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.
This commit is contained in:
Jesper Nilsson
parent
0f229504f8
commit
201ca54aa0
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@ -19,10 +19,10 @@
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*!
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*! ---------------------------------------------------------------------------
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*!
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*! (C) Copyright 1999-2002 Axis Communications AB, LUND, SWEDEN
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*! (C) Copyright 1999-2007 Axis Communications AB, LUND, SWEDEN
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*!
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*!***************************************************************************/
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/* $Id: i2c.c,v 1.2 2005/05/09 15:29:49 starvik Exp $ */
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/****************** INCLUDE FILES SECTION ***********************************/
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#include <linux/module.h>
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@ -79,6 +79,8 @@ static const char i2c_name[] = "i2c";
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#define i2c_delay(usecs) udelay(usecs)
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static DEFINE_SPINLOCK(i2c_lock); /* Protect directions etc */
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/****************** VARIABLE SECTION ************************************/
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static struct crisv32_iopin cris_i2c_clk;
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@ -252,6 +254,7 @@ i2c_getack(void)
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* generate ACK clock pulse
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*/
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i2c_clk(I2C_CLOCK_HIGH);
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#if 0
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/*
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* Use PORT PB instead of I2C
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* for input. (I2C not working)
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@ -264,6 +267,8 @@ i2c_getack(void)
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i2c_data(1);
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i2c_disable();
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i2c_dir_in();
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#endif
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/*
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* now wait for ack
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*/
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@ -271,11 +276,11 @@ i2c_getack(void)
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/*
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* check for ack
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*/
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if(i2c_getbit())
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if (i2c_getbit())
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ack = 0;
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i2c_delay(CLOCK_HIGH_TIME/2);
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if(!ack){
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if(!i2c_getbit()) /* receiver pulled SDA low */
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if (!ack) {
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if (!i2c_getbit()) /* receiver pulld SDA low */
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ack = 1;
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i2c_delay(CLOCK_HIGH_TIME/2);
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}
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@ -285,6 +290,7 @@ i2c_getack(void)
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* before we enable our output. If we keep data high
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* and enable output, we would generate a stop condition.
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*/
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#if 0
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i2c_data(I2C_DATA_LOW);
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/*
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@ -292,6 +298,7 @@ i2c_getack(void)
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*/
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i2c_enable();
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i2c_dir_out();
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#endif
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i2c_clk(I2C_CLOCK_LOW);
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i2c_delay(CLOCK_HIGH_TIME/4);
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/*
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@ -373,6 +380,137 @@ i2c_sendnack(void)
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i2c_dir_in();
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}
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/*#---------------------------------------------------------------------------
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*#
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*# FUNCTION NAME: i2c_write
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*#
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*# DESCRIPTION : Writes a value to an I2C device
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*#
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*#--------------------------------------------------------------------------*/
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int
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i2c_write(unsigned char theSlave, void *data, size_t nbytes)
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{
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int error, cntr = 3;
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unsigned char bytes_wrote = 0;
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unsigned char value;
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unsigned long flags;
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spin_lock(&i2c_lock);
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do {
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error = 0;
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/*
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* we don't like to be interrupted
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*/
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local_irq_save(flags);
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i2c_start();
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/*
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* send slave address
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*/
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i2c_outbyte((theSlave & 0xfe));
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/*
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* wait for ack
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*/
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if (!i2c_getack())
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error = 1;
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/*
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* send data
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*/
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for (bytes_wrote = 0; bytes_wrote < nbytes; bytes_wrote++) {
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memcpy(&value, data + bytes_wrote, sizeof value);
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i2c_outbyte(value);
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/*
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* now it's time to wait for ack
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*/
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if (!i2c_getack())
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error |= 4;
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}
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/*
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* end byte stream
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*/
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i2c_stop();
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/*
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* enable interrupt again
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*/
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local_irq_restore(flags);
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} while (error && cntr--);
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i2c_delay(CLOCK_LOW_TIME);
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spin_unlock(&i2c_lock);
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return -error;
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}
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/*#---------------------------------------------------------------------------
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*#
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*# FUNCTION NAME: i2c_read
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*#
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*# DESCRIPTION : Reads a value from an I2C device
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*#
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*#--------------------------------------------------------------------------*/
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int
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i2c_read(unsigned char theSlave, void *data, size_t nbytes)
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{
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unsigned char b = 0;
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unsigned char bytes_read = 0;
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int error, cntr = 3;
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unsigned long flags;
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spin_lock(&i2c_lock);
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do {
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error = 0;
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memset(data, 0, nbytes);
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/*
