Add a documentation of LED Multicolor LED class specific
sysfs attributes.
Add multicolor framework class documentation describing the
usage of the files created.
Signed-off-by: Dan Murphy <[email protected]>
---
.../ABI/testing/sysfs-class-led-multicolor | 35 +++++++
Documentation/leds/index.rst | 1 +
Documentation/leds/leds-class-multicolor.rst | 96 +++++++++++++++++++
3 files changed, 132 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-led-multicolor
create mode 100644 Documentation/leds/leds-class-multicolor.rst
diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor b/Documentation/ABI/testing/sysfs-class-led-multicolor
new file mode 100644
index 000000000000..65cb43de26e6
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-multicolor
@@ -0,0 +1,35 @@
+What: /sys/class/leds/<led>/brightness
+Date: Sept 2019
+KernelVersion: 5.5
+Contact: Dan Murphy <[email protected]>
+Description: read/write
+ Writing to this file will update all LEDs within the group to a
+ calculated percentage of what each color LED intensity is set
+ to. The percentage is calculated via the equation below:
+
+ led_brightness = brightness * <color>_intensity/<color>_max_intensity
+
+ For additional details please refer to
+ Documentation/leds/leds-class-multicolor.rst.
+
+ The value of the color is from 0 to
+ /sys/class/leds/<led>/max_brightness.
+
+What: /sys/class/leds/<led>/colors/<color>_intensity
+Date: Sept 2019
+KernelVersion: 5.5
+Contact: Dan Murphy <[email protected]>
+Description: read/write
+ The <color>_intensity file is created based on the color
+ defined by the registrar of the class.
+ There is one file per color presented.
+
+ The value of the color is from 0 to
+ /sys/class/leds/<led>/colors/<color>_max_intensity.
+
+What: /sys/class/leds/<led>/colors/<color>_max_intensity
+Date: Sept 2019
+KernelVersion: 5.5
+Contact: Dan Murphy <[email protected]>
+Description: read only
+ Maximum intensity level for the LED color.
diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index 060f4e485897..bc70c6aa7138 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -9,6 +9,7 @@ LEDs
leds-class
leds-class-flash
+ leds-class-multicolor
ledtrig-oneshot
ledtrig-transient
ledtrig-usbport
diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
new file mode 100644
index 000000000000..87a1588d7619
--- /dev/null
+++ b/Documentation/leds/leds-class-multicolor.rst
@@ -0,0 +1,96 @@
+====================================
+Multi Color LED handling under Linux
+====================================
+
+Description
+===========
+The multi color class groups monochrome LEDs and allows controlling two
+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.
+
+For more details on hue and lightness notions please refer to
+https://en.wikipedia.org/wiki/CIECAM02.
+
+Note that intensity files only cache the written value and the actual
+change of hardware state occurs upon writing brightness file. This
+allows for changing many factors of the perceived color in a virtually
+unnoticeable way for the human observer.
+
+Multicolor Class Control
+========================
+The multicolor class presents the LED groups under a directory called "colors".
+This directory is a child 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 have two files created under the colors directory
+<color>_intensity and <color>_max_intensity. These files will contain
+one of LED_COLOR_ID_* definitions from the header
+include/dt-bindings/leds/common.h.
+
+Directory Layout Example
+========================
+root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
+-rw-rwxr-- 1 root root 4096 Jul 7 03:10 red_max_intensity
+--w--wx-w- 1 root root 4096 Jul 7 03:10 red_intensity
+-rw-rwxr-- 1 root root 4096 Jul 7 03:10 green_max_intensity
+--w--wx-w- 1 root root 4096 Jul 7 03:10 green_intensity
+-rw-rwxr-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
+--w--wx-w- 1 root root 4096 Jul 7 03:10 blue_intensity
+
+Multicolor Class Brightness Control
+===================================
+The multiclor class framework will calculate each monochrome LEDs intensity.
+
+The brightness level for each LED is calculated based on the color LED
+intensity setting divided by the color LED max intensity setting multiplied by
+the requested brightness.
+
+led_brightness = brightness * <color>_intensity/<color>_max_intensity
+
+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 necessary to achieve a blueish violet output from the RGB LED group.
