/*
 * spi_master.c
 *
 * manage chip select externally.
 *
 * current version is BLOCKING. update later to use interrupt or DMA.
 */

#include "spi_master.h"



void spim_init()
{
    SPI_InitTypeDef spi = {0};

    spi.SPI_Direction   = SPI_Direction_2Lines_FullDuplex;
    spi.SPI_Mode        = SPI_Mode_Master;
    spi.SPI_DataSize    = SPI_DataSize_8b;
    spi.SPI_CPOL        = SPI_CPOL_High;
    spi.SPI_CPHA        = SPI_CPHA_2Edge;
    spi.SPI_NSS         = SPI_NSS_Soft;
    spi.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
    spi.SPI_FirstBit    = SPI_FirstBit_MSB;

    SPI_Init(SPI1, &spi);

    SPI_Cmd(SPI1, ENABLE);
}

void spim_write_raw(const uint8_t *data, uint16_t len)
{
    // todo: make non-blocking, timeout and error checking
    while (len) {
        if (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE)) {
            SPI_I2S_SendData(SPI1, *data);
            data++;
            len--;
        }
    }
}

void spim_write_reg8(uint8_t reg, const uint8_t *data, uint16_t len)
{
    spim_write_raw(&reg, 1);
    spim_write_raw(data, len);
}

void spim_read_raw(uint8_t *data, uint16_t len)
{
    // todo: non-blocking, timeout and error checking
    while (len) {
        while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_BSY)) {};

        if (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE)) {
            *data++ = SPI_I2S_ReceiveData(SPI1);
            len--;
        }
        SPI_I2S_SendData(SPI1, 0);
    }
}

void spim_read_reg8(uint8_t reg, uint8_t *data, uint16_t len)
{
    spim_write_raw(&reg, 1);
    spim_read_raw(data, len);
}