107 lines
2.3 KiB
C
107 lines
2.3 KiB
C
/*
|
|
* Copyright (c) 2018 Google LLC.
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <drivers/led_strip.h>
|
|
#include <drivers/spi.h>
|
|
|
|
struct apa102_data {
|
|
struct device *spi;
|
|
struct spi_config cfg;
|
|
};
|
|
|
|
static int apa102_update(struct device *dev, void *buf, size_t size)
|
|
{
|
|
struct apa102_data *data = dev->driver_data;
|
|
static const u8_t zeros[] = {0, 0, 0, 0};
|
|
static const u8_t ones[] = {0xFF, 0xFF, 0xFF, 0xFF};
|
|
const struct spi_buf tx_bufs[] = {
|
|
{
|
|
/* Start frame: at least 32 zeros */
|
|
.buf = (u8_t *)zeros,
|
|
.len = sizeof(zeros),
|
|
},
|
|
{
|
|
/* LED data itself */
|
|
.buf = buf,
|
|
.len = size,
|
|
},
|
|
{
|
|
/* End frame: at least 32 ones to clock the
|
|
* remaining bits to the LEDs at the end of
|
|
* the strip.
|
|
*/
|
|
.buf = (u8_t *)ones,
|
|
.len = sizeof(ones),
|
|
},
|
|
};
|
|
const struct spi_buf_set tx = {
|
|
.buffers = tx_bufs,
|
|
.count = ARRAY_SIZE(tx_bufs)
|
|
};
|
|
|
|
return spi_write(data->spi, &data->cfg, &tx);
|
|
}
|
|
|
|
static int apa102_update_rgb(struct device *dev, struct led_rgb *pixels,
|
|
size_t count)
|
|
{
|
|
u8_t *p = (u8_t *)pixels;
|
|
size_t i;
|
|
/* SOF (3 bits) followed by the 0 to 31 global dimming level */
|
|
u8_t prefix = 0xE0 | 31;
|
|
|
|
/* Rewrite to the on-wire format */
|
|
for (i = 0; i < count; i++) {
|
|
u8_t r = pixels[i].r;
|
|
u8_t g = pixels[i].g;
|
|
u8_t b = pixels[i].b;
|
|
|
|
*p++ = prefix;
|
|
*p++ = b;
|
|
*p++ = g;
|
|
*p++ = r;
|
|
}
|
|
|
|
BUILD_ASSERT(sizeof(struct led_rgb) == 4);
|
|
return apa102_update(dev, pixels, sizeof(struct led_rgb) * count);
|
|
}
|
|
|
|
static int apa102_update_channels(struct device *dev, u8_t *channels,
|
|
size_t num_channels)
|
|
{
|
|
/* Not implemented */
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int apa102_init(struct device *dev)
|
|
{
|
|
struct apa102_data *data = dev->driver_data;
|
|
|
|
data->spi = device_get_binding(DT_INST_0_APA_APA102_BUS_NAME);
|
|
if (!data->spi) {
|
|
return -ENODEV;
|
|
}
|
|
|
|
data->cfg.slave = DT_INST_0_APA_APA102_BASE_ADDRESS;
|
|
data->cfg.frequency = DT_INST_0_APA_APA102_SPI_MAX_FREQUENCY;
|
|
data->cfg.operation =
|
|
SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct apa102_data apa102_data_0;
|
|
|
|
static const struct led_strip_driver_api apa102_api = {
|
|
.update_rgb = apa102_update_rgb,
|
|
.update_channels = apa102_update_channels,
|
|
};
|
|
|
|
DEVICE_AND_API_INIT(apa102_0, DT_INST_0_APA_APA102_LABEL, apa102_init,
|
|
&apa102_data_0, NULL, POST_KERNEL,
|
|
CONFIG_LED_STRIP_INIT_PRIORITY, &apa102_api);
|