107 lines
2.3 KiB
C
107 lines
2.3 KiB
C
/*
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* Copyright (c) 2018 Google LLC.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT apa_apa102
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#include <errno.h>
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#include <drivers/led_strip.h>
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#include <drivers/spi.h>
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#include <drivers/gpio.h>
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#include <sys/util.h>
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struct apa102_config {
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struct spi_dt_spec bus;
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};
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static int apa102_update(const struct device *dev, void *buf, size_t size)
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{
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const struct apa102_config *config = dev->config;
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static const uint8_t zeros[] = { 0, 0, 0, 0 };
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static const uint8_t ones[] = { 0xFF, 0xFF, 0xFF, 0xFF };
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const struct spi_buf tx_bufs[] = {
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{
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/* Start frame: at least 32 zeros */
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.buf = (uint8_t *)zeros,
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.len = sizeof(zeros),
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},
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{
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/* LED data itself */
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.buf = buf,
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.len = size,
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},
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{
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/* End frame: at least 32 ones to clock the
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* remaining bits to the LEDs at the end of
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* the strip.
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*/
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.buf = (uint8_t *)ones,
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.len = sizeof(ones),
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},
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};
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const struct spi_buf_set tx = {
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.buffers = tx_bufs,
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.count = ARRAY_SIZE(tx_bufs)
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};
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return spi_write_dt(&config->bus, &tx);
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}
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static int apa102_update_rgb(const struct device *dev, struct led_rgb *pixels,
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size_t count)
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{
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uint8_t *p = (uint8_t *)pixels;
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size_t i;
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/* SOF (3 bits) followed by the 0 to 31 global dimming level */
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uint8_t prefix = 0xE0 | 31;
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/* Rewrite to the on-wire format */
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for (i = 0; i < count; i++) {
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uint8_t r = pixels[i].r;
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uint8_t g = pixels[i].g;
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uint8_t b = pixels[i].b;
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*p++ = prefix;
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*p++ = b;
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*p++ = g;
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*p++ = r;
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}
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BUILD_ASSERT(sizeof(struct led_rgb) == 4);
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return apa102_update(dev, pixels, sizeof(struct led_rgb) * count);
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}
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static int apa102_update_channels(const struct device *dev, uint8_t *channels,
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size_t num_channels)
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{
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/* Not implemented */
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return -EINVAL;
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}
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static int apa102_init(const struct device *dev)
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{
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const struct apa102_config *config = dev->config;
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if (!spi_is_ready(&config->bus)) {
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return -ENODEV;
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}
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return 0;
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}
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static const struct apa102_config apa102_config = {
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.bus = SPI_DT_SPEC_INST_GET(
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0, SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8), 0)
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};
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static const struct led_strip_driver_api apa102_api = {
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.update_rgb = apa102_update_rgb,
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.update_channels = apa102_update_channels,
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};
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DEVICE_DT_INST_DEFINE(0, apa102_init, NULL,
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NULL, &apa102_config, POST_KERNEL,
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CONFIG_LED_STRIP_INIT_PRIORITY, &apa102_api);
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