Hi All, I have few queries on of_platform_populate and of_platform_bus_probe functions.
Use-case is, I want to explicitly register platform devices from some nodes at post-core or late-init level(like child@1). And I don't want of_platform_populate to register platform devices for that node again, so I pass "simple-bus" in match-table. Problem is that exiting code for of_platform_populate probes it. Looking at the function documentation, which states of_platform_bus_probe will only create children of the root which are selected by the @matches argument. of_platform_populate walks the device tree and creates devices from nodes. It differs in that it follows the modern convention of requiring all device nodes to have a 'compatible' property, and it is suitable for creating devices which are children of the root node. Lets say If we call of_platform_populate(NULL, match_table, NULL, NULL) on a device trees like the below with struct of_device_id match_table[] = { { .compatible = "simple-bus", } {} }; parent@0{ compatible = "xxx,parent1", "simple-bus"; ... child@0 { compatible = "xxx,child0", "simple-bus"; ... }; child@1 { compatible = "xxx,child1"; ... }; child@2 { compatible = "xxx,child2", "simple-bus"; ... }; }; of_platform_bus_probe would create platform-devices for parent@0, child@0 and child@2 where as of_platform_populate would create platform-devices for parent@0, child@0, child@1 and child@2 nodes. So the question is why do we need to have @matches argument to of_platform_populate in the first place, if it creates all the devices by walking the dt nodes? It is bit confusing, As some platforms use of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL) assuming that only matching nodes will end up having platform device. Also some platforms use of_platform_bus_probe(NULL, match_table, NULL), where match table is of_default_bus_match_table. Am not 100% sure what is the right solution, but I think lot of platforms would want behavior like of_platform_bus_probe which takes lookups aswell. If the suggestion is to use of_platform_bus_probe, Which I can't use as It does not take Auxdata(lookups). Thanks, srini _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss