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");
144