From mboxrd@z Thu Jan  1 00:00:00 1970
From: Seb James <seb@peak.uklinux.net>
Date: Mon, 30 Jun 2003 13:36:37 +0100
Subject: [U-Boot-Users] soft_i2c and ds1307 with tqm823l
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To: u-boot@lists.denx.de

Just a couple of edits to my posting.

Seb James wrote:

> Hi,
>
> I'm working on getting a ds1307 realtime clock working with a tqm823l as
> a new user to u-boot (I've never compiled u-boot or ppcboot before).
>
> I'd like to make some improvements to the README which is already
> excellent but seems to have a couple of omissions, particularly
> regarding the configuration of u-boot to work with i2c.
>
>
> Firstly, the ds1307 code compiles fine, but of course it needs the i2c
> code to be compiled alongside it... 

...in order to be able to link it into the u-boot image.

> Although this is obvious, the newcomer
> to u-boot doesn't (i.e. I didn't) know that calling for ds1307.c to be
> compiled doesn't in itself cause the i2c code to be compiled, so a note
> to this effect in the realtime clock section of the README would be a
> helpful addition.
>
>
>
> Now, in trying to get I2C properly compiled, I find quite a lot of
> information about I2C setup in the README.
>
>
> Here's a line from the README (starting at line 907):
>
> "If this is selected, either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must
> be defined    to include the appropriate I2C driver."
>
>
> No mention is made of what values the 'appropriate driver' might have or
> where to look for them. I assume you might define something like this:
>
> #define CONFIG_HARD_I2C mpc8xx
>
> But I can't see what you'd write for CONFIG_SOFT_I2C. A bit more
> clarification here would be useful.
>
> There are a number of extra defines related to CONFIG_SOFT_I2C, such as
> I2C_INIT, I2C_PORT, etc. It's not too clear what these should be set to.


Regarding this line:

> The diff between my TQM823L.h and the original TQM823L.h is (also
> attached as changes.diff): 

sorry - the diff wasn't attached, this line shouldn't have been in the 
posting. I was going to do this and then decided it wasn't necessary.

>
>
> Some investigation has shown that I need to set I2C_SDA and I2C_SCL to
> the name of the correct functions.  What are the possibilities for
> these? The same seems to be true of I2C_READ.
>
> What are the units for I2C_DELAY? I'm assuming seconds. Why is there
> both I2C_DELAY and CFG_I2C_SPEED to configure? These seem to configure
> the same thing  - the speed of the I2C clock line.
>
> Ok, I think that should be enough for now,
>
> best regards,
>
> Seb James.
>
>
>
>
>
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