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/leds.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/slab.h>
16 #include <linux/spi/spi.h>
17 
18 struct dac124s085_led {
19 	struct led_classdev	ldev;
20 	struct spi_device	*spi;
21 	int			id;
22 	char			name[sizeof("dac124s085-3")];
23 
24 	struct mutex		mutex;
25 };
26 
27 struct dac124s085 {
28 	struct dac124s085_led leds[4];
29 };
30 
31 #define REG_WRITE		(0 << 12)
32 #define REG_WRITE_UPDATE	(1 << 12)
33 #define ALL_WRITE_UPDATE	(2 << 12)
34 #define POWER_DOWN_OUTPUT	(3 << 12)
35 
36 static int dac124s085_set_brightness(struct led_classdev *ldev,
37 				      enum led_brightness brightness)
38 {
39 	struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
40 						  ldev);
41 	u16 word;
42 	int ret;
43 
44 	mutex_lock(&led->mutex);
45 	word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
46 			   (brightness & 0xfff));
47 	ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));
48 	mutex_unlock(&led->mutex);
49 
50 	return ret;
51 }
52 
53 static int dac124s085_probe(struct spi_device *spi)
54 {
55 	struct dac124s085	*dac;
56 	struct dac124s085_led	*led;
57 	int i, ret;
58 
59 	dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);
60 	if (!dac)
61 		return -ENOMEM;
62 
63 	spi->bits_per_word = 16;
64 
65 	for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
66 		led		= dac->leds + i;
67 		led->id		= i;
68 		led->spi	= spi;
69 		snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
70 		mutex_init(&led->mutex);
71 		led->ldev.name = led->name;
72 		led->ldev.brightness = LED_OFF;
73 		led->ldev.max_brightness = 0xfff;
74 		led->ldev.brightness_set_blocking = dac124s085_set_brightness;
75 		ret = led_classdev_register(&spi->dev, &led->ldev);
76 		if (ret < 0)
77 			goto eledcr;
78 	}
79 
80 	spi_set_drvdata(spi, dac);
81 
82 	return 0;
83 
84 eledcr:
85 	while (i--)
86 		led_classdev_unregister(&dac->leds[i].ldev);
87 
88 	return ret;
89 }
90 
91 static int dac124s085_remove(struct spi_device *spi)
92 {
93 	struct dac124s085	*dac = spi_get_drvdata(spi);
94 	int i;
95 
96 	for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
97 		led_classdev_unregister(&dac->leds[i].ldev);
98 
99 	return 0;
100 }
101 
102 static struct spi_driver dac124s085_driver = {
103 	.probe		= dac124s085_probe,
104 	.remove		= dac124s085_remove,
105 	.driver = {
106 		.name	= "dac124s085",
107 	},
108 };
109 
110 module_spi_driver(dac124s085_driver);
111 
112 MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
113 MODULE_DESCRIPTION("DAC124S085 LED driver");
114 MODULE_LICENSE("GPL v2");
115 MODULE_ALIAS("spi:dac124s085");
116