File syn_spi_dev.h

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#ifndef SYN_SPI_DEV_H
#define SYN_SPI_DEV_H

#include "../common/syn_defs.h"
#include "../port/syn_port_spi.h"

#include <stddef.h>
#include <stdint.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

/* ── Device descriptor ──────────────────────────────────────────────────── */

typedef struct {
    uint8_t bus;      
    uint8_t cs;       
    uint8_t read_bit; 
} SYN_SPIDev;

/* ── API ────────────────────────────────────────────────────────────────── */

static inline void syn_spi_dev_init(SYN_SPIDev *dev, uint8_t bus, uint8_t cs, uint8_t read_bit)
{
    dev->bus = bus;
    dev->cs = cs;
    dev->read_bit = read_bit;
}

static inline uint8_t syn_spi_dev_read8(const SYN_SPIDev *dev, uint8_t reg)
{
    uint8_t tx[2] = {(uint8_t)(reg | dev->read_bit), 0x00};
    uint8_t rx[2] = {0, 0};

    syn_port_spi_cs_assert(dev->bus, dev->cs);
    syn_port_spi_transfer(dev->bus, tx, rx, 2);
    syn_port_spi_cs_deassert(dev->bus, dev->cs);

    return rx[1];
}

static inline SYN_Status syn_spi_dev_write8(const SYN_SPIDev *dev, uint8_t reg, uint8_t val)
{
    uint8_t tx[2] = {reg, val};

    syn_port_spi_cs_assert(dev->bus, dev->cs);
    syn_port_spi_transfer(dev->bus, tx, NULL, 2);
    syn_port_spi_cs_deassert(dev->bus, dev->cs);

    return SYN_OK;
}

static inline SYN_Status syn_spi_dev_read_burst(const SYN_SPIDev *dev, uint8_t reg, uint8_t *buf,
                                                size_t len)
{
    uint8_t tx_reg = (uint8_t)(reg | dev->read_bit);

    syn_port_spi_cs_assert(dev->bus, dev->cs);
    syn_port_spi_transfer(dev->bus, &tx_reg, NULL, 1);

    /* Subsequent clocks to read data */
    uint8_t zeros[32];
    memset(zeros, 0, sizeof(zeros));
    while (len > 0) {
        size_t chunk = (len > 32) ? 32 : len;
        syn_port_spi_transfer(dev->bus, zeros, buf, chunk);
        buf += chunk;
        len -= chunk;
    }

    syn_port_spi_cs_deassert(dev->bus, dev->cs);
    return SYN_OK;
}

static inline SYN_Status syn_spi_dev_write_burst(const SYN_SPIDev *dev, uint8_t reg,
                                                 const uint8_t *data, size_t len)
{
    syn_port_spi_cs_assert(dev->bus, dev->cs);
    syn_port_spi_transfer(dev->bus, &reg, NULL, 1);
    syn_port_spi_transfer(dev->bus, data, NULL, len);
    syn_port_spi_cs_deassert(dev->bus, dev->cs);

    return SYN_OK;
}

#ifdef __cplusplus
}
#endif

#endif /* SYN_SPI_DEV_H */