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.

diff --git a/arch/cris/arch-v32/drivers/i2c.c b/arch/cris/arch-v32/drivers/i2c.c
index f1edd2e359b2dcf3dac6a1fed0e6dd35d4000671..4eda3236792a878761f57d3dc57208cb496da43d 100644 (file)
--- a/arch/cris/arch-v32/drivers/i2c.c
+++ b/arch/cris/arch-v32/drivers/i2c.c
@@ -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
         */
@@ -271,11 +276,11 @@ i2c_getack(void)
        /*
         * check for ack
         */
-       if(i2c_getbit())
+       if (i2c_getbit())
                ack = 0;
        i2c_delay(CLOCK_HIGH_TIME/2);
-       if(!ack){
-               if(!i2c_getbit()) /* receiver pulled SDA low */
+       if (!ack) {
+               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;
 
-       /* Setup and enable the Port B I2C interface */
+       if (!first)
+               return res;
+
+       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;
+}
 
-        crisv32_io_get_name(&cris_i2c_data, CONFIG_ETRAX_I2C_DATA_PORT);
-        crisv32_io_get_name(&cris_i2c_clk, CONFIG_ETRAX_I2C_CLK_PORT);
+
+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 ********************************/

diff --git a/arch/cris/arch-v32/drivers/i2c.h b/arch/cris/arch-v32/drivers/i2c.h
index bfe1a13f9f35298957645ac9c7209e8e8a1e8ef4..c073cf4ba016282d11ea5ee7631bf54b288bb5a6 100644 (file)
--- a/arch/cris/arch-v32/drivers/i2c.h
+++ b/arch/cris/arch-v32/drivers/i2c.h
@@ -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);