This source file includes following definitions.
- __led_pwm_set
- led_pwm_set
- led_pwm_add
- led_pwm_create_fwnode
- led_pwm_probe
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12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/platform_device.h>
15 #include <linux/of_platform.h>
16 #include <linux/leds.h>
17 #include <linux/err.h>
18 #include <linux/pwm.h>
19 #include <linux/leds_pwm.h>
20 #include <linux/slab.h>
21
22 struct led_pwm_data {
23 struct led_classdev cdev;
24 struct pwm_device *pwm;
25 unsigned int active_low;
26 unsigned int period;
27 int duty;
28 };
29
30 struct led_pwm_priv {
31 int num_leds;
32 struct led_pwm_data leds[0];
33 };
34
35 static void __led_pwm_set(struct led_pwm_data *led_dat)
36 {
37 int new_duty = led_dat->duty;
38
39 pwm_config(led_dat->pwm, new_duty, led_dat->period);
40
41 if (new_duty == 0)
42 pwm_disable(led_dat->pwm);
43 else
44 pwm_enable(led_dat->pwm);
45 }
46
47 static int led_pwm_set(struct led_classdev *led_cdev,
48 enum led_brightness brightness)
49 {
50 struct led_pwm_data *led_dat =
51 container_of(led_cdev, struct led_pwm_data, cdev);
52 unsigned int max = led_dat->cdev.max_brightness;
53 unsigned long long duty = led_dat->period;
54
55 duty *= brightness;
56 do_div(duty, max);
57
58 if (led_dat->active_low)
59 duty = led_dat->period - duty;
60
61 led_dat->duty = duty;
62
63 __led_pwm_set(led_dat);
64
65 return 0;
66 }
67
68 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
69 struct led_pwm *led, struct fwnode_handle *fwnode)
70 {
71 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
72 struct pwm_args pargs;
73 int ret;
74
75 led_data->active_low = led->active_low;
76 led_data->cdev.name = led->name;
77 led_data->cdev.default_trigger = led->default_trigger;
78 led_data->cdev.brightness = LED_OFF;
79 led_data->cdev.max_brightness = led->max_brightness;
80 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
81
82 if (fwnode)
83 led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
84 else
85 led_data->pwm = devm_pwm_get(dev, led->name);
86 if (IS_ERR(led_data->pwm)) {
87 ret = PTR_ERR(led_data->pwm);
88 if (ret != -EPROBE_DEFER)
89 dev_err(dev, "unable to request PWM for %s: %d\n",
90 led->name, ret);
91 return ret;
92 }
93
94 led_data->cdev.brightness_set_blocking = led_pwm_set;
95
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97
98
99
100 pwm_apply_args(led_data->pwm);
101
102 pwm_get_args(led_data->pwm, &pargs);
103
104 led_data->period = pargs.period;
105 if (!led_data->period && (led->pwm_period_ns > 0))
106 led_data->period = led->pwm_period_ns;
107
108 ret = devm_led_classdev_register(dev, &led_data->cdev);
109 if (ret == 0) {
110 priv->num_leds++;
111 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
112 } else {
113 dev_err(dev, "failed to register PWM led for %s: %d\n",
114 led->name, ret);
115 }
116
117 return ret;
118 }
119
120 static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
121 {
122 struct fwnode_handle *fwnode;
123 struct led_pwm led;
124 int ret = 0;
125
126 memset(&led, 0, sizeof(led));
127
128 device_for_each_child_node(dev, fwnode) {
129 ret = fwnode_property_read_string(fwnode, "label", &led.name);
130 if (ret && is_of_node(fwnode))
131 led.name = to_of_node(fwnode)->name;
132
133 if (!led.name) {
134 fwnode_handle_put(fwnode);
135 return -EINVAL;
136 }
137
138 fwnode_property_read_string(fwnode, "linux,default-trigger",
139 &led.default_trigger);
140
141 led.active_low = fwnode_property_read_bool(fwnode,
142 "active-low");
143 fwnode_property_read_u32(fwnode, "max-brightness",
144 &led.max_brightness);
145
146 ret = led_pwm_add(dev, priv, &led, fwnode);
147 if (ret) {
148 fwnode_handle_put(fwnode);
149 break;
150 }
151 }
152
153 return ret;
154 }
155
156 static int led_pwm_probe(struct platform_device *pdev)
157 {
158 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
159 struct led_pwm_priv *priv;
160 int count, i;
161 int ret = 0;
162
163 if (pdata)
164 count = pdata->num_leds;
165 else
166 count = device_get_child_node_count(&pdev->dev);
167
168 if (!count)
169 return -EINVAL;
170
171 priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
172 GFP_KERNEL);
173 if (!priv)
174 return -ENOMEM;
175
176 if (pdata) {
177 for (i = 0; i < count; i++) {
178 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
179 NULL);
180 if (ret)
181 break;
182 }
183 } else {
184 ret = led_pwm_create_fwnode(&pdev->dev, priv);
185 }
186
187 if (ret)
188 return ret;
189
190 platform_set_drvdata(pdev, priv);
191
192 return 0;
193 }
194
195 static const struct of_device_id of_pwm_leds_match[] = {
196 { .compatible = "pwm-leds", },
197 {},
198 };
199 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
200
201 static struct platform_driver led_pwm_driver = {
202 .probe = led_pwm_probe,
203 .driver = {
204 .name = "leds_pwm",
205 .of_match_table = of_pwm_leds_match,
206 },
207 };
208
209 module_platform_driver(led_pwm_driver);
210
211 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
212 MODULE_DESCRIPTION("generic PWM LED driver");
213 MODULE_LICENSE("GPL v2");
214 MODULE_ALIAS("platform:leds-pwm");