Re: About a suspicious msleep during doxfer in s3c2410 i2c bus driver

[Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>]

On Wed, Jul 22, 2009 at 05:06:40PM +0100, Mark Brown wrote:
> On Thu, Jul 23, 2009 at 12:58:52AM +0900, Dongsoo Kim wrote:
> > 2009. 07. 22, ?????? 9:43, Mark Brown ??????:
> 
> > >My *recollection* is that this is mostly there for multi-master
> > >configurations.
> 
> > I  wish I could answer clearly about this but not having much
> > experience over various I2C bus devices so I can't say with a strict
> > "yes". But in my experience, I've never seen any i2c bus driver
> > serving platform data to be configured with delay support. Tho if it
> > is really necessary for some specified class of i2c devices, we
> > should make one.
> 
> It wasn't for the client devices, it was for issues with synchronisation
> with the controller hardware.  I'm just going on the basis of
> recollections of previous conversations with Ben here; I'm not sure to
> what extent this might be an issue with the way the hardware works
> requiring the driver to jump through hoops.

I think this has been in here for a while, and may well not be
necessary any more. If anyone else has tested this without the
msleep() here, then I'd be interested to know.

I will try and sort out testing a few boards as soon as possible to
see what is going on.
 
> > I'm wondering why anybody has been issued this topic yet. the driver
> > for s3c2410 i2c bus has been the way it is for ages I guess. It
> > obviously seems to be taking long time to write down registers
> > through the s3c2410 i2c bus driver than any other processor's i2c
> > driver. maybe not so many people using enormous i2c register
> > programming on Samsung processors could be the reason I suppose.
> > anyway, let's figure it out the best way we can.
> > Cheers,
> 
> I expect most people would, like you, much rather just remove the sleep
> from the driver since in practice that seems to work well.  For various
> reasons the S3C community isn't all that active upstream which doesn't
> help with issues like this.
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-- 
Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)

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