*!
*! ---------------------------------------------------------------------------
*!
-*! (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>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/init.h>
+#include <linux/smp_lock.h>
#include <asm/etraxi2c.h>
#define i2c_delay(usecs) udelay(usecs)
+static DEFINE_SPINLOCK(i2c_lock); /* Protect directions etc */
+
/****************** VARIABLE SECTION ************************************/
static struct crisv32_iopin cris_i2c_clk;
* generate ACK clock pulse
*/
i2c_clk(I2C_CLOCK_HIGH);
+#if 0
/*
* Use PORT PB instead of I2C
* for input. (I2C not working)
i2c_data(1);
i2c_disable();
i2c_dir_in();
+#endif
+
/*
* now wait for ack
*/
/*
* check for ack
*/
- if(i2c_getbit())
+ if (i2c_getbit())
ack = 0;
i2c_delay(CLOCK_HIGH_TIME/2);
- if(!ack){
- if(!i2c_getbit()) /* receiver pulld SDA low */
+ if (!ack) {
+ if (!i2c_getbit()) /* receiver pulld SDA low */
ack = 1;
i2c_delay(CLOCK_HIGH_TIME/2);
}
* 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);
/*
*/
i2c_enable();
i2c_dir_out();
+#endif
i2c_clk(I2C_CLOCK_LOW);
i2c_delay(CLOCK_HIGH_TIME/4);
/*
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_irqsave(&i2c_lock, flags);
+
+ do {
+ error = 0;
+
+ 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();
+
+ } while (error && cntr--);
+
+ i2c_delay(CLOCK_LOW_TIME);
+
+ spin_unlock_irqrestore(&i2c_lock, flags);
+
+ 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_irqsave(&i2c_lock, flags);
+
+ do {
+ error = 0;
+ memset(data, 0, nbytes);
+ /*
+ * 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();
+ } while (error && cntr--);
+
+ spin_unlock_irqrestore(&i2c_lock, flags);
+
+ return -error;
+}
+
/*#---------------------------------------------------------------------------
*#
*# FUNCTION NAME: i2c_writereg
int error, cntr = 3;
unsigned long flags;
+ spin_lock_irqsave(&i2c_lock, flags);
+
do {
error = 0;
- /*
- * we don't like to be interrupted
- */
- local_irq_save(flags);
i2c_start();
/*
* end byte stream
*/
i2c_stop();
- /*
- * enable interrupt again
- */
- local_irq_restore(flags);
-
} while(error && cntr--);
i2c_delay(CLOCK_LOW_TIME);
+ spin_unlock_irqrestore(&i2c_lock, flags);
+
return -error;
}
int error, cntr = 3;
unsigned long flags;
+ spin_lock_irqsave(&i2c_lock, flags);
+
do {
error = 0;
- /*
- * we don't like to be interrupted
- */
- local_irq_save(flags);
/*
* generate start condition
*/
* now it's time to wait for ack
*/
if(!i2c_getack())
- error = 1;
+ error |= 2;
/*
* repeat start condition
*/
* wait for ack
*/
if(!i2c_getack())
- error = 1;
+ error |= 4;
/*
* fetch register
*/
* end sequence
*/
i2c_stop();
- /*
- * enable interrupt again
- */
- local_irq_restore(flags);
} while(error && cntr--);
+ spin_unlock_irqrestore(&i2c_lock, flags);
+
return b;
}
static int
i2c_open(struct inode *inode, struct file *filp)
{
+ cycle_kernel_lock();
return 0;
}
unsigned int cmd, unsigned long arg)
{
if(_IOC_TYPE(cmd) != ETRAXI2C_IOCTYPE) {
- return -EINVAL;
+ return -ENOTTY;
}
switch (_IOC_NR(cmd)) {
.release = i2c_release,
};
-int __init
-i2c_init(void)
+static int __init i2c_init(void)
{
- int res;
+ static int res;
+ static int first = 1;
- /* Setup and enable the Port B I2C interface */
+ if (!first)
+ return res;
- crisv32_io_get_name(&cris_i2c_data, CONFIG_ETRAX_I2C_DATA_PORT);
- crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_I2C_CLK_PORT);
+ first = 0;
+
+ /* 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;
+}
+
+
+static int __init i2c_register(void)
+{
+ int res;
+
+ res = i2c_init();
+ if (res < 0)
+ return res;
/* register char device */
res = register_chrdev(I2C_MAJOR, i2c_name, &i2c_fops);
- if(res < 0) {
+ if (res < 0) {
printk(KERN_ERR "i2c: couldn't get a major number.\n");
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 ********************************/
git.openpandora.org / pandora-kernel.git / blobdiff