From: Andrew E. Mileski <andrewm@isoar.ca>
To: u-boot@lists.denx.de
Subject: [U-Boot] Detecting board revision that needs to be done after relocation
Date: Tue, 29 May 2012 15:13:43 -0400 [thread overview]
Message-ID: <4FC51FE7.4040408@isoar.ca> (raw)
In-Reply-To: <CAOMZO5CrgJ2w2RL7teiDadRq8=_3mLkz+hy1_Xg7BAW=d5bURw@mail.gmail.com>
On 05/28/2012 11:25 PM, Fabio Estevam wrote:
>
> I need to provide a get_board_rev() function that depends on I2C probe
> of a PMIC to decide between the board revision.
>
> I2C is only available after relocation, so what is the correct way to
> "delay" get_board_rev, so that it gets called only at a time when I2C
> is ready?
I2C is usually available earlier, as it is used to read the SPD on
memory modules.
When I last did it, I had to change U-Boot slightly to support a second
I2C bus, as the bus selection variable was located in flash before
relocation (very old version of U-Boot, so may not apply still).
I've only had a problem using I2C very early in the boot sequence, like
before the system clocks have been setup, then the solution to that was
to just use a GPIO strapping instead for clock selection.
--
Andrew E. Mileski
next prev parent reply other threads:[~2012-05-29 19:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-29 3:25 [U-Boot] Detecting board revision that needs to be done after relocation Fabio Estevam
2012-05-29 14:45 ` Marek Vasut
2012-05-29 15:55 ` Fabio Estevam
2012-05-29 19:13 ` Andrew E. Mileski [this message]
2012-06-04 14:31 ` Hebbar, Gururaja
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