1 /*
2 * Copyright (c) 2018 Google LLC.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT apa_apa102
8
9 #include <errno.h>
10 #include <zephyr/drivers/led_strip.h>
11 #include <zephyr/drivers/spi.h>
12 #include <zephyr/drivers/gpio.h>
13 #include <zephyr/sys/util.h>
14
15 struct apa102_config {
16 struct spi_dt_spec bus;
17 size_t length;
18 };
19
apa102_update(const struct device * dev,void * buf,size_t size)20 static int apa102_update(const struct device *dev, void *buf, size_t size)
21 {
22 const struct apa102_config *config = dev->config;
23 static const uint8_t zeros[] = { 0, 0, 0, 0 };
24 static const uint8_t ones[] = { 0xFF, 0xFF, 0xFF, 0xFF };
25 const struct spi_buf tx_bufs[] = {
26 {
27 /* Start frame: at least 32 zeros */
28 .buf = (uint8_t *)zeros,
29 .len = sizeof(zeros),
30 },
31 {
32 /* LED data itself */
33 .buf = buf,
34 .len = size,
35 },
36 {
37 /* End frame: at least 32 ones to clock the
38 * remaining bits to the LEDs at the end of
39 * the strip.
40 */
41 .buf = (uint8_t *)ones,
42 .len = sizeof(ones),
43 },
44 };
45 const struct spi_buf_set tx = {
46 .buffers = tx_bufs,
47 .count = ARRAY_SIZE(tx_bufs)
48 };
49
50 return spi_write_dt(&config->bus, &tx);
51 }
52
apa102_update_rgb(const struct device * dev,struct led_rgb * pixels,size_t count)53 static int apa102_update_rgb(const struct device *dev, struct led_rgb *pixels,
54 size_t count)
55 {
56 uint8_t *p = (uint8_t *)pixels;
57 size_t i;
58 /* SOF (3 bits) followed by the 0 to 31 global dimming level */
59 uint8_t prefix = 0xE0 | 31;
60
61 /* Rewrite to the on-wire format */
62 for (i = 0; i < count; i++) {
63 uint8_t r = pixels[i].r;
64 uint8_t g = pixels[i].g;
65 uint8_t b = pixels[i].b;
66
67 *p++ = prefix;
68 *p++ = b;
69 *p++ = g;
70 *p++ = r;
71 }
72
73 BUILD_ASSERT(sizeof(struct led_rgb) == 4);
74 return apa102_update(dev, pixels, sizeof(struct led_rgb) * count);
75 }
76
apa102_length(const struct device * dev)77 static size_t apa102_length(const struct device *dev)
78 {
79 const struct apa102_config *config = dev->config;
80
81 return config->length;
82 }
83
apa102_init(const struct device * dev)84 static int apa102_init(const struct device *dev)
85 {
86 const struct apa102_config *config = dev->config;
87
88 if (!spi_is_ready_dt(&config->bus)) {
89 return -ENODEV;
90 }
91
92 return 0;
93 }
94
95 static DEVICE_API(led_strip, apa102_api) = {
96 .update_rgb = apa102_update_rgb,
97 .length = apa102_length,
98 };
99
100 #define APA102_DEVICE(idx) \
101 static const struct apa102_config apa102_##idx##_config = { \
102 .bus = SPI_DT_SPEC_INST_GET( \
103 idx, \
104 SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8), \
105 0), \
106 .length = DT_INST_PROP(idx, chain_length), \
107 }; \
108 \
109 DEVICE_DT_INST_DEFINE(idx, \
110 apa102_init, \
111 NULL, \
112 NULL, \
113 &apa102_##idx##_config, \
114 POST_KERNEL, \
115 CONFIG_LED_STRIP_INIT_PRIORITY, \
116 &apa102_api);
117
118 DT_INST_FOREACH_STATUS_OKAY(APA102_DEVICE)
119
