From: Dan Murphy <dmurphy@ti.com>
To: <jacek.anaszewski@gmail.com>, <pavel@ucw.cz>
Cc: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
"Dan Murphy" <dmurphy@ti.com>,
linus.walleij@linaro.org, shawnguo@kernel.org,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Fabio Estevam" <festevam@gmail.com>,
"NXP Linux Team" <linux-imx@nxp.com>,
"Tony Lindgren" <tony@atomide.com>,
"Benoît Cousson" <bcousson@baylibre.com>
Subject: [PATCH v9 01/15] leds: multicolor: Add sysfs interface definition
Date: Wed, 25 Sep 2019 12:46:02 -0500 [thread overview]
Message-ID: <20190925174616.3714-2-dmurphy@ti.com> (raw)
In-Reply-To: <20190925174616.3714-1-dmurphy@ti.com>
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 <dmurphy@ti.com>
---
.../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 <dmurphy@ti.com>
+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 <dmurphy@ti.com>
+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 <dmurphy@ti.com>
+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
next prev parent reply other threads:[~2019-09-25 17:41 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 17:46 [PATCH v9 00/15] Multicolor Framework Dan Murphy
2019-09-25 17:46 ` Dan Murphy [this message]
2019-09-25 20:58 ` [PATCH v9 01/15] leds: multicolor: Add sysfs interface definition Jacek Anaszewski
2019-09-26 11:10 ` Pavel Machek
2019-09-26 12:08 ` Dan Murphy
2019-09-25 17:46 ` [PATCH v9 02/15] dt: bindings: Add multicolor class dt bindings documention Dan Murphy
2019-09-25 17:46 ` [PATCH v9 03/15] dt-bindings: leds: Add multicolor ID to the color ID list Dan Murphy
2019-09-25 17:46 ` [PATCH v9 04/15] " Dan Murphy
2019-09-25 17:46 ` [PATCH v9 05/15] leds: multicolor: Introduce a multicolor class definition Dan Murphy
2019-09-25 21:12 ` Jacek Anaszewski
2019-09-26 11:52 ` Dan Murphy
2019-09-28 10:09 ` Jacek Anaszewski
2019-09-28 18:31 ` Jacek Anaszewski
2019-09-25 17:46 ` [PATCH v9 06/15] dt: bindings: lp50xx: Introduce the lp50xx family of RGB drivers Dan Murphy
2019-09-25 17:46 ` [PATCH v9 07/15] leds: lp50xx: Add the LP50XX family of the RGB LED driver Dan Murphy
2019-09-25 21:27 ` Jacek Anaszewski
2019-09-26 11:59 ` Dan Murphy
2019-09-28 10:29 ` Jacek Anaszewski
2019-09-25 17:46 ` [PATCH v9 08/15] dt: bindings: lp55xx: Be consistent in the document with LED Dan Murphy
2019-09-25 21:31 ` Jacek Anaszewski
2019-09-26 12:00 ` Dan Murphy
2019-09-25 17:46 ` [PATCH v9 09/15] dt: bindings: lp55xx: Update binding for Multicolor Framework Dan Murphy
2019-09-25 21:34 ` Jacek Anaszewski
2019-09-26 12:00 ` Dan Murphy
2019-09-25 17:46 ` [PATCH v9 10/15] ARM: dts: n900: Add reg property to the LP5523 channel node Dan Murphy
2019-09-25 17:46 ` [PATCH v9 11/15] ARM: dts: imx6dl-yapp4: Add reg property to the lp5562 " Dan Murphy
2019-09-25 18:00 ` Fabio Estevam
2019-09-25 18:16 ` Dan Murphy
2019-09-25 17:46 ` [PATCH v9 12/15] ARM: dts: ste-href: Add reg property to the LP5521 channel nodes Dan Murphy
2019-10-04 21:30 ` Linus Walleij
2019-09-25 17:46 ` [PATCH v9 13/15] leds: lp55xx: Update the lp55xx to use the multi color framework Dan Murphy
2019-09-25 22:00 ` Jacek Anaszewski
2019-09-26 12:02 ` Dan Murphy
2019-09-29 13:01 ` Jacek Anaszewski
2019-09-30 16:31 ` Dan Murphy
2019-09-30 20:34 ` Dan Murphy
2019-09-25 17:46 ` [PATCH v9 14/15] leds: lp55xx: Fix checkpatch file permissions issues Dan Murphy
2019-09-25 17:46 ` [PATCH v9 15/15] leds: lp5523: Fix checkpatch issues in the code Dan Murphy
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