From: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
To: Igor Grinberg <grinberg-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
Cc: Haojian Zhuang
<haojian.zhuang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
eric.y.miao-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
sodaville-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org,
Dirk Brandewie
<dirk.brandewie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org,
tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 6/7] i2c/pxa2xx: reset the chip if the bus is not free
Date: Thu, 25 Nov 2010 14:39:01 +0100 [thread overview]
Message-ID: <4CEE66F5.30705@linutronix.de> (raw)
In-Reply-To: <4CEE602D.5090501-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
Igor Grinberg wrote:
> I don't think there is such a rule for this case, as if we "believe" the
> Developer Manual, but do the opposite - we can get into trouble...
> IMHO, at least we need to report a problem.
>
> Or may be in some way reset the slave device,
> if there is such an option available outside the i2c scope...
> (Yeah, I know this is a crazy idea...)
Doing the oposite what the manual says is not a good idea. Let's discard
the patch for now.
>>>> From my experience, in master mode resetting the controller
>>> does not help and if the bus is busy for too much time,
>>> there always was a h/w problem involved.
>> Looks like it.
>
> 1) Well, you should check if you have a pull-up resistors on that bus.
> 2) Or if the slave device chip is broken, then it should be replaced.
Thanks for the hint. I try to check the HW and see if there can be done
something about it.
Sebastian
WARNING: multiple messages have this Message-ID (diff)
From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 6/7] i2c/pxa2xx: reset the chip if the bus is not free
Date: Thu, 25 Nov 2010 14:39:01 +0100 [thread overview]
Message-ID: <4CEE66F5.30705@linutronix.de> (raw)
In-Reply-To: <4CEE602D.5090501@compulab.co.il>
Igor Grinberg wrote:
> I don't think there is such a rule for this case, as if we "believe" the
> Developer Manual, but do the opposite - we can get into trouble...
> IMHO, at least we need to report a problem.
>
> Or may be in some way reset the slave device,
> if there is such an option available outside the i2c scope...
> (Yeah, I know this is a crazy idea...)
Doing the oposite what the manual says is not a good idea. Let's discard
the patch for now.
>>>> From my experience, in master mode resetting the controller
>>> does not help and if the bus is busy for too much time,
>>> there always was a h/w problem involved.
>> Looks like it.
>
> 1) Well, you should check if you have a pull-up resistors on that bus.
> 2) Or if the slave device chip is broken, then it should be replaced.
Thanks for the hint. I try to check the HW and see if there can be done
something about it.
Sebastian
next prev parent reply other threads:[~2010-11-25 13:39 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-24 21:20 I2C support for Sodaville Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-1-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-24 21:20 ` [PATCH 1/7] i2c/pxa2xx: Don't touch ISAR if not in slave mode Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-2-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 23:52 ` Ben Dooks
2010-11-25 23:52 ` Ben Dooks
[not found] ` <20101125235255.GB15948-SMNkleLxa3Z6Wcw2j4pizdi2O/JbrIOy@public.gmane.org>
2010-11-26 18:28 ` [sodaville] " Sebastian Andrzej Siewior
2010-11-26 18:28 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 2/7] arm/pxa2xx: reorganize I2C files Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-3-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 23:55 ` Ben Dooks
2010-11-25 23:55 ` Ben Dooks
[not found] ` <20101125235520.GC15948-SMNkleLxa3Z6Wcw2j4pizdi2O/JbrIOy@public.gmane.org>
2010-11-26 0:03 ` Russell King - ARM Linux
2010-11-26 0:03 ` Russell King - ARM Linux
[not found] ` <20101126000341.GB9310-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2010-11-26 14:11 ` Sebastian Andrzej Siewior
2010-11-26 14:11 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 3/7] i2c/pxa2xx: Add PCI support for PXA I2C controller Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-4-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 23:59 ` Ben Dooks
2010-11-25 23:59 ` Ben Dooks
[not found] ` <20101125235933.GD15948-SMNkleLxa3Z6Wcw2j4pizdi2O/JbrIOy@public.gmane.org>
2010-11-26 14:16 ` Sebastian Andrzej Siewior
2010-11-26 14:16 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 4/7] i2c/pxa2xx: add support for shared IRQ handler Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-5-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 2:26 ` Haojian Zhuang
2010-11-25 2:26 ` Haojian Zhuang
2010-11-25 10:48 ` Sebastian Andrzej Siewior
2010-11-25 10:48 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 5/7] i2c/pxa2xx: check timeout correctly Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 6/7] i2c/pxa2xx: reset the chip if the bus is not free Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
[not found] ` <1290633617-15311-7-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 2:30 ` Haojian Zhuang
2010-11-25 2:30 ` Haojian Zhuang
[not found] ` <AANLkTikvN+==eTkoh7CTQyN0mbfvPhH6Uh9NX5QW7WFx-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-25 2:49 ` Haojian Zhuang
2010-11-25 2:49 ` Haojian Zhuang
[not found] ` <AANLkTi=8Xy3M7QGO54nt_r0_12z3+o8G5fAqQmxkTH4o-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-25 6:43 ` Igor Grinberg
2010-11-25 6:43 ` Igor Grinberg
[not found] ` <4CEE05A4.6030201-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
2010-11-25 7:04 ` Haojian Zhuang
2010-11-25 7:04 ` Haojian Zhuang
2010-11-25 12:24 ` Sebastian Andrzej Siewior
2010-11-25 12:24 ` Sebastian Andrzej Siewior
[not found] ` <4CEE5587.90109-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 13:10 ` Igor Grinberg
2010-11-25 13:10 ` Igor Grinberg
[not found] ` <4CEE602D.5090501-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
2010-11-25 13:39 ` Sebastian Andrzej Siewior [this message]
2010-11-25 13:39 ` Sebastian Andrzej Siewior
2010-11-24 21:20 ` [PATCH 7/7] i2c/pxa2xx: pass of_node from platform driver to adapter Sebastian Andrzej Siewior
2010-11-24 21:20 ` Sebastian Andrzej Siewior
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