2 * linux/drivers/leds-pwm.c
4 * simple PWM based LED control
6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/platform_device.h>
18 #include <linux/of_platform.h>
20 #include <linux/leds.h>
21 #include <linux/err.h>
22 #include <linux/pwm.h>
23 #include <linux/leds_pwm.h>
24 #include <linux/slab.h>
27 struct led_classdev cdev;
28 struct pwm_device *pwm;
29 unsigned int active_low;
36 struct led_pwm_data leds[0];
39 static void __led_pwm_set(struct led_pwm_data *led_dat)
41 int new_duty = led_dat->duty;
43 pwm_config(led_dat->pwm, new_duty, led_dat->period);
46 pwm_disable(led_dat->pwm);
48 pwm_enable(led_dat->pwm);
51 static int led_pwm_set(struct led_classdev *led_cdev,
52 enum led_brightness brightness)
54 struct led_pwm_data *led_dat =
55 container_of(led_cdev, struct led_pwm_data, cdev);
56 unsigned int max = led_dat->cdev.max_brightness;
57 unsigned long long duty = led_dat->period;
62 if (led_dat->active_low)
63 duty = led_dat->period - duty;
67 __led_pwm_set(led_dat);
72 static inline size_t sizeof_pwm_leds_priv(int num_leds)
74 return sizeof(struct led_pwm_priv) +
75 (sizeof(struct led_pwm_data) * num_leds);
78 static void led_pwm_cleanup(struct led_pwm_priv *priv)
80 while (priv->num_leds--)
81 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
84 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
85 struct led_pwm *led, struct device_node *child)
87 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
88 struct pwm_args pargs;
91 led_data->active_low = led->active_low;
92 led_data->cdev.name = led->name;
93 led_data->cdev.default_trigger = led->default_trigger;
94 led_data->cdev.brightness = LED_OFF;
95 led_data->cdev.max_brightness = led->max_brightness;
96 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
99 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
101 led_data->pwm = devm_pwm_get(dev, led->name);
102 if (IS_ERR(led_data->pwm)) {
103 ret = PTR_ERR(led_data->pwm);
104 if (ret != -EPROBE_DEFER)
105 dev_err(dev, "unable to request PWM for %s: %d\n",
110 led_data->cdev.brightness_set_blocking = led_pwm_set;
113 * FIXME: pwm_apply_args() should be removed when switching to the
116 pwm_apply_args(led_data->pwm);
118 pwm_get_args(led_data->pwm, &pargs);
120 led_data->period = pargs.period;
121 if (!led_data->period && (led->pwm_period_ns > 0))
122 led_data->period = led->pwm_period_ns;
124 ret = led_classdev_register(dev, &led_data->cdev);
127 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
129 dev_err(dev, "failed to register PWM led for %s: %d\n",
136 static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
138 struct device_node *child;
142 memset(&led, 0, sizeof(led));
144 for_each_child_of_node(dev->of_node, child) {
145 led.name = of_get_property(child, "label", NULL) ? :
148 led.default_trigger = of_get_property(child,
149 "linux,default-trigger", NULL);
150 led.active_low = of_property_read_bool(child, "active-low");
151 of_property_read_u32(child, "max-brightness",
152 &led.max_brightness);
154 ret = led_pwm_add(dev, priv, &led, child);
164 static int led_pwm_probe(struct platform_device *pdev)
166 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
167 struct led_pwm_priv *priv;
172 count = pdata->num_leds;
174 count = of_get_child_count(pdev->dev.of_node);
179 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
185 for (i = 0; i < count; i++) {
186 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
192 ret = led_pwm_create_of(&pdev->dev, priv);
196 led_pwm_cleanup(priv);
200 platform_set_drvdata(pdev, priv);
205 static int led_pwm_remove(struct platform_device *pdev)
207 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
209 led_pwm_cleanup(priv);
214 static const struct of_device_id of_pwm_leds_match[] = {
215 { .compatible = "pwm-leds", },
218 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
220 static struct platform_driver led_pwm_driver = {
221 .probe = led_pwm_probe,
222 .remove = led_pwm_remove,
225 .of_match_table = of_pwm_leds_match,
229 module_platform_driver(led_pwm_driver);
231 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
232 MODULE_DESCRIPTION("generic PWM LED driver");
233 MODULE_LICENSE("GPL v2");
234 MODULE_ALIAS("platform:leds-pwm");