Device tree node to major/minor?

[Simon Glass]

Hi,

I hope this is a stupid question with an easy answer, but I cannot find it.

I have a device tree node for an mmc block device and I want to use
that block device from another driver. I have a phandle which lets me
get the node of the mmc device, but I am not sure how to convert that
into a block_device. In order to do so, I think I need a major/minor
number. Of course the phandle might in fact point to a SCSI driver and
I want that to work correctly also.

I imagine I might be able to search through the wonders of sysfs in
user space, but is there a better way?

Thanks,
Simon