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1/*
2 * linux/drivers/leds-pwm.c
3 *
4 * simple PWM based LED control
5 *
6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
7 *
8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/platform_device.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};
32
33static void led_pwm_set(struct led_classdev *led_cdev,
34 enum led_brightness brightness)
35{
36 struct led_pwm_data *led_dat =
37 container_of(led_cdev, struct led_pwm_data, cdev);
38 unsigned int max = led_dat->cdev.max_brightness;
39 unsigned int period = led_dat->period;
40
41 if (brightness == 0) {
42 pwm_config(led_dat->pwm, 0, period);
43 pwm_disable(led_dat->pwm);
44 } else {
45 pwm_config(led_dat->pwm, brightness * period / max, period);
46 pwm_enable(led_dat->pwm);
47 }
48}
49
50static int led_pwm_probe(struct platform_device *pdev)
51{
52 struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
53 struct led_pwm *cur_led;
54 struct led_pwm_data *leds_data, *led_dat;
55 int i, ret = 0;
56
57 if (!pdata)
58 return -EBUSY;
59
60 leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
61 GFP_KERNEL);
62 if (!leds_data)
63 return -ENOMEM;
64
65 for (i = 0; i < pdata->num_leds; i++) {
66 cur_led = &pdata->leds[i];
67 led_dat = &leds_data[i];
68
69 led_dat->pwm = pwm_request(cur_led->pwm_id,
70 cur_led->name);
71 if (IS_ERR(led_dat->pwm)) {
72 ret = PTR_ERR(led_dat->pwm);
73 dev_err(&pdev->dev, "unable to request PWM %d\n",
74 cur_led->pwm_id);
75 goto err;
76 }
77
78 led_dat->cdev.name = cur_led->name;
79 led_dat->cdev.default_trigger = cur_led->default_trigger;
80 led_dat->active_low = cur_led->active_low;
81 led_dat->period = cur_led->pwm_period_ns;
82 led_dat->cdev.brightness_set = led_pwm_set;
83 led_dat->cdev.brightness = LED_OFF;
84 led_dat->cdev.max_brightness = cur_led->max_brightness;
85 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
86
87 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
88 if (ret < 0) {
89 pwm_free(led_dat->pwm);
90 goto err;
91 }
92 }
93
94 platform_set_drvdata(pdev, leds_data);
95
96 return 0;
97
98err:
99 if (i > 0) {
100 for (i = i - 1; i >= 0; i--) {
101 led_classdev_unregister(&leds_data[i].cdev);
102 pwm_free(leds_data[i].pwm);
103 }
104 }
105
106 kfree(leds_data);
107
108 return ret;
109}
110
111static int __devexit led_pwm_remove(struct platform_device *pdev)
112{
113 int i;
114 struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
115 struct led_pwm_data *leds_data;
116
117 leds_data = platform_get_drvdata(pdev);
118
119 for (i = 0; i < pdata->num_leds; i++) {
120 led_classdev_unregister(&leds_data[i].cdev);
121 pwm_free(leds_data[i].pwm);
122 }
123
124 kfree(leds_data);
125
126 return 0;
127}
128
129static struct platform_driver led_pwm_driver = {
130 .probe = led_pwm_probe,
131 .remove = __devexit_p(led_pwm_remove),
132 .driver = {
133 .name = "leds_pwm",
134 .owner = THIS_MODULE,
135 },
136};
137
138module_platform_driver(led_pwm_driver);
139
140MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
141MODULE_DESCRIPTION("PWM LED driver for PXA");
142MODULE_LICENSE("GPL");
143MODULE_ALIAS("platform:leds-pwm");
1/*
2 * linux/drivers/leds-pwm.c
3 *
4 * simple PWM based LED control
5 *
6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
7 *
8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
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
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 bool can_sleep;
33};
34
35struct led_pwm_priv {
36 int num_leds;
37 struct led_pwm_data leds[0];
38};
39
40static void __led_pwm_set(struct led_pwm_data *led_dat)
41{
42 int new_duty = led_dat->duty;
43
44 pwm_config(led_dat->pwm, new_duty, led_dat->period);
45
46 if (new_duty == 0)
47 pwm_disable(led_dat->pwm);
48 else
49 pwm_enable(led_dat->pwm);
50}
51
52static void led_pwm_set(struct led_classdev *led_cdev,
53 enum led_brightness brightness)
54{
55 struct led_pwm_data *led_dat =
56 container_of(led_cdev, struct led_pwm_data, cdev);
57 unsigned int max = led_dat->cdev.max_brightness;
58 unsigned long long duty = led_dat->period;
59
60 duty *= brightness;
61 do_div(duty, max);
62
63 if (led_dat->active_low)
64 duty = led_dat->period - duty;
65
66 led_dat->duty = duty;
