Re: I2C1 controller timed out issue

[Felipe Balbi <me@felipebalbi.com>]

On Sat, Dec 20, 2008 at 11:35:51AM -0600, Kainan Cha wrote:
> Balbi,
> 
> I have also seen this issue once in a while but I am using 2.6.24 kernel. Do
> you know which commits in the linux-omap git fixes this issue so I can
> backport?

Hmm, I suppose it's this one:

commit 663715fc55ea5d292171c6934a2b91d8f4874171
Author: Paul Walmsley <paul@pwsan.com>
Date:   Fri Oct 10 10:58:30 2008 -0600

    i2c-omap: fix I2C timeouts due to recursive omap_i2c_{un,}idle()
    
    omap_i2c_unidle() and omap_i2c_idle() are called recursively during
    omap_i2c_probe().  This is evidently unexpected and will wipe
    out the I2C interrupt enable register the second time that
    omap_i2c_idle() is called consecutively.  Any I2C transactions
    following a probe of a bus with at least one device on it will then
    time out.
    
    Fix by moving omap_i2c_idle() further up in omap_i2c_probe().  Ensure
    the I2C controller is marked as idle before the probe starts.  Also
    attempt to catch future reappearances of this bug early in development
    by warning in omap_i2c_{un,}idle() when they are called recursively.
    
    Problem reported by David Brownell <david-b@pacbell.net>.
    
    Tested on 3430SDP and 2430SDP.

But I'd say the changes to twl4030-core.c also helped and those will be
nasty to backport :-p

-- 
balbi