From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [RFC] binding for nvec mfd device Date: Tue, 24 Sep 2013 11:04:20 -0600 Message-ID: <5241C614.7030304@wwwdotorg.org> References: <1416005.VvfEeGuSWa@ax5200p> <17687182.lGWlO75r41@fb07-iapwap2.physik.uni-giessen.de> <5238CE1C.3050107@wwwdotorg.org> <2112732.zfJtNyCk0i@fb07-iapwap2.physik.uni-giessen.de> <52406E1E.5040005@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Andrey Danin Cc: Marc Dietrich , Mark Rutland , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Ian Campbell , "rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org" , Pawel Moll , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On 09/24/2013 01:19 AM, Andrey Danin wrote: > On Mon, Sep 23, 2013 at 8:36 PM, Stephen Warren I think you'd just have the following > > /* master */ > i2c@xxxxx { > foo@0x40 { > reg = ; > compatible = "nvidia,nvec"; > } > }; > > i2c@yyyy { > foo@40 { > reg = ; > compatible = "nvidia,nvec-slave"; > } > }; > > There's no need for the slave child node to know that it is mastered > from the Tegra I2C controller; all it cares about is that there is some > I2C bus that it needs to respond to transactions upon. > > This binding describes only case, when I2C device are connected to I2C > controller. > > Assume that I2C controller #1 (@xxxxx), I2C controller #2 (@yyyy), and > nvec I2C master device are connected to same bus. > How dt must be composed in this case ? Must i2c@xxxxx and i2c@yyyy be in > parent/child relation (in terms of dt) ? None of the I2C bindings currently allow one to specify that multiple of the on-SoC controllers are connected to the same bus. I'm not sure it's particularly useful to represent this anyway. Hardware hooked up like this is pretty rare to start with (i.e. I know of no board at all that's connected this way). I assume that if such HW did exist, you'd simply assign each I2C slave to a particular I2C master, and hence only put a DT node for it under a single DT master node. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html