Messages in this thread | | | Subject | Re: [PATCH v19 04/18] leds: multicolor: Introduce a multicolor class definition | From | Dan Murphy <> | Date | Sun, 5 Apr 2020 11:31:06 -0500 |
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On 4/5/20 11:28 AM, Randy Dunlap wrote: > On 4/5/20 9:18 AM, Dan Murphy wrote: >> Jacek >> >> On 4/5/20 10:08 AM, Jacek Anaszewski wrote: >>> Dan, >>> >>> On 4/3/20 4:39 PM, Dan Murphy wrote: >>>> Randy >>>> >>>> Thanks for the review >>>> >>>> On 4/2/20 10:47 PM, Randy Dunlap wrote: >>>>> Hi, >>>>> Here are a few changes for you to consider: >>>>> >>>>> On 4/2/20 1:42 PM, Dan Murphy wrote: >>>>>> Introduce a multicolor class that groups colored LEDs >>>>>> within a LED node. >>>>>> >>>>>> The multi color class groups monochrome LEDs and allows controlling two >>>>> multicolor >>>> Ack >>>>>> aspects of the final combined color: hue and lightness. The former is >>>>>> controlled via <color>_intensity files and the latter is controlled >>>>>> via brightness file. >>>>>> >>>>>> Signed-off-by: Dan Murphy <dmurphy@ti.com> >>>>>> --- >>>>>> diff --git a/Documentation/leds/leds-class-multicolor.rst >>>>>> b/Documentation/leds/leds-class-multicolor.rst >>>>>> new file mode 100644 >>>>>> index 000000000000..5bb004999248 >>>>>> --- /dev/null >>>>>> +++ b/Documentation/leds/leds-class-multicolor.rst >>>>>> @@ -0,0 +1,95 @@ >>>>>> +==================================== >>>>>> +Multi Color LED handling under Linux >>>>> Multicolor >>>> Ack >>>>>> +==================================== >>>>>> + >>>>>> +Description >>>>>> +=========== >>>>>> +The multi color class groups monochrome LEDs and allows controlling two >>>>> multicolor >>>> Ack >>>>>> +aspects of the final combined color: hue and lightness. The former is >>>>>> +controlled via the color_intensity array file and the latter is >>>>>> controlled >>>>>> +via brightness file. >>>>>> + >>>>>> +For more details on hue and lightness notions please refer to >>>>>> +https://en.wikipedia.org/wiki/CIECAM02. >>>>>> + >>>>>> +Multicolor Class Control >>>>>> +======================== >>>>>> +The multicolor class presents files that groups the colors as >>>>>> indexes in an >>>>>> +array. These files are children under the LED parent node created >>>>>> by the >>>>>> +led_class framework. The led_class framework is documented in >>>>>> led-class.rst >>>>>> +within this documentation directory. >>>>>> + >>>>>> +Each colored LED will be indexed under the color_* files. The order >>>>>> of the >>>>>> +colors are arbitrary the color_index file can be read to determine >>>>>> the color >>>>>> +to index value. >>>>>> + >>>>>> +The color_index file is an array that contains the string list of >>>>>> the colors as >>>>>> +they are defined in each color_* array file. >>>>>> + >>>>>> +The color_intensity is an array that can be read or written to for the >>>>>> +individual color intensities. All elements within this array must >>>>>> be written in >>>>>> +order for the color LED intensities to be updated. >>>>>> + >>>>>> +The color_max_intensity is an array that can be read to indicate >>>>>> each color LED >>>>>> +maximum intensity value. >>>>>> + >>>>>> +The num_color_leds file returns the total number of color LEDs that are >>>>>> +presented in each color_* array. >>>>>> + >>>>>> +Directory Layout Example >>>>>> +======================== >>>>>> +root:/sys/class/leds/multicolor:status# ls -lR >>>>>> +-rw-r--r-- 1 root root 4096 Oct 19 16:16 brightness >>>>>> +-r--r--r-- 1 root root 4096 Oct 19 16:16 color_index >>>>>> +-rw-r--r-- 1 root root 4096 Oct 19 16:16 >>>>>> color_intensity >>>>>> +-r--r--r-- 1 root root 4096 Oct 19 16:16 num_color_leds >>>>>> + >>>>>> +Multicolor Class Brightness Control >>>>>> +=================================== >>>>>> +The multiclor class framework will calculate each monochrome LEDs >>>>>> intensity. >>>>> multicolor >>>> Ack >>>>>> + >>>>>> +The brightness level for each LED is calculated based on the color LED >>>>>> +intensity setting divided by the parent max_brightness setting >>>>>> multiplied by >>>>>> +the requested brightness. >>>>>> + >>>>>> +led_brightness = brightness * color_intensity/max_brightness >>>>>> + >>>>>> +Example: >>>>>> +A user first writes the color_intensity file with the brightness levels >>>>>> +that for each LED that is necessary to achieve a blueish violet >>>>>> output from a >>>>> drop first "that". >>>> Ack >>>>> that are >>>>> necessary from an >>>> Ack and NACK the "from an". It is from a since R is a consonant >>> But it sounds like a vowel and this rule for creating articles >>> "applies to the sound of the letter beginning the word, not just the >>> letter itself" [0]. >>> >>> [0] https://www.grammar.com/a-vs-an-when-to-use/ >>> >> We have had the same internal debate here at work. >> >> How does "Red" when you say it sound like a vowel? It is definitely a "R" sound that is first not a vowel sound. >> >> To me "from an RGB" does not sound correct "from a RGB" is actually correct here because R or Red still leads with a consonant in both the sound and letter. >> >> If it sounds as if it is beginning with a vowel sound, *use an*. Like in "an honor" as the h is silent here. R is not silent in Red or RGB. > It depends on how one reads "from a RGB." Do you say/think the letters R G B > (I do), or do you think/say red-green-blue? > > From the [0] web page: > Articles with Acronyms, a or an > > Finally, the rule applies to acronyms as well. If you pronounce a letter as a letter and it begins with a vowel sound, you should precede it with an. The consonants with vowel sounds include f, h, l, m, n, r, s, and x. > > He flew in an SST. He fired an M‑1. He attended an FDA hearing. > > By the same token, if a vowel letter, with a consonant sound, is pronounced as a letter, you should use a. > > He made a U‑turn. > > Got it? So what is your grade? > > An A? A B? Surely not an F. > > I will change it. Its not that big of a change and not worth a continued debate
Dan
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