[PATCH 3/3] of/irq: Add interrupts-names property to name an irq resource

Hi Grant,

On 1/4/2012 8:17 AM, Grant Likely wrote:

On Mon, Dec 05, 2011 at 03:23:56PM +0100, Benoit Cousson wrote:

quoted

In a HW system, resources in general have name to identify them.
The is the case as well for IORESOURCE_IRQ resources filled by DT
"interrupts" entries.
The current DT mechanism is relying on the "interrupts" order to identify
the proper resource. This is error prone and not the natural way to
retrieve an information in general.

I do not agree with this assessment.  interrupt property order has
worked quite well for a very long time.  There are some uses cases
that want to access it by-name, but I expect accessing by-index to
continue to be the preferred method.  I'm going to drop this paragraph
from the commit text.

OK, fair enough. My point was when the HW description is providing names 
to list several IRQ resources, giving a number instead is error prone. 
If, on the other side, the spec is providing something like IRQ_A, B or 
C, then yes, the by-index is the natural one.

Considering that most IPs will anyway only have one IRQ line, the 
by-index method will be the most widely used.

quoted

Moreover, the resource does support a name and an API is available to
allow a driver to retrieve the resource using the name instead of an
index.

Add a interrupts-names property to allow the possiblity to provide a name
to any interrupts entries.
If the name is available, use it to name the resource, otherwise
keep the legacy device full name.

Signed-off-by: Benoit Cousson<redacted>
Cc: Grant Likely<redacted>
Cc: Rob Herring<redacted>
---
  .../devicetree/bindings/interrupts-names.txt       |   50 ++++++++++++++++++++
  drivers/of/irq.c                                   |   11 ++++-
  2 files changed, 60 insertions(+), 1 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/interrupts-names.txt

diff --git a/Documentation/devicetree/bindings/interrupts-names.txt b/Documentation/devicetree/bindings/interrupts-names.txt
new file mode 100644
index 0000000..d9a796d
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupts-names.txt

@@ -0,0 +1,50 @@
+interrupts-names property
+
+In a HW system, physical resources in general have name to identify them.
+The is the case as well for interrupt lines.
+The current DT mechanism is relying on the "interrupts" order to identify
+the proper resource. The interrupts-names is adding the possiblity to
+provide a name to interrupts entries.
+
+Usage:
+
+This attribute must be used along with a regular interrupts entry. If not
+it will be simply ignored.

This documentation is pretty much identical to the reg-names property
description.  I'll merge the two into a single file.

OK.

quoted

+
+
+Example:
+
+
+l4-abe {
+	compatible = "simple-bus";
+	#address-cells =<2>;
+	#size-cells =<1>;
+	ranges =<0 0 0x48000000 0x00001000>, /* MPU path */
+		<1 0 0x49000000 0x00001000>; /* L3 path */
+	mcasp {
+		compatible = "ti,mcasp";
+		reg =<0 0x10 0x10>,<0 0x20 0x10>,
+		<1 0x10 0x10>,<1 0x20 0x10>;
+		reg-names = "mpu", "dat",
+			    "dma", "dma_dat";
+		interrupts =<11>,<12>;
+		interrupts-names = "rx", "tx";

Nitpick: I'm going to change the property name to "interrupt-names"
(dropping the 's' from interrupts).  After playing with the clock
binding (clocks vs. clock-names) and looking at what could be done
with the gpio binding (gpios vs. gpio-names), I think it 'feels' more
consistent to drop the s.

Fully agree, I made a comment on that in the cover-letter because I was 
not fully happy with that either.

Merged, thanks.

Cool, thanks.

Regards,
Benoit