1818d03b3SSven Schwermer // SPDX-License-Identifier: GPL-2.0-only 2818d03b3SSven Schwermer /* 3818d03b3SSven Schwermer * PWM-based multi-color LED control 4818d03b3SSven Schwermer * 5818d03b3SSven Schwermer * Copyright 2022 Sven Schwermer <sven.schwermer@disruptive-technologies.com> 6818d03b3SSven Schwermer */ 7818d03b3SSven Schwermer 8818d03b3SSven Schwermer #include <linux/err.h> 9818d03b3SSven Schwermer #include <linux/kernel.h> 10818d03b3SSven Schwermer #include <linux/led-class-multicolor.h> 11818d03b3SSven Schwermer #include <linux/leds.h> 12818d03b3SSven Schwermer #include <linux/mod_devicetable.h> 13818d03b3SSven Schwermer #include <linux/module.h> 14818d03b3SSven Schwermer #include <linux/mutex.h> 15818d03b3SSven Schwermer #include <linux/platform_device.h> 16818d03b3SSven Schwermer #include <linux/property.h> 17818d03b3SSven Schwermer #include <linux/pwm.h> 18818d03b3SSven Schwermer 19818d03b3SSven Schwermer struct pwm_led { 20818d03b3SSven Schwermer struct pwm_device *pwm; 21818d03b3SSven Schwermer struct pwm_state state; 22818d03b3SSven Schwermer }; 23818d03b3SSven Schwermer 24818d03b3SSven Schwermer struct pwm_mc_led { 25818d03b3SSven Schwermer struct led_classdev_mc mc_cdev; 26818d03b3SSven Schwermer struct mutex lock; 27818d03b3SSven Schwermer struct pwm_led leds[]; 28818d03b3SSven Schwermer }; 29818d03b3SSven Schwermer 30818d03b3SSven Schwermer static int led_pwm_mc_set(struct led_classdev *cdev, 31818d03b3SSven Schwermer enum led_brightness brightness) 32818d03b3SSven Schwermer { 33818d03b3SSven Schwermer struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev); 34818d03b3SSven Schwermer struct pwm_mc_led *priv = container_of(mc_cdev, struct pwm_mc_led, mc_cdev); 35818d03b3SSven Schwermer unsigned long long duty; 36818d03b3SSven Schwermer int ret = 0; 37818d03b3SSven Schwermer int i; 38818d03b3SSven Schwermer 39818d03b3SSven Schwermer led_mc_calc_color_components(mc_cdev, brightness); 40818d03b3SSven Schwermer 41818d03b3SSven Schwermer mutex_lock(&priv->lock); 42818d03b3SSven Schwermer 43818d03b3SSven Schwermer for (i = 0; i < mc_cdev->num_colors; i++) { 44818d03b3SSven Schwermer duty = priv->leds[i].state.period; 45818d03b3SSven Schwermer duty *= mc_cdev->subled_info[i].brightness; 46818d03b3SSven Schwermer do_div(duty, cdev->max_brightness); 47818d03b3SSven Schwermer 48818d03b3SSven Schwermer priv->leds[i].state.duty_cycle = duty; 49818d03b3SSven Schwermer priv->leds[i].state.enabled = duty > 0; 50818d03b3SSven Schwermer ret = pwm_apply_state(priv->leds[i].pwm, 51818d03b3SSven Schwermer &priv->leds[i].state); 52818d03b3SSven Schwermer if (ret) 53818d03b3SSven Schwermer break; 54818d03b3SSven Schwermer } 55818d03b3SSven Schwermer 56818d03b3SSven Schwermer mutex_unlock(&priv->lock); 57818d03b3SSven Schwermer 58818d03b3SSven Schwermer return ret; 59818d03b3SSven Schwermer } 60818d03b3SSven Schwermer 61818d03b3SSven Schwermer static int iterate_subleds(struct device *dev, struct pwm_mc_led *priv, 62818d03b3SSven Schwermer struct fwnode_handle *mcnode) 63818d03b3SSven Schwermer { 64818d03b3SSven Schwermer struct mc_subled *subled = priv->mc_cdev.subled_info; 65818d03b3SSven Schwermer struct fwnode_handle *fwnode; 66818d03b3SSven Schwermer struct pwm_led *pwmled; 67818d03b3SSven Schwermer u32 color; 68818d03b3SSven Schwermer int ret; 69818d03b3SSven Schwermer 70818d03b3SSven Schwermer /* iterate over the nodes inside the multi-led node */ 71818d03b3SSven Schwermer fwnode_for_each_child_node(mcnode, fwnode) { 72818d03b3SSven Schwermer pwmled = &priv->leds[priv->mc_cdev.num_colors]; 73818d03b3SSven Schwermer pwmled->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL); 74818d03b3SSven Schwermer if (IS_ERR(pwmled->pwm)) { 75*399e7aa8SEmil Renner Berthing ret = dev_err_probe(dev, PTR_ERR(pwmled->pwm), "unable to request PWM\n"); 76818d03b3SSven Schwermer goto release_fwnode; 77818d03b3SSven Schwermer } 78818d03b3SSven Schwermer pwm_init_state(pwmled->pwm, &pwmled->state); 79818d03b3SSven Schwermer 80818d03b3SSven Schwermer ret = fwnode_property_read_u32(fwnode, "color", &color); 81818d03b3SSven Schwermer if (ret) { 82818d03b3SSven Schwermer dev_err(dev, "cannot read color: %d\n", ret); 83818d03b3SSven Schwermer goto release_fwnode; 84818d03b3SSven Schwermer } 85818d03b3SSven Schwermer 86818d03b3SSven Schwermer subled[priv->mc_cdev.num_colors].color_index = color; 87818d03b3SSven Schwermer priv->mc_cdev.num_colors++; 88818d03b3SSven Schwermer } 89818d03b3SSven Schwermer 90818d03b3SSven Schwermer return 0; 91818d03b3SSven Schwermer 92818d03b3SSven Schwermer release_fwnode: 93818d03b3SSven Schwermer fwnode_handle_put(fwnode); 94818d03b3SSven Schwermer return ret; 95818d03b3SSven Schwermer } 96818d03b3SSven Schwermer 97818d03b3SSven Schwermer static int led_pwm_mc_probe(struct platform_device *pdev) 98818d03b3SSven Schwermer { 99818d03b3SSven Schwermer struct fwnode_handle *mcnode, *fwnode; 100818d03b3SSven Schwermer struct led_init_data init_data = {}; 101818d03b3SSven Schwermer struct led_classdev *cdev; 102818d03b3SSven Schwermer struct mc_subled *subled; 103818d03b3SSven Schwermer struct pwm_mc_led *priv; 104818d03b3SSven Schwermer int count = 0; 105818d03b3SSven Schwermer int ret = 0; 106818d03b3SSven Schwermer 107818d03b3SSven Schwermer mcnode = device_get_named_child_node(&pdev->dev, "multi-led"); 108818d03b3SSven Schwermer if (!mcnode) 109818d03b3SSven Schwermer return dev_err_probe(&pdev->dev, -ENODEV, 110818d03b3SSven Schwermer "expected multi-led node\n"); 111818d03b3SSven Schwermer 112818d03b3SSven Schwermer /* count the nodes inside the multi-led node */ 113818d03b3SSven Schwermer fwnode_for_each_child_node(mcnode, fwnode) 114818d03b3SSven Schwermer count++; 115818d03b3SSven Schwermer 116818d03b3SSven Schwermer priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count), 117818d03b3SSven Schwermer GFP_KERNEL); 118818d03b3SSven Schwermer if (!priv) { 119818d03b3SSven Schwermer ret = -ENOMEM; 120818d03b3SSven Schwermer goto release_mcnode; 121818d03b3SSven Schwermer } 122818d03b3SSven Schwermer mutex_init(&priv->lock); 123818d03b3SSven Schwermer 124818d03b3SSven Schwermer subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL); 125818d03b3SSven