[U-Boot] [RFC PATCH] dm: ensure device names are unique

[Simon Glass]

Hi Stephen,

On 28 April 2016 at 09:55, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 04/27/2016 10:50 PM, Simon Glass wrote:
>>
>> Hi Stephen,
>>
>> On 26 April 2016 at 15:30, Stephen Warren wrote:
>>  > It is possible for HW to contain multiple instances of the same device.
>> In
>>  > this case, the name passed to device_bind() may not be unique across
>> all
>>  > devices within its uclass. One example is a system with multiple
>> identical
>>  > PCI Ethernet devices. Another might be a system with multiple identical
>>  > I2C GPIO expanders, each connected to a separate I2C bus, yet using the
>>  > same I2C address on that bus and hence having the same DT node name.
>>  >
>>  > Enhance the code to detect this situation, and append a sequence
>> number so
>>  > the device name to ensure uniqueness.
>>  >
>>  > Signed-off-by: Stephen Warren <swarren at nvidia.com <swarren at nvidia.com>>
>>
>> I would rather that the caller handles this. But failing this perhaps a
>> new function that does it? Is this for the Ethernet use case?
>
>
> Wouldn't all callers of this function simply call the new function? I'm not
> aware of any case where the code to avoid duplicate names would not be
> desired.
>
> I hit this for the Ethernet case, but I believe it applies to any type of
> device at all; see another possible trigger case in the commit description.

This does not happen with devices from the device tree. It only
happens with auto-probed devices. Your I2C GPIO example is odd but I'd
rather solve that by using the device tree node name.

I'd like to avoid putting things in the base code that we don't need
early on in boot. How about a helper function for those subsystems
that create devices outside the device tree system?

Regards,
Simon