public inbox for u-boot@lists.denx.de
 help / color / mirror / Atom feed
From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/2] WIP: tegra: i2c: Enable new CONFIG_SYS_I2C framework
Date: Tue, 13 Nov 2012 08:48:15 +0100	[thread overview]
Message-ID: <20121113074815.158C62002E1@gemini.denx.de> (raw)
In-Reply-To: <50A1E780.4090807@denx.de>

Dear Heiko,

In message <50A1E780.4090807@denx.de> you wrote:
> 
> > Equally, I think this model can work very well for manually coded board
> > files; the board file can directly instantiate all top-level I2C
> > adapters, and pass information to the I2C driver for those adapters
> > indicating which I2C devices are attached to the buses. Then, if one of
> > those devices happens to be an I2C bus mux, it can instantiate further
> > I2C buses, which in turn instantiate more devices based on the
> > parameters passed to the I2C bus mux driver.
> 
> Yep, possible ... but another approach ...

Thanks for pointing this out.

Stephen, the old design principle [1] to initialize devices only when
they are needed within U-Boot itself still applies.  We do not want to
initialize everything we can, but only what we really need ourself.

Quote:
Perfection is reached, not when there is no longer anything  to  add,
but when there is no longer anything to take away.
                                           - Antoine de Saint-Exupery

[1] See bullet # 2 at
    http://www.denx.de/wiki/view/U-Boot/DesignPrinciples#2_Keep_it_Fast

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
The more complex the mind, the greater the need for the simplicity of
play.
	-- Kirk, "Shore Leave", stardate 3025.8

  reply	other threads:[~2012-11-13  7:48 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-30 17:28 [U-Boot] [PATCH 1/2] tegra: i2c: Add function to know about current bus Simon Glass
2012-10-30 17:28 ` [U-Boot] [PATCH 2/2] WIP: tegra: i2c: Enable new CONFIG_SYS_I2C framework Simon Glass
2012-10-30 22:32   ` Stephen Warren
2012-10-31  6:00     ` Heiko Schocher
2012-10-31 15:41       ` Stephen Warren
2012-10-31 15:56         ` Simon Glass
2012-10-31 16:25           ` Stephen Warren
2012-11-01  7:42             ` Heiko Schocher
2012-11-01 17:03               ` Stephen Warren
2012-11-05 20:39                 ` Simon Glass
2012-11-08  7:02                   ` Heiko Schocher
2012-11-08 18:03                     ` Simon Glass
2012-11-08  6:47                 ` Heiko Schocher
2012-11-08 17:05                   ` Stephen Warren
2012-11-13  6:24                     ` Heiko Schocher
2012-11-13  7:48                       ` Wolfgang Denk [this message]
2012-11-13 17:30                       ` Stephen Warren
2012-10-31  5:53   ` Heiko Schocher
2012-10-31  5:26 ` [U-Boot] [PATCH 1/2] tegra: i2c: Add function to know about current bus Heiko Schocher
2012-11-05 20:43   ` Simon Glass
2012-11-08  7:05     ` Heiko Schocher

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=20121113074815.158C62002E1@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