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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * PWM-based multi-color LED control4 *5 * Copyright 2022 Sven Schwermer <sven.schwermer@disruptive-technologies.com>6 */7 8#include <linux/err.h>9#include <linux/kernel.h>10#include <linux/led-class-multicolor.h>11#include <linux/leds.h>12#include <linux/mod_devicetable.h>13#include <linux/module.h>14#include <linux/mutex.h>15#include <linux/platform_device.h>16#include <linux/property.h>17#include <linux/pwm.h>18 19struct pwm_led {20 struct pwm_device *pwm;21 struct pwm_state state;22 bool active_low;23};24 25struct pwm_mc_led {26 struct led_classdev_mc mc_cdev;27 struct mutex lock;28 struct pwm_led leds[];29};30 31static int led_pwm_mc_set(struct led_classdev *cdev,32 enum led_brightness brightness)33{34 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);35 struct pwm_mc_led *priv = container_of(mc_cdev, struct pwm_mc_led, mc_cdev);36 unsigned long long duty;37 int ret = 0;38 int i;39 40 led_mc_calc_color_components(mc_cdev, brightness);41 42 mutex_lock(&priv->lock);43 44 for (i = 0; i < mc_cdev->num_colors; i++) {45 duty = priv->leds[i].state.period;46 duty *= mc_cdev->subled_info[i].brightness;47 do_div(duty, cdev->max_brightness);48 49 if (priv->leds[i].active_low)50 duty = priv->leds[i].state.period - duty;51 52 priv->leds[i].state.duty_cycle = duty;53 priv->leds[i].state.enabled = duty > 0;54 ret = pwm_apply_might_sleep(priv->leds[i].pwm,55 &priv->leds[i].state);56 if (ret)57 break;58 }59 60 mutex_unlock(&priv->lock);61 62 return ret;63}64 65static int iterate_subleds(struct device *dev, struct pwm_mc_led *priv,66 struct fwnode_handle *mcnode)67{68 struct mc_subled *subled = priv->mc_cdev.subled_info;69 struct fwnode_handle *fwnode;70 struct pwm_led *pwmled;71 u32 color;72 int ret;73 74 /* iterate over the nodes inside the multi-led node */75 fwnode_for_each_child_node(mcnode, fwnode) {76 pwmled = &priv->leds[priv->mc_cdev.num_colors];77 pwmled->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);78 if (IS_ERR(pwmled->pwm)) {79 ret = dev_err_probe(dev, PTR_ERR(pwmled->pwm), "unable to request PWM\n");80 goto release_fwnode;81 }82 pwm_init_state(pwmled->pwm, &pwmled->state);83 pwmled->active_low = fwnode_property_read_bool(fwnode, "active-low");84 85 ret = fwnode_property_read_u32(fwnode, "color", &color);86 if (ret) {87 dev_err(dev, "cannot read color: %d\n", ret);88 goto release_fwnode;89 }90 91 subled[priv->mc_cdev.num_colors].color_index = color;92 priv->mc_cdev.num_colors++;93 }94 95 return 0;96 97release_fwnode:98 fwnode_handle_put(fwnode);99 return ret;100}101 102static int led_pwm_mc_probe(struct platform_device *pdev)103{104 struct fwnode_handle *mcnode, *fwnode;105 struct led_init_data init_data = {};106 struct led_classdev *cdev;107 struct mc_subled *subled;108 struct pwm_mc_led *priv;109 int count = 0;110 int ret = 0;111 112 mcnode = device_get_named_child_node(&pdev->dev, "multi-led");113 if (!mcnode)114 return dev_err_probe(&pdev->dev, -ENODEV,115 "expected multi-led node\n");116 117 /* count the nodes inside the multi-led node */118 fwnode_for_each_child_node(mcnode, fwnode)119 count++;120 121 priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),122 GFP_KERNEL);123 if (!priv) {124 ret = -ENOMEM;125 goto release_mcnode;126 }127 mutex_init(&priv->lock);128 129 subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL);130 if (!subled) {131 ret = -ENOMEM;132 goto release_mcnode;133 }134 priv->mc_cdev.subled_info = subled;135 136 /* init the multicolor's LED class device */137 cdev = &priv->mc_cdev.led_cdev;138 fwnode_property_read_u32(mcnode, "max-brightness",139 &cdev->max_brightness);140 cdev->flags = LED_CORE_SUSPENDRESUME;141 cdev->brightness_set_blocking = led_pwm_mc_set;142 143 ret = iterate_subleds(&pdev->dev, priv, mcnode);144 if (ret)145 goto release_mcnode;146 147 init_data.fwnode = mcnode;148 ret = devm_led_classdev_multicolor_register_ext(&pdev->dev,149 &priv->mc_cdev,150 &init_data);151 if (ret) {152 dev_err(&pdev->dev,153 "failed to register multicolor PWM led for %s: %d\n",154 cdev->name, ret);155 goto release_mcnode;156 }157 158 ret = led_pwm_mc_set(cdev, cdev->brightness);159 if (ret)160 return dev_err_probe(&pdev->dev, ret,161 "failed to set led PWM value for %s\n",162 cdev->name);163 164 platform_set_drvdata(pdev, priv);165 return 0;166 167release_mcnode:168 fwnode_handle_put(mcnode);169 return ret;170}171 172static const struct of_device_id of_pwm_leds_mc_match[] = {173 { .compatible = "pwm-leds-multicolor", },174 {}175};176MODULE_DEVICE_TABLE(of, of_pwm_leds_mc_match);177 178static struct platform_driver led_pwm_mc_driver = {179 .probe = led_pwm_mc_probe,180 .driver = {181 .name = "leds_pwm_multicolor",182 .of_match_table = of_pwm_leds_mc_match,183 },184};185module_platform_driver(led_pwm_mc_driver);186 187MODULE_AUTHOR("Sven Schwermer <sven.schwermer@disruptive-technologies.com>");188MODULE_DESCRIPTION("multi-color PWM LED driver");189MODULE_LICENSE("GPL v2");190MODULE_ALIAS("platform:leds-pwm-multicolor");191