Re: [PATCH] firmware: vpd: Add an interface to read VPD value

From: Srinivas Kandagatla
Date: Wed Oct 09 2019 - 10:05:18 EST

On 08/10/2019 16:14, Stephen Boyd wrote:
3) As my use case does not use device tree, it is hard for ASoC
machine to access nvmem device. I am wondering if I can use
nvm_cell_lookup so machine driver can find the nvmem device using a
con_id. But currently the cell lookup API requires a matched device,
which does not fit my usage because there will be different machine
drivers requesting the value.
I think I can still workaround this by adding the lookup table in
machine driver. This would seem to be a bit weird because I found that
most lookup table is added in provider side, not consumer side. Not
sure if this is logically correct.
Maybe Srini has some input here. It looks like your main concern is
consumer to provider mapping?

In non-DT setup, there are various ways to lookup nvmem provider.

1> nvmem_device_get()/put() using provider devid/name. I think you should be able to use this in your case.
2> nvmem_register_notifier() which notifies when nvmem provider is added to system.
3> nvmem_device_find() with own match function this will be merged in next window (

If none of these are of any help, could explain what exactly are you looking for w.r.t nvmem to be able to move to what Stephen Boyd suggested?