On Thu, Jan 29, 2015 at 09:07:31PM +1100, David Gibson wrote: > On Wed, Jan 28, 2015 at 08:20:11PM +0530, Nikhil Devshatwar wrote: > > This patch changes the dtc grammar to allow following syntax > > > > i2cexp: &i2c2 { > > ... > > }; > > > > Current device tree compiler allows to define multiple labels when defining > > the device node the first time. Typically device nodes are defined in > > DTSI files. Now these nodes can be overwritten for updating some of the > > properties. Typically, device nodes are overridden in DTS files. > > > > When working with adapter boards, most of the time adapter board can fit to > > multiple base boards. But depending on which base board it is connected to, > > the devices on the adapter board would be children of different devices. > > > > e.g. On dra7-evm.dts, i2c2 is exported for expansion connector whereas > > on dra72-evm.dts, i2c5 is exported for expansion connector. > > This causes a problem when writing a generic device tree file for > > the adapter board. Because, you cannot know whether all the devices on > > adapter board are present on i2c or i2c5. > > > > The problem can be solved by adding a common label (e.g. i2cexp) in both > > of the DTS files when overriding the device nodes for i2c2 or i2c5. > > This way, generic adapter board file would override the i2cexp. And > > depending on which base board you use the adapter board, all the devices > > are automatically added for correct device nodes. > > > > Signed-off-by: Nikhil Devshatwar <nikhil.nd@xxxxxx> > > Hi, sorry I didn't get around to responding to your earlier posting of > this. > > The concept is good, and the implementation looks fine. > > Only 2 things before I'm ready to merge: > 1) It wants a testcase > 2) I need to stare at the syntax for a while and convince myself > it's as good as we can reasonably do. ..and.. #2 is now done. Give me a testcase, and I'll merge. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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