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svenschwermerpavelmachek
svenschwermer
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leds: Add PWM multicolor driver
By allowing to group multiple monochrome PWM LEDs into multicolor LEDs, all involved LEDs can be controlled in-sync. This enables using effects using triggers, etc. Signed-off-by: Sven Schwermer <[email protected]> Reviewed-by: Andy Shevchenko <[email protected]> Signed-off-by: Pavel Machek <[email protected]>
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‎drivers/leds/Kconfig

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@@ -552,6 +552,17 @@ config LEDS_PWM
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help
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This option enables support for pwm driven LEDs
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config LEDS_PWM_MULTICOLOR
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tristate "PWM driven multi-color LED Support"
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depends on LEDS_CLASS_MULTICOLOR
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depends on PWM
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help
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This option enables support for PWM driven monochrome LEDs that are
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grouped into multicolor LEDs.
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To compile this driver as a module, choose M here: the module
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will be called leds-pwm-multicolor.
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config LEDS_REGULATOR
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tristate "REGULATOR driven LED support"
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depends on LEDS_CLASS

‎drivers/leds/Makefile

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@@ -73,6 +73,7 @@ obj-$(CONFIG_LEDS_PCA963X) += leds-pca963x.o
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obj-$(CONFIG_LEDS_PM8058) += leds-pm8058.o
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obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
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obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
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obj-$(CONFIG_LEDS_PWM_MULTICOLOR) += leds-pwm-multicolor.o
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obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
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obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
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obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o

‎drivers/leds/leds-pwm-multicolor.c

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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* PWM-based multi-color LED control
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*
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* Copyright 2022 Sven Schwermer <[email protected]>
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*/
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/led-class-multicolor.h>
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#include <linux/leds.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/pwm.h>
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struct pwm_led {
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struct pwm_device *pwm;
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struct pwm_state state;
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};
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struct pwm_mc_led {
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struct led_classdev_mc mc_cdev;
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struct mutex lock;
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struct pwm_led leds[];
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};
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static int led_pwm_mc_set(struct led_classdev *cdev,
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enum led_brightness brightness)
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{
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struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
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struct pwm_mc_led *priv = container_of(mc_cdev, struct pwm_mc_led, mc_cdev);
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unsigned long long duty;
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int ret = 0;
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int i;
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led_mc_calc_color_components(mc_cdev, brightness);
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mutex_lock(&priv->lock);
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for (i = 0; i < mc_cdev->num_colors; i++) {
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duty = priv->leds[i].state.period;
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duty *= mc_cdev->subled_info[i].brightness;
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do_div(duty, cdev->max_brightness);
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priv->leds[i].state.duty_cycle = duty;
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priv->leds[i].state.enabled = duty > 0;
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ret = pwm_apply_state(priv->leds[i].pwm,
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&priv->leds[i].state);
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if (ret)
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break;
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}
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mutex_unlock(&priv->lock);
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return ret;
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}
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static int iterate_subleds(struct device *dev, struct pwm_mc_led *priv,
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struct fwnode_handle *mcnode)
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{
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struct mc_subled *subled = priv->mc_cdev.subled_info;
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struct fwnode_handle *fwnode;
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struct pwm_led *pwmled;
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u32 color;
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int ret;
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/* iterate over the nodes inside the multi-led node */
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fwnode_for_each_child_node(mcnode, fwnode) {
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pwmled = &priv->leds[priv->mc_cdev.num_colors];
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pwmled->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
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if (IS_ERR(pwmled->pwm)) {
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ret = PTR_ERR(pwmled->pwm);
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dev_err(dev, "unable to request PWM: %d\n", ret);
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goto release_fwnode;
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}
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pwm_init_state(pwmled->pwm, &pwmled->state);
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ret = fwnode_property_read_u32(fwnode, "color", &color);
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if (ret) {
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dev_err(dev, "cannot read color: %d\n", ret);
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goto release_fwnode;
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}
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subled[priv->mc_cdev.num_colors].color_index = color;
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priv->mc_cdev.num_colors++;
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}
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return 0;
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release_fwnode:
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fwnode_handle_put(fwnode);
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return ret;
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}
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static int led_pwm_mc_probe(struct platform_device *pdev)
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{
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struct fwnode_handle *mcnode, *fwnode;
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struct led_init_data init_data = {};
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struct led_classdev *cdev;
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struct mc_subled *subled;
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struct pwm_mc_led *priv;
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int count = 0;
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int ret = 0;
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mcnode = device_get_named_child_node(&pdev->dev, "multi-led");
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if (!mcnode)
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return dev_err_probe(&pdev->dev, -ENODEV,
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"expected multi-led node\n");
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/* count the nodes inside the multi-led node */
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fwnode_for_each_child_node(mcnode, fwnode)
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count++;
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priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
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GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto release_mcnode;
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}
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mutex_init(&priv->lock);
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subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL);
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if (!subled) {
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ret = -ENOMEM;
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goto release_mcnode;
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}
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priv->mc_cdev.subled_info = subled;
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/* init the multicolor's LED class device */
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cdev = &priv->mc_cdev.led_cdev;
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fwnode_property_read_u32(mcnode, "max-brightness",
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&cdev->max_brightness);
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cdev->flags = LED_CORE_SUSPENDRESUME;
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cdev->brightness_set_blocking = led_pwm_mc_set;
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ret = iterate_subleds(&pdev->dev, priv, mcnode);
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if (ret)
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goto release_mcnode;
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init_data.fwnode = mcnode;
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ret = devm_led_classdev_multicolor_register_ext(&pdev->dev,
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&priv->mc_cdev,
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&init_data);
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if (ret) {
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dev_err(&pdev->dev,
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"failed to register multicolor PWM led for %s: %d\n",
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cdev->name, ret);
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goto release_mcnode;
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}
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ret = led_pwm_mc_set(cdev, cdev->brightness);
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if (ret)
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return dev_err_probe(&pdev->dev, ret,
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"failed to set led PWM value for %s: %d",
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cdev->name, ret);
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platform_set_drvdata(pdev, priv);
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return 0;
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release_mcnode:
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fwnode_handle_put(mcnode);
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return ret;
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}
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static const struct of_device_id of_pwm_leds_mc_match[] = {
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{ .compatible = "pwm-leds-multicolor", },
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{}
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};
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MODULE_DEVICE_TABLE(of, of_pwm_leds_mc_match);
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static struct platform_driver led_pwm_mc_driver = {
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.probe = led_pwm_mc_probe,
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.driver = {
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.name = "leds_pwm_multicolor",
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.of_match_table = of_pwm_leds_mc_match,
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},
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};
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module_platform_driver(led_pwm_mc_driver);
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MODULE_AUTHOR("Sven Schwermer <[email protected]>");
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MODULE_DESCRIPTION("multi-color PWM LED driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:leds-pwm-multicolor");

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