On 04/29/2016 10:28 AM, Simon Glass wrote:
Hi Stephen,
On 29 April 2016 at 10:23, Stephen Warren <swar...@wwwdotorg.org> wrote:
On 04/29/2016 07:23 AM, Simon Glass wrote:
Hi Stephen,
On 28 April 2016 at 09:55, Stephen Warren <swar...@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 <swar...@nvidia.com
<swar...@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.
DT itself imposes no such rule; node names must be unique only within their
parent node but there's no restriction on identical node names appearing in
different parts of the tree.
If U-Boot imposes that rule on DT, then there's no way in general that we
can guarantee U-Boot will be able to use standard DTs (i.e. identical to
those used by Linux or any other OS) for any platform; it'd be another
change someone would need to make to transform a DT to be "U-Boot
compatible", which rather reduces a potential benefit of DT for U-Boot;
being able to just drop a DT in and have it work.
U-Boot does not impose a rule. If you want duplicate device names you
can have them. I think it is bad practice though.
It would be possible for U-Boot to decouple its internal device name from
the DT node name. In which case, your statement would work. However, I don't
think that's the case at the moment, and in fact it's effectively what this
patch is doing, although admittedly there are other ways of doing this.
Anyway I believe my point stands. Whereas users can edit the device
tree and avoid conflicts they cannot do this with auto-probed devices.
So for that case we should have a way of allocating a name before
calling device_bind().
OK. I'm just going to solve this by unplugging the second Ethernet card,
or holding this patch locally for the case when I need to test the PCIe
port.
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