*! don't use PB_I2C if DS1302 uses same bits,
*! use PB.
*! $Log: i2c.c,v $
+*! Revision 1.13 2005/03/07 13:13:07 starvik
+*! Added spinlocks to protect states etc
+*!
+*! Revision 1.12 2005/01/05 06:11:22 starvik
+*! No need to do local_irq_disable after local_irq_save.
+*!
+*! Revision 1.11 2004/12/13 12:21:52 starvik
+*! Added I/O and DMA allocators from Linux 2.4
+*!
+*! Revision 1.9 2004/08/24 06:49:14 starvik
+*! Whitespace cleanup
+*!
+*! Revision 1.8 2004/06/08 08:48:26 starvik
+*! Removed unused code
+*!
+*! Revision 1.7 2004/05/28 09:26:59 starvik
+*! Modified I2C initialization to work in 2.6.
+*!
+*! Revision 1.6 2004/05/14 07:58:03 starvik
+*! Merge of changes from 2.4
+*!
*! Revision 1.4 2002/12/11 13:13:57 starvik
*! Added arch/ to v10 specific includes
*! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
*! (C) Copyright 1999-2002 Axis Communications AB, LUND, SWEDEN
*!
*!***************************************************************************/
-/* $Id: i2c.c,v 1.4 2002/12/11 13:13:57 starvik Exp $ */
+/* $Id: i2c.c,v 1.13 2005/03/07 13:13:07 starvik Exp $ */
/****************** INCLUDE FILES SECTION ***********************************/
#include <asm/arch/svinto.h>
#include <asm/io.h>
#include <asm/delay.h>
+#include <asm/arch/io_interface_mux.h>
#include "i2c.h"
#define I2C_DATA_HIGH 1
#define I2C_DATA_LOW 0
-#if 0
-/* TODO: fix this so the CONFIG_ETRAX_I2C_USES... is set in Config.in instead */
-#if defined(CONFIG_DS1302) && (CONFIG_DS1302_SDABIT==0) && \
- (CONFIG_DS1302_SCLBIT == 1)
-#define CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C
-#endif
-#endif
-
#ifdef CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C
/* Use PB and not PB_I2C */
#ifndef CONFIG_ETRAX_I2C_DATA_PORT
#define i2c_delay(usecs) udelay(usecs)
+static DEFINE_SPINLOCK(i2c_lock); /* Protect directions etc */
/****************** FUNCTION DEFINITION SECTION *************************/
}
i2c_clk(I2C_CLOCK_HIGH);
i2c_delay(CLOCK_HIGH_TIME);
+
+ /*
+ * we leave the clock low, getbyte is usually followed
+ * by sendack/nack, they assume the clock to be low
+ */
+ i2c_clk(I2C_CLOCK_LOW);
return aBitByte;
}
i2c_delay(CLOCK_HIGH_TIME/2);
}
+ /*
+ * our clock is high now, make sure data is low
+ * before we enable our output. If we keep data high
+ * and enable output, we would generate a stop condition.
