From: Wolfram Sang <w.sang@pengutronix.de>
To: Lars Poeschel <poeschel@lemonage.de>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-i2c@vger.kernel.org
Subject: Re: [PATCH RFC] misc/at24: distinguish between eeprom and fram chips
Date: Wed, 5 Dec 2012 17:41:53 +0100 [thread overview]
Message-ID: <20121205164153.GA5011@pengutronix.de> (raw)
In-Reply-To: <201212051043.07460.poeschel@lemonage.de>
[-- Attachment #1: Type: text/plain, Size: 1667 bytes --]
Hi,
On Wed, Dec 05, 2012 at 10:43:07AM +0100, Lars Poeschel wrote:
> I see there where to much "no"s to get anything in, but thank you for
> your comments and explanations.
Not necessarily, just not in this form :)
>
> > > I wanted to use a fm24c04 i2c fram chip with linux. I grepped the source
> > > and found nothing. I later found that my chip can be handled by at24
> > > eeprom driver. It creates a sysfs file called eeprom to read from and
> > > write to the chip. Userspace has no chance to distinguish if it is
> > > writing an eeprom or a fram chip.
> >
> > Why should it?
>
> Because writes are much faster and it doesn't have to take care on erase
> cycles. It could use other write strategies on such devices and update
> informations that have to survive power downs more often.
I agree. I think that a seperate attribute named e.g. 'page_size' would
be more helpful than renaming the binary file to fram?
> > The method of accessing EEPROMs is used by way more chips than FRAMs.
> > So, I'd prefer to have the text updated more generic like "EEPROMs and
> > similar devices like RAMs, ROMs, etc...". Describing setting .flags in
> > Kconfig is overkill.
>
> A patch updating Kconfig is below.
Looks good from a glimpse, will apply it later.
> No one knows all chips out there.
> For the fm24c04 I use page_size != chip_size. It does not buffer but it has
> two pages, 256 bytes each.
Yup, it uses two I2C adresses...
Thanks,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
next prev parent reply other threads:[~2012-12-05 16:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-04 16:58 [PATCH RFC] misc/at24: distinguish between eeprom and fram chips Lars Poeschel
2012-12-04 18:32 ` Wolfram Sang
2012-12-05 9:43 ` Lars Poeschel
2012-12-05 16:41 ` Wolfram Sang [this message]
2012-12-07 10:14 ` Lars Poeschel
2013-01-24 7:27 ` Wolfram Sang
2013-01-28 10:40 ` Lars Poeschel
2013-02-06 18:19 ` Lars Poeschel
2013-02-10 16:30 ` Wolfram Sang
2013-02-11 8:51 ` Lars Poeschel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121205164153.GA5011@pengutronix.de \
--to=w.sang@pengutronix.de \
--cc=gregkh@linuxfoundation.org \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=poeschel@lemonage.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).