[PATCH 5.10 068/106] drm/bridge: ti-sn65dsi86: Fix output polarity setting bug

Greg Kroah-Hartman
2022-12-12T13:16:22Z

From: Qiqi Zhang <eddy.zhang@rock-chips.com>

[ Upstream commit 8c115864501fc09932cdfec53d9ec1cde82b4a28 ]

According to the description in ti-sn65dsi86's datasheet:

CHA_HSYNC_POLARITY:
0 = Active High Pulse. Synchronization signal is high for the sync
pulse width. (default)
1 = Active Low Pulse. Synchronization signal is low for the sync
pulse width.

CHA_VSYNC_POLARITY:
0 = Active High Pulse. Synchronization signal is high for the sync
pulse width. (Default)
1 = Active Low Pulse. Synchronization signal is low for the sync
pulse width.

We should only set these bits when the polarity is negative.

Fixes: a095f15c00e2 ("drm/bridge: add support for sn65dsi86 bridge driver")
Signed-off-by: Qiqi Zhang <eddy.zhang@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221125104558.84616-1-eddy.zhang@rock-chips.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 1a58481037b3..77a447a3fb1d 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -621,9 +621,9 @@ static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
&pdata->bridge.encoder->crtc->state->adjusted_mode;
u8 hsync_polarity = 0, vsync_polarity = 0;

- if (mode->flags & DRM_MODE_FLAG_PHSYNC)
+ if (mode->flags & DRM_MODE_FLAG_NHSYNC)
hsync_polarity = CHA_HSYNC_POLARITY;
- if (mode->flags & DRM_MODE_FLAG_PVSYNC)
+ if (mode->flags & DRM_MODE_FLAG_NVSYNC)
vsync_polarity = CHA_VSYNC_POLARITY;

ti_sn_bridge_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
--
2.35.1