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

Srinivas Kandagatla
2018-08-21T16:57:52Z

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