From: Jacek Anaszewski <jacek.anaszewski@gmail.com>
To: Dan Murphy <dmurphy@ti.com>, robh+dt@kernel.org, pavel@ucw.cz
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org
Subject: Re: [PATCH 1/2] dt: bindings: lp5024: Introduce the lp5024 and lp5018 RGB driver
Date: Thu, 10 Jan 2019 20:57:50 +0100 [thread overview]
Message-ID: <8b126077-c200-ed34-03b7-6d43a22fb0c9@gmail.com> (raw)
In-Reply-To: <72112839-11d4-54be-df94-b2322f77cb0f@ti.com>
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@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.
>>
>
> 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.
> 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.
> 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.
--
Best regards,
Jacek Anaszewski
next prev parent reply other threads:[~2019-01-10 19:57 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-19 16:26 [PATCH 0/2] LP5024/18 LED introduction Dan Murphy
2018-12-19 16:26 ` [PATCH 1/2] dt: bindings: lp5024: Introduce the lp5024 and lp5018 RGB driver Dan Murphy
2018-12-28 23:53 ` Rob Herring
2018-12-31 18:54 ` Dan Murphy
2019-01-08 20:33 ` Jacek Anaszewski
2019-01-08 20:53 ` Dan Murphy
2019-01-08 21:16 ` Jacek Anaszewski
2019-01-08 21:22 ` Dan Murphy
2019-01-09 20:12 ` Jacek Anaszewski
2019-01-09 21:12 ` Dan Murphy
2019-01-09 21:28 ` Jacek Anaszewski
2019-01-09 21:31 ` Dan Murphy
2019-01-10 18:44 ` Jacek Anaszewski
2019-01-10 19:22 ` Dan Murphy
2019-01-10 19:57 ` Jacek Anaszewski [this message]
2019-01-10 20:43 ` Dan Murphy
2019-01-10 22:03 ` Jacek Anaszewski
2019-01-10 23:51 ` Dan Murphy
2019-01-11 12:38 ` Dan Murphy
2019-01-11 21:52 ` Jacek Anaszewski
2019-01-12 17:09 ` Dan Murphy
2019-01-12 19:48 ` Jacek Anaszewski
2019-01-14 12:27 ` Dan Murphy
2019-01-14 20:11 ` Jacek Anaszewski
2019-01-14 20:14 ` Dan Murphy
2019-01-14 20:28 ` Jacek Anaszewski
2019-01-14 20:29 ` Dan Murphy
2018-12-19 16:26 ` [PATCH 2/2] leds: lp5024: Add the LP5024/18 RGB LED driver Dan Murphy
2018-12-19 19:04 ` Dan Murphy
2018-12-19 19:34 ` Pavel Machek
2018-12-19 19:41 ` Dan Murphy
2018-12-19 20:10 ` Pavel Machek
2018-12-19 20:41 ` Dan Murphy
2018-12-19 21:36 ` Jacek Anaszewski
2018-12-19 21:50 ` Dan Murphy
2018-12-20 12:40 ` Vesa Jääskeläinen
2018-12-20 13:56 ` Dan Murphy
2019-01-01 13:45 ` Vesa Jääskeläinen
2019-01-03 22:05 ` Jacek Anaszewski
2019-01-03 23:19 ` Vesa Jääskeläinen
2019-01-03 23:34 ` Pavel Machek
2019-01-04 19:49 ` Vesa Jääskeläinen
2019-01-04 20:43 ` Pavel Machek
2019-01-04 19:12 ` Jacek Anaszewski
2019-01-04 20:12 ` Pavel Machek
2019-01-04 21:37 ` Jacek Anaszewski
2019-01-04 22:07 ` Pavel Machek
2019-01-05 12:16 ` Jacek Anaszewski
2019-01-05 12:31 ` Pavel Machek
2019-01-05 13:16 ` Jacek Anaszewski
2019-01-05 22:12 ` Generic RGB LED support was " Pavel Machek
2019-01-06 15:52 ` Jacek Anaszewski
2019-01-07 19:13 ` Jacek Anaszewski
2019-01-07 19:36 ` Dan Murphy
2019-01-07 20:59 ` Jacek Anaszewski
2019-01-07 21:14 ` Dan Murphy
2019-01-08 21:18 ` Jacek Anaszewski
2019-01-08 21:25 ` Dan Murphy
2019-01-10 12:46 ` Dan Murphy
2019-01-10 19:23 ` Jacek Anaszewski
2019-01-10 19:58 ` Dan Murphy
2019-01-10 21:02 ` Jacek Anaszewski
2019-01-10 21:07 ` Dan Murphy
2019-01-08 22:59 ` Pavel Machek
2019-01-09 7:11 ` Vesa Jääskeläinen
2019-01-13 16:37 ` Jacek Anaszewski
2019-01-05 0:39 ` Vesa Jääskeläinen
2019-01-07 19:34 ` Dan Murphy
2019-01-09 6:20 ` Vesa Jääskeläinen
2019-01-07 21:13 ` Jacek Anaszewski
2019-01-07 21:15 ` Dan Murphy
2019-01-09 6:46 ` Vesa Jääskeläinen
2019-01-13 16:36 ` Jacek Anaszewski
2018-12-20 20:31 ` Jacek Anaszewski
2018-12-21 7:32 ` Jacek Anaszewski
2018-12-21 13:05 ` Dan Murphy
2018-12-29 18:28 ` Jacek Anaszewski
2018-12-29 19:07 ` Pavel Machek
2018-12-30 17:09 ` Jacek Anaszewski
2018-12-30 17:35 ` Pavel Machek
2018-12-31 15:43 ` Jacek Anaszewski
2018-12-31 15:47 ` Jacek Anaszewski
2018-12-31 19:15 ` Dan Murphy
2019-01-01 14:42 ` Jacek Anaszewski
2019-01-01 18:11 ` Dan Murphy
2019-01-01 22:06 ` Jacek Anaszewski
2018-12-31 16:28 ` Pavel Machek
2019-01-01 14:26 ` Jacek Anaszewski
2018-12-19 22:03 ` Pavel Machek
2018-12-19 22:08 ` Dan Murphy
2018-12-19 22:27 ` Pavel Machek
2018-12-20 1:31 ` Dan Murphy
2018-12-20 9:06 ` Pavel Machek
2018-12-20 14:03 ` Dan Murphy
2019-01-08 21:10 ` Jacek Anaszewski
2019-01-08 21:17 ` Dan Murphy
2019-07-22 20:59 ` Backlight in motorola Droid 4 Pavel Machek
2019-07-23 15:53 ` Dan Murphy
2019-07-24 8:22 ` Pavel Machek
2019-07-24 12:45 ` Pavel Machek
2019-07-24 15:10 ` Dan Murphy
2019-07-24 15:22 ` Dan Murphy
2019-07-26 14:38 ` Dan Murphy
2019-07-29 22:00 ` Pavel Machek
2019-07-30 18:21 ` Dan Murphy
2019-07-30 21:52 ` Pavel Machek
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