Commit 201ca54a authored by Jesper Nilsson's avatar Jesper Nilsson
Browse files

CRIS v32: New version of I2C driver. 

- Add i2c_write and i2c_read as functions.
- Use spinlocks for critical regions.
- Add config item to set I2C data and clock port.
- Put unneeded testcode inside #if 0.
- Remove CVS id tag.
parent 0f229504

arch/cris/arch-v32/drivers/i2c.c

+185 −14
Original line number Diff line number Diff line
@@ -19,10 +19,10 @@ 
*!

*! ---------------------------------------------------------------------------

*!

*! (C) Copyright 1999-2002 Axis Communications AB, LUND, SWEDEN

*! (C) Copyright 1999-2007 Axis Communications AB, LUND, SWEDEN

*!

*!***************************************************************************/

/* $Id: i2c.c,v 1.2 2005/05/09 15:29:49 starvik Exp $ */



/****************** INCLUDE FILES SECTION ***********************************/



#include <linux/module.h>
@@ -79,6 +79,8 @@ static const char i2c_name[] = "i2c"; 


#define i2c_delay(usecs) udelay(usecs)



static DEFINE_SPINLOCK(i2c_lock); /* Protect directions etc */



/****************** VARIABLE SECTION ************************************/



static struct crisv32_iopin cris_i2c_clk;
@@ -252,6 +254,7 @@ i2c_getack(void) 
	 * generate ACK clock pulse

	 */

	i2c_clk(I2C_CLOCK_HIGH);

#if 0

	/*

	 * Use PORT PB instead of I2C

	 * for input. (I2C not working)
@@ -264,6 +267,8 @@ i2c_getack(void) 
	i2c_data(1);

	i2c_disable();

	i2c_dir_in();

#endif



	/*

	 * now wait for ack

	 */
@@ -275,7 +280,7 @@ i2c_getack(void) 
		ack = 0;

	i2c_delay(CLOCK_HIGH_TIME/2);

	if (!ack) {

		if(!i2c_getbit()) /* receiver pulled SDA low */

		if (!i2c_getbit()) /* receiver pulld SDA low */

			ack = 1;

		i2c_delay(CLOCK_HIGH_TIME/2);

	}
@@ -285,6 +290,7 @@ i2c_getack(void) 
    * before we enable our output. If we keep data high

    * and enable output, we would generate a stop condition.

    */

#if 0

   i2c_data(I2C_DATA_LOW);



	/*
@@ -292,6 +298,7 @@ i2c_getack(void) 
	 */

	i2c_enable();

	i2c_dir_out();

#endif

	i2c_clk(I2C_CLOCK_LOW);

	i2c_delay(CLOCK_HIGH_TIME/4);

	/*
@@ -373,6 +380,137 @@ i2c_sendnack(void) 
	i2c_dir_in();

}



/*#---------------------------------------------------------------------------

*#

*# FUNCTION NAME: i2c_write

*#

*# DESCRIPTION  : Writes a value to an I2C device

*#

*#--------------------------------------------------------------------------*/

int

i2c_write(unsigned char theSlave, void *data, size_t nbytes)

{

	int error, cntr = 3;

	unsigned char bytes_wrote = 0;

	unsigned char value;

	unsigned long flags;



	spin_lock(&i2c_lock);



	do {

		error = 0;

		/*

		 * we don't like to be interrupted

		 */

		local_irq_save(flags);



		i2c_start();

		/*

		 * send slave address

		 */

		i2c_outbyte((theSlave & 0xfe));

		/*

		 * wait for ack

		 */

		if (!i2c_getack())

			error = 1;

		/*

		 * send data

		 */

		for (bytes_wrote = 0; bytes_wrote < nbytes; bytes_wrote++) {

			memcpy(&value, data + bytes_wrote, sizeof value);

			i2c_outbyte(value);

			/*

			 * now it's time to wait for ack

			 */

			if (!i2c_getack())

				error |= 4;

		}

		/*

		 * end byte stream

		 */

		i2c_stop();

		/*

		 * enable interrupt again

		 */

		local_irq_restore(flags);



	} while (error && cntr--);



	i2c_delay(CLOCK_LOW_TIME);



	spin_unlock(&i2c_lock);



	return -error;

}



/*#---------------------------------------------------------------------------

*#

*# FUNCTION NAME: i2c_read

*#

*# DESCRIPTION  : Reads a value from an I2C device

*#

*#--------------------------------------------------------------------------*/

int

i2c_read(unsigned char theSlave, void *data, size_t nbytes)

