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/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/of_platform.h>
21 #include <linux/leds.h>
22 #include <linux/err.h>
23 #include <linux/pwm.h>
24 #include <linux/leds_pwm.h>
25 #include <linux/slab.h>
26 #include <linux/workqueue.h>
29 struct led_classdev cdev;
30 struct pwm_device *pwm;
31 struct work_struct work;
32 unsigned int active_low;
40 struct led_pwm_data leds[0];
43 static void __led_pwm_set(struct led_pwm_data *led_dat)
45 int new_duty = led_dat->duty;
47 pwm_config(led_dat->pwm, new_duty, led_dat->period);
50 pwm_disable(led_dat->pwm);
52 pwm_enable(led_dat->pwm);
55 static void led_pwm_work(struct work_struct *work)
57 struct led_pwm_data *led_dat =
58 container_of(work, struct led_pwm_data, work);
60 __led_pwm_set(led_dat);
63 static void led_pwm_set(struct led_classdev *led_cdev,
64 enum led_brightness brightness)
66 struct led_pwm_data *led_dat =
67 container_of(led_cdev, struct led_pwm_data, cdev);
68 unsigned int max = led_dat->cdev.max_brightness;
69 unsigned long long duty = led_dat->period;
75 if (led_dat->can_sleep)
76 schedule_work(&led_dat->work);
78 __led_pwm_set(led_dat);
81 static inline size_t sizeof_pwm_leds_priv(int num_leds)
83 return sizeof(struct led_pwm_priv) +
84 (sizeof(struct led_pwm_data) * num_leds);
87 static int led_pwm_create_of(struct platform_device *pdev,
88 struct led_pwm_priv *priv)
90 struct device_node *child;
93 for_each_child_of_node(pdev->dev.of_node, child) {
94 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
96 led_dat->cdev.name = of_get_property(child, "label",
97 NULL) ? : child->name;
99 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
100 if (IS_ERR(led_dat->pwm)) {
101 dev_err(&pdev->dev, "unable to request PWM for %s\n",
103 ret = PTR_ERR(led_dat->pwm);
106 /* Get the period from PWM core when n*/
107 led_dat->period = pwm_get_period(led_dat->pwm);
109 led_dat->cdev.default_trigger = of_get_property(child,
110 "linux,default-trigger", NULL);
111 of_property_read_u32(child, "max-brightness",
112 &led_dat->cdev.max_brightness);
114 led_dat->cdev.brightness_set = led_pwm_set;
115 led_dat->cdev.brightness = LED_OFF;
116 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
118 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
119 if (led_dat->can_sleep)
120 INIT_WORK(&led_dat->work, led_pwm_work);
122 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
124 dev_err(&pdev->dev, "failed to register for %s\n",
134 while (priv->num_leds--)
135 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
140 static int led_pwm_probe(struct platform_device *pdev)
142 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
143 struct led_pwm_priv *priv;
148 count = pdata->num_leds;
150 count = of_get_child_count(pdev->dev.of_node);
155 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
161 for (i = 0; i < count; i++) {
162 struct led_pwm *cur_led = &pdata->leds[i];
163 struct led_pwm_data *led_dat = &priv->leds[i];
165 led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
166 if (IS_ERR(led_dat->pwm)) {
167 ret = PTR_ERR(led_dat->pwm);
169 "unable to request PWM for %s\n",
174 led_dat->cdev.name = cur_led->name;
175 led_dat->cdev.default_trigger = cur_led->default_trigger;
176 led_dat->active_low = cur_led->active_low;
177 led_dat->period = cur_led->pwm_period_ns;
178 led_dat->cdev.brightness_set = led_pwm_set;
179 led_dat->cdev.brightness = LED_OFF;
180 led_dat->cdev.max_brightness = cur_led->max_brightness;
181 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
183 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
184 if (led_dat->can_sleep)
185 INIT_WORK(&led_dat->work, led_pwm_work);
187 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
191 priv->num_leds = count;
193 ret = led_pwm_create_of(pdev, priv);
198 platform_set_drvdata(pdev, priv);
204 led_classdev_unregister(&priv->leds[i].cdev);
209 static int led_pwm_remove(struct platform_device *pdev)
211 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
214 for (i = 0; i < priv->num_leds; i++) {
215 led_classdev_unregister(&priv->leds[i].cdev);
216 if (priv->leds[i].can_sleep)
217 cancel_work_sync(&priv->leds[i].work);
223 static const struct of_device_id of_pwm_leds_match[] = {
224 { .compatible = "pwm-leds", },
227 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
229 static struct platform_driver led_pwm_driver = {
230 .probe = led_pwm_probe,
231 .remove = led_pwm_remove,
234 .owner = THIS_MODULE,
235 .of_match_table = of_pwm_leds_match,
239 module_platform_driver(led_pwm_driver);
241 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
242 MODULE_DESCRIPTION("PWM LED driver for PXA");
243 MODULE_LICENSE("GPL");
244 MODULE_ALIAS("platform:leds-pwm");