leds: Add WM831x status LED driver
[linux-2.6.git] / drivers / leds / leds-dac124s085.c
1 /*
2  * Copyright 2008
3  * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
4  *
5  * This file is subject to the terms and conditions of version 2 of
6  * the GNU General Public License.  See the file COPYING in the main
7  * directory of this archive for more details.
8  *
9  * LED driver for the DAC124S085 SPI DAC
10  */
11
12 #include <linux/gfp.h>
13 #include <linux/leds.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/workqueue.h>
19 #include <linux/spi/spi.h>
20
21 struct dac124s085_led {
22         struct led_classdev     ldev;
23         struct spi_device       *spi;
24         int                     id;
25         int                     brightness;
26         char                    name[sizeof("dac124s085-3")];
27
28         struct mutex            mutex;
29         struct work_struct      work;
30         spinlock_t              lock;
31 };
32
33 struct dac124s085 {
34         struct dac124s085_led leds[4];
35 };
36
37 #define REG_WRITE               (0 << 12)
38 #define REG_WRITE_UPDATE        (1 << 12)
39 #define ALL_WRITE_UPDATE        (2 << 12)
40 #define POWER_DOWN_OUTPUT       (3 << 12)
41
42 static void dac124s085_led_work(struct work_struct *work)
43 {
44         struct dac124s085_led *led = container_of(work, struct dac124s085_led,
45                                                   work);
46         u16 word;
47
48         mutex_lock(&led->mutex);
49         word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
50                            (led->brightness & 0xfff));
51         spi_write(led->spi, (const u8 *)&word, sizeof(word));
52         mutex_unlock(&led->mutex);
53 }
54
55 static void dac124s085_set_brightness(struct led_classdev *ldev,
56                                       enum led_brightness brightness)
57 {
58         struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
59                                                   ldev);
60
61         spin_lock(&led->lock);
62         led->brightness = brightness;
63         schedule_work(&led->work);
64         spin_unlock(&led->lock);
65 }
66
67 static int dac124s085_probe(struct spi_device *spi)
68 {
69         struct dac124s085       *dac;
70         struct dac124s085_led   *led;
71         int i, ret;
72
73         dac = kzalloc(sizeof(*dac), GFP_KERNEL);
74         if (!dac)
75                 return -ENOMEM;
76
77         spi->bits_per_word = 16;
78
79         for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
80                 led             = dac->leds + i;
81                 led->id         = i;
82                 led->brightness = LED_OFF;
83                 led->spi        = spi;
84                 snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
85                 spin_lock_init(&led->lock);
86                 INIT_WORK(&led->work, dac124s085_led_work);
87                 mutex_init(&led->mutex);
88                 led->ldev.name = led->name;
89                 led->ldev.brightness = LED_OFF;
90                 led->ldev.max_brightness = 0xfff;
91                 led->ldev.brightness_set = dac124s085_set_brightness;
92                 ret = led_classdev_register(&spi->dev, &led->ldev);
93                 if (ret < 0)
94                         goto eledcr;
95         }
96
97         spi_set_drvdata(spi, dac);
98
99         return 0;
100
101 eledcr:
102         while (i--)
103                 led_classdev_unregister(&dac->leds[i].ldev);
104
105         spi_set_drvdata(spi, NULL);
106         kfree(dac);
107         return ret;
108 }
109
110 static int dac124s085_remove(struct spi_device *spi)
111 {
112         struct dac124s085       *dac = spi_get_drvdata(spi);
113         int i;
114
115         for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
116                 led_classdev_unregister(&dac->leds[i].ldev);
117                 cancel_work_sync(&dac->leds[i].work);
118         }
119
120         spi_set_drvdata(spi, NULL);
121         kfree(dac);
122
123         return 0;
124 }
125
126 static struct spi_driver dac124s085_driver = {
127         .probe          = dac124s085_probe,
128         .remove         = dac124s085_remove,
129         .driver = {
130                 .name   = "dac124s085",
131                 .owner  = THIS_MODULE,
132         },
133 };
134
135 static int __init dac124s085_leds_init(void)
136 {
137         return spi_register_driver(&dac124s085_driver);
138 }
139
140 static void __exit dac124s085_leds_exit(void)
141 {
142         spi_unregister_driver(&dac124s085_driver);
143 }
144
145 module_init(dac124s085_leds_init);
146 module_exit(dac124s085_leds_exit);
147
148 MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
149 MODULE_DESCRIPTION("DAC124S085 LED driver");
150 MODULE_LICENSE("GPL v2");