Thread (1 message) 1 message, 1 author, 2014-07-25

[PATCH 2/6] leds: add device tree bindings for syscon LEDs

From: robh@kernel.org (Rob Herring)
Date: 2014-07-25 14:07:02
Also in: linux-devicetree

On Fri, Jul 25, 2014 at 8:23 AM, Linus Walleij [off-list ref] wrote:
quoted hunk
This adds the device tree bindings used by syscon-based LEDs.

Cc: devicetree at vger.kernel.org
Cc: Bryan Wu <redacted>
Cc: Richard Purdie <redacted>
Signed-off-by: Linus Walleij <redacted>
---
 .../devicetree/bindings/leds/leds-syscon.txt       | 83 ++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-syscon.txt
diff --git a/Documentation/devicetree/bindings/leds/leds-syscon.txt b/Documentation/devicetree/bindings/leds/leds-syscon.txt
new file mode 100644
index 000000000000..460b9c3d1bd3
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-syscon.txt
@@ -0,0 +1,83 @@
+Device Tree Bindings for Syscon LEDs
+
+Required properties:
+- compatible : must be "syscon-leds".
Not really happy with the name... More below.
+- regmap : a phandle to a syscon node containing a regmap
+
+Each LED is represented as a sub-node of the syscon-leds device. Each
+node's name represents the name of the corresponding LED.
+
+LED sub-node properties:
+- offset : register offset to the register controlling this LED
+- mask : bit mask for the bit controlling this LED in the register
+  typically 0x01, 0x02, 0x04 ...
This would be a single bit, right? What about inverted bits (i.e. 0 is
on or 1 is on)?
+- label : (optional)
Please group all required and optional properties under those headings.
+  see Documentation/devicetree/bindings/leds/common.txt
+- linux,default-trigger : (optional)
+  see Documentation/devicetree/bindings/leds/common.txt
+- default-state: (optional) The initial state of the LED. Valid
+  values are "on", "off", and "keep". If the LED is already on or off
+  and the default-state property is set the to same value, then no
+  glitch should be produced where the LED momentarily turns off (or
+  on). The "keep" setting will keep the LED at whatever its current
+  state is, without producing a glitch.  The default is off if this
+  property is not present.
+
+Example:
+
+leds: leds at 08 {
+       compatible = "syscon-leds";
+       regmap = <&syscon>;
+
+       led at bit0 {
Perhaps we can define a way to express unit address as offset+bit like
<offset>_<bit> or <offset>.<bit>.

I think we should get rid of the leds node and put this within the
syscon device node and each node here should have a compatible
property. I think the compatible should be something like
"register-bit-led" (perhaps someone has a better name) as syscon is
somewhat linux specific term and you could use this binding for any
LEDs that have a single register bit control.

Rob
+               offset = <0x08>;
+               mask = <0x01>;
+               label = "versatile:0";
+               linux,default-trigger = "heartbeat";
+               default-state = "on";
+       };
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