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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/leds.h>
20#include <linux/err.h>
21#include <linux/pwm.h>
22#include <linux/leds_pwm.h>
23#include <linux/slab.h>
24
25struct led_pwm_data {
26 struct led_classdev cdev;
27 struct pwm_device *pwm;
28 unsigned int active_low;
29 unsigned int period;
30 int duty;
31};
32
33struct led_pwm_priv {
34 int num_leds;
35 struct led_pwm_data leds[0];
36};
37
38static void __led_pwm_set(struct led_pwm_data *led_dat)
39{
40 int new_duty = led_dat->duty;
41
42 pwm_config(led_dat->pwm, new_duty, led_dat->period);
43
44 if (new_duty == 0)
45 pwm_disable(led_dat->pwm);
46 else
47 pwm_enable(led_dat->pwm);
48}
49
50static int led_pwm_set(struct led_classdev *led_cdev,
51 enum led_brightness brightness)
52{
53 struct led_pwm_data *led_dat =
54 container_of(led_cdev, struct led_pwm_data, cdev);
55 unsigned int max = led_dat->cdev.max_brightness;
56 unsigned long long duty = led_dat->period;
57
58 duty *= brightness;
59 do_div(duty, max);
60
61 if (led_dat->active_low)
62 duty = led_dat->period - duty;
63
64 led_dat->duty = duty;
65
66 __led_pwm_set(led_dat);
67
68 return 0;
69}
70
71static inline size_t sizeof_pwm_leds_priv(int num_leds)
72{
73 return sizeof(struct led_pwm_priv) +
74 (sizeof(struct led_pwm_data) * num_leds);
75}
76
77static void led_pwm_cleanup(struct led_pwm_priv *priv)
78{
79 while (priv->num_leds--)
80 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
81}
82
83static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
84 struct led_pwm *led, struct device_node *child)
85{
86 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
87 struct pwm_args pargs;
88 int ret;
89
90 led_data->active_low = led->active_low;
91 led_data->cdev.name = led->name;
92 led_data->cdev.default_trigger = led->default_trigger;
93 led_data->cdev.brightness = LED_OFF;
94 led_data->cdev.max_brightness = led->max_brightness;
95 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
96
97 if (child)
98 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
99 else
100 led_data->pwm = devm_pwm_get(dev, led->name);
101 if (IS_ERR(led_data->pwm)) {
102 ret = PTR_ERR(led_data->pwm);
103 dev_err(dev, "unable to request PWM for %s: %d\n",
104 led->name, ret);
105 return ret;
106 }
107
108 led_data->cdev.brightness_set_blocking = led_pwm_set;
109
110
111
112
113
114 pwm_apply_args(led_data->pwm);
115
116 pwm_get_args(led_data->pwm, &pargs);
117
118 led_data->period = pargs.period;
119 if (!led_data->period && (led->pwm_period_ns > 0))
120 led_data->period = led->pwm_period_ns;
121
122 ret = led_classdev_register(dev, &led_data->cdev);
123 if (ret == 0) {
124 priv->num_leds++;
125 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
126 } else {
127 dev_err(dev, "failed to register PWM led for %s: %d\n",
128 led->name, ret);
129 }
130
131 return ret;
132}
133
134static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
135{
136 struct device_node *child;
137 struct led_pwm led;
138 int ret = 0;
139
140 memset(&led, 0, sizeof(led));
141
142 for_each_child_of_node(dev->of_node, child) {
143 led.name = of_get_property(child, "label", NULL) ? :
144 child->name;
145
146 led.default_trigger = of_get_property(child,
147 "linux,default-trigger", NULL);
148 led.active_low = of_property_read_bool(child, "active-low");
149 of_property_read_u32(child, "max-brightness",
150 &led.max_brightness);
151
152 ret = led_pwm_add(dev, priv, &led, child);
153 if (ret) {
154 of_node_put(child);
155 break;
156 }
157 }
158
159 return ret;
160}
161
162static int led_pwm_probe(struct platform_device *pdev)
163{
164 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
165 struct led_pwm_priv *priv;
166 int count, i;
167 int ret = 0;
168
169 if (pdata)
170 count = pdata->num_leds;
171 else
172 count = of_get_child_count(pdev->dev.of_node);
173
174 if (!count)
175 return -EINVAL;
176
177 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
178 GFP_KERNEL);
179 if (!priv)
180 return -ENOMEM;
181
182 if (pdata) {
183 for (i = 0; i < count; i++) {
184 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
185 NULL);
186 if (ret)
187 break;
188 }
189 } else {
190 ret = led_pwm_create_of(&pdev->dev, priv);
191 }
192
193 if (ret) {
194 led_pwm_cleanup(priv);
195 return ret;
196 }
197
198 platform_set_drvdata(pdev, priv);
199
200 return 0;
201}
202
203static int led_pwm_remove(struct platform_device *pdev)
204{
205 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
206
207 led_pwm_cleanup(priv);
208
209 return 0;
210}
211
212static const struct of_device_id of_pwm_leds_match[] = {
213 { .compatible = "pwm-leds", },
214 {},
215};
216MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
217
218static struct platform_driver led_pwm_driver = {
219 .probe = led_pwm_probe,
220 .remove = led_pwm_remove,
221 .driver = {
222 .name = "leds_pwm",
223 .of_match_table = of_pwm_leds_match,
224 },
225};
226
227module_platform_driver(led_pwm_driver);
228
229MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
230MODULE_DESCRIPTION("generic PWM LED driver");
231MODULE_LICENSE("GPL v2");
232MODULE_ALIAS("platform:leds-pwm");
233
