Dan, On 10/8/19 10:47 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 | 35 +++ > Documentation/leds/index.rst | 1 + > Documentation/leds/leds-class-multicolor.rst | 96 +++++++ > drivers/leds/Kconfig | 10 + > drivers/leds/Makefile | 1 + > drivers/leds/led-class-multicolor.c | 271 ++++++++++++++++++ > include/linux/led-class-multicolor.h | 143 +++++++++ > 7 files changed, 557 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..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@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 via the equation below: > + > + led_brightness = brightness * <color>_intensity/<color>_max_intensity This equation alone incites questions on how it is supposed to work. It would be better to present the whole algorithm for calculating combined color here. > + > + 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..7a695a29377e > --- /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-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 > + > +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 > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig > index 4b68520ac251..a1ede89afc9e 100644 > --- a/drivers/leds/Kconfig > +++ b/drivers/leds/Kconfig > @@ -30,6 +30,16 @@ config LEDS_CLASS_FLASH > for the flash related features of a LED device. It can be built > as a module. > > +config LEDS_CLASS_MULTI_COLOR > + tristate "LED Mulit Color LED Class Support" > + depends on LEDS_CLASS > + help > + This option enables the multicolor LED sysfs class in /sys/class/leds. > + It wraps LED class and adds multicolor LED specific sysfs attributes > + and kernel internal API to it. You'll need this to provide support > + for multicolor LEDs that are grouped together. This class is not > + intended for single color LEDs. It can be built as a module. > + > config LEDS_BRIGHTNESS_HW_CHANGED > bool "LED Class brightness_hw_changed attribute support" > depends on LEDS_CLASS > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile > index 2da39e896ce8..841038cfe35b 100644 > --- a/drivers/leds/Makefile > +++ b/drivers/leds/Makefile > @@ -4,6 +4,7 @@ > obj-$(CONFIG_NEW_LEDS) += led-core.o > obj-$(CONFIG_LEDS_CLASS) += led-class.o > obj-$(CONFIG_LEDS_CLASS_FLASH) += led-class-flash.o > +obj-$(CONFIG_LEDS_CLASS_MULTI_COLOR) += led-class-multicolor.o > obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o > > # LED Platform Drivers > diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c > new file mode 100644 > index 000000000000..89f4bc9e057c > --- /dev/null > +++ b/drivers/leds/led-class-multicolor.c > @@ -0,0 +1,271 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// LED Multi Color class interface > +// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ > + > +#include <linux/device.h> > +#include <linux/init.h> > +#include <linux/led-class-multicolor.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/uaccess.h> > + > +#include "leds.h" > + > +#define INTENSITY_NAME "_intensity" > +#define MAX_INTENSITY_NAME "_max_intensity" > + > +int led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev, > + enum led_brightness brightness, > + struct led_mc_color_conversion color_component[]) Now the function name doesn't match with the output array name. How about: - led_mc_brightness_to_color_components - led_mc_calc_color_components Other suggestions? > +{ > + struct led_mc_color_entry *priv; > + int i = 0; > + > + list_for_each_entry(priv, &mcled_cdev->color_list, list) { > + color_component[i].color_id = priv->led_color_id; > + color_component[i].brightness = brightness * > + priv->intensity / priv->max_intensity; > + i++; > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(led_mc_calc_brightness); > + > +static ssize_t intensity_store(struct device *dev, > + struct device_attribute *intensity_attr, > + const char *buf, size_t size) > +{ > + struct led_mc_color_entry *priv = container_of(intensity_attr, > + struct led_mc_color_entry, > + intensity_attr); > + struct led_classdev *led_cdev = priv->mcled_cdev->led_cdev; > + unsigned long value; > + ssize_t ret; > + > + mutex_lock(&led_cdev->led_access); > + > + ret = kstrtoul(buf, 10, &value); > + if (ret) > + goto unlock; > + > + if (value > priv->max_intensity) { > + ret = -EINVAL; > + goto unlock; > + } > + > + priv->intensity = value; > + ret = size; > + > +unlock: > + mutex_unlock(&led_cdev->led_access); > + return ret; > +} > + > +static ssize_t intensity_show(struct device *dev, > + struct device_attribute *intensity_attr, > + char *buf) > +{ > + struct led_mc_color_entry *priv = container_of(intensity_attr, > + struct led_mc_color_entry, > + intensity_attr); > + > + return sprintf(buf, "%d\n", priv->intensity); > +} > + > +static ssize_t max_intensity_show(struct device *dev, > + struct device_attribute *max_intensity_attr, > + char *buf) > +{ > + struct led_mc_color_entry *priv = container_of(max_intensity_attr, > + struct led_mc_color_entry, > + max_intensity_attr); > + > + return sprintf(buf, "%d\n", priv->max_intensity); > +} > + > +static struct attribute *led_color_attrs[] = { > + NULL, > +}; > + > +static struct attribute_group led_color_group = { > + .name = "colors", > + .attrs = led_color_attrs, > +}; > + > +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); > + > +max_intensity_err_out: > + kfree(max_intensity_file_name); > +intensity_err_out: > + kfree(intensity_file_name); > + return ret; > +} > + > +static int led_multicolor_init_color_dir(struct led_classdev_mc *mcled_cdev) > +{ > + struct led_classdev *led_cdev = mcled_cdev->led_cdev; > + int ret; > + int i; > + > + ret = sysfs_create_group(&led_cdev->dev->kobj, &led_color_group); > + if (ret) > + return ret; > + > + for (i = 0; i < LED_COLOR_ID_MAX; i++) { > + if (test_bit(i, &mcled_cdev->available_colors)) { > + ret = led_multicolor_init_color(mcled_cdev, i); > + if (ret) > + break; > + > + } > + } > + > + return ret; > +} > + > +int led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data) > +{ > + struct led_classdev *led_cdev; > + int ret; > + > + if (!mcled_cdev) > + return -EINVAL; > + > + led_cdev = mcled_cdev->led_cdev; > + INIT_LIST_HEAD(&mcled_cdev->color_list); > + > + /* Register led class device */ > + ret = led_classdev_register_ext(parent, led_cdev, init_data); > + if (ret) > + return ret; > + > + return led_multicolor_init_color_dir(mcled_cdev); > +} > +EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext); > + > +void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev) > +{ > + struct led_mc_color_entry *priv, *next; > + > + if (!mcled_cdev) > + return; > + > + list_for_each_entry_safe(priv, next, &mcled_cdev->color_list, list) > + list_del(&priv->list); > + > + sysfs_remove_group(&mcled_cdev->led_cdev->dev->kobj, &led_color_group); > + led_classdev_unregister(mcled_cdev->led_cdev); > +} > +EXPORT_SYMBOL_GPL(led_classdev_multicolor_unregister); > + > +static void devm_led_classdev_multicolor_release(struct device *dev, void *res) > +{ > + led_classdev_multicolor_unregister(*(struct led_classdev_mc **)res); > +} > + > +int devm_led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data) > +{ > + struct led_classdev_mc **dr; > + int ret; > + > + dr = devres_alloc(devm_led_classdev_multicolor_release, > + sizeof(*dr), GFP_KERNEL); > + if (!dr) > + return -ENOMEM; > + > + ret = led_classdev_multicolor_register(parent, mcled_cdev); > + if (ret) { > + devres_free(dr); > + return ret; > + } > + > + *dr = mcled_cdev; > + devres_add(parent, dr); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_register_ext); > + > +static int devm_led_classdev_multicolor_match(struct device *dev, > + void *res, void *data) > +{ > + struct led_classdev_mc **p = res; > + > + if (WARN_ON(!p || !*p)) > + return 0; > + > + return *p == data; > +} > + > +void devm_led_classdev_multicolor_unregister(struct device *dev, > + struct led_classdev_mc *mcled_cdev) > +{ > + WARN_ON(devres_release(dev, > + devm_led_classdev_multicolor_release, > + devm_led_classdev_multicolor_match, mcled_cdev)); > +} > +EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_unregister); > + > +MODULE_AUTHOR("Dan Murphy <dmurphy@xxxxxx>"); > +MODULE_DESCRIPTION("Multi Color LED class interface"); > +MODULE_LICENSE("GPL v2"); > diff --git a/include/linux/led-class-multicolor.h b/include/linux/led-class-multicolor.h > new file mode 100644 > index 000000000000..5d0cdca32223 > --- /dev/null > +++ b/include/linux/led-class-multicolor.h > @@ -0,0 +1,143 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* LED