On Thursday 02 October 2014 00:09:44 Rafael J. Wysocki wrote: > On Wednesday, October 01, 2014 09:47:40 AM Arnd Bergmann wrote: > > On Wednesday 01 October 2014 04:10:03 Rafael J. Wysocki wrote: > > I still have my reservations against the child accessors, and would > > like to hear what other people think. Passing a void pointer rather > > than struct fw_dev_node has both advantages and disadvantages, and > > I won't complain about either one if enough other people on the DT > > side would like to see the addition of the child functions. > > I actually would rather like to know if the people on the DT side have any > problems with the child functions. Sure, any kind of feedback would be helpful really. > Because, suppose that they wouldn't like those functions at all. What are we > supposed to do, then, honestly? Add the whole DT vs ACPI logic to the leds-gpio > and gpio_keys_polled drivers? But these drivers have no reason whatsoever > to include that. Zero. > > So suggestions welcome. > > [BTW, In principle we also could use something like > > typedef union dev_node { > struct acpi_device *acpi_node; > struct device_node *of_node; > } dev_node_t; > > instead of the (void *) for more type safety. It still is useful to pass the > parent pointer along with that, though.] Yes, I'm not worried about the implementation details. > > > Finally, device_for_each_child_node() is added for iterating over > > > the children of the device description object associated with a > > > given device. > > > > > > The interface covers both ACPI and Device Trees. > > > > > > This change set includes material from Mika Westerberg and Aaron Lu. > > > > > > > Regarding device_for_each_child_node(), the syntax is inconsistent > > with what we normally use, which can probably be changed. All of the > > DT for_each_* helpers are macros that are used like > > > > struct device *dev = ...; > > void *child; /* iterator */ > > > > device_for_each_child_node(dev, child) { > > u32 something; > > device_child_property_read_u32(dev, child, "propname", &something); > > > > do_something(dev, something); > > } > > > > If we get a consensus on having the child interfaces, I'd rather see > > them done this way than with a callback pointer, for consistency > > reasons. > > That certainly is doable, although the resulting macro would generate a rather > large chunk of code each time it is used. #define device_for_each_child_node(dev, child) \ for (child = device_get_next_child_node(dev, NULL), child, \ child = device_get_next_child_node(dev, child)) void *device_get_next_child_node(struct device *dev, void *child) { if (IS_ENABLED(CONFIG_OF) && dev->of_node) return of_get_next_child(dev->of_node, child); else if (IS_ENABLED(CONFIG_ACPI) && ...) return acpi_get_next_child(dev, child); return NULL; } Not any more code than what we have today for the DT-only case, and it's really just a function call in a loop. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html