1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
/*
* linux/drivers/leds-pwm.c
*
* simple PWM based LED control
*
* Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
*
* based on leds-gpio.c by Raphael Assenat <raph@8d.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <linux/fb.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/pwm.h>
#include <linux/leds_pwm.h>
#include <linux/slab.h>
struct led_pwm_data {
struct led_classdev cdev;
struct pwm_device *pwm;
unsigned int active_low;
unsigned int period;
};
struct led_pwm_priv {
int num_leds;
struct led_pwm_data leds[0];
};
static void led_pwm_set(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
struct led_pwm_data *led_dat =
container_of(led_cdev, struct led_pwm_data, cdev);
unsigned int max = led_dat->cdev.max_brightness;
unsigned int period = led_dat->period;
if (brightness == 0) {
pwm_config(led_dat->pwm, 0, period);
pwm_disable(led_dat->pwm);
} else {
pwm_config(led_dat->pwm, brightness * period / max, period);
pwm_enable(led_dat->pwm);
}
}
static inline size_t sizeof_pwm_leds_priv(int num_leds)
{
return sizeof(struct led_pwm_priv) +
(sizeof(struct led_pwm_data) * num_leds);
}
static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct device_node *child;
struct led_pwm_priv *priv;
int count, ret;
/* count LEDs in this device, so we know how much to allocate */
count = of_get_child_count(node);
if (!count)
return NULL;
priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
GFP_KERNEL);
if (!priv)
return NULL;
for_each_child_of_node(node, child) {
struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
led_dat->cdev.name = of_get_property(child, "label",
NULL) ? : child->name;
led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
if (IS_ERR(led_dat->pwm)) {
dev_err(&pdev->dev, "unable to request PWM for %s\n",
led_dat->cdev.name);
goto err;
}
/* Get the period from PWM core when n*/
led_dat->period = pwm_get_period(led_dat->pwm);
led_dat->cdev.default_trigger = of_get_property(child,
"linux,default-trigger", NULL);
of_property_read_u32(child, "max-brightness",
&led_dat->cdev.max_brightness);
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register for %s\n",
led_dat->cdev.name);
of_node_put(child);
goto err;
}
priv->num_leds++;
}
return priv;
err:
while (priv->num_leds--)
led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
return NULL;
}
static int led_pwm_probe(struct platform_device *pdev)
{
struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
struct led_pwm_priv *priv;
int i, ret = 0;
if (pdata && pdata->num_leds) {
priv = devm_kzalloc(&pdev->dev,
sizeof_pwm_leds_priv(pdata->num_leds),
GFP_KERNEL);
if (!priv)
return -ENOMEM;
for (i = 0; i < pdata->num_leds; i++) {
struct led_pwm *cur_led = &pdata->leds[i];
struct led_pwm_data *led_dat = &priv->leds[i];
led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
if (IS_ERR(led_dat->pwm)) {
ret = PTR_ERR(led_dat->pwm);
dev_err(&pdev->dev,
"unable to request PWM for %s\n",
cur_led->name);
goto err;
}
led_dat->cdev.name = cur_led->name;
led_dat->cdev.default_trigger = cur_led->default_trigger;
led_dat->active_low = cur_led->active_low;
led_dat->period = cur_led->pwm_period_ns;
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.max_brightness = cur_led->max_brightness;
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0)
goto err;
}
priv->num_leds = pdata->num_leds;
} else {
priv = led_pwm_create_of(pdev);
if (!priv)
return -ENODEV;
}
platform_set_drvdata(pdev, priv);
return 0;
err:
while (i--)
led_classdev_unregister(&priv->leds[i].cdev);
return ret;
}
static int led_pwm_remove(struct platform_device *pdev)
{
struct led_pwm_priv *priv = platform_get_drvdata(pdev);
int i;
for (i = 0; i < priv->num_leds; i++)
led_classdev_unregister(&priv->leds[i].cdev);
return 0;
}
static const struct of_device_id of_pwm_leds_match[] = {
{ .compatible = "pwm-leds", },
{},
};
MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
static struct platform_driver led_pwm_driver = {
.probe = led_pwm_probe,
.remove = led_pwm_remove,
.driver = {
.name = "leds_pwm",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(of_pwm_leds_match),
},
};
module_platform_driver(led_pwm_driver);
MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
MODULE_DESCRIPTION("PWM LED driver for PXA");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-pwm");
|
