From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: "Grygorii.Strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org"
<grygorii.strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: "Sekhar Nori" <nsekhar-l0cyMroinI0@public.gmane.org>,
"Uwe Kleine-König"
<u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Kevin Hilman"
<khilman-1D3HCaltpLuhEniVeURVKkEOCMrvLtNR@public.gmane.org>,
"Santosh Shilimkar"
<ssantosh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"Murali Karicheri" <m-karicheri2-l0cyMroinI0@public.gmane.org>,
"Alexander Sverdlin"
<alexander.sverdlin-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure
Date: Fri, 3 Apr 2015 22:18:46 +0200 [thread overview]
Message-ID: <20150403201846.GH2016@katana> (raw)
In-Reply-To: <550C67D6.3080909-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
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> > The I2C specs say in 3.1.16 that the recovery procedure should be used
> > when SDA is stuck low. So, I do wonder if we should apply the recovery
> > after a timeout. Stuck SDA might be one reason for timeout, but there
> > may be others...
>
> This is ancient code. And regarding your question -
> Might be it would be reasonable to add call of
> i2c_davinci_wait_bus_not_busy() at the end of i2c_davinci_xfer()?
> This way we will wait for Bus Free before performing recovery.
That might be an improvement, but the generic question still remains:
Is a timeout a reason for recovery? SDA stuck low is one reason for a
timeout. I have problems making up my mind here between being pragmatic
and being in accordance with the specs.
> Of course, i2c_davinci_wait_bus_not_busy() has to be fixed first
> as proposed by Alexander Sverdlin here:
> https://patchwork.ozlabs.org/patch/448994/.
Okay, good that you said it. So I'll give his patch series priority over
this one.
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WARNING: multiple messages have this Message-ID (diff)
From: wsa@the-dreams.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure
Date: Fri, 3 Apr 2015 22:18:46 +0200 [thread overview]
Message-ID: <20150403201846.GH2016@katana> (raw)
In-Reply-To: <550C67D6.3080909@linaro.org>
> > The I2C specs say in 3.1.16 that the recovery procedure should be used
> > when SDA is stuck low. So, I do wonder if we should apply the recovery
> > after a timeout. Stuck SDA might be one reason for timeout, but there
> > may be others...
>
> This is ancient code. And regarding your question -
> Might be it would be reasonable to add call of
> i2c_davinci_wait_bus_not_busy() at the end of i2c_davinci_xfer()?
> This way we will wait for Bus Free before performing recovery.
That might be an improvement, but the generic question still remains:
Is a timeout a reason for recovery? SDA stuck low is one reason for a
timeout. I have problems making up my mind here between being pragmatic
and being in accordance with the specs.
> Of course, i2c_davinci_wait_bus_not_busy() has to be fixed first
> as proposed by Alexander Sverdlin here:
> https://patchwork.ozlabs.org/patch/448994/.
Okay, good that you said it. So I'll give his patch series priority over
this one.
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WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: "Grygorii.Strashko@linaro.org" <grygorii.strashko@linaro.org>
Cc: "Sekhar Nori" <nsekhar@ti.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Kevin Hilman" <khilman@deeprootsystems.com>,
"Santosh Shilimkar" <ssantosh@kernel.org>,
"Murali Karicheri" <m-karicheri2@ti.com>,
"Alexander Sverdlin" <alexander.sverdlin@nokia.com>
Subject: Re: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure
Date: Fri, 3 Apr 2015 22:18:46 +0200 [thread overview]
Message-ID: <20150403201846.GH2016@katana> (raw)
In-Reply-To: <550C67D6.3080909@linaro.org>
[-- Attachment #1: Type: text/plain, Size: 1005 bytes --]
> > The I2C specs say in 3.1.16 that the recovery procedure should be used
> > when SDA is stuck low. So, I do wonder if we should apply the recovery
> > after a timeout. Stuck SDA might be one reason for timeout, but there
> > may be others...
>
> This is ancient code. And regarding your question -
> Might be it would be reasonable to add call of
> i2c_davinci_wait_bus_not_busy() at the end of i2c_davinci_xfer()?
> This way we will wait for Bus Free before performing recovery.
