ARM: mm: Recreate kernel mappings in early_paging_init()
[linux/fpc-iii.git] / drivers / leds / leds-pwm.c
blobbb6f948985413d4e8c1f5a6b575493a00b2ecef6
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 struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
87 struct device_node *node = pdev->dev.of_node;
88 struct device_node *child;
89 struct led_pwm_priv *priv;
90 int count, ret;
92 /* count LEDs in this device, so we know how much to allocate */
93 count = of_get_child_count(node);
94 if (!count)
95 return NULL;
97 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
98 GFP_KERNEL);
99 if (!priv)
100 return NULL;
102 for_each_child_of_node(node, child) {
103 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
105 led_dat->cdev.name = of_get_property(child, "label",
106 NULL) ? : child->name;
108 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
109 if (IS_ERR(led_dat->pwm)) {
110 dev_err(&pdev->dev, "unable to request PWM for %s\n",
111 led_dat->cdev.name);
112 goto err;
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);
131 if (ret < 0) {
132 dev_err(&pdev->dev, "failed to register for %s\n",
133 led_dat->cdev.name);
134 of_node_put(child);
135 goto err;
137 priv->num_leds++;
140 return priv;
141 err:
142 while (priv->num_leds--)
143 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
145 return NULL;
148 static int led_pwm_probe(struct platform_device *pdev)
150 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
151 struct led_pwm_priv *priv;
152 int i, ret = 0;
154 if (pdata && pdata->num_leds) {
155 priv = devm_kzalloc(&pdev->dev,
156 sizeof_pwm_leds_priv(pdata->num_leds),
157 GFP_KERNEL);
158 if (!priv)
159 return -ENOMEM;
161 for (i = 0; i < pdata->num_leds; 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);
168 dev_err(&pdev->dev,
169 "unable to request PWM for %s\n",
170 cur_led->name);
171 goto err;
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);
188 if (ret < 0)
189 goto err;
191 priv->num_leds = pdata->num_leds;
192 } else {
193 priv = led_pwm_create_of(pdev);
194 if (!priv)
195 return -ENODEV;
198 platform_set_drvdata(pdev, priv);
200 return 0;
202 err:
203 while (i--)
204 led_classdev_unregister(&priv->leds[i].cdev);
206 return ret;
209 static int led_pwm_remove(struct platform_device *pdev)
211 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
212 int i;
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);
220 return 0;
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,
232 .driver = {
233 .name = "leds_pwm",
234 .owner = THIS_MODULE,
235 .of_match_table = of_match_ptr(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");