include/spi/spi.h

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#ifndef SPI_H_INCLUDED
#define SPI_H_INCLUDED

#include <stdint.h>
#include <stdbool.h>
#include <compiler.h>
#include <assert.h>
#include <gpio/portmux_gpio.h>
#include <buffer.h>
#include <dmac/dma_controller.h>

#ifdef CONFIG_SPI_USE_DMA
# include "dma.h"
#else
/*
 * We will use the workqueue to achieve async behaviour
 * without drowning in recursive function/callback calls
 */
# include <workqueue.h>
#endif

typedef uint32_t spi_config_t;

struct spi_master
{
        void *port; 
        struct spi_request *first_request;
        struct spi_request **last_next;
#ifdef CONFIG_SPI_USE_DMA
        struct dmac_channel *dma_tx_channel;
        struct dmac_channel *dma_rx_channel;
        struct dmac_request dma_tx_request;
        struct dmac_request dma_rx_request;
#else
        struct workqueue_item workqueue_item;
#endif
};

struct spi_device
{
        struct spi_master *master;
        spi_config_t config;
        gpio_pin_t cs_pin;
};

enum local_buffer {
        LOCAL_TXBUF,
        LOCAL_RXBUF,
        NONE,
};

#define SPI_REQUEST_STOP        (1 << 0)

struct spi_request
{
        struct spi_device *device;
        struct buffer *txbuf;
        struct buffer *rxbuf;
        size_t bytes_transferred;
        int status;
        enum local_buffer local_buffer;
        unsigned long flags;
        void (*request_done)(struct spi_request *request, void *context);
        void *context;
        struct spi_request *next;
};

#define SPI_CPHA        (1 << 0)
#define SPI_CPOL        (1 << 1)
#define SPI_MODE_0      0
#define SPI_MODE_1      (SPI_CPHA)
#define SPI_MODE_2      (SPI_CPOL)
#define SPI_MODE_3      (SPI_CPOL | SPI_CPHA)

#ifdef __cplusplus
extern "C" {
#endif

void spi_setup_master(struct spi_master *master, unsigned int id);

static inline void portmux_enable_spi_cs(gpio_pin_t pin)
{
        portmux_select_gpio_pin(pin, PORTMUX_DIR_OUTPUT | PORTMUX_INIT_HIGH);
}

void spi_setup_device(
                struct spi_master *master,
                struct spi_device *device,
                unsigned long flags,
                uint32_t baudrate,
                gpio_pin_t cs_pin);

void spi_submit_request(
                struct spi_device *device,
                struct spi_request *request);

#ifdef __cplusplus
} /* extern "C" */
#endif

#endif  //SPI_H_INCLUDED

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