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

[Dongsoo Kim <dongsoo.kim-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi Ben,

2009. 07. 31, 오전 7:18, Ben Dooks 작성:

> 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've been tested without msleep on s3c64xx and also s5pc1xx. And it  
went well.
What I'm concerned is s3c24xx because I had no chance to test on it.
Cheers,

Nate

>>> 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/)
>
>  'a smiley only costs 4 bytes'