Re: [PATCH v5 00/21] nvmem: core: introduce NVMEM layouts

[Michael Walle]

Hi Alexander,

thanks for debugging. I'm not yet sure what is going wrong, so
I have some more questions below.

> > This causes the following errors on existing boards (imx8mq-tqma8mq-
> > mba8mx.dtb):
> > root@tqma8-common:~# uname -r
> > 6.2.0-rc2-next-20230105
> >
> > > OF: /soc@0: could not get #nvmem-cell-cells for /soc@0/bus@30000000/
> > efuse@30350000/soc-uid@4
> > > OF: /soc@0/bus@30800000/ethernet@30be0000: could not get #nvmem-cell-cells
> > for /soc@0/bus@30000000/efuse@30350000/mac-address@90
> >
> > These are caused because '#nvmem-cell-cells = <0>;' is not explicitly 
> > set in
> > DT.
> >
> > > TI DP83867 30be0000.ethernet-1:0e: error -EINVAL: failed to get nvmem cell
> > io_impedance_ctrl
> > > TI DP83867: probe of 30be0000.ethernet-1:0e failed with error -22
> >
> > These are caused because of_nvmem_cell_get() now returns -EINVAL 
> > instead of -
> > ENODEV if the requested nvmem cell is not available.

What do you mean with not available? Not yet available because of probe
order?

> Should we just assume #nvmem-cell-cells = <0> by default? I guess it's
> a safe assumption.

Actually, that's what patch 2/21 is for.

Alexander, did you verify that the EINVAL is returned by
of_parse_phandle_with_optional_args()?

-michael