+
+echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity
+echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity
+echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity
+
+red -
+ intensity = 138
+ max_intensity = 255
+green -
+ intensity = 43
+ max_intensity = 255
+blue -
+ intensity = 226
+ max_intensity = 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.
+
+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/brightness
+128
--
2.22.0.214.g8dca754b1e
Hi Dan,
Thank you for the v9.
This patch should me melded with 5/15.
On 9/25/19 7:46 PM, Dan Murphy wrote:
> Add a documentation of LED Multicolor LED class specific
> sysfs attributes.
>
> Add multicolor framework class documentation describing the
> usage of the files created.
>
> Signed-off-by: Dan Murphy <[email protected]>
> ---
> .../ABI/testing/sysfs-class-led-multicolor | 35 +++++++
> Documentation/leds/index.rst | 1 +
> Documentation/leds/leds-class-multicolor.rst | 96 +++++++++++++++++++
> 3 files changed, 132 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-led-multicolor
> create mode 100644 Documentation/leds/leds-class-multicolor.rst
>
> diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor b/Documentation/ABI/testing/sysfs-class-led-multicolor
> new file mode 100644
> index 000000000000..65cb43de26e6
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-multicolor
> @@ -0,0 +1,35 @@
> +What: /sys/class/leds/<led>/brightness
> +Date: Sept 2019
> +KernelVersion: 5.5
> +Contact: Dan Murphy <[email protected]>
> +Description: read/write
> + Writing to this file will update all LEDs within the group to a
> + calculated percentage of what each color LED intensity is set
> + to. The percentage is calculated via the equation below:
> +
> + led_brightness = brightness * <color>_intensity/<color>_max_intensity
> +
> + For additional details please refer to
> + Documentation/leds/leds-class-multicolor.rst.
> +
> + The value of the color is from 0 to
> + /sys/class/leds/<led>/max_brightness.
> +
> +What: /sys/class/leds/<led>/colors/<color>_intensity
> +Date: Sept 2019
> +KernelVersion: 5.5
> +Contact: Dan Murphy <[email protected]>
> +Description: read/write
> + The <color>_intensity file is created based on the color
> + defined by the registrar of the class.
> + There is one file per color presented.
> +
> + The value of the color is from 0 to
> + /sys/class/leds/<led>/colors/<color>_max_intensity.
> +
> +What: /sys/class/leds/<led>/colors/<color>_max_intensity
> +Date: Sept 2019
> +KernelVersion: 5.5
> +Contact: Dan Murphy <[email protected]>
> +Description: read only
> + Maximum intensity level for the LED color.
> diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
> index 060f4e485897..bc70c6aa7138 100644
> --- a/Documentation/leds/index.rst
> +++ b/Documentation/leds/index.rst
> @@ -9,6 +9,7 @@ LEDs
>
> leds-class
> leds-class-flash
> + leds-class-multicolor
> ledtrig-oneshot
> ledtrig-transient
> ledtrig-usbport
> diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
> new file mode 100644
> index 000000000000..87a1588d7619
> --- /dev/null
> +++ b/Documentation/leds/leds-class-multicolor.rst
> @@ -0,0 +1,96 @@
> +====================================
> +Multi Color LED handling under Linux
> +====================================
> +
> +Description
> +===========
> +The multi color class groups monochrome LEDs and allows controlling two
> +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.
> +
> +For more details on hue and lightness notions please refer to
> +https://en.wikipedia.org/wiki/CIECAM02.
> +
> +Note that intensity files only cache the written value and the actual
> +change of hardware state occurs upon writing brightness file. This
> +allows for changing many factors of the perceived color in a virtually
> +unnoticeable way for the human observer.
> +
> +Multicolor Class Control
> +========================
> +The multicolor class presents the LED groups under a directory called "colors".
> +This directory is a child 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 have two files created under the colors directory
> +<color>_intensity and <color>_max_intensity. These files will contain
> +one of LED_COLOR_ID_* definitions from the header
> +include/dt-bindings/leds/common.h.
