drm/sun4i: Disable unused DE2 sub-engines

Some sub-engines are unused. Disable them explicitly.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181104182705.18047-12-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun8i_mixer.c

@@ -463,6 +463,15 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master,
 	for (i = 0; i < DE2_MIXER_UNIT_SIZE; i += 4)
 		regmap_write(mixer->engine.regs, i, 0);
 
+	/* Disable unused sub-engines */
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_FCE_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_BWS_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_LTI_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_PEAK_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_ASE_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_FCC_EN, 0);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_DCSC_EN, 0);
+
 	/* Enable the mixer */
 	regmap_write(mixer->engine.regs, SUN8I_MIXER_GLOBAL_CTL,
 		     SUN8I_MIXER_GLOBAL_CTL_RT_EN);

drivers/gpu/drm/sun4i/sun8i_mixer.h

@@ -101,8 +101,8 @@
 #define SUN8I_MIXER_FBFMT_YUV411	14
 
 /*
- * These sub-engines are still unknown now, the EN registers are here only to
- * be used to disable these sub-engines.
+ * Sub-engines listed bellow are unused for now. The EN registers are here only
+ * to be used to disable these sub-engines.
  */
 #define SUN8I_MIXER_FCE_EN			0xa0000
 #define SUN8I_MIXER_BWS_EN			0xa2000