linux-kernel - Re: [PATCH 2/5] dt-bindings: nvmem: Convert xlnx,zynqmp-nvmem.txt to yaml

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Message-ID: <a032e313-d548-4bd3-a126-1b8c71095172@amd.com>
Date:   Fri, 13 Oct 2023 15:12:17 +0200
From:   Michal Simek <michal.simek@....com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        "Praveen Teja Kundanala" <praveen.teja.kundanala@....com>,
        <srinivas.kandagatla@...aro.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] dt-bindings: nvmem: Convert xlnx,zynqmp-nvmem.txt to
 yaml



On 10/13/23 15:10, Krzysztof Kozlowski wrote:
> On 13/10/2023 15:06, Michal Simek wrote:
>>
>>
>> On 10/13/23 14:54, Krzysztof Kozlowski wrote:
>>> On 13/10/2023 14:08, Michal Simek wrote:
>>>>
>>>>
>>>> On 10/13/23 13:58, Krzysztof Kozlowski wrote:
>>>>> On 13/10/2023 13:51, Michal Simek wrote:
>>>>>>
>>>>>>
>>>>>> On 10/13/23 13:46, Krzysztof Kozlowski wrote:
>>>>>>> On 13/10/2023 13:22, Michal Simek wrote:
>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>> +required:
>>>>>>>>>> +  - compatible
>>>>>>>>>
>>>>>>>>> required: block goes after patternProperties: block
>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>> +patternProperties:
>>>>>>>>>> +  "^soc_revision@0$":
>>>>>>>>>
>>>>>>>>> Why do you define individual memory cells? Is this part of a binding?
>>>>>>>>> IOW, OS/Linux requires this?
>>>>>>>>
>>>>>>>> nvmem has in kernel interface where you can reference to nodes. nvmem_cell_get()
>>>>>>>> calls. It means you should be able to describe internal layout that's why names
>>>>>>>> are used. And address in name is there because of reg property is used to
>>>>>>>> describe base offset and size.
>>>>>>>
>>>>>>> That's not really what I am asking. Why internal layout of memory must
>>>>>>> be part of the bindings?
>>>>>>
>>>>>> It doesn't need to be but offsets are hardcoded inside the driver itself and
>>>>>> they can't be different.
>>>>>
>>>>> Hm, where? I opened drivers/nvmem/zynqmp_nvmem.c and I do not see any
>>>>> hard-coded offsets.
>>>>
>>>> Current driver supports only soc revision from offset 0.
>>>> But if you look at 5/5 you need to define offsets where information is present.
>>>> +#define SOC_VERSION_OFFSET	0x0
>>>> +#define EFUSE_START_OFFSET	0xC
>>>> +#define EFUSE_END_OFFSET	0xFC
>>>> +#define EFUSE_PUF_START_OFFSET	0x100
>>>> +#define EFUSE_PUF_MID_OFFSET	0x140
>>>> +#define EFUSE_PUF_END_OFFSET	0x17F
>>>
>>> There is nothing like this in existing driver, so the argument that "I
>>> am adding this to the binding during conversion because driver needs it"
>>> is not true. Conversion is only a conversion.
>>
>> Conversion in 2/5 is adding only soc revision which is already there. It is
>> starting from 0 and world size is 1. And 0 is not listed because that's start
>> all the time.
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/nvmem/zynqmp_nvmem.c?h=v6.6-rc5#n39
> 
> This defines the nvmem config, not what should be where.

If you have only one entry you are also saying where it is.

Thanks,
Michal