linux-kernel - [PATCH 3/3] drm/bridge: fsl-ldb: Drop DE signal polarity inversion

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Date:   Fri,  1 Jul 2022 14:56:34 +0800
From:   Liu Ying <victor.liu@....com>
To:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     andrzej.hajda@...el.com, narmstrong@...libre.com,
        robert.foss@...aro.org, Laurent.pinchart@...asonboard.com,
        jonas@...boo.se, jernej.skrabec@...il.com, airlied@...ux.ie,
        daniel@...ll.ch, sam@...nborg.org, marex@...x.de, linux-imx@....com
Subject: [PATCH 3/3] drm/bridge: fsl-ldb: Drop DE signal polarity inversion

It's unnecessary to invert input data enable signal polarity
according to the output one. Let's drop the inversion.
Since ->atomic_check() does nothing more than the inversion,
it can be dropped entirely as well.

Without this patch, 'koe,tx26d202vm0bwa' LVDS panel connected
with i.MX8MP EVK board does not show any data on screen.

Fixes: 463db5c2ed4a ("drm: bridge: ldb: Implement simple Freescale i.MX8MP LDB bridge")
Cc: Andrzej Hajda <andrzej.hajda@...el.com>
Cc: Neil Armstrong <narmstrong@...libre.com>
Cc: Robert Foss <robert.foss@...aro.org>
Cc: Laurent Pinchart <Laurent.pinchart@...asonboard.com>
Cc: Jonas Karlman <jonas@...boo.se>
Cc: Jernej Skrabec <jernej.skrabec@...il.com>
Cc: David Airlie <airlied@...ux.ie>
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: Sam Ravnborg <sam@...nborg.org>
Cc: Marek Vasut <marex@...x.de>
Cc: NXP Linux Team <linux-imx@....com>
Signed-off-by: Liu Ying <victor.liu@....com>
---
 drivers/gpu/drm/bridge/fsl-ldb.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/drivers/gpu/drm/bridge/fsl-ldb.c b/drivers/gpu/drm/bridge/fsl-ldb.c
index d4f005eef6f6..4b503c544256 100644
--- a/drivers/gpu/drm/bridge/fsl-ldb.c
+++ b/drivers/gpu/drm/bridge/fsl-ldb.c
@@ -74,22 +74,6 @@ static int fsl_ldb_attach(struct drm_bridge *bridge,
 				 bridge, flags);
 }
 
-static int fsl_ldb_atomic_check(struct drm_bridge *bridge,
-				struct drm_bridge_state *bridge_state,
-				struct drm_crtc_state *crtc_state,
-				struct drm_connector_state *conn_state)
-{
-	/* Invert DE signal polarity. */
-	bridge_state->input_bus_cfg.flags &= ~(DRM_BUS_FLAG_DE_LOW |
-					       DRM_BUS_FLAG_DE_HIGH);
-	if (bridge_state->output_bus_cfg.flags & DRM_BUS_FLAG_DE_LOW)
-		bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_HIGH;
-	else if (bridge_state->output_bus_cfg.flags & DRM_BUS_FLAG_DE_HIGH)
-		bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_LOW;
-
-	return 0;
-}
-
 static void fsl_ldb_atomic_enable(struct drm_bridge *bridge,
 				  struct drm_bridge_state *old_bridge_state)
 {
@@ -241,7 +225,6 @@ fsl_ldb_mode_valid(struct drm_bridge *bridge,
 
 static const struct drm_bridge_funcs funcs = {
 	.attach = fsl_ldb_attach,
-	.atomic_check = fsl_ldb_atomic_check,
 	.atomic_enable = fsl_ldb_atomic_enable,
 	.atomic_disable = fsl_ldb_atomic_disable,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
-- 
2.25.1