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Armin WolfandLee Jones
2682d63086
Some multicolor LEDs support global brightness control in hardware, meaning that the maximum intensity of the color components is not connected to the maximum global brightness. Such LEDs cannot be described properly by the current multicolor LED class interface, because it assumes that the maximum intensity of each color component is described by the maximum global brightness of the LED. Fix this by introducing a new sysfs attribute called "multi_max_intensity" holding the maximum intensity values for the color components of a multicolor LED class device. Drivers can use the new max_intensity field inside struct mc_subled to tell the multicolor LED class code about those values. Intensity values written by userspace applications will be limited to this maximum value. Drivers for multicolor LEDs that do not support global brightness control in hardware might still want to use the maximum global LED brightness supplied via devicetree as the maximum intensity of each individual color component. Such drivers should set max_intensity to 0 so that the multicolor LED core can act accordingly. The lp50xx and ncp5623 LED drivers already use hardware-based control for the global LED brightness. Modify those drivers to correctly initalize .max_intensity to avoid being limited to the maximum global brightness supplied via devicetree. Reviewed-by: Werner Sembach <wse@tuxedocomputers.com> Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com> Signed-off-by: Armin Wolf <W_Armin@gmx.de> Link: https://patch.msgid.link/20260509214603.262368-2-W_Armin@gmx.de Signed-off-by: Lee Jones <lee@kernel.org>
109 lines
3.7 KiB
C
109 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* LED Multicolor class interface
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* Copyright (C) 2019-20 Texas Instruments Incorporated - http://www.ti.com/
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*/
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#ifndef _LINUX_MULTICOLOR_LEDS_H_INCLUDED
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#define _LINUX_MULTICOLOR_LEDS_H_INCLUDED
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#include <linux/leds.h>
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#include <dt-bindings/leds/common.h>
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/**
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* struct mc_subled - Color component description.
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* @color_index: Color ID.
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* @brightness: Scaled intensity.
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* @intensity: Current intensity.
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* @max_intensity: Maximum supported intensity value.
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* @channel: Channel index.
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*
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* Describes a color component of a multicolor LED. Many multicolor LEDs
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* do not support global brightness control in hardware, so they use
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* the brightness field in connection with led_mc_calc_color_components()
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* to perform the intensity scaling in software.
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* Such drivers should set max_intensity to 0 to signal the multicolor LED core
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* that the maximum global brightness of the LED class device should be used for
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* limiting incoming intensity values.
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*
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* Multicolor LEDs that do support global brightness control in hardware
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* should instead set max_intensity to the maximum intensity value supported
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* by the hardware for a given color component.
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*/
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struct mc_subled {
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unsigned int color_index;
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unsigned int brightness;
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unsigned int intensity;
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unsigned int max_intensity;
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unsigned int channel;
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};
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struct led_classdev_mc {
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/* led class device */
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struct led_classdev led_cdev;
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unsigned int num_colors;
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struct mc_subled *subled_info;
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};
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static inline struct led_classdev_mc *lcdev_to_mccdev(
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struct led_classdev *led_cdev)
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{
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return container_of(led_cdev, struct led_classdev_mc, led_cdev);
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}
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/**
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* led_classdev_multicolor_register_ext - register a new object of led_classdev
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* class with support for multicolor LEDs
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* @parent: the multicolor LED to register
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* @mcled_cdev: the led_classdev_mc structure for this device
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* @init_data: the LED class multicolor device initialization data
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*
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* Returns: 0 on success or negative error value on failure
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*/
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int led_classdev_multicolor_register_ext(struct device *parent,
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struct led_classdev_mc *mcled_cdev,
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struct led_init_data *init_data);
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/**
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* led_classdev_multicolor_unregister - unregisters an object of led_classdev
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* class with support for multicolor LEDs
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* @mcled_cdev: the multicolor LED to unregister
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*
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* Unregister a previously registered via led_classdev_multicolor_register
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* object
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*/
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void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev);
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/**
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* led_mc_calc_color_components() - Calculates component brightness values of a LED cluster.
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* @mcled_cdev - Multicolor LED class device of the LED cluster.
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* @brightness - Global brightness of the LED cluster.
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*
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* Calculates the brightness values for each color component of a monochrome LED cluster,
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* see Documentation/leds/leds-class-multicolor.rst for details.
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*/
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int led_mc_calc_color_components(struct led_classdev_mc *mcled_cdev,
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enum led_brightness brightness);
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int devm_led_classdev_multicolor_register_ext(struct device *parent,
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struct led_classdev_mc *mcled_cdev,
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struct led_init_data *init_data);
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void devm_led_classdev_multicolor_unregister(struct device *parent,
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struct led_classdev_mc *mcled_cdev);
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static inline int led_classdev_multicolor_register(struct device *parent,
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struct led_classdev_mc *mcled_cdev)
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{
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return led_classdev_multicolor_register_ext(parent, mcled_cdev, NULL);
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}
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static inline int devm_led_classdev_multicolor_register(struct device *parent,
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struct led_classdev_mc *mcled_cdev)
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{
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return devm_led_classdev_multicolor_register_ext(parent, mcled_cdev,
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NULL);
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}
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#endif /* _LINUX_MULTICOLOR_LEDS_H_INCLUDED */
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