Hi Dan,
On 1/9/19 10:31 PM, Dan Murphy wrote:
Jacek
On 1/9/19 3:28 PM, Jacek Anaszewski wrote:
On 1/9/19 10:12 PM, Dan Murphy wrote:
On 1/9/19 2:12 PM, Jacek Anaszewski wrote:
Hi Dan,
On 1/8/19 10:22 PM, Dan Murphy wrote:
On 1/8/19 3:16 PM, Jacek Anaszewski wrote:
On 1/8/19 9:53 PM, Dan Murphy wrote:
Jacek
On 1/8/19 2:33 PM, Jacek Anaszewski wrote:
Dan,
On 12/19/18 5:26 PM, Dan Murphy wrote:
Introduce the bindings for the Texas Instruments LP5024 and the LP5018
RGB LED device driver. The LP5024/18 can control RGB LEDs individually
or as part of a control bank group. These devices have the ability
to adjust the mixing control for the RGB LEDs to obtain different colors
independent of the overall brightness of the LED grouping.
Datasheet:
http://www.ti.com/lit/ds/symlink/lp5024.pdf
Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
---
.../devicetree/bindings/leds/leds-lp5024.txt | 63 +++++++++++++++++++
1 file changed, 63 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/leds-lp5024.txt
diff --git a/Documentation/devicetree/bindings/leds/leds-lp5024.txt b/Documentation/devicetree/bindings/leds/leds-lp5024.txt
new file mode 100644
index 000000000000..9567aa6f7813
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-lp5024.txt
@@ -0,0 +1,63 @@
+* Texas Instruments - LP5024/18 RGB LED driver
+
+The LM3692x is an ultra-compact, highly efficient,
+white-LED driver designed for LCD display backlighting.
+
+The main difference between the LP5024 and L5018 is the number of
+RGB LEDs they support. The LP5024 supports twenty four strings while the
+LP5018 supports eighteen strings.
+
+Required properties:
+ - compatible:
+ "ti,lp5018"
+ "ti,lp5024"
+ - reg : I2C slave address
+ - #address-cells : 1
+ - #size-cells : 0
+
+Optional properties:
+ - enable-gpios : gpio pin to enable/disable the device.
+ - vled-supply : LED supply
+
+Required child properties:
+ - reg : Is the child node iteration.
+ - led-sources : LP5024 - 0 - 7
+ LP5018 - 0 - 5
+ Declares the LED string or strings that the child node
+ will control. If ti,control-bank is set then this
+ property will contain multiple LED IDs.
+
+Optional child properties:
+ - label : see Documentation/devicetree/bindings/leds/common.txt
+ - linux,default-trigger :
+ see Documentation/devicetree/bindings/leds/common.txt
+ - ti,control-bank : Indicates that the LED strings declared in the
+ led-sources property are grouped within a control
+ bank for brightness and mixing control.
+
+Example:
+
+led-controller@28 {
+ compatible = "ti,lp5024";
+ reg = <0x28>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
+ vled-supply = <&vbatt>;
+
+ led@0 {
+ reg = <0>;
+ led-sources = <1>;
+ };
+
+ led@1 {
+ reg = <1>;
+ led-sources = <0 6>;
+ ti,control-bank;
Do you really need ti,control-bank? Doesn't led-sources array size
greater than 1 mean that the node describes control bank?
That will work too.
Also, does it make sense to have only two LEDs in the bank?
The array can populate all 7 LEDs in a single node. I only show 2 here as the example.
See the description above of the led-sources
OK, I confused RGB LED modules with banks.
Shouldn't we allow for defining either strings or RGB LED
triplets somehow then?
Well that is what this should be doing. If you define a single LED in LED sources then
the triplet is controlled via the associated LEDx_brightness register.
led-sources should map to iouts directly.
So, for RGB LED modules I would expect:
LED0: led-sources = <0 1 2>;
LED1: led-sources = <3 4 5>;
LED2: led-sources = <6 7 8>;
and so on.
for banks:
Bank A with iouts 0,3,6,9: led-sources<0 3 6 9>;
Bank B with iouts 2,4,10: led-sources<2 4 10>;
Bank C with iouts 5,8,11,14,17: led-sources<5 8 11 14 17>;
Ok the led-sources would need to be different then this as I don't define the sources for banks.
The led-sources for the banks and the individual groups will have different meanings within the same
document. I was attempting to keep the led-sources mapped to the LEDx_brightness registers as opposed to
the hardware outputs since the RGB LEDs are controlled and grouped by a single brightness register and if banked then
it would be controlled by the bank brightness register.
Describing these in the DT seems wrought with potential issues as the data sheet defines what outputs map to what bank and LED
registers.
Yes, that's why I mentioned the need for validation of led-sources.
But they have to be iouts. This property was introduced specifically
for such purposes.
Yes Pavel also mentioned that as well.
I will look into validating the sources. But there will be no mapping of the sources to the output that is done
in the hardware. This would just be a data sheet mapping since the outputs are not configurable.
Hmm, isn't the mapping defined in the hardware via LED_CONFIG0 register?
I have an impression that it defines whether LED belongs to an RGB LED
module or to a bank. Basing on that I created my DT example above.
--
Best regards,
Jacek Anaszewski