> +
> +Directory Layout Example
> +========================
> +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 red_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 red_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 green_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 green_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 blue_intensity
> +
> +Multicolor Class Brightness Control
> +===================================
> +The multiclor class framework will calculate each monochrome LEDs intensity.
> +
> +The brightness level for each LED is calculated based on the color LED
> +intensity setting divided by the color LED max intensity setting multiplied by
> +the requested brightness.
> +
> +led_brightness = brightness * <color>_intensity/<color>_max_intensity
> +
> +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 necessary to achieve a blueish violet output from the RGB LED group.
> +
> +echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity
> +echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity
> +echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity
> +
> +red -
> + intensity = 138
> + max_intensity = 255
> +green -
> + intensity = 43
> + max_intensity = 255
> +blue -
> + intensity = 226
> + max_intensity = 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.
> +
> +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/brightness
> +128
>
--
Best regards,
Jacek Anaszewski
Hi!
> diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
> new file mode 100644
> index 000000000000..87a1588d7619
> --- /dev/null
> +++ b/Documentation/leds/leds-class-multicolor.rst
> @@ -0,0 +1,96 @@
> +====================================
> +Multi Color LED handling under Linux
> +====================================
> +
> +Description
> +===========
> +The multi color class groups monochrome LEDs and allows controlling two
> +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.
> +
> +For more details on hue and lightness notions please refer to
> +https://en.wikipedia.org/wiki/CIECAM02.
> +
> +Note that intensity files only cache the written value and the actual
> +change of hardware state occurs upon writing brightness file. This
> +allows for changing many factors of the perceived color in a virtually
> +unnoticeable way for the human observer.
So unlike previous versions, userspace will need to write 4 files
instead of one in the common case.
> +Directory Layout Example
> +========================
> +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 red_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 red_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 green_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 green_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 blue_intensity
Permissions are way off here.
> +A user first writes the color LED brightness file with the brightness level that
> +is necessary to achieve a blueish violet output from the RGB LED group.
> +
> +echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity
> +echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity
> +echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity
No, you can't tell what kind of color this will result in.
Will you be on ELCE/OSS in Lyon?
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
Pavel
On 9/26/19 6:10 AM, Pavel Machek wrote:
> Hi!
>
>> diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
>> new file mode 100644
>> index 000000000000..87a1588d7619
>> --- /dev/null
>> +++ b/Documentation/leds/leds-class-multicolor.rst
>> @@ -0,0 +1,96 @@
>> +====================================
>> +Multi Color LED handling under Linux
>> +====================================
>> +
>> +Description
>> +===========
>> +The multi color class groups monochrome LEDs and allows controlling two
>> +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.
>> +
>> +For more details on hue and lightness notions please refer to
>> +https://en.wikipedia.org/wiki/CIECAM02.
>> +
>> +Note that intensity files only cache the written value and the actual
>> +change of hardware state occurs upon writing brightness file. This
>> +allows for changing many factors of the perceived color in a virtually
>> +unnoticeable way for the human observer.
> So unlike previous versions, userspace will need to write 4 files
> instead of one in the common case.
Request was made here in v5 of the patchset
https://lore.kernel.org/patchwork/patch/1126685/
>
>> +Directory Layout Example
>> +========================
>> +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
>> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 red_max_intensity
>> +--w--wx-w- 1 root root 4096 Jul 7 03:10 red_intensity
>> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 green_max_intensity
>> +--w--wx-w- 1 root root 4096 Jul 7 03:10 green_intensity
>> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
>> +--w--wx-w- 1 root root 4096 Jul 7 03:10 blue_intensity
> Permissions are way off here.
Yes Jacek made a comment in the code about octals.
>
>> +A user first writes the color LED brightness file with the brightness level that
>> +is necessary to achieve a blueish violet output from the RGB LED group.
>> +
>> +echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity
>> +echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity
>> +echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity
> No, you can't tell what kind of color this will result in.
I tested this combination on two devices (LP5523 and LP50xx) and it was
a blueish violet.
> Will you be on ELCE/OSS in Lyon?
Unfortunately no.
Dan
>
> Best regards,
> Pavel
>