Multicolor class interface > + * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ > + */ > + > +#ifndef __LINUX_MULTICOLOR_LEDS_H_INCLUDED > +#define __LINUX_MULTICOLOR_LEDS_H_INCLUDED > + > +#include <linux/leds.h> > +#include <dt-bindings/leds/common.h> > + > +struct led_classdev_mc; > + > +struct led_mc_color_conversion { > + int color_id; > + int brightness; > + int output_num; > +}; > + > +struct led_mc_color_entry { > + struct led_classdev_mc *mcled_cdev; > + > + struct device_attribute max_intensity_attr; > + struct device_attribute intensity_attr; > + > + enum led_brightness max_intensity; > + enum led_brightness intensity; > + > + struct list_head list; > + > + int led_color_id; > +}; > + > +struct led_classdev_mc { > + /* led class device */ > + struct led_classdev *led_cdev; > + struct list_head color_list; > + > + unsigned long available_colors; > + int num_leds; > +}; > +#ifdef CONFIG_LEDS_CLASS_MULTI_COLOR > +static inline struct led_classdev_mc *lcdev_to_mccdev( > + struct led_classdev *lcdev) > +{ > + return container_of(lcdev, struct led_classdev_mc, led_cdev); > +} > + > +/** > + * led_classdev_multicolor_register_ext - register a new object of led_classdev > + * class with support for multicolor LEDs > + * @parent: the multicolor LED to register > + * @mcled_cdev: the led_classdev_mc structure for this device > + * @init_data: the LED class Multi color device initialization data > + * > + * Returns: 0 on success or negative error value on failure > + */ > +int led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data); > + > +static inline int led_classdev_multicolor_register(struct device *parent, > + struct led_classdev_mc *mcled_cdev) > +{ > + return led_classdev_multicolor_register_ext(parent, mcled_cdev, NULL); > +} > + > +/** > + * led_classdev_multicolor_unregister - unregisters an object of led_classdev > + * class with support for multicolor LEDs > + * @mcled_cdev: the multicolor LED to unregister > + * > + * Unregister a previously registered via led_classdev_multicolor_register > + * object > + */ > +void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev); > + > +/* Calculate brightness for the monochrome LED cluster */ > +int led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev, > + enum led_brightness brightness, > + struct led_mc_color_conversion color_component[]); > + > +int devm_led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data); > + > +static inline int devm_led_classdev_multicolor_register(struct device *parent, > + struct led_classdev_mc *mcled_cdev) > +{ > + return devm_led_classdev_multicolor_register_ext(parent, mcled_cdev, > + NULL); > +} > + > +void devm_led_classdev_multicolor_unregister(struct device *parent, > + struct led_classdev_mc *mcled_cdev); > +#else > + > +static inline struct led_classdev_mc *lcdev_to_mccdev( > + struct led_classdev *lcdev) > +{ > + return NULL; > +} > + > +static inline int led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data) > +{ > + return -EINVAL; > +} > + > +static inline int led_classdev_multicolor_register(struct device *parent, > + struct led_classdev_mc *mcled_cdev) > +{ > + return -EINVAL; > +} > + > +static inline void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev) {} > + > +static inline int led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev, > + enum led_brightness brightness, > + struct led_mc_color_conversion color_component[]) > +{ > + return -EINVAL; > +} > + > +static inline int devm_led_classdev_multicolor_register_ext(struct device *parent, > + struct led_classdev_mc *mcled_cdev, > + struct led_init_data *init_data) > +{ > + return -EINVAL; > +} > + > +static inline int devm_led_classdev_multicolor_register(struct device *parent, > + struct led_classdev_mc *mcled_cdev) > +{ > + return -EINVAL; > +} Do you have use case for which these no-ops would be useful? We don't have no-ops for any of current LED API beside triggers, which are indeed useful. > +static inline void devm_led_classdev_multicolor_unregister(struct device *parent, > + struct led_classdev_mc *mcled_cdev) {} > + > +#endif /* CONFIG_LEDS_CLASS_MULTI_COLOR */ > +#endif /* __LINUX_MULTICOLOR_LEDS_H_INCLUDED */ > -- Best regards, Jacek Anaszewski
