i2c_gpio.c

This file contains routines to write to and read from the I2C bus using the GPIO pins of the CS5530

\ i2c_gpio.c
 *
 * This file contains routines to write to and read from the I2C bus using
 * the GPIO pins of the CS5530.
 *
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 *
 * Revision 1.0
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/* NSC_LIC_GPL
 *
 * National Semiconductor Corporation Gnu General Public License for Durango
 *
 * (GPL License with Export Notice)
 *
 * Copyright (c) 1999-2001
 * National Semiconductor Corporation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted under the terms of the GNU General 
 * Public License as published by the Free Software Foundation; either 
 * version 2 of the License, or (at your option) any later version  
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 * its contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission. 
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
 * NATIONAL SEMICONDUCTOR CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY 
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE, 
 * INTELLECTUAL PROPERTY INFRINGEMENT, OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE. See the GNU General Public License for more details. 
 *
 * EXPORT LAWS: THIS LICENSE ADDS NO RESTRICTIONS TO THE EXPORT LAWS OF 
 * YOUR JURISDICTION. It is licensee's responsibility to comply with 
 * any export regulations applicable in licensee's jurisdiction. Under 
 * CURRENT (2001) U.S. export regulations this software 
 * is eligible for export from the U.S. and can be downloaded by or 
 * otherwise exported or reexported worldwide EXCEPT to U.S. embargoed 
 * destinations which include Cuba, Iraq, Libya, North Korea, Iran, 
 * Syria, Sudan, Afghanistan and any other country to which the U.S. 
 * has embargoed goods and services. 
 *
 * You should have received a copy of the GNU General Public License 
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 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
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 * END_NSC_LIC_GPL */

/* STATIC VARIABLES TO STORE WHAT GPIO PINS TO USE */

int gpio_clock = 0;
int gpio_data = 0;

static int g_initialized = 0;

#define	I2CWRITE		0x00	/* Write address */
#define	I2CREAD			0x01	/* Read address */

#define	I2CACK			0x00	/* Ack value */
#define	I2CNACK			0x01	/* Not - ack value */

#define		CS5530_ID	(0x80000000 | (0x00<<16) | (0x12<<11) | (0<<8) | 0x00)
#define		CS5530_GPIO	(0x80000000 | (0x00<<16) | (0x12<<11) | (0<<8) | 0x90)
#define		SDA		0x0800
#define		SCL		0x0400
#define		SDADIR	0x0008
#define		SCLDIR	0x0004

int I2C_init(void);
void I2C_cleanup(void);

int I2C_Read(unsigned char address, unsigned int reg, unsigned long *p_value,
	     unsigned int bytes);
int I2C_Write(unsigned char address, unsigned int reg, unsigned long value,
	      unsigned int bytes);
int I2CAL_init(void);
void I2CAL_cleanup(void);

void I2CAL_output_clock(int state);
void I2CAL_output_data(int state);
unsigned char I2CAL_input_data(void);

void I2CAL_set_data_for_input(void);
void I2CAL_set_data_for_output(void);

void SendI2CStart(void);
void SendI2CData(unsigned char inData);

unsigned char ReceiveI2CAck(void);
void SendI2CStop(void);
void SendI2CNack(void);
void SendI2CAck(void);
unsigned char ReceiveI2CData(void);

int gpio_i2c_reset(unsigned char busnum, short adr, char freq);
int gpio_i2c_write(unsigned char busnum, unsigned char chipadr,
		   unsigned char subadr, unsigned char bytes,
		   unsigned char *data);
int gpio_i2c_read(unsigned char busnum, unsigned char chipadr,
		  unsigned char subadr, unsigned char bytes,
		  unsigned char *data);
int gpio_i2c_select_gpio(int clock, int data);
int gpio_i2c_init(void);
void gpio_i2c_cleanup(void);

/* ### ADD ### ANY LOCAL ROUTINE DEFINITIONS SPECIFIC TO GPIO */

/*---------------------------------------------------------------------------
 * gfx_i2c_reset
 *
 * This routine resets the I2C bus.
 *---------------------------------------------------------------------------
 */

#if GFX_I2C_DYNAMIC
int
gpio_i2c_reset(unsigned char busnum, short adr, char freq)
#else
int
gfx_i2c_reset(unsigned char busnum, short adr, char freq)
#endif
{
   /* ### ADD ### Any code needed to reset the state of the GPIOs. */
   return GFX_STATUS_OK;
}

