On Wed, 2020-06-03 at 15:27 +0530, Vaibhav Jain wrote:
> Two things here:
> 1. Why not use the new ndctl_bus_has_of_node helper here? and
> 2. This looks redundant. add_papr_dimm() is only called if
> ndctl_bus_has_of_node() during add_dimm.
Presently we have two different nvdimm implementations:
* papr-scm: handled by arch/powerpc/platforms/pseries/papr_scm kernel module.
* nvdimm-n: handled by drivers/nvdimm/of_pmem kernel module.
Both nvdimms are exposed to the kernel via device tree nodes but different
'compatible' properties. This patchset only adds support for 'papr-scm'
'ndctl_bus_has_of_node()' simply indicates if the nvdimm has an
open-firmware compatible devicetree node associated with it and doesnt
necessarily indicate if its papr-scm compliant.
Hence validating the 'compatible' attribute value is necessary here.
Please see a more detailed info below regarding the 'compatible' sysfs
Understood - one more question:
Would it be useful to wrap the 'compatible' check into an API similar to
_has_of_node - say ndctl_bus_is_papr_compatible()? I'm not too strongly
attached this, there is only one user so far after all, but it seemed
like an easy thing that might get copy-pasted around in the future.