Re: [PATCH 1/3] Device tree binding documentation for chromeos-firmware

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 02/12/15 15:15, Rob Herring wrote:
On Tue, Dec 01, 2015 at 07:12:49PM +0000, Martyn Welch wrote:
This patch adds documentation for the chromeos-firmware binding.

Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Pawel Moll <pawel.moll@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>
---
  .../devicetree/bindings/misc/chromeos-firmware.txt | 27 ++++++++++++++++++++++

bindings/firmware/ please.

  1 file changed, 27 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/misc/chromeos-firmware.txt

diff --git a/Documentation/devicetree/bindings/misc/chromeos-firmware.txt b/Documentation/devicetree/bindings/misc/chromeos-firmware.txt
new file mode 100644
index 0000000..8240611
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/chromeos-firmware.txt
@@ -0,0 +1,27 @@

<snip>

+
+Each signal is represented as a sub-node of "chromeos_firmware":
+Subnode properties:
+
+	- gpios: OF device-tree gpio specification.
+
+Example nodes:
+
+	chromeos_firmware {

This should go under /firmware


I've changed this to be:

	firmware {
		chromeos {
			...
		};
	];

Which I generally accept (assuming this is considered a part of the firmware) as a better way to represent this in the device tree, however this has the nasty side effect of causing the device tree parsing to avoid parsing the chromeos child and seeing it's compatible property (as the firmware node isn't a bus), resulting in the probe routine not being called.

If I add a 'compatible = "simple-bus"' property to the firmware node it works, but this doesn't seem quite right as I believe "simple-bus" is defined as a "simple memory mapped bus".

I /could/ rewrite the initialisation to call of_find_compatible_node(), but this seems rather hacky and inefficient. I can think of 2 other ways this could be resolved:

(1) As this is only tangentially related to firmware, I rename it something like "chromeos-signals" and make it it's own node. In essence this driver provides a mechanism built on top of specific GPIO (ala gpio-keys seems to be, after-all this has a similar use of resources to that).

(2) Add a compatible string something like 'compatible="logical-group";' to the firmware node and add that too the bus matching logic. This would have the advantage of solving this in the general case (I guess there are other instances where a grouping of things more logically rather than physically connected would ideally be grouped together), though I expect there may be some strong views regarding this approach.

Would either of those be acceptable or is there a better way of resolving this that I've missed?

Martyn
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]
  Powered by Linux