linux-kernel - Re: [PATCH v3 0/2] nvmem: skip nodes with compatibles other than "nvmem-cell"

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Date:   Mon, 16 Nov 2020 18:04:26 +0100
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     Rob Herring <robh@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     devicetree@...r.kernel.org, ceggers@...i.de,
        linux-kernel@...r.kernel.org, kernel@...gutronix.de
Subject: Re: [PATCH v3 0/2] nvmem: skip nodes with compatibles other than
 "nvmem-cell"

Hello Rob,
Hello Srini,

On 02.11.20 16:23, Ahmad Fatoum wrote:
>>> I think instead, nvmem cells should be contained within a partition. 
>>> The partition should then have a compatible to indicate it contains 
>>> nvmem cells.
>>
>> I thought I had understood what needs to be done, but now that I finally have time
>> to do it, I see that this only solves the second issue "extending the NVMEM binding
>> to nodes that already have other child nodes, e.g., MTD and its partitions".
>>
>> The first issue: "future extension of e.g. eeprom nodes by any child nodes other than
>> nvmem cells" isn't solved by having a containing partition.
>>
>>
>> My issue is that the bootloader fixes up a partitions { compatible = "fixed-partitions"; }
>> child node into the kernel device tree. The NVMEM core driver tries to parse all eeprom child
>> nodes as cells and will make the driver probe of the EEPROM fail, because it can't parse that
>> fixed-partitions node as a nvmem cell.
>>
>> To allow for co-existence of NVMEM cells and other subnodes, would following patch be
>> acceptable to you and Srini?
> 
> Gentle ping. Would the patch below be acceptable?

Did you have time to look at this?

> 
>>
>> ---------------------------------------- 8< --------------------------------------
>> --- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
>> +++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
>> @@ -45,7 +45,15 @@ properties:
>>  patternProperties:
>>    "^.*@[0-9a-f]+$":
>>      type: object
>> -
>> +    if:
>> +      not:
>> +        properties:
>> +          compatible:
>> +    then:
>> +      $ref: "#/definitions/nvmem-cell"
>> +
>> +definitions:
>> +  nvmem-cell:
>>      properties:
>>        reg:
>>          maxItems: 1
> 
> Cheers,
> Ahmad
> 

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