On Mon, Oct 13, 2025 at 09:26:06AM +0800, Chaoyi Chen wrote: > On 10/12/2025 2:52 AM, Dmitry Baryshkov wrote: > > > On Sat, Oct 11, 2025 at 11:32:31AM +0800, Chaoyi Chen wrote: > > > From: Chaoyi Chen <[email protected]> > > > > > > The RK3399 has two USB/DP combo PHY and one CDN-DP controller. And > > > the CDN-DP can be switched to output to one of the PHYs. If both ports > > > are plugged into DP, DP will select the first port for output. > > > > > > This patch adds support for multiple bridges, enabling users to flexibly > > > select the output port. For each PHY port, a separate encoder and bridge > > > are registered. > > > > > > The change is based on the DRM AUX HPD bridge, rather than the > > > extcon approach. This requires the DT to correctly describe the > > > connections between the first bridge in bridge chain and DP > > > controller. For example, the bridge chain may be like this: > > > > > > PHY aux birdge -> fsa4480 analog audio switch bridge -> > > > onnn,nb7vpq904m USB reminder bridge -> USB-C controller AUX HPD bridge > > > > > > In this case, the connection relationships among the PHY aux bridge > > > and the DP contorller need to be described in DT. > > > > > > In addition, the cdn_dp_parse_hpd_bridge_dt() will parses it and > > > determines whether to register one or two bridges. > > > > > > Since there is only one DP controller, only one of the PHY ports can > > > output at a time. The key is how to switch between different PHYs, > > > which is handled by cdn_dp_switch_port() and cdn_dp_enable(). > > > > > > There are two cases: > > > > > > 1. Neither bridge is enabled. In this case, both bridges can > > > independently read the EDID, and the PHY port may switch before > > > reading the EDID. > > > > > > 2. One bridge is already enabled. In this case, other bridges are not > > > allowed to read the EDID. So we will try to return the cached EDID. > > > > > > Since the scenario of two ports plug in at the same time is rare, > > > I don't have a board which support two TypeC connector to test this. > > > Therefore, I tested forced switching on a single PHY port, as well as > > > output using a fake PHY port alongside a real PHY port. > > > > > > Signed-off-by: Chaoyi Chen <[email protected]> > > > --- > > > > > > + /* One endpoint may correspond to one HPD bridge. */ > > > + for_each_of_graph_port_endpoint(port, dp_ep) { > > > + struct device_node *phy_bridge_node __free(device_node) = > > > + of_graph_get_remote_port_parent(dp_ep); > > > + > > > + bridge = of_drm_find_bridge(phy_bridge_node); > > > + if (!bridge) { > > > + ret = -EPROBE_DEFER; > > > + goto out; > > > + } > > > + > > > + dp->hpd_bridge_valid = true; > > > + dp->hpd_bridge_list[count].bridge = bridge; > > > + dp->hpd_bridge_list[count].parent = dp; > > > + dp->hpd_bridge_list[count].id = count; > > This looks misnamed. They are not necessarily HPD bridges. There can be > > a random chain between your controller and the actual output / connector > > /etc. > > Yes, and more precisely, this should be `pervious_bridge_list` . Will fix in > v6.
I think the typical convention is around next_bridge, not previous. -- With best wishes Dmitry
