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ac2dd0f1 GL |
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"); | |
e0626e38 | 151 | MODULE_ALIAS("spi:dac124s085"); |