67
68 __led_pwm_set(led_dat);
69}
70
71static int led_pwm_set_blocking(struct led_classdev *led_cdev,
72 enum led_brightness brightness)
73{
74 led_pwm_set(led_cdev, brightness);
75 return 0;
76}
77
78static inline size_t sizeof_pwm_leds_priv(int num_leds)
79{
80 return sizeof(struct led_pwm_priv) +
81 (sizeof(struct led_pwm_data) * num_leds);
82}
83
84static void led_pwm_cleanup(struct led_pwm_priv *priv)
85{
86 while (priv->num_leds--)
87 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
88}
89
90static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
91 struct led_pwm *led, struct device_node *child)
92{
93 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
94 int ret;
95
96 led_data->active_low = led->active_low;
97 led_data->cdev.name = led->name;
98 led_data->cdev.default_trigger = led->default_trigger;
99 led_data->cdev.brightness = LED_OFF;
100 led_data->cdev.max_brightness = led->max_brightness;
101 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
102
103 if (child)
104 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
105 else
106 led_data->pwm = devm_pwm_get(dev, led->name);
107 if (IS_ERR(led_data->pwm)) {
108 ret = PTR_ERR(led_data->pwm);
109 dev_err(dev, "unable to request PWM for %s: %d\n",
110 led->name, ret);
111 return ret;
112 }
113
114 led_data->can_sleep = pwm_can_sleep(led_data->pwm);
115 if (!led_data->can_sleep)
116 led_data->cdev.brightness_set = led_pwm_set;
117 else
118 led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
119
120 led_data->period = pwm_get_period(led_data->pwm);
121 if (!led_data->period && (led->pwm_period_ns > 0))
122 led_data->period = led->pwm_period_ns;
123
124 ret = led_classdev_register(dev, &led_data->cdev);
125 if (ret == 0) {
126 priv->num_leds++;
127 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
128 } else {
129 dev_err(dev, "failed to register PWM led for %s: %d\n",
130 led->name, ret);
131 }
132
133 return ret;
134}
135
136static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
137{
138 struct device_node *child;
139 struct led_pwm led;
140 int ret = 0;
141
142 memset(&led, 0, sizeof(led));
143
144 for_each_child_of_node(dev->of_node, child) {
145 led.name = of_get_property(child, "label", NULL) ? :
146 child->name;
147
148 led.default_trigger = of_get_property(child,
149 "linux,default-trigger", NULL);
150 led.active_low = of_property_read_bool(child, "active-low");
151 of_property_read_u32(child, "max-brightness",
152 &led.max_brightness);
153
154 ret = led_pwm_add(dev, priv, &led, child);
155 if (ret) {
156 of_node_put(child);
157 break;
158 }
159 }
160
161 return ret;
162}
163
164static int led_pwm_probe(struct platform_device *pdev)
165{
166 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
167 struct led_pwm_priv *priv;
168 int count, i;
169 int ret = 0;
170
171 if (pdata)
172 count = pdata->num_leds;
173 else
174 count = of_get_child_count(pdev->dev.of_node);
175
176 if (!count)
177 return -EINVAL;
178
179 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
180 GFP_KERNEL);
181 if (!priv)
182 return -ENOMEM;
183
184 if (pdata) {
185 for (i = 0; i < count; i++) {
186 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
187 NULL);
188 if (ret)
189 break;
190 }
191 } else {
192 ret = led_pwm_create_of(&pdev->dev, priv);
193 }
194
195 if (ret) {
196 led_pwm_cleanup(priv);
197 return ret;
198 }
199
200 platform_set_drvdata(pdev, priv);
201
202 return 0;
203}
204
205static int led_pwm_remove(struct platform_device *pdev)
206{
207 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
208
209 led_pwm_cleanup(priv);
210
211 return 0;
212}
213
214static const struct of_device_id of_pwm_leds_match[] = {
215 { .compatible = "pwm-leds", },
216 {},
217};
218MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
219
220static struct platform_driver led_pwm_driver = {
221 .probe = led_pwm_probe,
222 .remove = led_pwm_remove,
223 .driver = {
224 .name = "leds_pwm",
225 .of_match_table = of_pwm_leds_match,
226 },
227};
228
229module_platform_driver(led_pwm_driver);
230
231MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
232MODULE_DESCRIPTION("generic PWM LED driver");
233MODULE_LICENSE("GPL v2");
234MODULE_ALIAS("platform:leds-pwm");