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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 | ||
25 | struct led_pwm_data { | |
26 | struct led_classdev cdev; | |
27 | struct pwm_device *pwm; | |
28 | unsigned int active_low; | |
29 | unsigned int period; | |
30 | unsigned int max_brightness; | |
31 | }; | |
32 | ||
33 | static 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->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 | ||
50 | static 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 | dev_err(&pdev->dev, "unable to request PWM %d\n", | |
73 | cur_led->pwm_id); | |
74 | goto err; | |
75 | } | |
76 | ||
77 | led_dat->cdev.name = cur_led->name; | |
78 | led_dat->cdev.default_trigger = cur_led->default_trigger; | |
79 | led_dat->active_low = cur_led->active_low; | |
80 | led_dat->max_brightness = cur_led->max_brightness; | |
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.flags |= LED_CORE_SUSPENDRESUME; | |
85 | ||
86 | ret = led_classdev_register(&pdev->dev, &led_dat->cdev); | |
87 | if (ret < 0) { | |
88 | pwm_free(led_dat->pwm); | |
89 | goto err; | |
90 | } | |
91 | } | |
92 | ||
93 | platform_set_drvdata(pdev, leds_data); | |
94 | ||
95 | return 0; | |
96 | ||
97 | err: | |
98 | if (i > 0) { | |
99 | for (i = i - 1; i >= 0; i--) { | |
100 | led_classdev_unregister(&leds_data[i].cdev); | |
101 | pwm_free(leds_data[i].pwm); | |
102 | } | |
103 | } | |
104 | ||
105 | kfree(leds_data); | |
106 | ||
107 | return ret; | |
108 | } | |
109 | ||
110 | static int __devexit led_pwm_remove(struct platform_device *pdev) | |
111 | { | |
112 | int i; | |
113 | struct led_pwm_platform_data *pdata = pdev->dev.platform_data; | |
114 | struct led_pwm_data *leds_data; | |
115 | ||
116 | leds_data = platform_get_drvdata(pdev); | |
117 | ||
118 | for (i = 0; i < pdata->num_leds; i++) { | |
119 | led_classdev_unregister(&leds_data[i].cdev); | |
120 | pwm_free(leds_data[i].pwm); | |
121 | } | |
122 | ||
123 | kfree(leds_data); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | ||
128 | static struct platform_driver led_pwm_driver = { | |
129 | .probe = led_pwm_probe, | |
130 | .remove = __devexit_p(led_pwm_remove), | |
131 | .driver = { | |
132 | .name = "leds_pwm", | |
133 | .owner = THIS_MODULE, | |
134 | }, | |
135 | }; | |
136 | ||
137 | static int __init led_pwm_init(void) | |
138 | { | |
139 | return platform_driver_register(&led_pwm_driver); | |
140 | } | |
141 | ||
142 | static void __exit led_pwm_exit(void) | |
143 | { | |
144 | platform_driver_unregister(&led_pwm_driver); | |
145 | } | |
146 | ||
147 | module_init(led_pwm_init); | |
148 | module_exit(led_pwm_exit); | |
149 | ||
150 | MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>"); | |
151 | MODULE_DESCRIPTION("PWM LED driver for PXA"); | |
152 | MODULE_LICENSE("GPL"); | |
153 | MODULE_ALIAS("platform:leds-pwm"); |