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@rock-chips.com>
Signed-off-by: Algea Cao <algea.cao@rock-chips.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251028-phy-hdptx-fixes-v1-3-ecc642a59d94@collabora.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
index 8ba9b53c2309b22a496574b7731377049f50068f..29de2f7bdae8a31958e31b0a64281532fd76e64d 100644 (file)
--- 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] = {