From: Dan Murphy <dmurphy@ti.com>
To: Jacek Anaszewski <jacek.anaszewski@gmail.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: Wed, 9 Jan 2019 15:31:10 -0600 [thread overview]
Message-ID: <adcd7987-f7fc-ae1f-9aa4-cebcbf01ad58@ti.com> (raw)
In-Reply-To: <ae700129-7b59-c92b-0c0a-b57a6f230ff7@gmail.com>
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.
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
next prev parent reply other threads:[~2019-01-09 21:31 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 [this message]
2019-01-10 18:44 ` Jacek Anaszewski
2019-01-10 19:22 ` Dan Murphy
2019-01-10 19:57 ` Jacek Anaszewski
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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