[RFC] dcss: fix attaching to sn56dsi86 bridge

From: Lukas F. Hartmann
Date: Tue Nov 24 2020 - 12:22:28 EST


The sn56dsi86 DSI to eDP bridge driver does not support attaching
without a drm connector. This patch makes the attachment work. Required
for the display chain in MNT Reform 2.0 (DCSS->NWL DSI->SN56DSI86->EDP).

Signed-off-by: Lukas F. Hartmann <lukas@xxxxxxxxx>
---
drivers/gpu/drm/imx/dcss/dcss-kms.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/imx/dcss/dcss-kms.c b/drivers/gpu/drm/imx/dcss/dcss-kms.c
index 135a62366..4967f828b 100644
--- a/drivers/gpu/drm/imx/dcss/dcss-kms.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-kms.c
@@ -82,6 +82,7 @@ static int dcss_kms_bridge_connector_init(struct dcss_kms_dev *kms)
struct drm_crtc *crtc = (struct drm_crtc *)&kms->crtc;
struct drm_panel *panel;
struct drm_bridge *bridge;
+ struct drm_connector_list_iter iter;
int ret;

ret = drm_of_find_panel_or_bridge(ddev->dev->of_node, 0, 0,
@@ -104,19 +105,19 @@ static int dcss_kms_bridge_connector_init(struct dcss_kms_dev *kms)
return ret;
}

- ret = drm_bridge_attach(encoder, bridge, NULL,
- DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+ ret = drm_bridge_attach(encoder, bridge, NULL, 0);
if (ret < 0) {
dev_err(ddev->dev, "Unable to attach bridge %pOF\n",
bridge->of_node);
return ret;
}

- kms->connector = drm_bridge_connector_init(ddev, encoder);
- if (IS_ERR(kms->connector)) {
- dev_err(ddev->dev, "Unable to create bridge connector.\n");
- return PTR_ERR(kms->connector);
- }
+ /*
+ * This hack to look up the connector is copied from mxsfb.
+ */
+ drm_connector_list_iter_begin(ddev, &iter);
+ kms->connector = drm_connector_list_iter_next(&iter);
+ drm_connector_list_iter_end(&iter);

drm_connector_attach_encoder(kms->connector, encoder);

--
2.28.0