That might be an improvement, but the generic question still remains:
Is a timeout a reason for recovery? SDA stuck low is one reason for a
timeout. I have problems making up my mind here between being pragmatic
and being in accordance with the specs.
> Of course, i2c_davinci_wait_bus_not_busy() has to be fixed first
> as proposed by Alexander Sverdlin here:
> https://patchwork.ozlabs.org/patch/448994/.
Okay, good that you said it. So I'll give his patch series priority over
this one.
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next prev parent reply other threads:[~2015-04-03 20:18 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-01 15:34 [PATCH v3 0/5] i2c: davinci improvements and fixes Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
[not found] ` <1417448047-15236-1-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org>
2014-12-01 15:34 ` [PATCH v3 1/5] i2c: i2c-davinci: switch to use platform_get_irq Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
[not found] ` <1417448047-15236-2-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org>
2014-12-04 18:28 ` Wolfram Sang
2014-12-04 18:28 ` Wolfram Sang
2014-12-04 18:28 ` Wolfram Sang
2014-12-01 15:34 ` [PATCH v3 2/5] i2c: davinci: generate STP always when NACK is received Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-04 18:28 ` Wolfram Sang
2014-12-04 18:28 ` Wolfram Sang
2014-12-01 15:34 ` [PATCH v3 3/5] i2c: recovery: change input parameter to i2c_adapter for prepare/unprepare_recovery Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
[not found] ` <1417448047-15236-4-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org>
2014-12-04 18:29 ` Wolfram Sang
2014-12-04 18:29 ` Wolfram Sang
2014-12-04 18:29 ` Wolfram Sang
2015-03-05 18:41 ` Grygorii Strashko
2015-03-05 18:41 ` Grygorii Strashko
2015-03-05 18:41 ` Grygorii Strashko
2015-03-12 11:32 ` Alexander Sverdlin
2015-03-12 11:32 ` Alexander Sverdlin
2015-03-12 11:32 ` Alexander Sverdlin
[not found] ` <55017943.6040603-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
2015-03-13 10:15 ` Grygorii.Strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org
2015-03-13 10:15 ` Grygorii.Strashko@linaro.org
2015-03-13 10:15 ` Grygorii.Strashko@linaro.org
[not found] ` <5502B8DA.70504-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-03-13 15:45 ` Felipe Balbi
2015-03-13 15:45 ` Felipe Balbi
2015-03-13 15:45 ` Felipe Balbi
2014-12-01 15:34 ` [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2015-03-12 11:45 ` Alexander Sverdlin
2015-03-12 11:45 ` Alexander Sverdlin
[not found] ` <1417448047-15236-5-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org>
2015-03-18 20:31 ` Wolfram Sang
2015-03-18 20:31 ` Wolfram Sang
2015-03-18 20:31 ` Wolfram Sang
2015-03-20 18:32 ` Grygorii.Strashko@linaro.org
2015-03-20 18:32 ` Grygorii.Strashko@linaro.org
[not found] ` <550C67D6.3080909-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-04-03 20:18 ` Wolfram Sang [this message]
2015-04-03 20:18 ` Wolfram Sang
2015-04-03 20:18 ` Wolfram Sang
2015-04-06 13:11 ` Grygorii.Strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org
2015-04-06 13:11 ` Grygorii.Strashko@linaro.org
2015-04-06 13:11 ` Grygorii.Strashko@linaro.org
[not found] ` <55228613.2060607-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2015-04-06 16:09 ` Wolfram Sang
2015-04-06 16:09 ` Wolfram Sang
2015-04-06 16:09 ` Wolfram Sang
2015-04-06 16:28 ` Grygorii.Strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org
2015-04-06 16:28 ` Grygorii.Strashko@linaro.org
2015-04-06 16:28 ` Grygorii.Strashko@linaro.org
2014-12-01 15:34 ` [PATCH 5/5] i2c: davinci: use ICPFUNC to toggle I2C as gpio for bus recovery Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
2014-12-01 15:34 ` Grygorii Strashko
[not found] ` <1417448047-15236-6-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org>
2015-04-01 14:38 ` Alexander Sverdlin
2015-04-01 14:38 ` Alexander Sverdlin
2015-04-01 14:38 ` Alexander Sverdlin
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