Messages in this thread | | | Subject | Re: [PATCH v4 2/2] documention: leds: Add multicolor class documentation | From | Jacek Anaszewski <> | Date | Sun, 9 Jun 2019 17:15:57 +0200 |
| |
Hi Dan,
On 5/30/19 8:16 PM, Dan Murphy wrote: [...] > +Multicolor Class Brightness Control > +----------------------------------- > +The multicolor class will redirect the device drivers call back > +function for brightness control to the multicolor class brightness > +control function. > + > +The brightness level for each LED is calculated based on the color LED > +brightness setting divided by the color LED max brightness setting multiplied by > +the requested value. > + > +led_brightness = requested_value*(led_color_brightness/led_color_max_brightness) > + > +Example: > +Three LEDs are present in the group as defined in "Directory Layout Example" > +within this document. > + > +A user first writes the color LED brightness file with the brightness level that > +is neccesary to achieve a blueish violet output from the RGB LED group. > + > +echo 138 > /sys/class/leds/rgb:grouped_leds/red/brightness > +echo 43 > /sys/class/leds/rgb:grouped_leds/green/brightness > +echo 226 > /sys/class/leds/rgb:grouped_leds/blue/brightness > + > +red - > + brightness = 138 > + max_brightness = 255 > +green - > + brightness = 43 > + max_brightness = 255 > +blue - > + brightness = 226 > + max_brightness = 255 > + > +The user can control the brightness of that RGB group by writing the parent > +'brightness' control. Assuming a parent max_brightness of 255 the user may want > +to dim the LED color group to half. The user would write a value of 128 to the > +parent brightness file then the values written to each LED will be adjusted > +base on this value > + > +cat /sys/class/leds/rgb:grouped_leds/max_brightness > +255 > +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness > + > +adjusted_red_value = 128 * (138/255) = 69 > +adjusted_green_value = 128 * (43/255) = 21 > +adjusted_blue_value = 128 * (226/255) = 113 > + > +Reading the parent brightness file will return the current brightness value of > +the color LED group.
I've tested this algorithm with python script and at least on my LED monitor it works as expected. Attached is the script I've come up with.
> +cat /sys/class/leds/rgb:grouped_leds/max_brightness > +255 > + > +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness > + > +cat /sys/class/leds/rgb:grouped_leds/max_brightness > +128 > + > + >
-- Best regards, Jacek Anaszewski #!/usr/bin/python3.5
from PIL import Image import sys import time
WIDTH = 500 HEIGHT = 500
def print_usage(): print ('Usage: led_color.py RED GREEN BLUE TOP_BRIGHTNESS') sys.exit(0)
def main(): if len(sys.argv) != 5: print_usage()
MAX_R = int(sys.argv[4]) MAX_G = int(sys.argv[4]) MAX_B = int(sys.argv[4])
R = int(sys.argv[1]) G = int(sys.argv[2]) B = int(sys.argv[3]) TB = int(sys.argv[4])
for BR in range(1,TB+1): OUT_R = int(BR * R / MAX_R) OUT_G = int(BR * G / MAX_G) OUT_B = int(BR * B / MAX_B)
print("red: {}, green: {}, blue: {}".format(OUT_R, OUT_G, OUT_B))
img = Image.new("RGB", (WIDTH,HEIGHT), (OUT_R,OUT_G,OUT_B)) img.show() time.sleep(0.1)
if __name__ == "__main__": main()
| |