[PATCH] drm/meson: add YUV422 output support

[Christian Hewitt]

From: Dongjin Kim <tobetter at gmail.com>

Support YUV422 output from the Amlogic Meson SoC VPU to the HDMI
controller. Without this YUV422 format out of the HDMI encoder
leads to using the dw-hdmi YUV444 to YUV422 color conversion which
gives wrong colors and a green line on the left edge of the screen.

Signed-off-by: Dongjin Kim <tobetter at gmail.com>
Signed-off-by: Christian Hewitt <christianshewitt at gmail.com>
Tested-by: Furkan Kardame <f.kardame at manjaro.org>
---
I've had this patch in my sources for some time now; originally picked
from Dongjin's mainline branches for Hardkernel boards and tweaked for
some minor renaming after DRM bridge changes were merged. Furkhan has
reminded me this is still needed a couple of days ago and now the same
issue is reported on the mailing list [0] so best to submit it. If a
fixes tag is required? please advise the commit and i'll resend.

 drivers/gpu/drm/meson/meson_encoder_hdmi.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
index 5e306de6f485..08529efb4405 100644
--- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
@@ -218,7 +218,8 @@ static void meson_encoder_hdmi_atomic_enable(struct drm_bridge *bridge,
 	if (encoder_hdmi->output_bus_fmt == MEDIA_BUS_FMT_UYYVYY8_0_5X24) {
 		ycrcb_map = VPU_HDMI_OUTPUT_CRYCB;
 		yuv420_mode = true;
-	}
+	} else if (encoder_hdmi->output_bus_fmt == MEDIA_BUS_FMT_UYVY8_1X16)
+		ycrcb_map = VPU_HDMI_OUTPUT_CRYCB;
 
 	/* VENC + VENC-DVI Mode setup */
 	meson_venc_hdmi_mode_set(priv, vic, ycrcb_map, yuv420_mode, mode);
@@ -230,6 +231,10 @@ static void meson_encoder_hdmi_atomic_enable(struct drm_bridge *bridge,
 		/* Setup YUV420 to HDMI-TX, no 10bit diphering */
 		writel_relaxed(2 | (2 << 2),
 			       priv->io_base + _REG(VPU_HDMI_FMT_CTRL));
+	else if (encoder_hdmi->output_bus_fmt == MEDIA_BUS_FMT_UYVY8_1X16)
+		/* Setup YUV422 to HDMI-TX, no 10bit diphering */
+		writel_relaxed(1 | (2 << 2),
+				priv->io_base + _REG(VPU_HDMI_FMT_CTRL));
 	else
 		/* Setup YUV444 to HDMI-TX, no 10bit diphering */
 		writel_relaxed(0, priv->io_base + _REG(VPU_HDMI_FMT_CTRL));
@@ -257,6 +262,7 @@ static void meson_encoder_hdmi_atomic_disable(struct drm_bridge *bridge,
 
 static const u32 meson_encoder_hdmi_out_bus_fmts[] = {
 	MEDIA_BUS_FMT_YUV8_1X24,
+	MEDIA_BUS_FMT_UYVY8_1X16,
 	MEDIA_BUS_FMT_UYYVYY8_0_5X24,
 };
 
-- 
2.17.1