spi.c

linux下的SPI总线驱动程序

#include <linux/autoconf.h>
#include <asicRegs.h>
#include <rtl8651_tblAsicDrv.h>
#include "rtl_glue.h"
#include "rtl_types.h"
#include "rtl_errno.h"
#include "assert.h"

#include "gpio.h"
#include "spi.h"



/*
@func int32 | _rtl865x_spi_init | Initialize SPI device
@parm rtl8651_spi_dev_t* | pDev | Structure to store device information
@parm uint32 | gpioSCLK | GPIO ID of SCLK
@parm uint32 | gpioCS_ | GPIO ID of CS_
@parm uint32 | gpioSDI | GPIO ID of SDI
@parm uint32 | gpioSDO | GPIO ID of SDO
@parm uint32 | maxSpeed | how fast SPI driver can generate the SCLK signal (unit: HZ)
@rvalue SUCCESS | success.
@rvalue FAILED | failed. Parameter error.
@comm
*/
int32 _rtl865x_spi_init( rtl8651_spi_dev_t* pDev, 
	gpioID gpioSCLK, 
	gpioID gpioCS_, 
	gpioID gpioSDI, 
	gpioID gpioSDO, int32 maxSpeed )
{
	pDev->gpioSCLK = gpioSCLK;
	pDev->gpioCS_ = gpioCS_;
	pDev->gpioSDI = gpioSDI;
	pDev->gpioSDO = gpioSDO;
	pDev->SClkDelayLoop = GetSysClockRate() / maxSpeed;

	rtlglue_printf("SCLK = %d\n", pDev->SClkDelayLoop);

	_rtl865x_initGpioPin( gpioSCLK, GPIO_PERI_GPIO, GPIO_DIR_OUT, GPIO_INT_DISABLE );
	_rtl865x_initGpioPin( gpioCS_, GPIO_PERI_GPIO, GPIO_DIR_OUT, GPIO_INT_DISABLE );
	_rtl865x_initGpioPin( gpioSDI, GPIO_PERI_GPIO, GPIO_DIR_OUT, GPIO_INT_DISABLE );
	_rtl865x_initGpioPin( gpioSDO, GPIO_PERI_GPIO, GPIO_DIR_IN, GPIO_INT_DISABLE );
	
	return SUCCESS;
}


/*
@func int32 | _rtl865x_spi_rawRead | Read several bits from SPI
@parm rtl8651_spi_dev_t* | pDev | Structure containing device information
@parm uint32* | pData | Pointer to store data
@parm uint32 | bits | Number bits of data wanted to read
@rvalue SUCCESS | success.
@rvalue FAILED | failed. Parameter error.
@comm
*/
int32 _rtl865x_spi_rawRead( rtl8651_spi_dev_t* pDev, void* pData, int32 bits )
{
	uint32 delayLoop;
	uint8* pch = pData;
	
	if ( pData == NULL ) return FAILED;
	
	_rtl865x_setGpioDataBit( pDev->gpioCS_, 1 ); /* raise the CS_ */
	_rtl865x_setGpioDataBit( pDev->gpioSCLK, 1 ); /* raise the SCLK */
	for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */

	_rtl865x_setGpioDataBit( pDev->gpioCS_, 0 ); /* fall down the CS_ */
	for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */

	for( bits--; bits >= 0; bits-- )
	{

		uint32 buf;

		_rtl865x_setGpioDataBit( pDev->gpioSCLK, 0 ); /* fall down the SCLK */
		for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */

		pch[bits/8] &= ~((uint8)1<<(bits&0x7));
		_rtl865x_getGpioDataBit( pDev->gpioSDO, &buf );
		pch[bits/8] |= buf?((uint8)1<<(bits&0x7)):0;
		
		_rtl865x_setGpioDataBit( pDev->gpioSCLK, 1 ); /* raising up the SCLK */
		for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */
	}	
	
	_rtl865x_setGpioDataBit( pDev->gpioCS_, 1 ); /* raise the CS_ */
	
	return SUCCESS;
}


/*
@func int32 | _rtl865x_spi_rawWrite | Write several bits from SPI
@parm rtl8651_spi_dev_t* | pDev | Structure containing device information
@parm uint32* | pData | Pointer to data
@parm uint32 | bits | Number bits of data wanting to write
@rvalue SUCCESS | success.
@rvalue FAILED | failed. Parameter error.
@comm
*/
int32 _rtl865x_spi_rawWrite( rtl8651_spi_dev_t* pDev, void* pData, int32 bits )
{
	uint32 delayLoop;
	uint8* pch = pData;
	
	if ( pData == NULL ) return FAILED;
	
	_rtl865x_setGpioDataBit( pDev->gpioCS_, 1 );  /* raise the CS_ */
	_rtl865x_setGpioDataBit( pDev->gpioSCLK, 1 ); /* raise the SCLK */
	for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */

	_rtl865x_setGpioDataBit( pDev->gpioCS_, 0 ); /* fall down the CS_ */
	for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */

	for( bits-- ; bits >= 0; bits-- )
	{
		_rtl865x_setGpioDataBit( pDev->gpioSDI, (pch[bits/8]&((uint32)1<<(bits&0x7)))?1:0 );
		_rtl865x_setGpioDataBit( pDev->gpioSCLK, 0 ); /* fall down the SCLK */
		for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */
		_rtl865x_setGpioDataBit( pDev->gpioSCLK, 1 ); /* raising up the SCLK */
		for( delayLoop = pDev->SClkDelayLoop; delayLoop > 0 ; delayLoop-- ); /* delay for a while */
	}	
	
	_rtl865x_setGpioDataBit( pDev->gpioCS_, 1 ); /* raise the CS_ */
	
	return SUCCESS;
}


/*
@func int32 | _rtl865x_spi_exit | Called when a SPI device is released
@parm rtl8651_spi_dev_t* | pDev | Structure containing device information
@rvalue SUCCESS | success.
@rvalue FAILED | failed. Parameter error.
@comm
*/
int32 _rtl865x_spi_exit( rtl8651_spi_dev_t* pDev )
{
	return SUCCESS;
}