{

	unsigned char b = 0;

	unsigned char bytes_read = 0;

	int error, cntr = 3;

	unsigned long flags;



	spin_lock(&i2c_lock);



	do {

		error = 0;

		memset(data, 0, nbytes);

		/*

		 * we don't like to be interrupted

		 */

		local_irq_save(flags);

		/*

		 * generate start condition

		 */

		i2c_start();

		/*

		 * send slave address

		 */

		i2c_outbyte((theSlave | 0x01));

		/*

		 * wait for ack

		 */

		if (!i2c_getack())

			error = 1;

		/*

		 * fetch data

		 */

		for (bytes_read = 0; bytes_read < nbytes; bytes_read++) {

			b = i2c_inbyte();

			memcpy(data + bytes_read, &b, sizeof b);



			if (bytes_read < (nbytes - 1))

				i2c_sendack();

		}

		/*

		 * last received byte needs to be nacked

		 * instead of acked

		 */

		i2c_sendnack();

		/*

		 * end sequence

		 */

		i2c_stop();

		/*

		 * enable interrupt again

		 */

		local_irq_restore(flags);

	} while (error && cntr--);



	spin_unlock(&i2c_lock);



	return -error;

}



/*#---------------------------------------------------------------------------

*#

*# FUNCTION NAME: i2c_writereg
@@ -387,6 +525,8 @@ i2c_writereg(unsigned char theSlave, unsigned char theReg, 
	int error, cntr = 3;

	unsigned long flags;



	spin_lock(&i2c_lock);



	do {

		error = 0;

		/*
@@ -431,11 +571,12 @@ i2c_writereg(unsigned char theSlave, unsigned char theReg, 
		 * enable interrupt again

		 */

		local_irq_restore(flags);



	} while(error && cntr--);



	i2c_delay(CLOCK_LOW_TIME);



	spin_unlock(&i2c_lock);



	return -error;

}
@@ -453,6 +594,8 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg) 
	int error, cntr = 3;

	unsigned long flags;



	spin_lock(&i2c_lock);



	do {

		error = 0;

		/*
@@ -482,7 +625,7 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg) 
		 * now it's time to wait for ack

		 */

		if(!i2c_getack())

			error = 1;

			error |= 2;

		/*

		 * repeat start condition

		 */
@@ -496,7 +639,7 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg) 
		 * wait for ack

		 */

		if(!i2c_getack())

			error = 1;

			error |= 4;

		/*

		 * fetch register

		 */
@@ -517,6 +660,8 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg) 


	} while(error && cntr--);



	spin_unlock(&i2c_lock);



	return b;

}
@@ -583,12 +728,37 @@ static const struct file_operations i2c_fops = { 
int __init

i2c_init(void)

{

	int res;

	static int res;

	static int first = 1;



	if (!first)

		return res;



	/* Setup and enable the Port B I2C interface */

	first = 0;



        crisv32_io_get_name(&cris_i2c_data, CONFIG_ETRAX_I2C_DATA_PORT);

        crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_I2C_CLK_PORT);

	/* Setup and enable the DATA and CLK pins */



	res = crisv32_io_get_name(&cris_i2c_data,

		CONFIG_ETRAX_V32_I2C_DATA_PORT);

	if (res < 0)

		return res;



	res = crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_V32_I2C_CLK_PORT);

	crisv32_io_set_dir(&cris_i2c_clk, crisv32_io_dir_out);



	return res;

}





int __init

i2c_register(void)

{



	int res;



	res = i2c_init();

	if (res < 0)

		return res;



	/* register char device */
@@ -598,13 +768,14 @@ i2c_init(void) 
		return res;

	}



	printk(KERN_INFO "I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n");

	printk(KERN_INFO

		"I2C driver v2.2, (c) 1999-2007 Axis Communications AB\n");



	return 0;

}



/* this makes sure that i2c_init is called during boot */



module_init(i2c_init);

module_init(i2c_register);



/****************** END OF FILE i2c.c ********************************/

arch/cris/arch-v32/drivers/i2c.h

+2 −0
Original line number Diff line number Diff line
@@ -3,6 +3,8 @@ 


/* High level I2C actions */

int __init i2c_init(void);

int i2c_write(unsigned char theSlave, void *data, size_t nbytes);

int i2c_read(unsigned char theSlave, void *data, size_t nbytes);

int i2c_writereg(unsigned char theSlave, unsigned char theReg, unsigned char theValue);

unsigned char i2c_readreg(unsigned char theSlave, unsigned char theReg);

CRA Git | Maintained and supported by SUSTech CRA and CCSE