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* we don't like to be interrupted
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*/
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local_irq_save(flags);
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/*
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* generate start condition
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*/
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i2c_start();
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/*
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* send slave address
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*/
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i2c_outbyte((theSlave | 0x01));
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/*
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* wait for ack
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*/
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if (!i2c_getack())
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error = 1;
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/*
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* fetch data
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*/
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for (bytes_read = 0; bytes_read < nbytes; bytes_read++) {
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b = i2c_inbyte();
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memcpy(data + bytes_read, &b, sizeof b);
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if (bytes_read < (nbytes - 1))
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i2c_sendack();
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}
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/*
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* last received byte needs to be nacked
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* instead of acked
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*/
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i2c_sendnack();
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/*
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* end sequence
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*/
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i2c_stop();
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/*
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* enable interrupt again
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*/
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local_irq_restore(flags);
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} while (error && cntr--);
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spin_unlock(&i2c_lock);
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return -error;
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}
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/*#---------------------------------------------------------------------------
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*#
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*# FUNCTION NAME: i2c_writereg
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@ -387,6 +525,8 @@ i2c_writereg(unsigned char theSlave, unsigned char theReg,
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int error, cntr = 3;
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unsigned long flags;
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spin_lock(&i2c_lock);
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do {
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error = 0;
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/*
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@ -431,11 +571,12 @@ i2c_writereg(unsigned char theSlave, unsigned char theReg,
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* enable interrupt again
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*/
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local_irq_restore(flags);
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} while(error && cntr--);
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i2c_delay(CLOCK_LOW_TIME);
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spin_unlock(&i2c_lock);
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return -error;
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}
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@ -453,6 +594,8 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg)
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int error, cntr = 3;
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unsigned long flags;
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spin_lock(&i2c_lock);
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do {
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error = 0;
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/*
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@ -482,7 +625,7 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg)
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* now it's time to wait for ack
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*/
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if(!i2c_getack())
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error = 1;
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error |= 2;
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/*
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* repeat start condition
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*/
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@ -496,7 +639,7 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg)
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* wait for ack
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*/
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if(!i2c_getack())
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error = 1;
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error |= 4;
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/*
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* fetch register
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*/
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@ -517,6 +660,8 @@ i2c_readreg(unsigned char theSlave, unsigned char theReg)
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} while(error && cntr--);
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spin_unlock(&i2c_lock);
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return b;
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}
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@ -583,12 +728,37 @@ static const struct file_operations i2c_fops = {
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int __init
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i2c_init(void)
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{
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static int res;
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static int first = 1;
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if (!first)
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return res;
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first = 0;
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/* Setup and enable the DATA and CLK pins */
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res = crisv32_io_get_name(&cris_i2c_data,
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CONFIG_ETRAX_V32_I2C_DATA_PORT);
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if (res < 0)
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return res;
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res = crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_V32_I2C_CLK_PORT);
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crisv32_io_set_dir(&cris_i2c_clk, crisv32_io_dir_out);
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return res;
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}
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int __init
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i2c_register(void)
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{
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int res;
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/* Setup and enable the Port B I2C interface */
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crisv32_io_get_name(&cris_i2c_data, CONFIG_ETRAX_I2C_DATA_PORT);
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crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_I2C_CLK_PORT);
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res = i2c_init();
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if (res < 0)
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return res;
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/* register char device */
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@ -598,13 +768,14 @@ i2c_init(void)
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return res;
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}
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printk(KERN_INFO "I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n");
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printk(KERN_INFO
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"I2C driver v2.2, (c) 1999-2007 Axis Communications AB\n");
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return 0;
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}
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/* this makes sure that i2c_init is called during boot */
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module_init(i2c_init);
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module_init(i2c_register);
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/****************** END OF FILE i2c.c ********************************/
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@ -3,6 +3,8 @@
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/* High level I2C actions */
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int __init i2c_init(void);
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int i2c_write(unsigned char theSlave, void *data, size_t nbytes);
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int i2c_read(unsigned char theSlave, void *data, size_t nbytes);
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int i2c_writereg(unsigned char theSlave, unsigned char theReg, unsigned char theValue);
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unsigned char i2c_readreg(unsigned char theSlave, unsigned char theReg);
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