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Subject: Re: [PATCH 2/2] mtd: spi-nor: add initial sysfs support
To:     Michael Walle <michael@walle.cc>
CC:     <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <p.yadav@ti.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>
References: <20210318092406.5340-1-michael@walle.cc>
 <20210318092406.5340-3-michael@walle.cc>
 <658af7ad-c4ee-1c25-b51b-1f66b657aade@ti.com>
 <4f1de957288118d5a627027ec4c37973@walle.cc>
From:   Vignesh Raghavendra <vigneshr@ti.com>
Message-ID: <e14029f2-587d-0f89-98ee-c08b550bf282@ti.com>
Date:   Tue, 6 Apr 2021 17:13:47 +0530
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On 4/6/21 2:17 PM, Michael Walle wrote:
> Hi,
> 
> Am 2021-04-06 09:56, schrieb Vignesh Raghavendra:
>> Hi,
>>
>> On 3/18/21 2:54 PM, Michael Walle wrote:
>>> Add support to show the name and JEDEC identifier as well as to dump the
>>> SFDP table. Not all flashes list their SFDP table contents in their
>>> datasheet. So having that is useful. It might also be helpful in bug
>>> reports from users.
>>>
>>
>> Sorry for the delay..
>>
>> There is already debugfs support for dumping JEDEC ID [1]. Any reason to
>> add sysfs entry as well?
> 
> This is per mtd while the sfdp is per flash device. IMHO both should
> be at the same place.
> 
>> That brings up another question. Since SFDP dumps are more of a debug
>> aid, should this be a debugfs entry rather than sysfs entry?
> 
> And you're not the first one asking that. My argument was that the
> debugfs might not be available just when you need it. A developer
> could easily rebuild a kernel, but imagine some user with a COTS
> distro and some problems, then it is not that easy anymore. But
> thats your call to make.
> 
>> Note that sysfs entries are userspace ABIs just like syscalls and thus
>> need to be documented in Documentation/ABI/testing/ or
>> Documentation/ABI/stable. Thus need to be carefully designed compared to
>> debugfs which are much more flexible.
> 
> Ok. But I don't see a problem adding these read-only files
>  /sfdp
>  /name
>  /jedec-id
> 

Hmm, ok. but do add documentation please.

Regards
Vignesh