Messages in this thread | | | Subject | Re: [PATCH 1/2] dt: bindings: lp5024: Introduce the lp5024 and lp5018 RGB driver | From | Jacek Anaszewski <> | Date | Thu, 10 Jan 2019 19:44:43 +0100 |
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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@ti.com> >>>>>>>>> --- >>>>>>>>> .../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
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