| Message ID | 1422456611-15447-1-git-send-email-nikhil.nd@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@ti.com> 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.
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@ti.com> > > 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.
diff --git a/dtc-parser.y b/dtc-parser.y index ea57e0a..5a897e3 100644 --- a/dtc-parser.y +++ b/dtc-parser.y @@ -140,6 +140,18 @@ devicetree: { $$ = merge_nodes($1, $3); } + + | devicetree DT_LABEL DT_REF nodedef + { + struct node *target = get_node_by_ref($1, $3); + + add_label(&target->labels, $2); + if (target) + merge_nodes(target, $4); + else + ERROR(&@3, "Label or path %s not found", $3); + $$ = $1; + } | devicetree DT_REF nodedef { struct node *target = get_node_by_ref($1, $2);
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@ti.com> --- dtc-parser.y | 12 ++++++++++++ 1 file changed, 12 insertions(+)