blob: 23ebd2c19531aa75c5683b53bfe73495bc5ba348 [file] [log] [blame]
/*
* 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);