diff options
Diffstat (limited to 'drivers/gpu/drm/sun4i/sun4i_tcon.c')
| -rw-r--r-- | drivers/gpu/drm/sun4i/sun4i_tcon.c | 55 |
1 files changed, 51 insertions, 4 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 5adb643ed41d..b13a7c2029df 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -403,6 +403,53 @@ static int sun4i_tcon_init_regmap(struct device *dev, return 0; } +/* + * On SoCs with the old display pipeline design (Display Engine 1.0), + * the TCON is always tied to just one backend. Hence we can traverse + * the of_graph upwards to find the backend our tcon is connected to, + * and take its ID as our own. + * + * We can either identify backends from their compatible strings, which + * means maintaining a large list of them. Or, since the backend is + * registered and binded before the TCON, we can just go through the + * list of registered backends and compare the device node. + */ +static struct sun4i_backend *sun4i_tcon_find_backend(struct sun4i_drv *drv, + struct device_node *node) +{ + struct device_node *port, *ep, *remote; + struct sun4i_backend *backend; + + port = of_graph_get_port_by_id(node, 0); + if (!port) + return ERR_PTR(-EINVAL); + + for_each_available_child_of_node(port, ep) { + remote = of_graph_get_remote_port_parent(ep); + if (!remote) + continue; + + /* does this node match any registered backends? */ + list_for_each_entry(backend, &drv->backend_list, list) { + if (remote == backend->node) { + of_node_put(remote); + of_node_put(port); + return backend; + } + } + + /* keep looking through upstream ports */ + backend = sun4i_tcon_find_backend(drv, remote); + if (!IS_ERR(backend)) { + of_node_put(remote); + of_node_put(port); + return backend; + } + } + + return ERR_PTR(-EINVAL); +} + static int sun4i_tcon_bind(struct device *dev, struct device *master, void *data) { @@ -412,9 +459,11 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master, struct sun4i_tcon *tcon; int ret; - /* Wait for a backend to be registered */ - if (list_empty(&drv->backend_list)) + backend = sun4i_tcon_find_backend(drv, dev->of_node); + if (IS_ERR(backend)) { + dev_err(dev, "Couldn't find matching backend\n"); return -EPROBE_DEFER; + } tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL); if (!tcon) @@ -464,8 +513,6 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master, goto err_free_dotclock; } - backend = list_first_entry(&drv->backend_list, - struct sun4i_backend, list); tcon->crtc = sun4i_crtc_init(drm, backend, tcon); if (IS_ERR(tcon->crtc)) { dev_err(dev, "Couldn't create our CRTC\n"); |