blob: b148f8d5c8fb7d94d8ec8917933fc2078bcf3432 [file] [log] [blame]
/*
* Copyright (c) 2017 Linaro Limited
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/drivers/led_strip.h>
#include <errno.h>
#include <string.h>
#if DT_NODE_HAS_STATUS(DT_INST(0, greeled_lpd8806), okay)
#define DT_DRV_COMPAT greeled_lpd8806
#else
#define DT_DRV_COMPAT greeled_lpd8803
#endif
#define LOG_LEVEL CONFIG_LED_STRIP_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(lpd880x);
#include <zephyr/zephyr.h>
#include <zephyr/device.h>
#include <zephyr/drivers/spi.h>
#include <zephyr/sys/util.h>
/*
* LPD880X SPI master configuration:
*
* - mode 0 (the default), 8 bit, MSB first, one-line SPI
* - no shenanigans (no CS hold, release device lock, not an EEPROM)
*/
#define LPD880X_SPI_OPERATION (SPI_OP_MODE_MASTER | \
SPI_TRANSFER_MSB | \
SPI_WORD_SET(8))
struct lpd880x_config {
struct spi_dt_spec bus;
};
static int lpd880x_update(const struct device *dev, void *data, size_t size)
{
const struct lpd880x_config *config = dev->config;
/*
* Per the AdaFruit reverse engineering notes on the protocol,
* a zero byte propagates through at most 32 LED driver ICs.
* The LPD8803 is the worst case, at 3 output channels per IC.
*/
uint8_t reset_size = ceiling_fraction(ceiling_fraction(size, 3), 32);
uint8_t reset_buf[reset_size];
uint8_t last = 0x00;
const struct spi_buf bufs[3] = {
{
/* Prepares the strip to shift in new data values. */
.buf = reset_buf,
.len = reset_size
},
{
/* Displays the serialized pixel data. */
.buf = data,
.len = size
},
{
/* Ensures the last byte of pixel data is displayed. */
.buf = &last,
.len = sizeof(last)
}
};
const struct spi_buf_set tx = {
.buffers = bufs,
.count = 3
};
size_t rc;
(void)memset(reset_buf, 0x00, reset_size);
rc = spi_write_dt(&config->bus, &tx);
if (rc) {
LOG_ERR("can't update strip: %d", rc);
}
return rc;
}
static int lpd880x_strip_update_rgb(const struct device *dev,
struct led_rgb *pixels,
size_t num_pixels)
{
uint8_t *px = (uint8_t *)pixels;
uint8_t r, g, b;
size_t i;
/*
* Overwrite a prefix of the pixels array with its on-wire
* representation, eliminating padding/scratch garbage, if any.
*/
for (i = 0; i < num_pixels; i++) {
r = 0x80 | (pixels[i].r >> 1);
g = 0x80 | (pixels[i].g >> 1);
b = 0x80 | (pixels[i].b >> 1);
/*
* GRB is the ordering used by commonly available
* LPD880x strips.
*/
*px++ = g;
*px++ = r;
*px++ = b;
}
return lpd880x_update(dev, pixels, 3 * num_pixels);
}
static int lpd880x_strip_update_channels(const struct device *dev,
uint8_t *channels,
size_t num_channels)
{
size_t i;
for (i = 0; i < num_channels; i++) {
channels[i] = 0x80 | (channels[i] >> 1);
}
return lpd880x_update(dev, channels, num_channels);
}
static int lpd880x_strip_init(const struct device *dev)
{
const struct lpd880x_config *config = dev->config;
if (!spi_is_ready(&config->bus)) {
LOG_ERR("SPI device %s not ready", config->bus.bus->name);
return -ENODEV;
}
return 0;
}
static const struct lpd880x_config lpd880x_config = {
.bus = SPI_DT_SPEC_INST_GET(0, LPD880X_SPI_OPERATION, 0)
};
static const struct led_strip_driver_api lpd880x_strip_api = {
.update_rgb = lpd880x_strip_update_rgb,
.update_channels = lpd880x_strip_update_channels,
};
DEVICE_DT_INST_DEFINE(0, lpd880x_strip_init, NULL,
NULL, &lpd880x_config,
POST_KERNEL, CONFIG_LED_STRIP_INIT_PRIORITY,
&lpd880x_strip_api);