linux-kernel - [PATCH v2 04/14] phy: rockchip: samsung-hdptx: Prevent Inter-Pair Skew from exceeding the limits

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Message-Id: <20250805-phy-hdptx-frl-v2-4-d118bd4b6e0b@collabora.com>
Date: Tue, 05 Aug 2025 14:56:46 +0300
From: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
To: Vinod Koul <vkoul@...nel.org>, 
 Kishon Vijay Abraham I <kishon@...nel.org>, 
 Heiko Stuebner <heiko@...ech.de>, Algea Cao <algea.cao@...k-chips.com>, 
 Dmitry Baryshkov <lumag@...nel.org>
Cc: kernel@...labora.com, linux-phy@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-rockchip@...ts.infradead.org
Subject: [PATCH v2 04/14] phy: rockchip: samsung-hdptx: Prevent Inter-Pair
 Skew from exceeding the limits

Fixup PHY deskew FIFO to prevent the phase of D2 lane going ahead of
other lanes.  It's worth noting this might only happen when dealing with
HDMI 2.0 rates.

Fixes: 553be2830c5f ("phy: rockchip: Add Samsung HDMI/eDP Combo PHY driver")
Co-developed-by: Algea Cao <algea.cao@...k-chips.com>
Signed-off-by: Algea Cao <algea.cao@...k-chips.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
---
 drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
index 9751f7ad00f4faf7041dbf4339f633e09f97b107..5605610465bc812737f773e0f6232cb6dbdc78a4 100644
--- a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
+++ b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
@@ -668,13 +668,9 @@ static const struct reg_sequence rk_hdtpx_common_lane_init_seq[] = {
 
 static const struct reg_sequence rk_hdtpx_tmds_lane_init_seq[] = {
 	REG_SEQ0(LANE_REG(0312), 0x00),
-	REG_SEQ0(LANE_REG(031e), 0x00),
 	REG_SEQ0(LANE_REG(0412), 0x00),
-	REG_SEQ0(LANE_REG(041e), 0x00),
 	REG_SEQ0(LANE_REG(0512), 0x00),
-	REG_SEQ0(LANE_REG(051e), 0x00),
 	REG_SEQ0(LANE_REG(0612), 0x00),
-	REG_SEQ0(LANE_REG(061e), 0x08),
 	REG_SEQ0(LANE_REG(0303), 0x2f),
 	REG_SEQ0(LANE_REG(0403), 0x2f),
 	REG_SEQ0(LANE_REG(0503), 0x2f),
@@ -687,6 +683,11 @@ static const struct reg_sequence rk_hdtpx_tmds_lane_init_seq[] = {
 	REG_SEQ0(LANE_REG(0406), 0x1c),
 	REG_SEQ0(LANE_REG(0506), 0x1c),
 	REG_SEQ0(LANE_REG(0606), 0x1c),
+	/* Keep Inter-Pair Skew in the limits */
+	REG_SEQ0(LANE_REG(031e), 0x02),
+	REG_SEQ0(LANE_REG(041e), 0x02),
+	REG_SEQ0(LANE_REG(051e), 0x02),
+	REG_SEQ0(LANE_REG(061e), 0x0a),
 };
 
 static struct tx_drv_ctrl tx_drv_ctrl_rbr[4][4] = {

-- 
2.50.0