Re: [PATCH v9 0/9] Add simple NVMEM Framework via regmap.

From: Stefan Wahren <stefan.wahren@i2se.com>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Andrew Lunn <andrew@lunn.ch>
Cc: wxt@rock-chips.com, linux-api@vger.kernel.org,
	Rob Herring <robh+dt@kernel.org>,
	sboyd@codeaurora.org, arnd@arndb.de,
	linux-arm-kernel@lists.infradead.org, khilman@kernel.org,
	s.hauer@pengutronix.de,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	mporter@konsulko.com, pantelis.antoniou@konsulko.com,
	devicetree@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	maitysanchayan@gmail.com, p.zabel@pengutronix.de
Subject: Re: [PATCH v9 0/9] Add simple NVMEM Framework via regmap.
Date: Mon, 10 Aug 2015 13:24:38 +0200 (CEST)	[thread overview]
Message-ID: <997560650.82109.1439205878609.JavaMail.open-xchange@oxbsltgw00.schlund.de> (raw)
In-Reply-To: <55C87EEF.6020609@linaro.org>

Hi Srinivas,
hi Andrew,

[add Sanchayan and Philipp]

> Srinivas Kandagatla <srinivas.kandagatla@linaro.org> hat am 10. August 2015 um
> 12:37 geschrieben:
>
>
> Hi Andrew,
>
> On 09/08/15 16:19, Andrew Lunn wrote:
> > Hi Srinivas
> >
> > The AT24 eeprom driver contains the comment:
> >
> > /*
> > * Export the EEPROM bytes through sysfs, since that's convenient.
> > * By default, only root should see the data (maybe passwords etc)
> > */
> >
> > and as you would expect from this:
> >
> > # ls -l
> > ./devices/platform/soc/soc:aips-bus@40000000/40066000.i2c/i2c-0/0-0050/eeprom
> > -rw------- 1 root root 512 Aug 9 10:16
> > ./devices/platform/soc/soc:aips-bus@40000000/40066000.i2c/i2c-0/0-0050/eeprom
> >
> > The AT25 and the MAX6875 driver are the same.
> >
> > However nvmem has different defaults:
> >
> > # ls -l
> > ./devices/platform/soc/soc:aips-bus@40000000/40066000.i2c/i2c-0/0-0050/0-00500/nvmem
> > -rw-r--r-- 1 root root 0 Aug 9 10:16
> > ./devices/platform/soc/soc:aips-bus@40000000/40066000.i2c/i2c-0/0-0050/0-00500/nvmem
> >
> Yes, nvmem by default sets the read permission for everyone S_IRUGO.
> Which was the most common use case.

i can only speak for mxs-ocotp, but root-only access is sufficient.

>
> > Has this been considered and discussed?
> Thanks for bringing this up, No, we did not discuss this explicitly, but
> it should not be an issue to accommodate this. Provider still have
> flexibility to configure such things.

IMHO it would better the default settings of the framework would be compatible
and same restrictive as the eeprom drivers.

In case a provider needs more privileges, it should be his job.

>
> As a first patchset we wanted to keep the framework simple and add
> features as we move on.

That's true, but it's an ABI too. So changing default settings soon is better.

Regards
Stefan

>
> Thanks,
> srini
> >
> > Thanks
> > Andrew
> >
>
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