From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Cousson, Benoit" Subject: Re: How to handle named resources with DT? Date: Tue, 9 Aug 2011 23:08:09 +0200 Message-ID: <4E41A1B9.1060400@ti.com> References: <4E40FC88.5090403@ti.com> <20110809162907.GA630@manju-WNB7PBC4801-0006> <4E4166F0.9050401@ti.com> <4E4172A8.3030101@ti.com> <4E417BD5.8080409@freescale.com> <20110809205723.GE11568@ponder.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110809205723.GE11568-e0URQFbLeQY2iJbIjFUEsiwD8/FfD2ys@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: Grant Likely Cc: "Hilman, Kevin" , Paul Walmsley , "G, Manjunath Kondaiah" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , Scott Wood , linux-omap , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On 8/9/2011 10:57 PM, Grant Likely wrote: > On Tue, Aug 09, 2011 at 01:26:29PM -0500, Scott Wood wrote: >> On 08/09/2011 12:47 PM, Cousson, Benoit wrote: >>> On 8/9/2011 7:23 PM, Grant Likely wrote: >>>> There is no analogous mechanism for _byname in the device tree. The >>>> DT binding for a device must explicitly state what order the register >>>> ranges are in. The driver will need to be adapted. >>> >>> That seems to be a small regression for my point of view. Relying on the >>> order is not super safe. This is not very readable either. That's for >>> that exact reason that we changed our drivers to use >>> platform_get_resource_byname. That's probably the reason why that API is >>> there as well. >>> For the same IP, the number of entries can vary depending of the SoC >>> revision. >>> By using the _byname, we can check if the resource is there or not >>> without having to care about the position. >> >> You could have a named u32 property that contains the reg index, e.g.: >> >> dev { >> reg =<0x20000 0x200 0x24000 0x200>; >> foo-reg =<0>; >> bar-reg =<1>; >> }; > > That's a little nasty. A reg-names = "foo", "bar"; would probably be > better. Yep, I agree. And what about something like that? reg = <0x20000 0x200>, "foo", <0x20000 0x200>, "bar" ; It is doable? Regards, Benoit