1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2008
4  * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
5  *
6  * LED driver for the DAC124S085 SPI DAC
7  */
8 
9 #include <linux/leds.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/slab.h>
13 #include <linux/spi/spi.h>
14 
15 struct dac124s085_led {
16 	struct led_classdev	ldev;
17 	struct spi_device	*spi;
18 	int			id;
19 	char			name[sizeof("dac124s085-3")];
20 
21 	struct mutex		mutex;
22 };
23 
24 struct dac124s085 {
25 	struct dac124s085_led leds[4];
26 };
27 
28 #define REG_WRITE		(0 << 12)
29 #define REG_WRITE_UPDATE	(1 << 12)
30 #define ALL_WRITE_UPDATE	(2 << 12)
31 #define POWER_DOWN_OUTPUT	(3 << 12)
32 
33 static int dac124s085_set_brightness(struct led_classdev *ldev,
34 				      enum led_brightness brightness)
35 {
36 	struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
37 						  ldev);
38 	u16 word;
39 	int ret;
40 
41 	mutex_lock(&led->mutex);
42 	word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
43 			   (brightness & 0xfff));
44 	ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));
45 	mutex_unlock(&led->mutex);
46 
47 	return ret;
48 }
49 
50 static int dac124s085_probe(struct spi_device *spi)
51 {
52 	struct dac124s085	*dac;
53 	struct dac124s085_led	*led;
54 	int i, ret;
55 
56 	dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);
57 	if (!dac)
58 		return -ENOMEM;
59 
60 	spi->bits_per_word = 16;
61 
62 	for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
63 		led		= dac->leds + i;
64 		led->id		= i;
65 		led->spi	= spi;
66 		snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
67 		mutex_init(&led->mutex);
68 		led->ldev.name = led->name;
69 		led->ldev.brightness = LED_OFF;
70 		led->ldev.max_brightness = 0xfff;
71 		led->ldev.brightness_set_blocking = dac124s085_set_brightness;
72 		ret = led_classdev_register(&spi->dev, &led->ldev);
73 		if (ret < 0)
74 			goto eledcr;
75 	}
76 
77 	spi_set_drvdata(spi, dac);
78 
79 	return 0;
80 
81 eledcr:
82 	while (i--)
83 		led_classdev_unregister(&dac->leds[i].ldev);
84 
85 	return ret;
86 }
87 
88 static int dac124s085_remove(struct spi_device *spi)
89 {
90 	struct dac124s085	*dac = spi_get_drvdata(spi);
91 	int i;
92 
93 	for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
94 		led_classdev_unregister(&dac->leds[i].ldev);
95 
96 	return 0;
97 }
98 
99 static struct spi_driver dac124s085_driver = {
100 	.probe		= dac124s085_probe,
101 	.remove		= dac124s085_remove,
102 	.driver = {
103 		.name	= "dac124s085",
104 	},
105 };
106 
107 module_spi_driver(dac124s085_driver);
108 
109 MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
110 MODULE_DESCRIPTION("DAC124S085 LED driver");
111 MODULE_LICENSE("GPL v2");
112 MODULE_ALIAS("spi:dac124s085");
113