On Wed, 24 Feb 2016 17:04:49 +0100
Jacek Anaszewski [off-list ref] wrote:

Hi David,

Thanks for the patch.

On 02/23/2016 07:17 PM, David Rivshin (Allworx) wrote:

quoted

From: David Rivshin <redacted>

This adds a binding description for the is31fl3236/35/18/16 I2C LED
drivers.

Signed-off-by: David Rivshin <redacted>
---
  .../devicetree/bindings/leds/leds-is31fl32xx.txt   | 51 ++++++++++++++++++++++
  1 file changed, 51 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/leds/leds-is31fl32xx.txt

diff --git a/Documentation/devicetree/bindings/leds/leds-is31fl32xx.txt b/Documentation/devicetree/bindings/leds/leds-is31fl32xx.txt
new file mode 100644
index 0000000..0a05a1d
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-is31fl32xx.txt

@@ -0,0 +1,51 @@
+Binding for ISSI IS31FL32xx LED Drivers
+
+The IS31FL32xx family of LED drivers are I2C devices with multiple
+constant-current channels, each with independent 256-level PWM control.
+Each LED is represented as a sub-node of the device.
+
+Required properties:
+- compatible: one of
+	issi,is31fl3236
+	issi,is31fl3235
+	issi,is31fl3218
+	issi,is31fl3216
+- reg: I2C slave address
+- address-cells : must be 1
+- size-cells : must be 0
+
+LED sub-node properties:
+- reg : LED channel number (1..N)
+- max-brightness : (optional) Maximum brightness possible for the LED.  

Please use led-max-microamp instead. You can refer to
Documentation/devicetree/bindings/leds/common.txt for detailed
description.

FYI, I think I got that property from leds-pwm, since these use PWMs 
internally, although I don't actually use it myself. 

I can see how led-max-microamp could be a useful property, however 
I'm uncertain about computing cdev->max_brightness from it as these 
devices look to control their max current via an external resistor. 
I suppose either the resistor value, or the resultant max-current 
would need to be given in the devicetree, and then that used along
with led-max-microamp to compute cdev->max_brightness. Although I'd 
want it to be optional as I suspect most users don't need any 
restriction. Also, I don't think I can properly test the result, 
which always makes me nervous. 

Would it be acceptable to simply remove the max-brightness property
without adding led-max-microamp? It can always be added if a user
turns out to need it in the future. Or do you feel strongly that
led-max-microamp should be in the binding from the start?

quoted

+  Default is 255.
+- label :  (optional)
+  see Documentation/devicetree/bindings/leds/common.txt
+- linux,default-trigger :  (optional)
+  see Documentation/devicetree/bindings/leds/common.txt
+
+
+Example:
+
+leds: is31fl3236@3c {
+	compatible = "issi,is31fl3236";
+	reg = <0x3c>;  

You're missing address-cells and size-cells in this example.

Indeed, I missed that when I renamed the child node property
from 'chan' to 'reg'.

quoted

+
+	led@1 {
+		reg = <1>;
+		label = "EB:blue:usr0";
+		max-brightness = <128>;
+	};
+	led@2 {
+		reg = <2>;
+		label = "EB:blue:usr1";
+	};
+	...
+	led@36 {
+		reg = <36>;
+		label = "EB:blue:usr35";
+		max-brightness = <255>;
+	};
+};
+
+For more product information please see the link below:
+http://www.issi.com/US/product-analog-fxled-driver.shtml
\ No newline at end of file