1 files changed, 611 insertions, 0 deletions

diff --git a/arch/cris/arch-v32/drivers/i2c.c b/arch/cris/arch-v32/drivers/i2c.c
new file mode 100644
index 000000000000..440c20a94963
--- /dev/null
+++ b/arch/cris/arch-v32/drivers/i2c.c
@@ -0,0 +1,611 @@
+/*!***************************************************************************
+*!
+*! FILE NAME  : i2c.c
+*!
+*! DESCRIPTION: implements an interface for IIC/I2C, both directly from other
+*!              kernel modules (i2c_writereg/readreg) and from userspace using
+*!              ioctl()'s
+*!
+*! Nov 30 1998  Torbjorn Eliasson  Initial version.
+*!              Bjorn Wesen        Elinux kernel version.
+*! Jan 14 2000  Johan Adolfsson    Fixed PB shadow register stuff -
+*!                                 don't use PB_I2C if DS1302 uses same bits,
+*!                                 use PB.
+*| June 23 2003 Pieter Grimmerink  Added 'i2c_sendnack'. i2c_readreg now
+*|                                 generates nack on last received byte,
+*|                                 instead of ack.
+*|                                 i2c_getack changed data level while clock
+*|                                 was high, causing DS75 to see  a stop condition
+*!
+*! ---------------------------------------------------------------------------
+*!
+*! (C) Copyright 1999-2002 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/sched.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/config.h>
+
+#include <asm/etraxi2c.h>
+
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/delay.h>
+
+#include "i2c.h"
+
+/****************** I2C DEFINITION SECTION *************************/
+
+#define D(x)
+
+#define I2C_MAJOR 123  /* LOCAL/EXPERIMENTAL */
+static const char i2c_name[] = "i2c";
+
+#define CLOCK_LOW_TIME            8
+#define CLOCK_HIGH_TIME           8
+#define START_CONDITION_HOLD_TIME 8
+#define STOP_CONDITION_HOLD_TIME  8
+#define ENABLE_OUTPUT 0x01
+#define ENABLE_INPUT 0x00
+#define I2C_CLOCK_HIGH 1
+#define I2C_CLOCK_LOW 0
+#define I2C_DATA_HIGH 1
+#define I2C_DATA_LOW 0
+
+#define i2c_enable()
+#define i2c_disable()
+
+/* enable or disable output-enable, to select output or input on the i2c bus */
+
+#define i2c_dir_out() crisv32_io_set_dir(&cris_i2c_data, crisv32_io_dir_out)
+#define i2c_dir_in() crisv32_io_set_dir(&cris_i2c_data, crisv32_io_dir_in)
+
+/* control the i2c clock and data signals */
+
+#define i2c_clk(x) crisv32_io_set(&cris_i2c_clk, x)
+#define i2c_data(x) crisv32_io_set(&cris_i2c_data, x)
+
+/* read a bit from the i2c interface */
+
+#define i2c_getbit() crisv32_io_rd(&cris_i2c_data)
+
+#define i2c_delay(usecs) udelay(usecs)
+
+/****************** VARIABLE SECTION ************************************/
+
+static struct crisv32_iopin cris_i2c_clk;
+static struct crisv32_iopin cris_i2c_data;
+
+/****************** FUNCTION DEFINITION SECTION *************************/
+
+
+/* generate i2c start condition */
+
+void
+i2c_start(void)
+{
+        /*
+         * SCL=1 SDA=1
+         */
+        i2c_dir_out();
+        i2c_delay(CLOCK_HIGH_TIME/6);
+        i2c_data(I2C_DATA_HIGH);
+        i2c_clk(I2C_CLOCK_HIGH);
+        i2c_delay(CLOCK_HIGH_TIME);
+        /*
+         * SCL=1 SDA=0
+         */
+        i2c_data(I2C_DATA_LOW);
+        i2c_delay(START_CONDITION_HOLD_TIME);
+        /*
+         * SCL=0 SDA=0
+         */
+        i2c_clk(I2C_CLOCK_LOW);
+        i2c_delay(CLOCK_LOW_TIME);
+}
+
+/* generate i2c stop condition */
+
+void
+i2c_stop(void)
+{
+        i2c_dir_out();
+
+        /*
+         * SCL=0 SDA=0
+         */
+        i2c_clk(I2C_CLOCK_LOW);
+        i2c_data(I2C_DATA_LOW);
+        i2c_delay(CLOCK_LOW_TIME*2);
+        /*
+         * SCL=1 SDA=0
+         */
+        i2c_clk(I2C_CLOCK_HIGH);
+        i2c_delay(CLOCK_HIGH_TIME*2);
+        /*
+         * SCL=1 SDA=1
+         */
+        i2c_data(I2C_DATA_HIGH);
+        i2c_delay(STOP_CONDITION_HOLD_TIME);
+
+        i2c_dir_in();
+}
+
+/* write a byte to the i2c interface */
+
+void
+i2c_outbyte(unsigned char x)
+{
+        int i;
+
+        i2c_dir_out();
+
+        for (i = 0; i < 8; i++) {
+                if (x & 0x80) {
+                        i2c_data(I2C_DATA_HIGH);
+                } else {
+                        i2c_data(I2C_DATA_LOW);
+                }
+
+                i2c_delay(CLOCK_LOW_TIME/2);
+                i2c_clk(I2C_CLOCK_HIGH);
+                i2c_delay(CLOCK_HIGH_TIME);
+                i2c_clk(I2C_CLOCK_LOW);
+                i2c_delay(CLOCK_LOW_TIME/2);
+                x <<= 1;
+        }
+        i2c_data(I2C_DATA_LOW);
+        i2c_delay(CLOCK_LOW_TIME/2);
+
+        /*
+         * enable input
+         */
+        i2c_dir_in();
+}
+
+/* read a byte from the i2c interface */
+
