From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Tue, 30 Jul 2013 11:34:12 -0600 Subject: Defining schemas for Device Tree In-Reply-To: References: <2469263.vMN09Q7Tzi@flatron> <51F6E30B.7060106@wwwdotorg.org> <1706112.Xn49tiCSKF@thinkpad> <20130730102511.GM9858@sirena.org.uk> <51F7F596.6020503@wwwdotorg.org> Message-ID: <51F7F914.6040709@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/30/2013 11:29 AM, jonsmirl at gmail.com wrote: > On Tue, Jul 30, 2013 at 1:19 PM, Stephen Warren wrote: >> >> On 07/30/2013 07:14 AM, jonsmirl at gmail.com wrote: >>> On Tue, Jul 30, 2013 at 6:25 AM, Mark Brown wrote: >>>> On Mon, Jul 29, 2013 at 08:30:29PM -0400, jonsmirl at gmail.com wrote: >>>> >>>>> This... >>>>> tx-dma-channel = <&pdma0 7>; /* preliminary */ >>>>> rx-dma-channel = <&pdma0 6>; /* preliminary */ >>>> >>>>> Probably should be >>>>> dmas = <&pdma0 7>,<&pdma0 6>; >>>>> dma-names = "tx", "rx"; >>>> >>>> It should be - the latter is the generic DMA binding. There's a lot of >>>> bindings in the kernel that predate that but people are currently >>>> working to transfer over, this is one of the examples of instability >>>> that everyone is talking about. >>> >>> Is something similar to this possible in device tree syntax? >>> dmas = <"tx" &pdma0 7>, <"rx" &pdma0 6>; >> >> I /think/ you can physically write that in *.dts, or something very >> similar; with the strings outside the <>: >> >> dmas = "tx", <&pdma0 7>, "rx", <&pdma0 6>; >> >> However, there's been strong push-back (i.e. doing that has not been >> allowed at all) on attempting to mix variable-length strings and >> fixed-length/alignment integer cells in the same property. This is >> primarily because you then can't ensure that the integer cell data is >> aligned in the DTB (dtc and/or the DTB format spec does/requires/allows > > Can we turn the strings into string phandles? Then they'd be fixed sized. I believe that phandles point at nodes not arbitrary data, so no. Now, could the DTB format be enhanced to allow that? Perhaps, although we'd need a different string syntax to enable it, since existing bindings would require the current inline-string format. That's getting outside the realm of schemas and making active changes to the DT format though... > That might provide a way to internationalize the strings too. I don't think internationalization is needed; DT is an interface to drivers/SW, rather than something end-user-visible.