/*
 * Copyright (C) 2016 Freie Universität Berlin
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     lpd8808
 * @{
 *
 * @file
 * @brief       LPD8808 based LED strip driver implementation
 *
 * @author      Hauke Petersen <mail@haukepetersen.de>
 *
 * @}
 */

#include <string.h>

#include "lpd8808.h"

/**
 * @brief   Shift a single byte to the strip
 *
 * @param[in] dev   device to use
 * @param[in] d     byte to shift out
 */
static void put_byte(lpd8808_t *dev, uint8_t d)
{
    for (int i = 0; i < 8; i++) {
        gpio_write(dev->pin_dat, d & 0x80);
        gpio_set(dev->pin_clk);
        gpio_clear(dev->pin_clk);
        d <<= 1;
    }
}

/**
 * @brief   Flush the previous input
 *
 * LPD8808 based strips need to be flushed after loading values for each LED.
 * This is done by feeding the strip with one zero byte for every 32 LEDs on
 * the strip.
 *
 * @param[in] dev   device to flush
 */
static void flush(lpd8808_t *dev)
{
    for (int i = 0; i < ((dev->led_cnt + 31) / 32); i++) {
        put_byte(dev, 0);
    }
}

int lpd8808_init(lpd8808_t *dev, const lpd8808_params_t *params)
{
    memcpy(dev, params, sizeof(lpd8808_params_t));

    /* initialize pins */
    gpio_init(dev->pin_dat, GPIO_OUT);
    gpio_init(dev->pin_clk, GPIO_OUT);
    flush(dev);

    return 0;
}

void lpd8808_load_rgb(lpd8808_t *dev, color_rgb_t vals[])
{
    for (int i = 0; i < dev->led_cnt; i++) {
        put_byte(dev, ((vals[i].g >> 1) | 0x80));
        put_byte(dev, ((vals[i].r >> 1) | 0x80));
        put_byte(dev, ((vals[i].b >> 1) | 0x80));
    }
    flush(dev);
}