On Tue, 25 Jan 2022 16:12:26 +0100
sven@xxxxxxxxxxxxxxxx wrote:
> From: Sven Schwermer <sven.schwermer@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
>
> 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 <sven.schwermer@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/leds/Kconfig | 8 ++
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-pwm-multicolor.c | 184 +++++++++++++++++++++++++++++
> 3 files changed, 193 insertions(+)
> create mode 100644 drivers/leds/leds-pwm-multicolor.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 6090e647daee..bae1f63f6195 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -552,6 +552,14 @@ config LEDS_PWM
> help
> This option enables support for pwm driven LEDs
>
> +config LEDS_PWM_MULTICOLOR
> + tristate "PWM driven multi-color LED Support"
> + depends on LEDS_CLASS_MULTICOLOR
> + depends on PWM
> + help
> + This option enables support for PWM driven monochrome LEDs that are
> + grouped into multicolor LEDs.
> +
> config LEDS_REGULATOR
> tristate "REGULATOR driven LED support"
> depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index e58ecb36360f..ba2c2c1edf12 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -73,6 +73,7 @@ obj-$(CONFIG_LEDS_PCA963X) += leds-pca963x.o
> obj-$(CONFIG_LEDS_PM8058) += leds-pm8058.o
> obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
> obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
> +obj-$(CONFIG_LEDS_PWM_MULTICOLOR) += leds-pwm-multicolor.o
> obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
> obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
> obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
> diff --git a/drivers/leds/leds-pwm-multicolor.c b/drivers/leds/leds-pwm-multicolor.c
> new file mode 100644
> index 000000000000..c54bed4536d3
> --- /dev/null
> +++ b/drivers/leds/leds-pwm-multicolor.c
> @@ -0,0 +1,184 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * PWM-based multi-color LED control
> + *
> + * Copyright 2022 Sven Schwermer <sven.schwermer@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/led-class-multicolor.h>
> +#include <linux/leds.h>
> +#include <linux/err.h>
> +#include <linux/pwm.h>
> +#include <linux/mutex.h>
sort headers alphabetically
> +
> +struct pwm_led {
> + struct pwm_device *pwm;
> + struct pwm_state pwmstate;
maybe rename pwmstate to just state?
> +};
> +
> +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)
> +{
> + int i;
> + unsigned long long duty;
> + int ret = 0;
> + 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);
> +
> + 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].pwmstate.period;
> + duty *= mc_cdev->subled_info[i].brightness;
> + do_div(duty, cdev->max_brightness);
> +
> + priv->leds[i].pwmstate.duty_cycle = duty;
> + priv->leds[i].pwmstate.enabled = duty > 0;
> + ret = pwm_apply_state(priv->leds[i].pwm,
> + &priv->leds[i].pwmstate);
> + if (ret)
> + break;
> + }
> +
> + mutex_unlock(&priv->lock);
> +
> + return ret;
> +}
> +
> +static int led_pwm_mc_probe(struct platform_device *pdev)
> +{
> + struct fwnode_handle *mcnode, *fwnode;
> + int count = 0;
> + struct pwm_mc_led *priv;
> + struct mc_subled *subled;
> + struct led_classdev *cdev;
> + struct pwm_led *pwmled;
> + u32 color;
> + int ret = 0;
> + struct led_init_data init_data = {};
> +
> + mcnode = device_get_named_child_node(&pdev->dev, "multi-led");
> + if (!mcnode) {
> + dev_err(&pdev->dev, "expected multi-led node\n");
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + /* 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 out;
> + }
> + mutex_init(&priv->lock);
> +
> + subled = devm_kcalloc(&pdev->dev, count, sizeof(*subled), GFP_KERNEL);
> + if (!subled) {
> + ret = -ENOMEM;
> + goto destroy_mutex;
> + }
> + priv->mc_cdev.subled_info = subled;
> +
> + /* init the multicolor's LED class device */
> + cdev = &priv->mc_cdev.led_cdev;
> + fwnode_property_read_string(mcnode, "label", &cdev->name);
label is deprecated, do not introduce in new bindings
> + cdev->brightness = LED_OFF;
dont use this LED_OFF/LED_ON constants, they are deprecated
> + fwnode_property_read_u32(mcnode, "max-brightness",
> + &cdev->max_brightness);
> + cdev->flags = LED_CORE_SUSPENDRESUME;
> + cdev->brightness_set_blocking = led_pwm_mc_set;
> +
> + /* 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(&pdev->dev, fwnode, NULL);
> + if (IS_ERR(pwmled->pwm)) {
> + ret = PTR_ERR(pwmled->pwm);
> + dev_err(&pdev->dev, "unable to request PWM: %d\n", ret);
you need to release the fwnode with fwnode_handle_put(fwnode) here
> + goto destroy_mutex;
> + }
> + pwm_init_state(pwmled->pwm, &pwmled->pwmstate);
> +
> + ret = fwnode_property_read_u32(fwnode, "color", &color);
> + if (ret) {
> + dev_err(&pdev->dev, "cannot read color: %d\n", ret);
you need to release the fwnode with fwnode_handle_put(fwnode) here
> + goto destroy_mutex;
> + }
> +
> + subled[priv->mc_cdev.num_colors].color_index = color;
> + subled[priv->mc_cdev.num_colors].channel =
> + priv->mc_cdev.num_colors;
> + ++priv->mc_cdev.num_colors;
> + }
> +
> + 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 destroy_mutex;
> + }
> +
> + ret = led_pwm_mc_set(cdev, cdev->brightness);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to set led PWM value for %s: %d",
> + cdev->name, ret);
> + goto destroy_mutex;
> + }
> +
you need to release mcnode with fwnode_handle_put(). You increased reference
count with device_get_named_child_node()
> + platform_set_drvdata(pdev, priv);
> + return 0;
> +
> +destroy_mutex:
> + mutex_destroy(&priv->lock);
> +out:
here as well you need to release mcnode with fwnode_handle_put()
> + return ret;
> +}
> +
> +static int led_pwm_mc_remove(struct platform_device *pdev)
> +{
> + struct pwm_mc_led *priv = platform_get_drvdata(pdev);
> +
> + mutex_destroy(&priv->lock);
> + return 0;
> +}
> +
> +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,
> + .remove = led_pwm_mc_remove,
> + .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@xxxxxxxxxxxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("multi-color PWM LED driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:leds-pwm-multicolor");
