From: Grant Likely <grant.likely@secretlab.ca>
To: Karol Lewandowski <k.lewandowsk@samsung.com>, w.sang@pengutronix.de
Cc: ben-linux@fluff.org, khali@linux-fr.org,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
hskinnemoen@gmail.com, dirk.brandewie@gmail.com,
bigeasy@linutronix.de, m.szyprowski@samsung.com,
kyungmin.park@samsung.com
Subject: Re: [PATCH 0/2] i2c: Don't assume bus nr 0 if none was specified
Date: Sat, 17 Mar 2012 10:50:56 +0000 [thread overview]
Message-ID: <20120317105056.BC9EE3E093F@localhost> (raw)
In-Reply-To: <4F6331AF.3010007@samsung.com>
On Fri, 16 Mar 2012 13:27:27 +0100, Karol Lewandowski <k.lewandowsk@samsung.com> wrote:
> On 16.03.2012 13:19, Karol Lewandowski wrote:
>
> > Hi,
> >
> > i2c controller drivers used to assume bus number 0 when none (-1) was specified.
> >
> > This worked on non-device tree systems, where one could explicitly specify
> > bus number via platform data. On DT-enabled systems bus number is always -1.
> >
> > Some drivers assume bus number 0 when -1 is specified. This patchset kills
> > this logic and switches to dynamic bus allocation (default when -1 is provided[1]).
>
>
> [ I must have lost actual problem description while rewording
> message itself... ]
>
> Problem arises when multiple drivers (or multiple instances
> of one driver) try to assume the same fixed bus number (0).
>
> This causes simply causes i2c_add_numbered_bus() to fail.
> Leaving -1 works perfectly, as registration function switches
> to dynamic id registration.
Patch series looks good to me. You'll need acks from the affected users.
g.
prev parent reply other threads:[~2012-03-17 15:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-16 12:19 [PATCH 0/2] i2c: Don't assume bus nr 0 if none was specified Karol Lewandowski
2012-03-16 12:19 ` [PATCH 1/2] i2c-pxa: Drop leftover comment Karol Lewandowski
2012-03-16 12:19 ` [PATCH 2/2] i2c: Dynamically assign adapter id if it wasn't explictly specified Karol Lewandowski
2012-03-22 15:28 ` Karol Lewandowski
2012-03-22 16:11 ` Russell King - ARM Linux
2012-03-22 17:03 ` Karol Lewandowski
2012-03-22 16:58 ` David Daney
2012-03-22 17:48 ` Karol Lewandowski
2012-03-22 18:07 ` David Daney
2012-03-22 21:47 ` Wolfram Sang
2012-03-26 9:14 ` Karol Lewandowski
2012-03-16 12:27 ` [PATCH 0/2] i2c: Don't assume bus nr 0 if none was specified Karol Lewandowski
2012-03-17 10:50 ` Grant Likely [this message]
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