Hi all, Allow me to compare this approach with some work Linus W [1] did a while back, which I've just noticed. Pauls' approach: - Perhaps the shortest one possible Porting an existing DSI panel to DBI is 3 lines of code - compat line in the SPI/DSI bridge, a bus_type and mipi_dsi_maybe_register_tiny_driver() call The clever use of the DSI type (equal to zero) means that things will work w/o updating existing dsi hosts and devices in panel/. Yet in the very unlikely case that the panel does not support DSI, we will still allow it. Although thinking about the type I wonder if it can accommodate all use-cases: Since we can have a device (panel) capable of DSI+SPI it makes sense for it to expose the type bitmask, not the host. Although, what if the host itself supports DSI+SPI.? Now we can extrapolate that with a host (say fimd/exynos I think) which supports a SPI panel (s6e63m0) while having of_graph_get_port_by_id(0)? - Strange (ab)use of the DSI bus for DBI (SPI, 6800, 8080 etc) We care about existing users (DT) and it sounds unlikely (based on previous discussion) that DBI + SPI/6800... will make it into DT. So the current approach seems quite reasonable IMHO. Linus' approach: - Clear separation of DSI/SPI Compat strings are still duplicated, although in separate files - Minor code motion and slightly more invasive porting overall Much of the boilerplate can be reduced via helper lib and macros. Even then it's unlikely we'll reach the 3 line delta as with Paul's approach. - Does not handle tiny-dsi (dummy) drm driver It seems doable, with minor changes Personally I'm on the fence and a deciding factor for me is if Paul's approach can handle all the combinations of host/device type support. That said, the input from people likely to do the work would be highly appreciated. Once a decision is made, an illustrative series + todo entry would be great to have. -Emil [1] https://lists.freedesktop.org/archives/dri-devel/2020-May/266079.html _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
