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15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/platform_device.h>
19#include <linux/of_platform.h>
20#include <linux/fb.h>
21#include <linux/leds.h>
22#include <linux/err.h>
23#include <linux/pwm.h>
24#include <linux/leds_pwm.h>
25#include <linux/slab.h>
26#include <linux/workqueue.h>
27
28struct led_pwm_data {
29 struct led_classdev cdev;
30 struct pwm_device *pwm;
31 struct work_struct work;
32 unsigned int active_low;
33 unsigned int period;
34 int duty;
35 bool can_sleep;
36};
37
38struct led_pwm_priv {
39 int num_leds;
40 struct led_pwm_data leds[0];
41};
42
43static void __led_pwm_set(struct led_pwm_data *led_dat)
44{
45 int new_duty = led_dat->duty;
46
47 pwm_config(led_dat->pwm, new_duty, led_dat->period);
48
49 if (new_duty == 0)
50 pwm_disable(led_dat->pwm);
51 else
52 pwm_enable(led_dat->pwm);
53}
54
55static void led_pwm_work(struct work_struct *work)
56{
57 struct led_pwm_data *led_dat =
58 container_of(work, struct led_pwm_data, work);
59
60 __led_pwm_set(led_dat);
61}
62
63static void led_pwm_set(struct led_classdev *led_cdev,
64 enum led_brightness brightness)
65{
66 struct led_pwm_data *led_dat =
67 container_of(led_cdev, struct led_pwm_data, cdev);
68 unsigned int max = led_dat->cdev.max_brightness;
69 unsigned int period = led_dat->period;
70
71 led_dat->duty = brightness * period / max;
72
73 if (led_dat->can_sleep)
74 schedule_work(&led_dat->work);
75 else
76 __led_pwm_set(led_dat);
77}
78
79static inline size_t sizeof_pwm_leds_priv(int num_leds)
80{
81 return sizeof(struct led_pwm_priv) +
82 (sizeof(struct led_pwm_data) * num_leds);
83}
84
85static int led_pwm_create_of(struct platform_device *pdev,
86 struct led_pwm_priv *priv)
87{
88 struct device_node *node = pdev->dev.of_node;
89 struct device_node *child;
90 int ret;
91
92 for_each_child_of_node(node, child) {
93 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
94
95 led_dat->cdev.name = of_get_property(child, "label",
96 NULL) ? : child->name;
97
98 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
99 if (IS_ERR(led_dat->pwm)) {
100 dev_err(&pdev->dev, "unable to request PWM for %s\n",
101 led_dat->cdev.name);
102 ret = PTR_ERR(led_dat->pwm);
103 goto err;
104 }
105
106 led_dat->period = pwm_get_period(led_dat->pwm);
107
108 led_dat->cdev.default_trigger = of_get_property(child,
109 "linux,default-trigger", NULL);
110 of_property_read_u32(child, "max-brightness",
111 &led_dat->cdev.max_brightness);
112
113 led_dat->cdev.brightness_set = led_pwm_set;
114 led_dat->cdev.brightness = LED_OFF;
115 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
116
117 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
118 if (led_dat->can_sleep)
119 INIT_WORK(&led_dat->work, led_pwm_work);
120
121 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
122 if (ret < 0) {
123 dev_err(&pdev->dev, "failed to register for %s\n",
124 led_dat->cdev.name);
125 of_node_put(child);
126 goto err;
127 }
128 priv->num_leds++;
129 }
130
131 return 0;
132err:
133 while (priv->num_leds--)
134 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
135
136 return ret;
137}
138
139static int led_pwm_probe(struct platform_device *pdev)
140{
141 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
142 struct led_pwm_priv *priv;
143 int count, i;
144 int ret = 0;
145
146 if (pdata)
147 count = pdata->num_leds;
148 else
149 count = of_get_child_count(pdev->dev.of_node);
150
151 if (!count)
152 return -EINVAL;
153
154 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
155 GFP_KERNEL);
156 if (!priv)
157 return -ENOMEM;
158
159 if (pdata) {
160 for (i = 0; i < count; i++) {
161 struct led_pwm *cur_led = &pdata->leds[i];
162 struct led_pwm_data *led_dat = &priv->leds[i];
163
164 led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
165 if (IS_ERR(led_dat->pwm)) {
166 ret = PTR_ERR(led_dat->pwm);
167 dev_err(&pdev->dev,
168 "unable to request PWM for %s\n",
169 cur_led->name);
170 goto err;
171 }
172
173 led_dat->cdev.name = cur_led->name;
174 led_dat->cdev.default_trigger = cur_led->default_trigger;
175 led_dat->active_low = cur_led->active_low;
176 led_dat->period = cur_led->pwm_period_ns;
177 led_dat->cdev.brightness_set = led_pwm_set;
178 led_dat->cdev.brightness = LED_OFF;
179 led_dat->cdev.max_brightness = cur_led->max_brightness;
180 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
181
182 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
183 if (led_dat->can_sleep)
184 INIT_WORK(&led_dat->work, led_pwm_work);
185
186 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
187 if (ret < 0)
188 goto err;
189 }
190 priv->num_leds = count;
191 } else {
192 ret = led_pwm_create_of(pdev, priv);
193 if (ret)
194 return ret;
195 }
196
197 platform_set_drvdata(pdev, priv);
198
199 return 0;
200
201err:
202 while (i--)
203 led_classdev_unregister(&priv->leds[i].cdev);
204
205 return ret;
206}
207
208static int led_pwm_remove(struct platform_device *pdev)
209{
210 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
211 int i;
212
213 for (i = 0; i < priv->num_leds; i++) {
214 led_classdev_unregister(&priv->leds[i].cdev);
215 if (priv->leds[i].can_sleep)
216 cancel_work_sync(&priv->leds[i].work);
217 }
218
219 return 0;
220}
221
222static const struct of_device_id of_pwm_leds_match[] = {
223 { .compatible = "pwm-leds", },
224 {},
225};
226MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
227
228static struct platform_driver led_pwm_driver = {
229 .probe = led_pwm_probe,
230 .remove = led_pwm_remove,
231 .driver = {
232 .name = "leds_pwm",
233 .owner = THIS_MODULE,
234 .of_match_table = of_pwm_leds_match,
235 },
236};
237
238module_platform_driver(led_pwm_driver);
239
240MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
241MODULE_DESCRIPTION("PWM LED driver for PXA");
242MODULE_LICENSE("GPL");
243MODULE_ALIAS("platform:leds-pwm");
244
