Hi Krzysztof, On Wed, 12 Feb 2025 06:54:19 +0100 Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > On 05/02/2025 18:39, Herve Codina wrote: > > > > dev_dbg(&adap->dev, "of_i2c: walking child nodes from %pOF\n", bus); > > > > - /* Register device directly attached to this bus */ > > + /* > > + * Register device directly described in this bus node before looking > > + * at extensions. > > + */ > > for_each_available_child_of_node(bus, node) { > > + /* Filter out extension node */ > > + if (of_node_name_eq(node, "i2c-bus-extension")) > > Where is the ABI documented? > > > + continue; > > + > > if (of_node_test_and_set_flag(node, OF_POPULATED)) > > continue; > > > > @@ -103,6 +110,23 @@ static void of_i2c_register_children(struct i2c_adapter *adap, > > of_node_clear_flag(node, OF_POPULATED); > > } > > } > > + > > + /* Look at extensions */ > > + for_each_available_child_of_node(bus, node) { > > + if (!of_node_name_eq(node, "i2c-bus-extension")) > > + continue; > > + > > + extension = of_parse_phandle(node, "i2c-bus", 0); > > And this? > > > + if (!extension) > > + continue; > > + I know the binding is not present in this RFC series. As I mentioned in my cover letter, the binding that needs to be updated is available in dt-schema repo [0]. When the binding is be accepted in dt-schema repo, I will not be able to change it and because two repos are involved, I cannot send the binding and the implementation in the same series. Before sending a patch to update the binding in dt-schema repo, I would like first to discuss the proposed i2c bus extension idea in terms of: 1) DT properties naming and purpose 2) implementation [0] https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/i2c/i2c-controller.yaml Best regards, Hervé