diff options
Diffstat (limited to 'drivers/leds/rgb/leds-pwm-multicolor.c')
| -rw-r--r-- | drivers/leds/rgb/leds-pwm-multicolor.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/leds/rgb/leds-pwm-multicolor.c b/drivers/leds/rgb/leds-pwm-multicolor.c new file mode 100644 index 000000000..46cd062b8 --- /dev/null +++ b/drivers/leds/rgb/leds-pwm-multicolor.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PWM-based multi-color LED control + * + * Copyright 2022 Sven Schwermer <sven.schwermer@disruptive-technologies.com> + */ + +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/led-class-multicolor.h> +#include <linux/leds.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/pwm.h> + +struct pwm_led { + struct pwm_device *pwm; + struct pwm_state state; + bool active_low; +}; + +struct pwm_mc_led { + struct led_classdev_mc mc_cdev; + struct mutex lock; + struct pwm_led leds[]; +}; + +static int led_pwm_mc_set(struct led_classdev *cdev, + enum led_brightness brightness) +{ + struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev); + struct pwm_mc_led *priv = container_of(mc_cdev, struct pwm_mc_led, mc_cdev); + unsigned long long duty; + int ret = 0; + int i; + + led_mc_calc_color_components(mc_cdev, brightness); + + mutex_lock(&priv->lock); + + for (i = 0; i < mc_cdev->num_colors; i++) { + duty = priv->leds[i].state.period; + duty *= mc_cdev->subled_info[i].brightness; + do_div(duty, cdev->max_brightness); + + if (priv->leds[i].active_low) + duty = priv->leds[i].state.period - duty; + + priv->leds[i].state.duty_cycle = duty; + priv->leds[i].state.enabled = duty > 0; + ret = pwm_apply_state(priv->leds[i].pwm, + &priv->leds[i].state); + if (ret) + break; + } + + mutex_unlock(&priv->lock); + + return ret; +} + +static int iterate_subleds(struct device *dev, struct pwm_mc_led *priv, + struct fwnode_handle *mcnode) +{ + struct mc_subled *subled = priv->mc_cdev.subled_info; + struct fwnode_handle *fwnode; + struct pwm_led *pwmled; + u32 color; + int ret; + + /* iterate over the nodes inside the multi-led node */ + fwnode_for_each_child_node(mcnode, fwnode) { + pwmled = &priv->leds[priv->mc_cdev.num_colors]; + pwmled->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL); + if (IS_ERR(pwmled->pwm)) { + ret = dev_err_probe(dev, PTR_ERR(pwmled->pwm), "unable to request PWM\n"); + goto release_fwnode; + } + pwm_init_state(pwmled->pwm, &pwmled->state); + pwmled->active_low = fwnode_property_read_bool(fwnode, "active-low"); + + ret = fwnode_property_read_u32(fwnode, "color", &color); + if (ret) { + dev_err(dev, "cannot read color: %d\n", ret); + goto release_fwnode; + } + + subled[priv->mc_cdev.num_colors].color_index = color; + priv->mc_cdev.num_colors++; + } + + return 0; + +release_fwnode: + fwnode_handle_put(fwnode); + return ret; +} + +static int led_pwm_mc_probe(struct platform_device *pdev) +{ + struct fwnode_handle *mcnode, *fwnode; + struct led_init_data init_data = {}; + struct led_classdev *cdev; + struct mc_subled *subled; + struct pwm_mc_led *priv; + int count = 0; + int ret = 0; + + mcnode = device_get_named_child_node(&pdev->dev, "multi-led"); + if (!mcnode) + return dev_err_probe(&pdev->dev, -ENODEV, + "expected multi-led node\n"); + + /* count the nodes inside the multi-led node */ + fwnode_for_each_child_node(mcnode, fwnode) + count++; + + priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count), + GFP_KERNEL); + if (!priv) { + ret = -ENOMEM; + goto release_mcnode; + } + mutex_init(&priv->lock); + + subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL); + if (!subled) { + ret = -ENOMEM; + goto release_mcnode; + } + priv->mc_cdev.subled_info = subled; + + /* init the multicolor's LED class device */ + cdev = &priv->mc_cdev.led_cdev; + fwnode_property_read_u32(mcnode, "max-brightness", + &cdev->max_brightness); + cdev->flags = LED_CORE_SUSPENDRESUME; + cdev->brightness_set_blocking = led_pwm_mc_set; + + ret = iterate_subleds(&pdev->dev, priv, mcnode); + if (ret) + goto release_mcnode; + + init_data.fwnode = mcnode; + ret = devm_led_classdev_multicolor_register_ext(&pdev->dev, + &priv->mc_cdev, + &init_data); + if (ret) { + dev_err(&pdev->dev, + "failed to register multicolor PWM led for %s: %d\n", + cdev->name, ret); + goto release_mcnode; + } + + ret = led_pwm_mc_set(cdev, cdev->brightness); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "failed to set led PWM value for %s\n", + cdev->name); + + platform_set_drvdata(pdev, priv); + return 0; + +release_mcnode: + fwnode_handle_put(mcnode); + return ret; +} + +static const struct of_device_id of_pwm_leds_mc_match[] = { + { .compatible = "pwm-leds-multicolor", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_pwm_leds_mc_match); + +static struct platform_driver led_pwm_mc_driver = { + .probe = led_pwm_mc_probe, + .driver = { + .name = "leds_pwm_multicolor", + .of_match_table = of_pwm_leds_mc_match, + }, +}; +module_platform_driver(led_pwm_mc_driver); + +MODULE_AUTHOR("Sven Schwermer <sven.schwermer@disruptive-technologies.com>"); +MODULE_DESCRIPTION("multi-color PWM LED driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:leds-pwm-multicolor"); |