/*---------------------------------------------------------------------------
 * gfx_i2c_select_gpio
 *
 * This routine selects which GPIO pins to use.
 *---------------------------------------------------------------------------
 */
#if GFX_I2C_DYNAMIC
int
gpio_i2c_select_gpio(int clock, int data)
#else
int
gfx_i2c_select_gpio(int clock, int data)
#endif
{
   gpio_clock = clock;
   gpio_data = data;
   return (0);
}

/*---------------------------------------------------------------------------
 * gfx_i2c_write
 *
 * This routine writes data to the specified I2C address.
 *---------------------------------------------------------------------------
 */
#if GFX_I2C_DYNAMIC
int
gpio_i2c_write(unsigned char busnum, unsigned char address, unsigned char reg,
	       unsigned char bytes, unsigned char *value)
#else
int
gfx_i2c_write(unsigned char busnum, unsigned char address, unsigned char reg,
	      unsigned char bytes, unsigned char *value)
#endif
{
   /* ### ADD ### CODE TO WRITE BYTE TO I2B BUS */

   int restart_count = 0;

   while (restart_count++ < 5) {
      /* set the access pointer register. */
      /* The address is shifted left by one to make room for Read/Write bit */
      SendI2CStart();
      SendI2CData((char)((address << 1) | I2CWRITE));
      if (!ReceiveI2CAck()) {
	 SendI2CStop();
	 gfx_delay_milliseconds(10);
	 continue;
      }
      SendI2CData((unsigned char)reg);
      if (!ReceiveI2CAck()) {
	 SendI2CStop();
	 gfx_delay_milliseconds(10);
	 continue;
      }

      /* write the first byte */
      SendI2CData(*value);
      if (!ReceiveI2CAck()) {
	 SendI2CStop();
	 gfx_delay_milliseconds(10);
	 continue;
      }

      /* write the second byte. */
      if (bytes == 2) {
	 SendI2CData(*(value + 1));
	 if (!ReceiveI2CAck()) {
	    SendI2CStop();
	    gfx_delay_milliseconds(10);
	    continue;
	 }
      }

      /* done. */
      SendI2CStop();

      return 0;
   }

   return (0);

}

/*---------------------------------------------------------------------------
 * gfx_i2c_read
 *
 * This routine reads data from the specified I2C address.
 *---------------------------------------------------------------------------
 */
#if GFX_I2C_DYNAMIC
int
gpio_i2c_read(unsigned char busnum, unsigned char address, unsigned char reg,
	      unsigned char bytes, unsigned char *p_value)
#else
int
gfx_i2c_read(unsigned char busnum, unsigned char address, unsigned char reg,
	     unsigned char bytes, unsigned char *p_value)
#endif
{
   /* ### ADD ### CODE TO WRITE BYTE TO I2B BUS */
   /* For now return clock and data pins */

   int restart_count = 0;

   if (!p_value)
      return (1);

   while (restart_count++ < 5) {
      /* set the access pointer register. */
      /* The address is shifted left by one to make room for Read/Write bit  */
      SendI2CStart();
      SendI2CData((char)((address << 1) | I2CWRITE));
      if (!ReceiveI2CAck()) {
	 SendI2CStop();
	 gfx_delay_milliseconds(10);
	 continue;
      }
      SendI2CData((unsigned char)(reg & 0xFF));
      SendI2CNack();

      /* read the first data byte. */
      SendI2CStart();
      SendI2CData((char)((address << 1) | I2CREAD));
      if (!ReceiveI2CAck()) {
	 SendI2CStop();
	 gfx_delay_milliseconds(10);
	 continue;
      }
      *p_value = ReceiveI2CData();

      /* read the second byte. */
      if (bytes == 2) {
	 SendI2CAck();
	 *(p_value + 1) = ReceiveI2CData();
      }

      /* done. */
      SendI2CNack();
      SendI2CStop();

      return 0;
   }

   return (1);
}

/* Added i2c/gpio code to test fs451 chip. */

/*
//----------------------------------------------------------------------
//
//	void SendI2CStart(void)
//	
//	Sends an I2C start signal on the bus.
//	
//----------------------------------------------------------------------
*/
void
SendI2CStart(void)
{
   I2CAL_output_data(1);
   I2CAL_output_clock(1);
   I2CAL_output_data(0);
   I2CAL_output_clock(0);
}