Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API

[Srinivas Kandagatla]

On 21/08/18 14:34, Srinivas Kandagatla wrote:
> On 21/08/18 12:31, Boris Brezillon wrote:
> > >     * struct nvmem_config - NVMEM device configuration
> > > @@ -58,6 +62,7 @@ struct nvmem_config {
> > >           bool                    root_only;
> > >           nvmem_reg_read_t        reg_read;
> > >           nvmem_reg_write_t       reg_write;
> > > +       nvmem_match_t           match;
> > >           int     size;
> > >           int     word_size;
> > >           int     stride;
> > That might work if nvmem cells are defined directly under the mtdnode.
> Layout should not matter! which is the purpose of this callback.
>
> The only purpose of this callback is to tell nvmem core that the 
> node(nvmem cell) belongs to that provider or not, if it is then we 
> successfully found the provider. Its up to the provider on which layout 
> it describes nvmem cells. Additionally the provider can add additional 
> sanity checks in this match function to ensure that cell is correctly 
> represented.
>
>
> > If we go for this approach, I'd recommend replacing this ->match() hook
> > by ->is_nvmem_cell() and pass it the cell node instead of the nvmem
> > node, because what we're really after here is knowing which subnode is
> > an nvmem cell and which subnode is not.
>
> I agree on passing cell node instead of its parent. Regarding basic 
> validating if its nvmem cell or not, we can check compatible string in 
> nvmem core if we decide to use "nvmem-cell" compatible.
>
> Also just in case if you missed this, nvmem would not iterate the
Sorry !! i hit send button too quickly I guess.

What I meant to say here, is that nvmem core would not iterate the 
provider node in any case.

Only time it looks at the cell node is when a consumer requests for the 
cell.

--srini