Schwermer if (!subled) { 126818d03b3SSven Schwermer ret = -ENOMEM; 127818d03b3SSven Schwermer goto release_mcnode; 128818d03b3SSven Schwermer } 129818d03b3SSven Schwermer priv->mc_cdev.subled_info = subled; 130818d03b3SSven Schwermer 131818d03b3SSven Schwermer /* init the multicolor's LED class device */ 132818d03b3SSven Schwermer cdev = &priv->mc_cdev.led_cdev; 133818d03b3SSven Schwermer fwnode_property_read_u32(mcnode, "max-brightness", 134818d03b3SSven Schwermer &cdev->max_brightness); 135818d03b3SSven Schwermer cdev->flags = LED_CORE_SUSPENDRESUME; 136818d03b3SSven Schwermer cdev->brightness_set_blocking = led_pwm_mc_set; 137818d03b3SSven Schwermer 138818d03b3SSven Schwermer ret = iterate_subleds(&pdev->dev, priv, mcnode); 139818d03b3SSven Schwermer if (ret) 140818d03b3SSven Schwermer goto release_mcnode; 141818d03b3SSven Schwermer 142818d03b3SSven Schwermer init_data.fwnode = mcnode; 143818d03b3SSven Schwermer ret = devm_led_classdev_multicolor_register_ext(&pdev->dev, 144818d03b3SSven Schwermer &priv->mc_cdev, 145818d03b3SSven Schwermer &init_data); 146818d03b3SSven Schwermer if (ret) { 147818d03b3SSven Schwermer dev_err(&pdev->dev, 148818d03b3SSven Schwermer "failed to register multicolor PWM led for %s: %d\n", 149818d03b3SSven Schwermer cdev->name, ret); 150818d03b3SSven Schwermer goto release_mcnode; 151818d03b3SSven Schwermer } 152818d03b3SSven Schwermer 153818d03b3SSven Schwermer ret = led_pwm_mc_set(cdev, cdev->brightness); 154818d03b3SSven Schwermer if (ret) 155818d03b3SSven Schwermer return dev_err_probe(&pdev->dev, ret, 156818d03b3SSven Schwermer "failed to set led PWM value for %s: %d", 157818d03b3SSven Schwermer cdev->name, ret); 158818d03b3SSven Schwermer 159818d03b3SSven Schwermer platform_set_drvdata(pdev, priv); 160818d03b3SSven Schwermer return 0; 161818d03b3SSven Schwermer 162818d03b3SSven Schwermer release_mcnode: 163818d03b3SSven Schwermer fwnode_handle_put(mcnode); 164818d03b3SSven Schwermer return ret; 165818d03b3SSven Schwermer } 166818d03b3SSven Schwermer 167818d03b3SSven Schwermer static const struct of_device_id of_pwm_leds_mc_match[] = { 168818d03b3SSven Schwermer { .compatible = "pwm-leds-multicolor", }, 169818d03b3SSven Schwermer {} 170818d03b3SSven Schwermer }; 171818d03b3SSven Schwermer MODULE_DEVICE_TABLE(of, of_pwm_leds_mc_match); 172818d03b3SSven Schwermer 173818d03b3SSven Schwermer static struct platform_driver led_pwm_mc_driver = { 174818d03b3SSven Schwermer .probe = led_pwm_mc_probe, 175818d03b3SSven Schwermer .driver = { 176818d03b3SSven Schwermer .name = "leds_pwm_multicolor", 177818d03b3SSven Schwermer .of_match_table = of_pwm_leds_mc_match, 178818d03b3SSven Schwermer }, 179818d03b3SSven Schwermer }; 180818d03b3SSven Schwermer module_platform_driver(led_pwm_mc_driver); 181818d03b3SSven Schwermer 182818d03b3SSven Schwermer MODULE_AUTHOR("Sven Schwermer <sven.schwermer@disruptive-technologies.com>"); 183818d03b3SSven Schwermer MODULE_DESCRIPTION("multi-color PWM LED driver"); 184818d03b3SSven Schwermer MODULE_LICENSE("GPL v2"); 185818d03b3SSven Schwermer MODULE_ALIAS("platform:leds-pwm-multicolor"); 186