[PATCH v4 20/24] drm/bridge: sn65dsi86: Register and attach our DSI device at probe

From: Maxime Ripard
Date: Fri Sep 10 2021 - 06:14:32 EST


In order to avoid any probe ordering issue, the best practice is to move
the secondary MIPI-DSI device registration and attachment to the
MIPI-DSI host at probe time. Let's do this.

Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 74 ++++++++++++++-------------
1 file changed, 38 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index b5662269ff95..7f71329536a2 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -667,58 +667,27 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
return container_of(bridge, struct ti_sn65dsi86, bridge);
}

-static int ti_sn_bridge_attach(struct drm_bridge *bridge,
- enum drm_bridge_attach_flags flags)
+static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
{
int ret, val;
- struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
struct mipi_dsi_host *host;
struct mipi_dsi_device *dsi;
struct device *dev = pdata->dev;
const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
.channel = 0,
.node = NULL,
- };
+ };

- if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
- DRM_ERROR("Fix bridge driver to make connector optional!");
- return -EINVAL;
- }
-
- pdata->aux.drm_dev = bridge->dev;
- ret = drm_dp_aux_register(&pdata->aux);
- if (ret < 0) {
- drm_err(bridge->dev, "Failed to register DP AUX channel: %d\n", ret);
- return ret;
- }
-
- ret = ti_sn_bridge_connector_init(pdata);
- if (ret < 0)
- goto err_conn_init;
-
- /*
- * TODO: ideally finding host resource and dsi dev registration needs
- * to be done in bridge probe. But some existing DSI host drivers will
- * wait for any of the drm_bridge/drm_panel to get added to the global
- * bridge/panel list, before completing their probe. So if we do the
- * dsi dev registration part in bridge probe, before populating in
- * the global bridge list, then it will cause deadlock as dsi host probe
- * will never complete, neither our bridge probe. So keeping it here
- * will satisfy most of the existing host drivers. Once the host driver
- * is fixed we can move the below code to bridge probe safely.
- */
host = of_find_mipi_dsi_host_by_node(pdata->host_node);
if (!host) {
DRM_ERROR("failed to find dsi host\n");
- ret = -ENODEV;
- goto err_dsi_host;
+ return -ENODEV;
}

dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
if (IS_ERR(dsi)) {
DRM_ERROR("failed to create dsi device\n");
- ret = PTR_ERR(dsi);
- goto err_dsi_host;
+ return PTR_ERR(dsi);
}

/* TODO: setting to 4 MIPI lanes always for now */
@@ -736,10 +705,35 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,
ret = devm_mipi_dsi_attach(dev, dsi);
if (ret < 0) {
DRM_ERROR("failed to attach dsi to host\n");
- goto err_dsi_host;
+ return ret;
}
pdata->dsi = dsi;

+ return 0;
+}
+
+static int ti_sn_bridge_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
+ int ret;
+
+ if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+ DRM_ERROR("Fix bridge driver to make connector optional!");
+ return -EINVAL;
+ }
+
+ pdata->aux.drm_dev = bridge->dev;
+ ret = drm_dp_aux_register(&pdata->aux);
+ if (ret < 0) {
+ drm_err(bridge->dev, "Failed to register DP AUX channel: %d\n", ret);
+ return ret;
+ }
+
+ ret = ti_sn_bridge_connector_init(pdata);
+ if (ret < 0)
+ goto err_conn_init;
+
/* We never want the next bridge to *also* create a connector: */
flags |= DRM_BRIDGE_ATTACH_NO_CONNECTOR;

@@ -1223,7 +1217,15 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,

drm_bridge_add(&pdata->bridge);

+ ret = ti_sn_attach_host(pdata);
+ if (ret)
+ goto err_remove_bridge;
+
return 0;
+
+err_remove_bridge:
+ drm_bridge_remove(&pdata->bridge);
+ return ret;
}

static void ti_sn_bridge_remove(struct auxiliary_device *adev)
--
2.31.1