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

[Stephen Warren <swarren@wwwdotorg.org>]

On 04/26/2016 03:30 PM, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
>
> 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@nvidia.com>
> ---
> Some possible issues with this patch:
>
> 1) Doing this in bind() rather than probe() means dev->seq isn't
> available, so can't be used to generate the unique name. This process
> should be done during bind() rather than probe() though, since devices can
> be seen (e.g. by running "dm tree") before they're probed. Perhaps the
> uclass_resolve_seq() should be called by bind() not probe().
>
> 2) uclass_find_device_by_name() needs to look up the uclass pointer again
> even though device_bind() already knows it.
>
> 3) Iterating over the list to find the count of devices in the uclass is a
> bit annoying. Should the uclass maintain this count so it doesn't need to
> be re-calculated each time?

4) This causes "ut dm autobind" to fail. I'll investigate that locally, 
but won't bother reposting until the questions above are considered.