added i2c eeprom driver

9358cb8b · Tomasz Wlostowski · 282dd8cb · 9358cb8b
Commit 9358cb8b authored Apr 13, 2011 by Tomasz Wlostowski
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i2c.c dev/i2c.c +105 -0

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--- a/dev/i2c.c
+++ b/dev/i2c.c
+#include "types.h"
+#include "board.h"
+#include "gpio.h"
+
+#define I2C_DELAY 100
+
+static void mi2c_delay()
+{
+    int i;
+    for(i=0;i<I2C_DELAY;i++) asm volatile ("nop");
+}
+
+#define M_SDA_OUT(x) { gpio_out(GPIO_PIN_SDA_OUT, x); mi2c_delay(); }
+#define M_SCL_OUT(x) { gpio_out(GPIO_PIN_SCL_OUT, x); mi2c_delay(); }
+#define M_SDA_IN gpio_in(GPIO_PIN_SDA_IN)
+
+void mi2c_start()
+{
+  M_SDA_OUT(0);
+  M_SCL_OUT(0);
+}
+
+void mi2c_repeat_start()
+{
+  M_SDA_OUT(1);
+  M_SCL_OUT(1);
+  M_SDA_OUT(0);
+  M_SCL_OUT(0);
+}
+
+void mi2c_stop()
+{
+  M_SDA_OUT(0);
+  M_SCL_OUT(1);
+  M_SDA_OUT(1);
+}
+
+unsigned char mi2c_put_byte(unsigned char data)
+{
+  char i;
+  unsigned char ack;
+
+  for (i=0;i<8;i++, data<<=1)
+    {
+      M_SDA_OUT(data&0x80);
+      M_SCL_OUT(1);
+      M_SCL_OUT(0);
+    }
+
+  M_SDA_OUT(1);
+  M_SCL_OUT(1);
+
+  ack = M_SDA_IN;	/* ack: sda is pulled low ->success.	 */
+
+  M_SCL_OUT(0);
+  M_SDA_OUT(0);
+
+  return ack!=0;
+}
+
+void mi2c_get_byte(unsigned char *data)
+{
+
+  int i;
+  unsigned char indata = 0;
+
+  /* assert: scl is low */
+  M_SCL_OUT(0);
+
+  for (i=0;i<8;i++)
+    {
+      M_SCL_OUT(1);
+      indata <<= 1;
+      if ( M_SDA_IN ) indata |= 0x01;
+      M_SCL_OUT(0);
+    }
+
+  M_SDA_OUT(1);
+  *data= indata;
+}
+
+void mi2c_init()
+{
+    gpio_dir(GPIO_PIN_SDA_OUT, 1);
+    gpio_dir(GPIO_PIN_SCL_OUT, 1);
+    gpio_dir(GPIO_PIN_SDA_IN, 0);
+        
+		
+  M_SCL_OUT(1);
+  M_SDA_OUT(1);
+}
+
+void mi2c_scan()
+{
+    int i;
+    
+    for(i=0;i<0x80;i++)
+    {
+	mi2c_start();
+	mprintf("scan %d\n",i);
+	if(!mi2c_put_byte(i<<1)) mprintf("found : %x\n", i);
+	mi2c_stop();
+	
+    }    
+}