Loading...
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#include <linux/workqueue.h>
26
27struct led_pwm_data {
28 struct led_classdev cdev;
29 struct pwm_device *pwm;
30 struct work_struct work;
31 unsigned int active_low;
32 unsigned int period;
33 int duty;
34 bool can_sleep;
35};
36
37struct led_pwm_priv {
38 int num_leds;
39 struct led_pwm_data leds[0];
40};
41
42static void __led_pwm_set(struct led_pwm_data *led_dat)
43{
44 int new_duty = led_dat->duty;
45
46 pwm_config(led_dat->pwm, new_duty, led_dat->period);
47
48 if (new_duty == 0)
49 pwm_disable(led_dat->pwm);
50 else
51 pwm_enable(led_dat->pwm);
52}
53
54static void led_pwm_work(struct work_struct *work)
55{
56 struct led_pwm_data *led_dat =
57 container_of(work, struct led_pwm_data, work);
58
59 __led_pwm_set(led_dat);
60}
61
62static void led_pwm_set(struct led_classdev *led_cdev,
63 enum led_brightness brightness)
64{
65 struct led_pwm_data *led_dat =
66 container_of(led_cdev, struct led_pwm_data, cdev);
67 unsigned int max = led_dat->cdev.max_brightness;
68 unsigned long long duty = led_dat->period;
69
70 duty *= brightness;
71 do_div(duty, max);
72 led_dat->duty = duty;
73
74 if (led_dat->can_sleep)
75 schedule_work(&led_dat->work);
76 else
77 __led_pwm_set(led_dat);
78}
79
80static inline size_t sizeof_pwm_leds_priv(int num_leds)
81{
82 return sizeof(struct led_pwm_priv) +
83 (sizeof(struct led_pwm_data) * num_leds);
84}
85
86static void led_pwm_cleanup(struct led_pwm_priv *priv)
87{
88 while (priv->num_leds--) {
89 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
90 if (priv->leds[priv->num_leds].can_sleep)
91 cancel_work_sync(&priv->leds[priv->num_leds].work);
92 }
93}
94
95static int led_pwm_create_of(struct platform_device *pdev,
96 struct led_pwm_priv *priv)
97{
98 struct device_node *child;
99 int ret;
100
101 for_each_child_of_node(pdev->dev.of_node, child) {
102 struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
103
104 led_dat->cdev.name = of_get_property(child, "label",
105 NULL) ? : child->name;
106
107 led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
108 if (IS_ERR(led_dat->pwm)) {
109 dev_err(&pdev->dev, "unable to request PWM for %s\n",
110 led_dat->cdev.name);
111 ret = PTR_ERR(led_dat->pwm);
112 goto err;
113 }
114 /* Get the period from PWM core when n*/
115 led_dat->period = pwm_get_period(led_dat->pwm);
116
117 led_dat->cdev.default_trigger = of_get_property(child,
118 "linux,default-trigger", NULL);
119 of_property_read_u32(child, "max-brightness",
120 &led_dat->cdev.max_brightness);
121
122 led_dat->cdev.brightness_set = led_pwm_set;
123 led_dat->cdev.brightness = LED_OFF;
124 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
125
126 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
127 if (led_dat->can_sleep)
128 INIT_WORK(&led_dat->work, led_pwm_work);
129
130 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
131 if (ret < 0) {
132 dev_err(&pdev->dev, "failed to register for %s\n",
133 led_dat->cdev.name);
134 of_node_put(child);
135 goto err;
136 }
137 priv->num_leds++;
138 }
139
140 return 0;
141err:
142 led_pwm_cleanup(priv);
143
144 return ret;
145}
146
147static int led_pwm_probe(struct platform_device *pdev)
148{
149 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
150 struct led_pwm_priv *priv;
151 int count, i;
152 int ret = 0;
153
154 if (pdata)
155 count = pdata->num_leds;
156 else
157 count = of_get_child_count(pdev->dev.of_node);
158
159 if (!count)
160 return -EINVAL;
161
162 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
163 GFP_KERNEL);
164 if (!priv)
165 return -ENOMEM;
166
167 if (pdata) {
168 for (i = 0; i < count; i++) {
169 struct led_pwm *cur_led = &pdata->leds[i];
170 struct led_pwm_data *led_dat = &priv->leds[i];
171
172 led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
173 if (IS_ERR(led_dat->pwm)) {
174 ret = PTR_ERR(led_dat->pwm);
175 dev_err(&pdev->dev,
176 "unable to request PWM for %s\n",
177 cur_led->name);
178 goto err;
179 }
180
181 led_dat->cdev.name = cur_led->name;
182 led_dat->cdev.default_trigger = cur_led->default_trigger;
183 led_dat->active_low = cur_led->active_low;
184 led_dat->period = cur_led->pwm_period_ns;
185 led_dat->cdev.brightness_set = led_pwm_set;
186 led_dat->cdev.brightness = LED_OFF;
187 led_dat->cdev.max_brightness = cur_led->max_brightness;
188 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
189
190 led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);
191 if (led_dat->can_sleep)
192 INIT_WORK(&led_dat->work, led_pwm_work);
193
194 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
195 if (ret < 0)
196 goto err;
197 }
198 priv->num_leds = count;
199 } else {
200 ret = led_pwm_create_of(pdev, priv);
201 if (ret)
202 return ret;
203 }
204
205 platform_set_drvdata(pdev, priv);
206
207 return 0;
208
209err:
210 priv->num_leds = i;
211 led_pwm_cleanup(priv);
212
213 return ret;
214}
215
216static int led_pwm_remove(struct platform_device *pdev)
217{
218 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
219
220 led_pwm_cleanup(priv);
221
222 return 0;
223}
224
225static const struct of_device_id of_pwm_leds_match[] = {
226 { .compatible = "pwm-leds", },
227 {},
228};
229MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
230
231static struct platform_driver led_pwm_driver = {
232 .probe = led_pwm_probe,
233 .remove = led_pwm_remove,
234 .driver = {
235 .name = "leds_pwm",
236 .owner = THIS_MODULE,
237 .of_match_table = of_pwm_leds_match,
238 },
239};
240
241module_platform_driver(led_pwm_driver);
242
243MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
244MODULE_DESCRIPTION("PWM LED driver for PXA");
245MODULE_LICENSE("GPL");
246MODULE_ALIAS("platform:leds-pwm");