1
2
3
4
5
6
7
8
9
10
11
12
13
14
15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/platform_device.h>
18#include <linux/of_platform.h>
19#include <linux/fb.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>
26
27struct led_pwm_data {
28 struct led_classdev cdev;
29 struct pwm_device *pwm;
30 struct work_struct work;
31 unsigned int active_low;
32 unsigned int period;
33 int duty;
34 bool can_sleep;
35};
36
37struct led_pwm_priv {
38 int num_leds;
39 struct led_pwm_data leds[0];
40};
41
42static void __led_pwm_set(struct led_pwm_data *led_dat)
43{
44 int new_duty = led_dat->duty;
45
46 pwm_config(led_dat->pwm, new_duty, led_dat->period);
47
48 if (new_duty == 0)
49 pwm_disable(led_dat->pwm);
50 else
51 pwm_enable(led_dat->pwm);
52}
53
54static void led_pwm_work(struct work_struct *work)
55{
56 struct led_pwm_data *led_dat =
57 container_of(work, struct led_pwm_data, work);
58
59 __led_pwm_set(led_dat);
60}
61
62static void led_pwm_set(struct led_classdev *led_cdev,
63 enum led_brightness brightness)
64{
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;
69
70 duty *= brightness;
71 do_div(duty, max);
72
73 if (led_dat->active_low)
74 duty = led_dat->period - duty;
75
76 led_dat->duty = duty;
77
78 if (led_dat->can_sleep)
79 schedule_work(&led_dat->work);
80 else
81 __led_pwm_set(led_dat);
82}
83
84static inline size_t sizeof_pwm_leds_priv(int num_leds)
85{
86 return sizeof(struct led_pwm_priv) +
87 (sizeof(struct led_pwm_data) * num_leds);
88}
89
90static void led_pwm_cleanup(struct led_pwm_priv *priv)
91{
92 while (priv->num_leds--) {
93 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
94 if (priv->leds[priv->num_leds].can_sleep)
95 cancel_work_sync(&priv->leds[priv->num_leds].work);
96 }
97}
98
99static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
100 struct led_pwm *led, struct device_node *child)
101{
102 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
103 int ret;
104
105 led_data->active_low = led->active_low;
106 led_data->cdev.name = led->name;
107 led_data->cdev.default_trigger = led->default_trigger;
108 led_data->cdev.brightness_set = led_pwm_set;
109 led_data->cdev.brightness = LED_OFF;
110 led_data->cdev.max_brightness = led->max_brightness;
111 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
112
113 if (child)
114 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
115 else
116 led_data->pwm = devm_pwm_get(dev, led->name);
117 if (IS_ERR(led_data->pwm)) {
118 ret = PTR_ERR(led_data->pwm);
119 dev_err(dev, "unable to request PWM for %s: %d\n",
120 led->name, ret);
121 return ret;
122 }
123
124 led_data->can_sleep = pwm_can_sleep(led_data->pwm);
125 if (led_data->can_sleep)
126 INIT_WORK(&led_data->work, led_pwm_work);
127
128 led_data->period = pwm_get_period(led_data->pwm);
129 if (!led_data->period && (led->pwm_period_ns > 0))
130 led_data->period = led->pwm_period_ns;
131
132 ret = led_classdev_register(dev, &led_data->cdev);
133 if (ret == 0) {
134 priv->num_leds++;
135 } else {
136 dev_err(dev, "failed to register PWM led for %s: %d\n",
137 led->name, ret);
138 }
139
140 return ret;
141}
142
143static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
144{
145 struct device_node *child;
146 struct led_pwm led;
147 int ret = 0;
148
149 memset(&led, 0, sizeof(led));
150
151 for_each_child_of_node(dev->of_node, child) {
152 led.name = of_get_property(child, "label", NULL) ? :
153 child->name;
154
155 led.default_trigger = of_get_property(child,
156 "linux,default-trigger", NULL);
157 led.active_low = of_property_read_bool(child, "active-low");
158 of_property_read_u32(child, "max-brightness",
159 &led.max_brightness);
160
161 ret = led_pwm_add(dev, priv, &led, child);
162 if (ret) {
163 of_node_put(child);
164 break;
165 }
166 }
167
168 return ret;
169}
170
171static int led_pwm_probe(struct platform_device *pdev)
172{
173 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
174 struct led_pwm_priv *priv;
175 int count, i;
176 int ret = 0;
177
178 if (pdata)
179 count = pdata->num_leds;
180 else
181 count = of_get_child_count(pdev->dev.of_node);
182
183 if (!count)
184 return -EINVAL;
185
186 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
187 GFP_KERNEL);
188 if (!priv)
189 return -ENOMEM;
190
191 if (pdata) {
192 for (i = 0; i < count; i++) {
193 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
194 NULL);
195 if (ret)
196 break;
197 }
198 } else {
199 ret = led_pwm_create_of(&pdev->dev, priv);
200 }
201
202 if (ret) {
203 led_pwm_cleanup(priv);
204 return ret;
205 }
206
207 platform_set_drvdata(pdev, priv);
208
209 return 0;
210}
211
212static int led_pwm_remove(struct platform_device *pdev)
213{
214 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
215
216 led_pwm_cleanup(priv);
217
218 return 0;
219}
220
221static const struct of_device_id of_pwm_leds_match[] = {
222 { .compatible = "pwm-leds", },
223 {},
224};
225MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
226
227static struct platform_driver led_pwm_driver = {
228 .probe = led_pwm_probe,
229 .remove = led_pwm_remove,
230 .driver = {
231 .name = "leds_pwm",
232 .of_match_table = of_pwm_leds_match,
233 },
234};
235
236module_platform_driver(led_pwm_driver);
237
238MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
239MODULE_DESCRIPTION("PWM LED driver for PXA");
240MODULE_LICENSE("GPL");
241MODULE_ALIAS("platform:leds-pwm");
242
