From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely 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 Message-ID: <20120317105056.BC9EE3E093F@localhost> References: <1331900343-6743-1-git-send-email-k.lewandowsk@samsung.com> <4F6331AF.3010007@samsung.com> Return-path: In-Reply-To: <4F6331AF.3010007-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Karol Lewandowski , w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org Cc: ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hskinnemoen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, dirk.brandewie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Fri, 16 Mar 2012 13:27:27 +0100, Karol Lewandowski 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.