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// 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: %d",
cdev->name, ret);
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");
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