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. Dan > common LED bindings say: > > - led-sources : List of device current outputs the LED is connected to. The > outputs are identified by the numbers that must be defined > in the LED device binding documentation. > >>> We could additionally mark banks with ti,control-bank, >> >> We would have to keep the ti,control-bank node based on the above. >> >>> but I'm not sure if it would ease parsing, since >>> you will have to validate iouts configuration anyway. >>> >>>> If you have multiple LED sources defined in the led-sources then those LEDs would be grouped in the bank. >>>> I guess I need to provide some protection or a warning if a DT defines two banks because there is only one bank control. >>> >>> Does the hardware allow the IOUT to belong to an RGB LED module >>> and to a bank in the same time? >>> >> >> No it does not. LED_CONFIG0 sets the bit if it is control bank or not. > > OK, so validation will also have to check if led-sources definitions > are not mutually exclusive between child DT nodes. For consistency it > would be really better if bank definitions also used led-sources. > >> Section 8.3.2 in the data sheet says >> "When a channel is configured in >> LED bank-control mode, the related color mixing and intensity control is governed by the bank control registers >> (BANK_A_COLOR, BANK_B_COLOR, BANK_C_COLOR, and BANK_BRIGHTNESS) regardless of the inputs >> on its own color-mixing and intensity-control registers." >> > -- ------------------ Dan Murphy
