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>
25 #include <linux/workqueue.h>
28 struct led_classdev cdev;
29 struct pwm_device *pwm;
30 struct work_struct work;
31 unsigned int active_low;
39 struct led_pwm_data leds[0];
42 static void __led_pwm_set(struct led_pwm_data *led_dat)
44 int new_duty = led_dat->duty;
46 pwm_config(led_dat->pwm, new_duty, led_dat->period);
49 pwm_disable(led_dat->pwm);
51 pwm_enable(led_dat->pwm);
54 static void led_pwm_work(struct work_struct *work)
56 struct led_pwm_data *led_dat =
57 container_of(work, struct led_pwm_data, work);
59 __led_pwm_set(led_dat);
62 static void led_pwm_set(struct led_classdev *led_cdev,
63 enum led_brightness brightness)
65 struct led_pwm_data *led_dat =
66 container_of(led_cdev, struct led_pwm_data, cdev);
67 unsigned int max = led_dat->cdev.max_brightness;
68 unsigned long long duty = led_dat->period;
74 if (led_dat->can_sleep)
75 schedule_work(&led_dat->work);
77 __led_pwm_set(led_dat);
80 static inline size_t sizeof_pwm_leds_priv(int num_leds)
82 return sizeof(struct led_pwm_priv) +
83 (sizeof(struct led_pwm_data) * num_leds);
86 static void led_pwm_cleanup(struct led_pwm_priv *priv)
88 while (priv->num_leds--) {
89 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
90 if (priv->leds[priv->num_leds].can_sleep)
91 cancel_work_sync(&priv->leds[priv->num_leds].work);
95 static int led_pwm_create_of(struct platform_device *pdev,
96 struct led_pwm_priv *priv)
98 struct device_node *child;
101 for_each_child_of_node(pdev->dev.of_node, child) {
102 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
104 led_dat->cdev.name = of_get_property(child, "label",
105 NULL) ? : child->name;
107 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
108 if (IS_ERR(led_dat->pwm)) {
109 dev_err(&pdev->dev, "unable to request PWM for %s\n",
111 ret = PTR_ERR(led_dat->pwm);
114 /* Get the period from PWM core when n*/
115 led_dat->period = pwm_get_period(led_dat->pwm);
117 led_dat->cdev.default_trigger = of_get_property(child,
118 "linux,default-trigger", NULL);
119 of_property_read_u32(child, "max-brightness",
120 &led_dat->cdev.max_brightness);
122 led_dat->cdev.brightness_set = led_pwm_set;
123 led_dat->cdev.brightness = LED_OFF;
124 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
126 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
127 if (led_dat->can_sleep)
128 INIT_WORK(&led_dat->work, led_pwm_work);
130 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
132 dev_err(&pdev->dev, "failed to register for %s\n",
142 led_pwm_cleanup(priv);
147 static int led_pwm_probe(struct platform_device *pdev)
149 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
150 struct led_pwm_priv *priv;
155 count = pdata->num_leds;
157 count = of_get_child_count(pdev->dev.of_node);
162 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
168 for (i = 0; i < count; i++) {
169 struct led_pwm *cur_led = &pdata->leds[i];
170 struct led_pwm_data *led_dat = &priv->leds[i];
172 led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
173 if (IS_ERR(led_dat->pwm)) {
174 ret = PTR_ERR(led_dat->pwm);
176 "unable to request PWM for %s\n",
181 led_dat->cdev.name = cur_led->name;
182 led_dat->cdev.default_trigger = cur_led->default_trigger;
183 led_dat->active_low = cur_led->active_low;
184 led_dat->period = cur_led->pwm_period_ns;
185 led_dat->cdev.brightness_set = led_pwm_set;
186 led_dat->cdev.brightness = LED_OFF;
187 led_dat->cdev.max_brightness = cur_led->max_brightness;
188 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
190 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
191 if (led_dat->can_sleep)
192 INIT_WORK(&led_dat->work, led_pwm_work);
194 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
198 priv->num_leds = count;
200 ret = led_pwm_create_of(pdev, priv);
205 platform_set_drvdata(pdev, priv);
211 led_pwm_cleanup(priv);
216 static int led_pwm_remove(struct platform_device *pdev)
218 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
220 led_pwm_cleanup(priv);
225 static const struct of_device_id of_pwm_leds_match[] = {
226 { .compatible = "pwm-leds", },
229 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
231 static struct platform_driver led_pwm_driver = {
232 .probe = led_pwm_probe,
233 .remove = led_pwm_remove,
236 .owner = THIS_MODULE,
237 .of_match_table = of_pwm_leds_match,
241 module_platform_driver(led_pwm_driver);
243 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
244 MODULE_DESCRIPTION("PWM LED driver for PXA");
245 MODULE_LICENSE("GPL");
246 MODULE_ALIAS("platform:leds-pwm");