[PATCH v4 08/12] drm: bridge: samsung-dsim: Add atomic_check

[Jagan Teki <jagan@amarulasolutions.com>]

Explicit fixing up of mode_flags is required for DSIM present
in i.MX8M SoC.

At least the LCDIF + DSIM needs active low sync polarities in
order to correlate the correct sync flags of the surrounding
components in the chain to make sure the whole pipeline can
work properly.

So, add DSIM_QUIRK_FIXUP_SYNC_POL to handle this fixup via bridge
atomic_check.

v4:
* none

v3:
* add DSIM_QUIRK_FIXUP_SYNC_POL to handle mode_flasg fixup

v2:
* none

v1:
* fix mode flags in atomic_check instead of mode_fixup

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++++++++
 include/drm/bridge/samsung-dsim.h     |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index b6d17c0c9e58..724fd76435c6 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1341,6 +1341,23 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
 	pm_runtime_put_sync(dsi->dev);
 }
 
+static int samsung_dsim_atomic_check(struct drm_bridge *bridge,
+				     struct drm_bridge_state *bridge_state,
+				     struct drm_crtc_state *crtc_state,
+				     struct drm_connector_state *conn_state)
+{
+	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
+	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+
+	if (dsi->driver_data->quirks & DSIM_QUIRK_FIXUP_SYNC_POL) {
+		/* At least LCDIF + DSIM needs active low sync */
+		adjusted_mode->flags |= (DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+		adjusted_mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
+	}
+
+	return 0;
+}
+
 static void samsung_dsim_mode_set(struct drm_bridge *bridge,
 				  const struct drm_display_mode *mode,
 				  const struct drm_display_mode *adjusted_mode)
@@ -1363,6 +1380,7 @@ static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
 	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset			= drm_atomic_helper_bridge_reset,
+	.atomic_check			= samsung_dsim_atomic_check,
 	.atomic_pre_enable		= samsung_dsim_atomic_pre_enable,
 	.atomic_enable			= samsung_dsim_atomic_enable,
 	.atomic_disable			= samsung_dsim_atomic_disable,
diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
index 95d3f89aec4f..62e1078f43cc 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -36,6 +36,7 @@ struct samsung_dsim_transfer {
 
 enum samsung_dsim_quirks {
 	DSIM_QUIRK_PLAT_DATA		= BIT(0),
+	DSIM_QUIRK_FIXUP_SYNC_POL	= BIT(1),
 };
 
 struct samsung_dsim_driver_data {
-- 
2.25.1