Re: [PATCH v19 04/18] leds: multicolor: Introduce a multicolor class definition
From: Dan Murphy
Date: Sun Apr 05 2020 - 12:37:01 EST
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
ÂÂÂÂÂÂ 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@xxxxxx>
---
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
ÂÂÂ Multicolor
Ack
+====================================
+
+Description
+===========
+The multi color class groups monochrome LEDs and allows controlling two
ÂÂÂÂÂÂÂ 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--ÂÂÂ 1 rootÂÂÂÂ rootÂÂÂÂÂÂÂÂÂ 4096 Oct 19 16:16 brightness
+-r--r--r--ÂÂÂ 1 rootÂÂÂÂ rootÂÂÂÂÂÂÂÂÂ 4096 Oct 19 16:16 color_index
+-rw-r--r--ÂÂÂ 1 rootÂÂÂÂ rootÂÂÂÂÂÂÂÂÂ 4096 Oct 19 16:16
color_intensity
+-r--r--r--ÂÂÂ 1 rootÂÂÂÂ rootÂÂÂÂÂÂÂÂÂ 4096 Oct 19 16:16 num_color_leds
+
+Multicolor Class Brightness Control
+===================================
+The multiclor class framework will calculate each monochrome LEDs
intensity.
ÂÂÂÂÂÂÂ 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
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ that are
necessaryÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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,Â*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 Mâ1. 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 Uâturn.
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