Hi Maxime,
On Wed, Nov 18, 2020 at 06:48:05PM +0100, Maxime Ripard wrote:
On Mon, Oct 12, 2020 at 02:00:30AM +0300, Laurent Pinchart wrote:
-static int drm_of_lvds_get_remote_pixels_type(
const struct device_node *port_node)+static int drm_of_lvds_get_remote_pixels_type(const struct device_node *endpoint) {
- struct device_node *endpoint = NULL;
- int pixels_type = -EPIPE;
- struct device_node *remote_port;
- int pixels_type;
- for_each_child_of_node(port_node, endpoint) {
struct device_node *remote_port;int current_pt;if (!of_node_name_eq(endpoint, "endpoint"))continue;remote_port = of_graph_get_remote_port(endpoint);if (!remote_port) {of_node_put(remote_port);return -EPIPE;}current_pt = drm_of_lvds_get_port_pixels_type(remote_port);
- remote_port = of_graph_get_remote_port(endpoint);
- if (!remote_port) { of_node_put(remote_port);
You can drop this line.
if (pixels_type < 0)pixels_type = current_pt;/** Sanity check, ensure that all remote endpoints have the same* pixel type. We may lift this restriction later if we need to* support multiple sinks with different dual-link* configurations by passing the endpoints explicitly to* drm_of_lvds_get_dual_link_pixel_order().*/Shouldn't we keep this check when endpoint_id is -1 in drm_of_lvds_get_dual_link_pixel_order() ?
I tried to do that, and I'm not quite really sure how to go around it.
This scans all the endpoints in a given port.
However, now that we have the device, port id and endpoint id, we need to use of_graph_get_port_by_id to get the port matching the device and port id, and iterate over all its endpoint as done here.
The trouble is that of_graph_get_port_by_id expects a !const device_node, yet drm_of_lvds_get_dual_link_pixel_order (and seems to be doing so rightfully), so that creates a warning because we drop the const there.
of_graph_get_port_by_id() doesn't seem to modify the device_node passed to it, couldn't it be modified to take a const pointer ?
Changing the prototype to passing only the port device_node doesn't really work either, since it would be const, and we would need to call of_graph_get_endpoint_by_regs (so having the parent device_node, through of_graph_get_port_parent) and of_graph_get_port_parent takes a !const port device_node.
I guess we could drop const entirely from our function, but that doesn't look right either..