Re: [PATCH v15 04/19] leds: multicolor: Introduce a multicolor class definition
From: Dan Murphy
Date: Mon Oct 28 2019 - 15:37:42 EST
Jacek
On 10/28/19 2:22 PM, Jacek Anaszewski wrote:
Dan,
Thank you for the v15.
On 10/28/19 7:36 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
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>
---
.../ABI/testing/sysfs-class-led-multicolor | 36 +++
Documentation/leds/index.rst | 1 +
Documentation/leds/leds-class-multicolor.rst | 100 +++++++
drivers/leds/Kconfig | 10 +
drivers/leds/Makefile | 1 +
drivers/leds/led-class-multicolor.c | 271 ++++++++++++++++++
include/linux/led-class-multicolor.h | 139 +++++++++
7 files changed, 558 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-led-multicolor
create mode 100644 Documentation/leds/leds-class-multicolor.rst
create mode 100644 drivers/leds/led-class-multicolor.c
create mode 100644 include/linux/led-class-multicolor.h
diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor b/Documentation/ABI/testing/sysfs-class-led-multicolor
new file mode 100644
index 000000000000..3d1f9d726c70
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-multicolor
@@ -0,0 +1,36 @@
+What: /sys/class/leds/<led>/brightness
+Date: Sept 2019
+KernelVersion: 5.5
+Contact: Dan Murphy <dmurphy@xxxxxx>
+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 for each grouped LED 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@xxxxxx>
+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@xxxxxx>
+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..c8a224cead51
--- /dev/null
+++ b/Documentation/leds/leds-class-multicolor.rst
@@ -0,0 +1,100 @@
+====================================
+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/
s/rgb/multicolor/ according to the led_colors[LED_COLOR_ID_MULTI].
Ack but this probably would not be multicolor either based on LED node
naming conventions.
+-rw-r--r-- 1 root root 4096 Jul 7 03:10 blue_intensity
+-r--r--r-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
+-rw-r--r-- 1 root root 4096 Jul 7 03:10 green_intensity
+-r--r--r-- 1 root root 4096 Jul 7 03:10 green_max_intensity
+-rw-r--r-- 1 root root 4096 Jul 7 03:10 red_intensity
+-r--r--r-- 1 root root 4096 Jul 7 03:10 red_max_intensity
+
[...]
+static int led_multicolor_init_color(struct led_classdev_mc *mcled_cdev,
+ int color_id)
+{
+ struct led_classdev *led_cdev = mcled_cdev->led_cdev;
+ struct led_mc_color_entry *mc_priv;
+ char *intensity_file_name;
+ char *max_intensity_file_name;
+ size_t len;
+ int ret;
+
+ mc_priv = devm_kzalloc(led_cdev->dev, sizeof(*mc_priv), GFP_KERNEL);
+ if (!mc_priv)
+ return -ENOMEM;
+
+ mc_priv->led_color_id = color_id;
+ mc_priv->mcled_cdev = mcled_cdev;
+
+ sysfs_attr_init(&mc_priv->intensity_attr.attr);
+ len = strlen(led_colors[color_id]) + strlen(INTENSITY_NAME) + 1;
+ intensity_file_name = kzalloc(len, GFP_KERNEL);
+ if (!intensity_file_name)
+ return -ENOMEM;
+
+ snprintf(intensity_file_name, len, "%s%s",
+ led_colors[color_id], INTENSITY_NAME);
+ mc_priv->intensity_attr.attr.name = intensity_file_name;
+ mc_priv->intensity_attr.attr.mode = 0644;
+ mc_priv->intensity_attr.store = intensity_store;
+ mc_priv->intensity_attr.show = intensity_show;
+ ret = sysfs_add_file_to_group(&led_cdev->dev->kobj,
+ &mc_priv->intensity_attr.attr,
+ led_color_group.name);
+ if (ret)
+ goto intensity_err_out;
+
+ sysfs_attr_init(&mc_priv->max_intensity_attr.attr);
+ len = strlen(led_colors[color_id]) + strlen(MAX_INTENSITY_NAME) + 1;
+ max_intensity_file_name = kzalloc(len, GFP_KERNEL);
+ if (!max_intensity_file_name) {
+ ret = -ENOMEM;
+ goto intensity_err_out;
+ }
+
+ snprintf(max_intensity_file_name, len, "%s%s",
+ led_colors[color_id], MAX_INTENSITY_NAME);
+ mc_priv->max_intensity_attr.attr.name = max_intensity_file_name;
+ mc_priv->max_intensity_attr.attr.mode = 0444;
+ mc_priv->max_intensity_attr.show = max_intensity_show;
+ ret = sysfs_add_file_to_group(&led_cdev->dev->kobj,
+ &mc_priv->max_intensity_attr.attr,
+ led_color_group.name);
+ if (ret)
+ goto max_intensity_err_out;
+
+ mc_priv->max_intensity = LED_FULL;
+ list_add_tail(&mc_priv->list, &mcled_cdev->color_list);
I still would prefer dynamically allocated array here. Also there are
things I would see differently in the patch 13/19 as already discussed.
Nonetheless I am giving my preliminary ack for this series just to
give a hint to others to join the review.
Replies were given on the 13/19 patch.
Dan