From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] [PATCH 1/1] Fix I2C for m547x/548x and m5445x processors.
Date: Mon, 07 Jul 2008 20:02:17 +0200 [thread overview]
Message-ID: <20080707180217.B3DFA248FE@gemini.denx.de> (raw)
In-Reply-To: Your message of "Mon, 07 Jul 2008 18:17:45 +0200." <1215447465.12657.15.camel@localhost>
In message <1215447465.12657.15.camel@localhost> you wrote:
>
> I just extended the fsl_i2c.c driver that already uses a precomputed
Yes, I know. I never understood what such a complicated driver for
sich a simple protocol was good for, especially as we don't do
multimegabytepersecond transfers over such a bus.
> table to setup the fsl i2c. I haven't invented these values but just
> copied from the 547x and 5445x manuals. Furthermore, the h/w i2c is more
> accurate that the simple bitbanging.
Accurate? There is no requirement to be "accurate" anywhere in the
I2C protocol. It is a simple, brain-dead protokol where timing is
highly uncritical. And given that we need it to read a few bytes from
EEPROM or RTC or similar I really see no benefit in using such a
complicated driver.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
How many seconds are there in a year? If I tell you there are 3.155 x
10^7, you won't even try to remember it. On the other hand, who could
forget that, to within half a percent, pi seconds is a nanocentury.
- Tom Duff, Bell Labs
next prev parent reply other threads:[~2008-07-07 18:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-07 14:08 [U-Boot-Users] [COLDFIRE] Luigi 'Comio' Mantellini
2008-07-07 14:08 ` [U-Boot-Users] [PATCH 1/1] Fix I2C for m547x/548x and m5445x processors Luigi 'Comio' Mantellini
2008-07-07 14:59 ` Wolfgang Denk
2008-07-07 16:17 ` Luigi 'Comio' Mantellini
2008-07-07 18:02 ` Wolfgang Denk [this message]
2008-07-07 19:24 ` Luigi 'Comio' Mantellini
2008-07-09 13:22 ` Timur Tabi
-- strict thread matches above, loose matches on Subject: below --
2008-07-07 14:11 [U-Boot-Users] [COLDFIRE] I2C patch 547x/548x cpus Luigi 'Comio' Mantellini
2008-07-07 14:11 ` [U-Boot-Users] [PATCH 1/1] Fix I2C for m547x/548x and m5445x processors Luigi 'Comio' Mantellini
2008-07-07 14:17 ` Luigi 'Comio' Mantellini
2008-07-09 13:25 ` Timur Tabi
2008-07-09 13:40 ` Luigi 'Comio' Mantellini
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=20080707180217.B3DFA248FE@gemini.denx.de \
--to=wd@denx.de \
--cc=u-boot@lists.denx.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