All of lore.kernel.org
 help / color / mirror / Atom feed
From: Felix Radensky <felix@embedded-sol.com>
To: Scott Wood <scottwood@freescale.com>
Cc: "linuxppc-dev@ozlabs.org list" <linuxppc-dev@ozlabs.org>,
	"linuxppc-embedded@ozlabs.org" <linuxppc-embedded@ozlabs.org>
Subject: Re: I2C mux and device tree
Date: Tue, 28 Oct 2008 00:33:30 +0200	[thread overview]
Message-ID: <490641BA.4030808@embedded-sol.com> (raw)
In-Reply-To: <490625B0.3050203@freescale.com>

Hi, Scott

Scott Wood wrote:
> [added linuxppc-dev for a wider audience]
>
> Felix Radensky wrote:
>> I run linux-2.6.26 on custom 460EX based board.
>> This platform has PCA9548 I2C mux on I2C bus 0.
>> I was wondering how can I describe the mux itself
>> and devices behind it (e.g RTC and temperature sensors)
>> in the device tree.
>
> Describe it as a node that is both an i2c client and an i2c controller.
>
> The Sun i2c binding says that i2c devices should have two reg cells, 
> the first being the bus number within the controller, and the second 
> being a shifted-left-by-one i2c bus address (as opposed to the 
> one-cell non-shifted address we currently use, because the Sun binding 
> wasn't known to us at the time).
>
> We could extend of_register_i2c_devices to understand two-cell 
> addresses, and call it once for each sub-bus with the bus number as a 
> parameter.
>
That would be nice.
I have everything working now, using platform data and 
i2c_register_board_info() in board setup
code. But it would be great to have everything defined in device tree.
>> If this is impossible at the moment, what other means
>> exist to work with devices behind the mux ? I have
>> found the pca954x patch and related virtual i2c patch
>> and was able to integrate them intro my kernel.
>
> You'll have to update it to be a new-style i2c device, unless there's 
> a newer version floating around that what a quick google search turned 
> up.
>
The latest version uses new-style i2c device, see
http://www.mail-archive.com/i2c%40lm-sensors.org/msg01538.html

Unfortunately it was not accepted.
> -Scott
>
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded

      reply	other threads:[~2008-10-27 23:05 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-25  9:02 I2C mux and device tree Felix Radensky
2008-10-27 20:33 ` Scott Wood
2008-10-27 22:33   ` Felix Radensky [this message]

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=490641BA.4030808@embedded-sol.com \
    --to=felix@embedded-sol.com \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=linuxppc-embedded@ozlabs.org \
    --cc=scottwood@freescale.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.