On Tue, 20 May 2014 13:30:02 -0500, Rob Herring <[email protected]> wrote:
> On Tue, May 20, 2014 at 1:50 AM, Grant Likely <[email protected]>
> wrote:
> > On Sun, 18 May 2014 18:11:07 -0500, Rob Herring <[email protected]>
> > wrote:
> >> On Sun, May 18, 2014 at 12:01 PM, Ezequiel Garcia
> >> <[email protected]> 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.
> >
> > The device's uevent file in sysfs contains both the ->name and
> > ->full_name values for a node. Does that help you?
> >
> > The big problem is not the structure under /sys/devices, but rather the
> > symlinks to devices that appear under /sys/bus/*/devices. If two leaf
> > nodes have the same name, then they will conflict when they get added to
> > a bus_type's array of devices.
> >
> > Another way to handle it is to only add the suffix when a conflict
> > actually occurs. That requires checking first whether or not a name will
> > conflict and ammending it only when that happens. I don't know if that
> > can be done nicely. I'll take a look.
>
> That was my idea as well and to move to a local number so you have
> something like deviceA, deviceA.1, deviceB, deviceB.1 (maybe the
> number is always appended). Perhaps a random number instead so no one
> expects the names to be an ABI. ;)
Another idea: how about fix the name to alwasy be the final component of
the path name, followed by phandle. Anything that doesn't have a phandle
can be assigned one at boot. That would guarantee uniqueness without the
cost of trying to find duplicates.
for example:
uart@10043000:0012
g.
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