+unsigned char
+i2c_inbyte(void)
+{
+        unsigned char aBitByte = 0;
+        int i;
+
+        /* Switch off I2C to get bit */
+        i2c_disable();
+        i2c_dir_in();
+        i2c_delay(CLOCK_HIGH_TIME/2);
+
+        /* Get bit */
+        aBitByte |= i2c_getbit();
+
+        /* Enable I2C */
+        i2c_enable();
+        i2c_delay(CLOCK_LOW_TIME/2);
+
+        for (i = 1; i < 8; i++) {
+                aBitByte <<= 1;
+                /* Clock pulse */
+                i2c_clk(I2C_CLOCK_HIGH);
+                i2c_delay(CLOCK_HIGH_TIME);
+                i2c_clk(I2C_CLOCK_LOW);
+                i2c_delay(CLOCK_LOW_TIME);
+
+                /* Switch off I2C to get bit */
+                i2c_disable();
+                i2c_dir_in();
+                i2c_delay(CLOCK_HIGH_TIME/2);
+
+                /* Get bit */
+                aBitByte |= i2c_getbit();
+
+                /* Enable I2C */
+                i2c_enable();
+                i2c_delay(CLOCK_LOW_TIME/2);
+        }
+        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;
+}
+
+/*#---------------------------------------------------------------------------
+*#
+*# FUNCTION NAME: i2c_getack
+*#
+*# DESCRIPTION  : checks if ack was received from ic2
+*#
+*#--------------------------------------------------------------------------*/
+
+int
+i2c_getack(void)
+{
+        int ack = 1;
+        /*
+         * enable output
+         */
+        i2c_dir_out();
+        /*
+         * Release data bus by setting
+         * data high
+         */
+        i2c_data(I2C_DATA_HIGH);
+        /*
+         * enable input
+         */
+        i2c_dir_in();
+        i2c_delay(CLOCK_HIGH_TIME/4);
+        /*
+         * generate ACK clock pulse
+         */
+        i2c_clk(I2C_CLOCK_HIGH);
+        /*
+         * Use PORT PB instead of I2C
+         * for input. (I2C not working)
+         */
+        i2c_clk(1);
+        i2c_data(1);
+        /*
+         * switch off I2C
+         */
+        i2c_data(1);
+        i2c_disable();
+        i2c_dir_in();
+        /*
+         * now wait for ack
+         */
+        i2c_delay(CLOCK_HIGH_TIME/2);
+        /*
+         * check for ack
+         */
+        if(i2c_getbit())
+                ack = 0;
+        i2c_delay(CLOCK_HIGH_TIME/2);
+        if(!ack){
+                if(!i2c_getbit()) /* receiver pulld SDA low */
+                        ack = 1;
+                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_enable();
+        i2c_dir_out();
+        i2c_clk(I2C_CLOCK_LOW);
+        i2c_delay(CLOCK_HIGH_TIME/4);
+        /*
+         * enable output
+         */
+        i2c_dir_out();
+        /*
+         * remove ACK clock pulse
+         */
+        i2c_data(I2C_DATA_HIGH);
+        i2c_delay(CLOCK_LOW_TIME/2);
+        return ack;
+}
+
+/*#---------------------------------------------------------------------------
+*#
+*# FUNCTION NAME: I2C::sendAck
+*#
+*# DESCRIPTION  : Send ACK on received data
+*#
+*#--------------------------------------------------------------------------*/
+void
+i2c_sendack(void)
+{
+        /*
+         * enable output
+         */
+        i2c_delay(CLOCK_LOW_TIME);
+        i2c_dir_out();
+        /*
+         * set ack pulse high
+         */
+        i2c_data(I2C_DATA_LOW);
+        /*
+         * 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/6);
+        /*
+         * reset data out
+         */
+        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();
+}
+
+/*#---------------------------------------------------------------------------
+*#
+*# FUNCTION NAME: i2c_writereg
+*#
+*# DESCRIPTION  : Writes a value to an I2C device
+*#
+*#--------------------------------------------------------------------------*/
+int
+i2c_writereg(unsigned char theSlave, unsigned char theReg,
+             unsigned char theValue)
+{
+        int error, cntr = 3;
+        unsigned long flags;
+
+        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;
+                /*
+                 * now select register
+                 */
+                i2c_dir_out();
+                i2c_outbyte(theReg);
+                /*
+                 * now it's time to wait for ack
+                 */
+                if(!i2c_getack())
+                        error |= 2;
+                /*
+                 * send register register data
+                 */
+                i2c_outbyte(theValue);
+                /*
+                 * 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);
+
+        return -error;
+}
+
+/*#---------------------------------------------------------------------------
+*#
+*# FUNCTION NAME: i2c_readreg
+*#
+*# DESCRIPTION  : Reads a value from the decoder registers.
