x86/xen: resume timer irqs early
[linux/fpc-iii.git] / drivers / leds / leds-pwm.c
blob305e88a6f625d4f07c7bae9642d96eb26a5936d6
1 /*
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>
20 #include <linux/fb.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>
28 struct led_pwm_data {
29 struct led_classdev cdev;
30 struct pwm_device *pwm;
31 struct work_struct work;
32 unsigned int active_low;
33 unsigned int period;
34 int duty;
35 bool can_sleep;
38 struct led_pwm_priv {
39 int num_leds;
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);
49 if (new_duty == 0)
50 pwm_disable(led_dat->pwm);
51 else
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 int period = led_dat->period;
71 led_dat->duty = brightness * period / max;
73 if (led_dat->can_sleep)
74 schedule_work(&led_dat->work);
75 else
76 __led_pwm_set(led_dat);
79 static inline size_t sizeof_pwm_leds_priv(int num_leds)
81 return sizeof(struct led_pwm_priv) +
82 (sizeof(struct led_pwm_data) * num_leds);
85 static void led_pwm_cleanup(struct led_pwm_priv *priv)
87 while (priv->num_leds--) {
88 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
89 if (priv->leds[priv->num_leds].can_sleep)
90 cancel_work_sync(&priv->leds[priv->num_leds].work);
94 static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
96 struct device_node *node = pdev->dev.of_node;
97 struct device_node *child;
98 struct led_pwm_priv *priv;
99 int count, ret;
101 /* count LEDs in this device, so we know how much to allocate */
102 count = of_get_child_count(node);
103 if (!count)
104 return NULL;
106 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
107 GFP_KERNEL);
108 if (!priv)
109 return NULL;
111 for_each_child_of_node(node, child) {
112 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
114 led_dat->cdev.name = of_get_property(child, "label",
115 NULL) ? : child->name;
117 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
118 if (IS_ERR(led_dat->pwm)) {
119 dev_err(&pdev->dev, "unable to request PWM for %s\n",
120 led_dat->cdev.name);
121 goto err;
123 /* Get the period from PWM core when n*/
124 led_dat->period = pwm_get_period(led_dat->pwm);
126 led_dat->cdev.default_trigger = of_get_property(child,
127 "linux,default-trigger", NULL);
128 of_property_read_u32(child, "max-brightness",
129 &led_dat->cdev.max_brightness);
131 led_dat->cdev.brightness_set = led_pwm_set;
132 led_dat->cdev.brightness = LED_OFF;
133 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
135 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
136 if (led_dat->can_sleep)
137 INIT_WORK(&led_dat->work, led_pwm_work);
139 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
140 if (ret < 0) {
141 dev_err(&pdev->dev, "failed to register for %s\n",
142 led_dat->cdev.name);
143 of_node_put(child);
144 goto err;
146 priv->num_leds++;
149 return priv;
150 err:
151 led_pwm_cleanup(priv);
153 return NULL;
156 static int led_pwm_probe(struct platform_device *pdev)
158 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
159 struct led_pwm_priv *priv;
160 int i, ret = 0;
162 if (pdata && pdata->num_leds) {
163 priv = devm_kzalloc(&pdev->dev,
164 sizeof_pwm_leds_priv(pdata->num_leds),
165 GFP_KERNEL);
166 if (!priv)
167 return -ENOMEM;
169 for (i = 0; i < pdata->num_leds; i++) {
170 struct led_pwm *cur_led = &pdata->leds[i];
171 struct led_pwm_data *led_dat = &priv->leds[i];
173 led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
174 if (IS_ERR(led_dat->pwm)) {
175 ret = PTR_ERR(led_dat->pwm);
176 dev_err(&pdev->dev,
177 "unable to request PWM for %s\n",
178 cur_led->name);
179 goto err;
182 led_dat->cdev.name = cur_led->name;
183 led_dat->cdev.default_trigger = cur_led->default_trigger;
184 led_dat->active_low = cur_led->active_low;
185 led_dat->period = cur_led->pwm_period_ns;
186 led_dat->cdev.brightness_set = led_pwm_set;
187 led_dat->cdev.brightness = LED_OFF;
188 led_dat->cdev.max_brightness = cur_led->max_brightness;
189 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
191 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
192 if (led_dat->can_sleep)
193 INIT_WORK(&led_dat->work, led_pwm_work);
195 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
196 if (ret < 0)
197 goto err;
199 priv->num_leds = pdata->num_leds;
200 } else {
201 priv = led_pwm_create_of(pdev);
202 if (!priv)
203 return -ENODEV;
206 platform_set_drvdata(pdev, priv);
208 return 0;
210 err:
211 priv->num_leds = i;
212 led_pwm_cleanup(priv);
214 return ret;
217 static int led_pwm_remove(struct platform_device *pdev)
219 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
221 led_pwm_cleanup(priv);
223 return 0;
226 static const struct of_device_id of_pwm_leds_match[] = {
227 { .compatible = "pwm-leds", },
230 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
232 static struct platform_driver led_pwm_driver = {
233 .probe = led_pwm_probe,
234 .remove = led_pwm_remove,
235 .driver = {
236 .name = "leds_pwm",
237 .owner = THIS_MODULE,
238 .of_match_table = of_match_ptr(of_pwm_leds_match),
242 module_platform_driver(led_pwm_driver);
244 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
245 MODULE_DESCRIPTION("PWM LED driver for PXA");
246 MODULE_LICENSE("GPL");
247 MODULE_ALIAS("platform:leds-pwm");