+ */
+ i2c_data(I2C_DATA_LOW);
+
/*
* end clock pulse
*/
*/
i2c_data(I2C_DATA_HIGH);
i2c_delay(CLOCK_LOW_TIME);
-
+
+ i2c_dir_in();
+}
+
+/*#---------------------------------------------------------------------------
+*#
+*# FUNCTION NAME: i2c_sendnack
+*#
+*# DESCRIPTION : Sends NACK on received data
+*#
+*#--------------------------------------------------------------------------*/
+void
+i2c_sendnack(void)
+{
+ /*
+ * enable output
+ */
+ i2c_delay(CLOCK_LOW_TIME);
+ i2c_dir_out();
+ /*
+ * set data high
+ */
+ i2c_data(I2C_DATA_HIGH);
+ /*
+ * generate clock pulse
+ */
+ i2c_delay(CLOCK_HIGH_TIME/6);
+ i2c_clk(I2C_CLOCK_HIGH);
+ i2c_delay(CLOCK_HIGH_TIME);
+ i2c_clk(I2C_CLOCK_LOW);
+ i2c_delay(CLOCK_LOW_TIME);
+
i2c_dir_in();
}
int error, cntr = 3;
unsigned long flags;
+ spin_lock(&i2c_lock);
+
do {
error = 0;
/*
* we don't like to be interrupted
*/
local_irq_save(flags);
- local_irq_disable();
i2c_start();
/*
} while(error && cntr--);
i2c_delay(CLOCK_LOW_TIME);
-
+
+ spin_unlock(&i2c_lock);
+
return -error;
}
int error, cntr = 3;
unsigned long flags;
+ spin_lock(&i2c_lock);
+
do {
error = 0;
/*
* we don't like to be interrupted
*/
local_irq_save(flags);
- local_irq_disable();
/*
* generate start condition
*/
*/
b = i2c_inbyte();
/*
- * send Ack
+ * last received byte needs to be nacked
+ * instead of acked
*/
i2c_sendack();
/*
} while(error && cntr--);
+ spin_unlock(&i2c_lock);
+
return b;
}
.release = i2c_release,
};
-static int __init
+int __init
i2c_init(void)
{
- int res;
+ static int res = 0;
+ static int first = 1;
+
+ if (!first) {
+ return res;
+ }
/* Setup and enable the Port B I2C interface */
#ifndef CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C
+ if ((res = cris_request_io_interface(if_i2c, "I2C"))) {
+ printk(KERN_CRIT "i2c_init: Failed to get IO interface\n");
+ return res;
+ }
+
*R_PORT_PB_I2C = port_pb_i2c_shadow |=
IO_STATE(R_PORT_PB_I2C, i2c_en, on) |
IO_FIELD(R_PORT_PB_I2C, i2c_d, 1) |
IO_FIELD(R_PORT_PB_I2C, i2c_clk, 1) |
IO_STATE(R_PORT_PB_I2C, i2c_oe_, enable);
-#endif
port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir0);
port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir1);
*R_PORT_PB_DIR = (port_pb_dir_shadow |=
IO_STATE(R_PORT_PB_DIR, dir0, input) |
IO_STATE(R_PORT_PB_DIR, dir1, output));
+#else
+ if ((res = cris_io_interface_allocate_pins(if_i2c,
+ 'b',
+ CONFIG_ETRAX_I2C_DATA_PORT,
+ CONFIG_ETRAX_I2C_DATA_PORT))) {
+ printk(KERN_WARNING "i2c_init: Failed to get IO pin for I2C data port\n");
+ return res;
+ } else if ((res = cris_io_interface_allocate_pins(if_i2c,
+ 'b',
+ CONFIG_ETRAX_I2C_CLK_PORT,
+ CONFIG_ETRAX_I2C_CLK_PORT))) {
+ cris_io_interface_free_pins(if_i2c,
+ 'b',
+ CONFIG_ETRAX_I2C_DATA_PORT,
+ CONFIG_ETRAX_I2C_DATA_PORT);
+ printk(KERN_WARNING "i2c_init: Failed to get IO pin for I2C clk port\n");
+ }
+#endif
+
+ return res;
+}
- /* register char device */
+static int __init
+i2c_register(void)
+{
+ int res;
- res = register_chrdev(I2C_MAJOR, i2c_name, &i2c_fops);
+ res = i2c_init();
+ if (res < 0)
+ return res;
+ res = register_chrdev(I2C_MAJOR, i2c_name, &i2c_fops);
if(res < 0) {
printk(KERN_ERR "i2c: couldn't get a major number.\n");
return res;
}
- printk("I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n");
+ printk(KERN_INFO "I2C driver v2.2, (c) 1999-2004 Axis Communications AB\n");
return 0;
}
-/* this makes sure that i2c_init is called during boot */
+/* this makes sure that i2c_register is called during boot */
-module_init(i2c_init);
+module_init(i2c_register);
/****************** END OF FILE i2c.c ********************************/
git://git.onelab.eu / linux-2.6.git / blobdiff