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dianjixz
88 lines
3.8 KiB
C
88 lines
3.8 KiB
C
/*
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* Simple Linux wrapper for access to /dev/spidev
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* File: "spi.h"
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*/
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#ifndef __LINUX_SPI_H__
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#define __LINUX_SPI_H__
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//-----------------------------------------------------------------------------
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#include <linux/spi/spidev.h>
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#include <stdint.h>
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//-----------------------------------------------------------------------------
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// common error codes (return values)
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#define SPI_ERR_NONE 0 // no error, success
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#define SPI_ERR_OPEN -1 // failed to open the bus
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#define SPI_ERR_SET_MODE -2 // can't set bus mode
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#define SPI_ERR_GET_MODE -3 // can't get bus mode
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#define SPI_ERR_GET_LSB -4 // can't get 'LSB first'
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#define SPI_ERR_SET_BITS -5 // can't set bits per word
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#define SPI_ERR_GET_BITS -6 // can't get bits per word
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#define SPI_ERR_SET_SPEED -7 // can't set max speed [Hz]
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#define SPI_ERR_GET_SPEED -8 // can't get max speed [Hz]
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#define SPI_ERR_READ -9 // can't read
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#define SPI_ERR_WRITE -10 // can't write
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#define SPI_ERR_EXCHANGE -11 // can't read/write
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//----------------------------------------------------------------------------
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#ifdef SPI_DEBUG
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# include <stdio.h> // fprintf()
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# define SPI_DBG(fmt, arg...) fprintf(stderr, "SPI: " fmt "\n", ## arg)
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#else
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# define SPI_DBG(fmt, ...) // debug output off
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#endif // SPI_DEBUG
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//----------------------------------------------------------------------------
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// `spi_t` type structure
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typedef struct spi_ {
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int fd; // file descriptor: fd = open(filename, O_RDWR);
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__u32 speed; // speed [Hz]
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__u8 mode; // SPI mode
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__u8 lsb; // LSB first
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__u8 bits; // bits per word
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} spi_t;
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//----------------------------------------------------------------------------
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#ifdef __cplusplus
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extern "C"
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{
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#endif // __cplusplus
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//----------------------------------------------------------------------------
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// open and init SPIdev
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// * spi_mode may have next mask: SPI_LOOP | SPI_CPHA | SPI_CPOL |
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// SPI_LSB_FIRST | SPI_CS_HIGH SPI_3WIRE | SPI_NO_CS | SPI_READY
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// or 0 by zefault
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int spi_init(spi_t *self,
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const char *device, // filename like "/dev/spidev0.0"
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int mode, // SPI_* (look "linux/spi/spidev.h")
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int bits, // bits per word (usually 8)
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int speed); // max speed [Hz]
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//----------------------------------------------------------------------------
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// sets mode on existing spi
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int spi_set_mode(spi_t* self, int mode);
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//----------------------------------------------------------------------------
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// sets speed on existing spi
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int spi_set_speed(spi_t* self, int speed);
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//----------------------------------------------------------------------------
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// close SPIdev file and free memory
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void spi_free(spi_t *self);
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//----------------------------------------------------------------------------
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// read data from SPIdev
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int spi_read(spi_t *self, void* rx_buf, int len);
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//----------------------------------------------------------------------------
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// write data to SPIdev
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int spi_write(spi_t *self, const void* tx_buf, int len);
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//----------------------------------------------------------------------------
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// read and write `len` bytes from/to SPIdev
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int spi_exchange(spi_t *self, void* rx_buf, const void* tx_buf, int len);
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//----------------------------------------------------------------------------
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// read data from SPIdev from specific register address
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int spi_read_reg8(spi_t *self, uint8_t reg_addr, void* rx_buf, int len);
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//----------------------------------------------------------------------------
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// write data to SPIdev to specific register address
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int spi_write_reg8(spi_t *self, uint8_t reg_addr, const void* tx_buf, int len);
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//----------------------------------------------------------------------------
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#ifdef __cplusplus
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}
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#endif // __cplusplus
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//----------------------------------------------------------------------------
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#endif // __LINUX_SPI_H__
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/*** end of "spi.h" file ***/ |