
+			   SUN8I_MIXER_BLEND_PIPE_CTL_EN(chan), val);
 }
 
 static int sun8i_mixer_drm_format_to_layer(struct drm_plane *plane,
@@ -98,7 +107,7 @@ int sun8i_mixer_update_layer_coord(struct sun8i_mixer *mixer,
 					      state->crtc_h));
 		DRM_DEBUG_DRIVER("Updating blender size\n");
 		regmap_write(mixer->engine.regs,
-			     SUN8I_MIXER_BLEND_ATTR_INSIZE(0),
+			     SUN8I_MIXER_BLEND_ATTR_INSIZE(chan),
 			     SUN8I_MIXER_SIZE(state->crtc_w,
 					      state->crtc_h));
 		regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_OUTSIZE,
@@ -322,20 +331,17 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master,
 	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_BKCOLOR,
 		     SUN8I_MIXER_BLEND_COLOR_BLACK);
 
-	/* Initialize blender */
+	/*
+	 * Set fill color of bottom plane to black. Generally not needed
+	 * except when VI plane is at bottom (zpos = 0) and enabled.
+	 */
 	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_PIPE_CTL,
-		     SUN8I_MIXER_BLEND_PIPE_CTL_EN(0) |
 		     SUN8I_MIXER_BLEND_PIPE_CTL_FC_EN(0));
-
-	regmap_write(mixer->engine.regs,
-		     SUN8I_MIXER_BLEND_ATTR_FCOLOR(0),
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ATTR_FCOLOR(0),
 		     SUN8I_MIXER_BLEND_COLOR_BLACK);
 
-	/* Select the first UI channel */
-	DRM_DEBUG_DRIVER("Selecting channel %d (first UI channel)\n",
-			 mixer->cfg->vi_num);
-	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ROUTE,
-		     mixer->cfg->vi_num);
+	/* Fixed zpos for now */
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ROUTE, 0x43210);
 
 	plane_cnt = mixer->cfg->vi_num + mixer->cfg->ui_num;
 	for (i = 0; i < plane_cnt; i++)