+*#
+*#--------------------------------------------------------------------------*/
+unsigned char
+i2c_readreg(unsigned char theSlave, unsigned char theReg)
+{
+        unsigned char b = 0;
+        int error, cntr = 3;
+        unsigned long flags;
+
+        do {
+                error = 0;
+                /*
+                 * we don't like to be interrupted
+                 */
+                local_irq_save(flags);
+                /*
+                 * generate start condition
+                 */
+                i2c_start();
+
+                /*
+                 * send slave address
+                 */
+                i2c_outbyte((theSlave & 0xfe));
+                /*
+                 * wait for ack
+                 */
+                if(!i2c_getack())
+                        error = 1;
+                /*
+                 * now select register
+                 */
+                i2c_dir_out();
+                i2c_outbyte(theReg);
+                /*
+                 * now it's time to wait for ack
+                 */
+                if(!i2c_getack())
+                        error = 1;
+                /*
+                 * repeat start condition
+                 */
+                i2c_delay(CLOCK_LOW_TIME);
+                i2c_start();
+                /*
+                 * send slave address
+                 */
+                i2c_outbyte(theSlave | 0x01);
+                /*
+                 * wait for ack
+                 */
+                if(!i2c_getack())
+                        error = 1;
+                /*
+                 * fetch register
+                 */
+                b = i2c_inbyte();
+                /*
+                 * 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--);
+
+        return b;
+}
+
+static int
+i2c_open(struct inode *inode, struct file *filp)
+{
+        return 0;
+}
+
+static int
+i2c_release(struct inode *inode, struct file *filp)
+{
+        return 0;
+}
+
+/* Main device API. ioctl's to write or read to/from i2c registers.
+ */
+
+static int
+i2c_ioctl(struct inode *inode, struct file *file,
+          unsigned int cmd, unsigned long arg)
+{
+        if(_IOC_TYPE(cmd) != ETRAXI2C_IOCTYPE) {
+                return -EINVAL;
+        }
+
+        switch (_IOC_NR(cmd)) {
+                case I2C_WRITEREG:
+                        /* write to an i2c slave */
+                        D(printk("i2cw %d %d %d\n",
+                                 I2C_ARGSLAVE(arg),
+                                 I2C_ARGREG(arg),
+                                 I2C_ARGVALUE(arg)));
+
+                        return i2c_writereg(I2C_ARGSLAVE(arg),
+                                            I2C_ARGREG(arg),
+                                            I2C_ARGVALUE(arg));
+                case I2C_READREG:
+                {
+                        unsigned char val;
+                        /* read from an i2c slave */
+                        D(printk("i2cr %d %d ",
+                                I2C_ARGSLAVE(arg),
+                                I2C_ARGREG(arg)));
+                        val = i2c_readreg(I2C_ARGSLAVE(arg), I2C_ARGREG(arg));
+                        D(printk("= %d\n", val));
+                        return val;
+                }
+                default:
+                        return -EINVAL;
+
+        }
+
+        return 0;
+}
+
+static struct file_operations i2c_fops = {
+        owner:    THIS_MODULE,
+        ioctl:    i2c_ioctl,
+        open:     i2c_open,
+        release:  i2c_release,
+};
+
+int __init
+i2c_init(void)
+{
+        int res;
+
+        /* Setup and enable the Port B I2C interface */
+
+        crisv32_io_get_name(&cris_i2c_data, CONFIG_ETRAX_I2C_DATA_PORT);
+        crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_I2C_CLK_PORT);
+
+        /* register char device */
+
+        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(KERN_INFO "I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n");
+
+        return 0;
+}
+
+/* this makes sure that i2c_init is called during boot */
+
+module_init(i2c_init);
+
+/****************** END OF FILE i2c.c ********************************/