Jacek On 1/12/19 1:48 PM, Jacek Anaszewski wrote: > Hi Dan, > > On 1/12/19 6:09 PM, Dan Murphy wrote: >> Jacek >> >> On 1/11/19 3:52 PM, Jacek Anaszewski wrote: >>> Dan, >>> >>> On 1/11/19 1:38 PM, Dan Murphy wrote: >>>> Jacek >>>> >>>> Sorry I missed some replies >>>> >>>> On 1/10/19 4:03 PM, Jacek Anaszewski wrote: >>>>> On 1/10/19 9:43 PM, Dan Murphy wrote: >>>>>> Jacek >>>>>> >>>>>> On 1/10/19 1:57 PM, Jacek Anaszewski wrote: >>>>>>> Dan, >>>>>>> >>>>>>> On 1/10/19 8:22 PM, Dan Murphy wrote: >>>>>>>> Jacek >>>>>>>> >>>>>>>> On 1/10/19 12:44 PM, Jacek Anaszewski wrote: >>>>>>>>> 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. >>>>>>>>> >>>>>>>> >>>>>>>> Yes so if you turn on the bank control for LED0 and LED1 then >>>>>>>> out 0, 3 are mapped to BANK A >>>>>>>> out 1, 4 are mapped to BANK B >>>>>>> >>>>>>> Just noticed that I made a mistake in my example, it should have been: >>>>>>> >>>>>>> Bank B with iouts 1,4,10: led-sources<1 4 10>; >>>>>>> >>>>>>>> out 2, 5 are mapped to BANK C >>>>>>> >>>>>>> Correct. >>>>>>> >>>>>>>> All done automatically in the hardware and the LED0_BRIGHTNESS and LED1_BRIGHTNESS registers have no affect on the brightness >>>>>>> >>>>>>> That's right. >>>>>>> >>>>>>>> If we grouped the LEDs into a bank the led-sources would look more like this >>>>>>>> led-sources = < 0 1 2 3 4 5 >; >>>>>>> >>>>>>> Why? This would be a mix of three banks. Like you listed above. >>>>>>> I'm still interpreting led-sources elements as iout identifiers. >>>>>>> >>>>>> >>>>>> I am as well but as I tried to explain that if you define OUT0 as bank controlled then OUT1 and OUT2 are also bank controlled >>>>>> within the hardware. We have no control of that. If BIT(0) and BIT(1) are set in the LED_CONFIG0 register then OUT0, 1, 2, 3, 4 and 5 are all bank controlled. >>>>> >>>>> There is naming conflict I noticed just now - LEDn_BANK_EN bits >>>>> in LED_CONFIG0 register enable RGB LED modules, and not BANKs (A,B,C). >>>>> >>>>>> These OUTPUTs will appear as a single RGB LED grouping. >>>>> >>>>> Single? W would rather expect that we get two RGB LED modules, whose >>>>> brightness will be controlled via LED0_BRIGHTNESS and LED1_BRIGHTNESS >>>>> registers respectively. >>>>> >>>>>>>> ti,control-bank; // But this can be omitted as led-sources is greater then 3 >>>>>>>> >>>>>>>> non-banked case would be >>>>>>>> led-sources = < 0 1 2 >; >>>>>>> >>>>>>> Agreed here. It would be LED0 RGB LED module. >>>>>>>> But the actual OUT numbers don't matter in the bank case unless we do the validation. There would need to be an algorithim >>>>>>>> that translates these output to the correct LEDx register and CONFIG0 bits. Basically if OUT0 is mapped to the bank then OUT1 and OUT2 >>>>>>>> are inherently mapped to the bank. >>>>>>> >>>>>>> To three separate banks, right? >>>>>>> OUT0 - bank A, OUT1 - bank B, OUT2 - bank C. >>>>>> >>>>>> Yes but there is no BANK output pin just like there is no dedicated LEDn output pin. The banks are grouped internally to the device >>>>>> so again if OUT0 and OUT3 are defined as banked then 1, 2, 4, and 5 are all mapped to the bank. 1 BANK brightness register and 3 bank >>>>>> color adjustment registers. >>>>> >>>>> Here as above, I would expect two separate banks - LED0 and LED1. >>>>> Moreover - not 3 color adjustment registers, but six - one per iout: >>>>> OUT0_COLOR to OUT5_COLOR. >>>>> >>>> >>>> When the LEDs are banked the banked LEDs are controlled by the bank registers not the LEDx registers >>>> so you should only see 3 color adjustments on the banked LEDs. >>>> >>>>>>>> They cannot be separated so the device theoretically treats the RGB group as a single LED. And >>>>>>>> when banked it treats the groups of RGBs that are defined as a single LED. >>>>>>>> >>>>>>>> This is why it was easier use the LEDx out as the virtual out as we only need to define the group number(s) that are controled by the >>>>>>>> LED file presented to the user space. >>>>>>> >>>>>>> I suspect there is logical clash here due to interpreting >>>>>>> led-sources elements as iouts in one case and LEDn modules >>>>>>> in the other case. >>>>>>> >>>>>> >>>>>> Yes. When the RGBs are banked you have to think of them as a single RGB LED cluster and not as separate RGB LED clusters. >>>>> >>>>> We have RGB LED modules (enabled with LEDn_Bank_EN bits) and three >>>>> banks (A,B,C), which are enabled by default, am I right? >>>> >>>> No. Independent LED modules are enabled by default. You have to explicitly enable the banks. >>>> >>>>> >>>>> Bank A iouts: 0, 3 ,6, 9, 12, 15 >>>>> Bank B iouts: 1, 4, 7, 10, 13, 16 >>>>> Bank C iouts: 2, 5, 8, 11, 14, 17 >>>>> >>>>> When RGB LED module is enabled (via LEDn_Bank_EN bit), >>>>> the BANK_{A.B,C}_COLOR and BANK_BRIGHTNESS