1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/drivers/leds-pwm.c
5 * simple PWM based LED control
7 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
9 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/platform_device.h>
15 #include <linux/of_platform.h>
16 #include <linux/leds.h>
17 #include <linux/err.h>
18 #include <linux/pwm.h>
19 #include <linux/leds_pwm.h>
20 #include <linux/slab.h>
23 struct led_classdev cdev;
24 struct pwm_device *pwm;
25 unsigned int active_low;
32 struct led_pwm_data leds[0];
35 static void __led_pwm_set(struct led_pwm_data *led_dat)
37 int new_duty = led_dat->duty;
39 pwm_config(led_dat->pwm, new_duty, led_dat->period);
42 pwm_disable(led_dat->pwm);
44 pwm_enable(led_dat->pwm);
47 static int led_pwm_set(struct led_classdev *led_cdev,
48 enum led_brightness brightness)
50 struct led_pwm_data *led_dat =
51 container_of(led_cdev, struct led_pwm_data, cdev);
52 unsigned int max = led_dat->cdev.max_brightness;
53 unsigned long long duty = led_dat->period;
58 if (led_dat->active_low)
59 duty = led_dat->period - duty;
63 __led_pwm_set(led_dat);
68 static inline size_t sizeof_pwm_leds_priv(int num_leds)
70 return sizeof(struct led_pwm_priv) +
71 (sizeof(struct led_pwm_data) * num_leds);
74 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
75 struct led_pwm *led, struct device_node *child)
77 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
78 struct pwm_args pargs;
81 led_data->active_low = led->active_low;
82 led_data->cdev.name = led->name;
83 led_data->cdev.default_trigger = led->default_trigger;
84 led_data->cdev.brightness = LED_OFF;
85 led_data->cdev.max_brightness = led->max_brightness;
86 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
89 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
91 led_data->pwm = devm_pwm_get(dev, led->name);
92 if (IS_ERR(led_data->pwm)) {
93 ret = PTR_ERR(led_data->pwm);
94 if (ret != -EPROBE_DEFER)
95 dev_err(dev, "unable to request PWM for %s: %d\n",
100 led_data->cdev.brightness_set_blocking = led_pwm_set;
103 * FIXME: pwm_apply_args() should be removed when switching to the
106 pwm_apply_args(led_data->pwm);
108 pwm_get_args(led_data->pwm, &pargs);
110 led_data->period = pargs.period;
111 if (!led_data->period && (led->pwm_period_ns > 0))
112 led_data->period = led->pwm_period_ns;
114 ret = devm_of_led_classdev_register(dev, child, &led_data->cdev);
117 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
119 dev_err(dev, "failed to register PWM led for %s: %d\n",
126 static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
128 struct device_node *child;
132 memset(&led, 0, sizeof(led));
134 for_each_child_of_node(dev->of_node, child) {
135 led.name = of_get_property(child, "label", NULL) ? :
138 led.default_trigger = of_get_property(child,
139 "linux,default-trigger", NULL);
140 led.active_low = of_property_read_bool(child, "active-low");
141 of_property_read_u32(child, "max-brightness",
142 &led.max_brightness);
144 ret = led_pwm_add(dev, priv, &led, child);
154 static int led_pwm_probe(struct platform_device *pdev)
156 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
157 struct led_pwm_priv *priv;
162 count = pdata->num_leds;
164 count = of_get_child_count(pdev->dev.of_node);
169 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
175 for (i = 0; i < count; i++) {
176 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
182 ret = led_pwm_create_of(&pdev->dev, priv);
188 platform_set_drvdata(pdev, priv);
193 static const struct of_device_id of_pwm_leds_match[] = {
194 { .compatible = "pwm-leds", },
197 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
199 static struct platform_driver led_pwm_driver = {
200 .probe = led_pwm_probe,
203 .of_match_table = of_pwm_leds_match,
207 module_platform_driver(led_pwm_driver);
209 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
210 MODULE_DESCRIPTION("generic PWM LED driver");
211 MODULE_LICENSE("GPL v2");
212 MODULE_ALIAS("platform:leds-pwm");