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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/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
26struct led_pwm_data {
27 struct led_classdev cdev;
28 struct pwm_device *pwm;
29 unsigned int active_low;
30 unsigned int period;
31 int duty;
32};
33
34struct led_pwm_priv {
35 int num_leds;
36 struct led_pwm_data leds[0];
37};
38
39static void __led_pwm_set(struct led_pwm_data *led_dat)
40{
41 int new_duty = led_dat->duty;
42
43 pwm_config(led_dat->pwm, new_duty, led_dat->period);
44
45 if (new_duty == 0)
46 pwm_disable(led_dat->pwm);
47 else
48 pwm_enable(led_dat->pwm);
49}
50
51static int led_pwm_set(struct led_classdev *led_cdev,
52 enum led_brightness brightness)
53{
54 struct led_pwm_data *led_dat =
55 container_of(led_cdev, struct led_pwm_data, cdev);
56 unsigned int max = led_dat->cdev.max_brightness;
57 unsigned long long duty = led_dat->period;
58
59 duty *= brightness;
60 do_div(duty, max);
61
62 if (led_dat->active_low)
63 duty = led_dat->period - duty;
64
65 led_dat->duty = duty;
66
67 __led_pwm_set(led_dat);
68
69 return 0;
70}
71
72static inline size_t sizeof_pwm_leds_priv(int num_leds)
73{
74 return sizeof(struct led_pwm_priv) +
75 (sizeof(struct led_pwm_data) * num_leds);
76}
77
78static void led_pwm_cleanup(struct led_pwm_priv *priv)
79{
80 while (priv->num_leds--)
81 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
82}
83
84static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
85 struct led_pwm *led, struct device_node *child)
86{
87 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
88 struct pwm_args pargs;
89 int ret;
90
91 led_data->active_low = led->active_low;
92 led_data->cdev.name = led->name;
93 led_data->cdev.default_trigger = led->default_trigger;
94 led_data->cdev.brightness = LED_OFF;
95 led_data->cdev.max_brightness = led->max_brightness;
96 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
97
98 if (child)
99 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
100 else
101 led_data->pwm = devm_pwm_get(dev, led->name);
102 if (IS_ERR(led_data->pwm)) {
103 ret = PTR_ERR(led_data->pwm);
104 dev_err(dev, "unable to request PWM for %s: %d\n",
105 led->name, ret);
106 return ret;
107 }
108
109 led_data->cdev.brightness_set_blocking = led_pwm_set;
110
111
112
113
114
115 pwm_apply_args(led_data->pwm);
116
117 pwm_get_args(led_data->pwm, &pargs);
118
119 led_data->period = pargs.period;
120 if (!led_data->period && (led->pwm_period_ns > 0))
121 led_data->period = led->pwm_period_ns;
122
123 ret = led_classdev_register(dev, &led_data->cdev);
124 if (ret == 0) {
125 priv->num_leds++;
126 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
127 } else {
128 dev_err(dev, "failed to register PWM led for %s: %d\n",
129 led->name, ret);
130 }
131
132 return ret;
133}
134
135static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
136{
137 struct device_node *child;
138 struct led_pwm led;
139 int ret = 0;
140
141 memset(&led, 0, sizeof(led));
142
143 for_each_child_of_node(dev->of_node, child) {
144 led.name = of_get_property(child, "label", NULL) ? :
145 child->name;
146
147 led.default_trigger = of_get_property(child,
148 "linux,default-trigger", NULL);
149 led.active_low = of_property_read_bool(child, "active-low");
150 of_property_read_u32(child, "max-brightness",
151 &led.max_brightness);
152
153 ret = led_pwm_add(dev, priv, &led, child);
154 if (ret) {
155 of_node_put(child);
156 break;
157 }
158 }
159
160 return ret;
161}
162
163static int led_pwm_probe(struct platform_device *pdev)
164{
165 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
166 struct led_pwm_priv *priv;
167 int count, i;
168 int ret = 0;
169
170 if (pdata)
171 count = pdata->num_leds;
172 else
173 count = of_get_child_count(pdev->dev.of_node);
174
175 if (!count)
176 return -EINVAL;
177
178 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
179 GFP_KERNEL);
180 if (!priv)
181 return -ENOMEM;
182
183 if (pdata) {
184 for (i = 0; i < count; i++) {
185 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
186 NULL);
187 if (ret)
188 break;
189 }
190 } else {
191 ret = led_pwm_create_of(&pdev->dev, priv);
192 }
193
194 if (ret) {
195 led_pwm_cleanup(priv);
196 return ret;
197 }
198
199 platform_set_drvdata(pdev, priv);
200
201 return 0;
202}
203
204static int led_pwm_remove(struct platform_device *pdev)
205{
206 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
207
208 led_pwm_cleanup(priv);
209
210 return 0;
211}
212
213static const struct of_device_id of_pwm_leds_match[] = {
214 { .compatible = "pwm-leds", },
215 {},
216};
217MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
218
219static struct platform_driver led_pwm_driver = {
220 .probe = led_pwm_probe,
221 .remove = led_pwm_remove,
222 .driver = {
223 .name = "leds_pwm",
224 .of_match_table = of_pwm_leds_match,
225 },
226};
227
228module_platform_driver(led_pwm_driver);
229
230MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
231MODULE_DESCRIPTION("generic PWM LED driver");
232MODULE_LICENSE("GPL v2");
233MODULE_ALIAS("platform:leds-pwm");
234
