[PATCH v2 3/9] drm/rockchip: vop2: Fix the HDMI sync polarity on RK3588

[Arun Iyengar via B4 Relay <devnull+aiyengar1990.gmail.com@kernel.org>]

From: Arun Iyengar <aiyengar1990@gmail.com>

rk3588_set_intf_mux() passes the POLFLAG bits of the mode to
rk3588_get_hdmi_pol(), which decodes them as DRM mode flags: the
VSYNC_POSITIVE bit is taken for DRM_MODE_FLAG_NHSYNC and POLFLAG_DCLK_INV
for DRM_MODE_FLAG_NVSYNC. As a result GRF_VO1_CON0 marks the HSYNC of
every +HSync/+VSync mode (e.g. all 1080p, 2160p CTA modes) as negative
and both syncs of -HSync/-VSync modes (e.g. 720x480, 640x480) as
positive.

The bits in GRF_VO1_CON0 are set for a negative sync; that is how the
vendor kernel programs them (vop2_get_hdmi_pol(), called with the mode
flags, sets them for DRM_MODE_FLAG_NHSYNC/NVSYNC on RK3588). Decode the
POLFLAG bits accordingly.

Fixes: 5a028e8f062f ("drm/rockchip: vop2: Add support for rk3588")
Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>
---
 drivers/gpu/drm/rockchip/rockchip_vop2_reg.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_vop2_reg.c b/drivers/gpu/drm/rockchip/rockchip_vop2_reg.c
index 659fd0a3ab63..7c48b440cb29 100644
--- a/drivers/gpu/drm/rockchip/rockchip_vop2_reg.c
+++ b/drivers/gpu/drm/rockchip/rockchip_vop2_reg.c
@@ -1687,12 +1687,16 @@ static u32 rk3588_get_mipi_port_mux(int vp_id)
 		return 0;
 }
 
-static u32 rk3588_get_hdmi_pol(u32 flags)
+/*
+ * The HDMI sync polarity bits in GRF_VO1_CON0 are set for an active low
+ * (negative) sync.
+ */
+static u32 rk3588_get_hdmi_pol(u32 polflags)
 {
 	u32 val;
 
-	val = (flags & DRM_MODE_FLAG_NHSYNC) ? BIT(HSYNC_POSITIVE) : 0;
-	val |= (flags & DRM_MODE_FLAG_NVSYNC) ? BIT(VSYNC_POSITIVE) : 0;
+	val = (polflags & BIT(HSYNC_POSITIVE)) ? 0 : BIT(HSYNC_POSITIVE);
+	val |= (polflags & BIT(VSYNC_POSITIVE)) ? 0 : BIT(VSYNC_POSITIVE);
 
 	return val;
 }

-- 
2.55.0