On Sun, May 18, 2014 at 12:01 PM, Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx> wrote: > When creating a device object for a devicetree node, the device name > is created by using the node name and the 'reg' property, to make a name > such as "a000.foo_device". > > For certain devices without an associated address, and hence no 'reg' property, > the current code attempts to make a unique name, by using a global integer. > Names look like "foo_device.1", "bar_device.2", and so on. > Examples of such devices are: gpio-keys', backlights and rotary-encoders. > > The system cannot know such devices name before hand, given they are determined > by the kernel probe order and by the nodes present in the devicetree. This can > be problematic, on systems that are tied to the device's name, e.g. when > catching hotplug events. > > In order to fix the name, this commit removes the global integer uniqueness > enforcement and instead uses the node name for the device name. The rationale > behind such change, is that there's no way two nodes with the same node name > are associated to two different devices, by the nature of the devicetree. > In other words, it's impossible to produce a name collision for these kind > of devices. This is perfectly legal: /bus1/device /bus2/device Only the full name has to be unique. > > Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx> > --- > Hello Grant, Rob: > > I'm pretty sure there's a good reason for the existence of the atomic magic > integer, so this is not a *real* patch, but rather a bold attempt at asking you > some explanations for this. > > Under what circumstances does the magic integer avoids a name collision? > Will this propposal introduce a regression? See the recent changes to this function in linux-next and the associated discussion of those commits. Rob -- 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
