On 04/29/2016 10:28 AM, Simon Glass wrote:
Hi Stephen,
On 29 April 2016 at 10:23, Stephen Warren swarren@wwwdotorg.org wrote:
On 04/29/2016 07:23 AM, Simon Glass wrote:
Hi Stephen,
On 28 April 2016 at 09:55, Stephen Warren swarren@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@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.