Hi Sven,
Thanks for the patch. Few comments below.
On 1/25/22 10:22 AM, 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 b6742b4231bf..2e5058696fa6 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -586,6 +586,14 @@ 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 2a698df9da57..152f69374632 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -79,6 +79,7 @@ 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>
+
+struct pwm_led {
+ struct pwm_device *pwm;
+ struct pwm_state pwmstate;
+};
+
+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);
LED core has the support for parsing LED name, so you can skip it.
+ cdev->brightness = LED_OFF;
devm_kzalloc() handles that.
+ 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);
+ 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);
+ goto destroy_mutex;
+ }
+
+ subled[priv->mc_cdev.num_colors].color_index = color;
+ subled[priv->mc_cdev.num_colors].channel =
+ priv->mc_cdev.num_colors;
channel property can be meaningful only for the LED controllers that can
control many LED outputs. In case of pwm controllers you're using LED id
to pwmstate mapping in led_pwm_mc_set().
+ ++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;
+ }
+
+ platform_set_drvdata(pdev, priv);
+ return 0;
+
+destroy_mutex:
+ mutex_destroy(&priv->lock);
+out:
+ 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");
--
Best regards,
Jacek Anaszewski
