Update SPI driver

stm-firmware/include/stm-periph/spi.h

@@ -21,4 +21,42 @@
 #ifndef __SPI_H__
 #define __SPI_H__
 
+#include <stm32/stm32f4xx.h>
+#include <stdbool.h>
+
+enum stm_spi_prescaler {
+	SPI_PRSC_DIV2 = 0,
+	SPI_PRSC_DIV4 = 1,
+	SPI_PRSC_DIV8 = 2,
+	SPI_PRSC_DIV16 = 3,
+	SPI_PRSC_DIV32 = 4,
+	SPI_PRSC_DIV64 = 5,
+	SPI_PRSC_DIV128 = 6,
+	SPI_PRSC_DIV256 = 7,
+};
+
+struct stm_spi_settings {
+	void (*cs_activate)(void);
+	void (*cs_deactivate)(void);
+	bool cpol;
+	bool cpha;
+	bool master;
+	bool msb_first;
+	enum stm_spi_prescaler prescaler;
+};
+
+struct stm_spi_dev {
+	uint32_t magic;
+	SPI_TypeDef *spi_regs;
+	struct stm_spi_settings settings;
+};
+
+typedef void * stm_spi_handle;
+
+stm_spi_handle spi_init(struct stm_spi_dev *spi_dev_struct, SPI_TypeDef *spi_regs, const struct stm_spi_settings *settings);
+
+void spi_deinit(stm_spi_handle handle);
+
+int spi_transfer(stm_spi_handle handle, const uint8_t *tx, uint8_t *rx, uint32_t count, bool handle_cs);
+
 #endif /* __SPI_H__ */