registers >>>>> lose control over related IOUTs in favour of LEDn_BRIGHTNESS and >>>>> related OUTn_COLOR registers. Is it correct? >>>> >>>> No it is the opposite. When the bit is enabled LED banking is enabled and the BANK brightness and color registers over >>>> ride the LEDx color and brightness registers. >>>> >>>> Default is independent control of the RGB via the LEDx color and brightness registers. >>>> >>>>> >>>>>> As you know the brightness is controlled by the single BANK_BRIGHTNESS register. So identifying each output in the led-sources is >>>>>> misleading as the hardware does this all on the chip. This is why I just mapped each output to the Virtual LEDx module. >>>>> >>>>> Ekhm, I messed something here. >>>>> >>>>> So for this I would define a single LED class device. >>>>> Related DT node would not need led-sources at all, >>>>> but only ti,control-bank. The semantics would be: >>>>> controls all iouts not taken by RGB LED modules. >>>>> >>>> >>>> Hmm. I guess I will put that on hold until you read the responses. I am not sure that would work or >>>> that would be really clean. I still believe that mapping led-sources to the LEDx module number is the cleanest >>>> simplest solution since the driver cannot inter mix different outputs for enablement. >>> >>> I've read the doc again more carefully and hopefully I finally have >>> proper understanding. Let's check it. >>> >>> 1. On reset LED_CONFIG0 bits are zeroed, which means >>> LEDn module independent control mode. >>> 2. LEDn modules (i.e. IOUT triplets) are controlled independently, >>> with use of LEDn_BRIGHTNESS registers, and each IOUT color can >>> be adjusted using OUTn_CONTROL registers. >>> 3. LEDn_Bank_EN bits, when set to 1, assign given RGB LED module >>> to one global bank, controlled via BANK_BRIGHTNESS and BANK_n_COLOR >>> registers. >>> >>> Having that, I'd see led-sources definitions as follows >>> (led-sources element is IOUT identifier) >>> >>> 1. >>> >>> - LED0, LED1, LED2, LED3 modules controlled by separate >>> LED class devices >>> >>> led-sources = <0 1 2> // LED0 >>> led-sources = <3 4 5> // LED1 >>> led-sources = <6 7 8> // LED2 >>> led-sources = <9 10 11> // LED3 >>> >>> 2. >>> >>> - LED0 and LED3 modules assigned to the bank, and controlled >>> by one LED class device, >>> - LED1 and LED2 modules controlled by separate LED class devices >>> >>> led-sources = <0 1 2 9 10 11> // Bank with LED0 and LED3 >>> led-sources = <3 4 5> // LED1 >>> led-sources = <6 7 8> // LED2 >>> >>> >>> So now I see your point. It would be indeed easier >>> to switch to LEDn module identifiers for led-sources >>> elements. With that the definitions would look like >>> this: >>> >>> >>> 1. >>> >>> - LED0, LED1, LED2, LED3 modules controlled by separate >>> LED class devices >>> >>> led-sources = <0> // LED0 >>> led-sources = <1> // LED1 >>> led-sources = <2> // LED2 >>> led-sources = <3> // LED3 >>> >>> 2. >>> >>> - LED0 and LED3 modules assigned to the bank, and controlled >>> by one LED class device, >>> - LED1 and LED2 modules controlled by separate LED class devices >>> >>> led-sources = <0 3> // Bank with LED0 and LED3 >>> led-sources = <1> // LED1 >>> led-sources = <2> // LED2 >>> >> >> This is exactly how I submitted the code. >> >>> >>> But, I don't think use of led-sources is justified in >>> this case. I propose to introduce device specific properties: >>> >>> ti,led-module and ti,led-bank >>> >>> With that we would have: >>> >>> ti,led-bank = <0 3> // Bank with LED0 and LED3 modules >>> ti,led-module = <1> // LED1 >>> ti.led-module = <2> // LED2 >>> >> >> We are now aligned. I can change the led-sources to the TI specific if there are no further objections. >> In doing this I can eliminate the ti,control-bank property. >> >>> >>>>> I would also add Table 1 contents (Bank Number and LED Number >>>>> Assignment) to the DT bindings. >>>>> >>>> >>>> Should I add that to the DT binding or reference the data sheet table since this driver will support 4 different devices >>>> with varying number of outputs from 18-36. >>> >>> My first thought was to show full table, but four different >>> mappings would add too much noise. So the reference to the data >>> sheet should suffice. >>> >> >> OK >> >> One last question I am going to add the LP5036 and 30 which have the same technology but slightly different register maps. >> Should I rename the driver to LP5036.c as the 30, 24 and 18 would technically be subsets? > > How about leds-lp50xx.c ? You can also create a library like > drivers/leds/leds-lp55xx-common.c if that would simplify the code. > A library would be overkill. Is it just the DT that we don't want to use wild cards in naming? leds-lp50xx.c is a fine name to me. Dan -- ------------------ Dan Murphy
