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From:   Jammy Huang <jammy_huang@aspeedtech.com>
To:     <eajames@linux.ibm.com>, <mchehab@kernel.org>, <joel@jms.id.au>,
        <andrew@aj.id.au>, <linux-media@vger.kernel.org>,
        <openbmc@lists.ozlabs.org>, <linux-arm-kernel@lists.infradead.org>,
        <linux-aspeed@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>
CC:     Paul Menzel <pmenzel@molgen.mpg.de>
Subject: [PATCH v3] media: aspeed: Use full swing as JFIF to fix incorrect color
Date:   Thu, 10 Feb 2022 17:29:45 +0800
Message-ID: <20220210092945.5027-1-jammy_huang@aspeedtech.com>
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Current settings for video capture rgb-2-yuv is BT.601(studio swing),
but JFIF uses BT.601(full swing) to deocde. This mismatch will lead
to incorrect color. For example, input RGB value, (0, 0, 255), will
become (16, 16, 235) after jpg decoded.

Add an enum, aspeed_video_capture_format, to define VR008[7:6]
capture format and correct default settings for video capture to fix
the problem.

VR008[7:6] decides the data format for video capture as below:
* 00: CCIR601 studio swing compliant YUV format
* 01: CCIR601 full swing compliant YUV format
* 10: RGB format
* 11: Gray color mode

Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
---
v3:
 - update commit message
 - update enum's naming to append '_SWING'
v2:
 - update subject from 'media: aspeed: Fix-incorrect-color' to
   'media: aspeed: Use full swing as JFIF to fix incorrect'
 - update commit message
 - add enum, aspeed_video_capture_format, to define VR008[7:6]
---
 drivers/media/platform/aspeed-video.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
index eb9c17ac0e14..ee702f9b708b 100644
--- a/drivers/media/platform/aspeed-video.c
+++ b/drivers/media/platform/aspeed-video.c
@@ -86,8 +86,6 @@
 #define  VE_CTRL_SOURCE			BIT(2)
 #define  VE_CTRL_INT_DE			BIT(4)
 #define  VE_CTRL_DIRECT_FETCH		BIT(5)
-#define  VE_CTRL_YUV			BIT(6)
-#define  VE_CTRL_RGB			BIT(7)
 #define  VE_CTRL_CAPTURE_FMT		GENMASK(7, 6)
 #define  VE_CTRL_AUTO_OR_CURSOR		BIT(8)
 #define  VE_CTRL_CLK_INVERSE		BIT(11)
@@ -202,6 +200,15 @@ enum {
 	VIDEO_CLOCKS_ON,
 };
 
+// for VE_CTRL_CAPTURE_FMT
+enum aspeed_video_capture_format {
+	VIDEO_CAP_FMT_YUV_STUDIO_SWING = 0,
+	VIDEO_CAP_FMT_YUV_FULL_SWING,
+	VIDEO_CAP_FMT_RGB,
+	VIDEO_CAP_FMT_GRAY,
+	VIDEO_CAP_FMT_MAX
+};
+
 struct aspeed_video_addr {
 	unsigned int size;
 	dma_addr_t dma;
@@ -1089,7 +1096,8 @@ static void aspeed_video_init_regs(struct aspeed_video *video)
 	u32 comp_ctrl = VE_COMP_CTRL_RSVD |
 		FIELD_PREP(VE_COMP_CTRL_DCT_LUM, video->jpeg_quality) |
 		FIELD_PREP(VE_COMP_CTRL_DCT_CHR, video->jpeg_quality | 0x10);
-	u32 ctrl = VE_CTRL_AUTO_OR_CURSOR;
+	u32 ctrl = VE_CTRL_AUTO_OR_CURSOR |
+		FIELD_PREP(VE_CTRL_CAPTURE_FMT, VIDEO_CAP_FMT_YUV_FULL_SWING);
 	u32 seq_ctrl = video->jpeg_mode;
 
 	if (video->frame_rate)
-- 
2.25.1