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This diff has been restricted to the following files: 'i2c.c'

#
# old_revision [7ac10cd34167baa43683a09e9e9e6778e691171d]
# new_revision [23a3e9a50b4034343e3bd217d2c225dcaec064dd]
#
# add_file "i2c.c"
#  content [7f5362fc29f8f8f81682424c73930b5e3044c994]
#
============================================================
--- /dev/null	
+++ i2c.c	7f5362fc29f8f8f81682424c73930b5e3044c994
@@ -0,0 +1,164 @@
+
+#include "i2c.h"
+#include "interrupt.h"
+#include "event.h"
+
+#define I2CBASE  0xE001C000
+
+#define I2CONSET 0x00
+#define I2STAT   0x04
+#define I2DAT    0x08
+#define I2ADR    0x0c
+#define I2SCLH   0x10
+#define I2SCLL   0x14
+#define I2CONCLR 0x18
+
+#define IREG(x) (((volatile unsigned char *)I2CBASE)[x])
+#define IWREG(x) (((volatile unsigned int *)I2CBASE)[(x)/sizeof(unsigned int)])
+
+#define AAFLAG (1<<2)
+#define SIFLAG (1<<3)
+#define STOFLAG (1<<4)
+#define STAFLAG (1<<5)
+
+#define SI (IREG(I2CONSET) & SIFLAG)
+
+void __attribute__((interrupt("IRQ"))) i2c_interrupt_handler(void);
+
+struct i2c_transaction *i2c_transaction;
+int i2c_bytes;
+
+void init_i2c(void)
+{
+	IREG(I2CONSET) = 0x40; /* Enable I2C ready for Master Tx */
+	/* Set up for just under 400kHz */
+#ifdef I2C_FAST
+	IWREG(I2SCLL) = (25 * 100);
+	IWREG(I2SCLH) = (12 * 100);
+#else
+	IWREG(I2SCLL) = 73; /* ~100kHz */
+	IWREG(I2SCLH) = 73;
+#endif
+	interrupt_register(I2C0, i2c_interrupt_handler);
+}
+
+int i2c_conreg(void)
+{
+	return IREG(I2CONSET);
+}
+
+int i2c_statreg(void)
+{
+	return IREG(I2STAT);
+}
+
+bool i2c_busy(void)
+{
+	return i2c_transaction != NULL;
+}
+
+bool i2c_start_transaction(struct i2c_transaction *t)
+{
+	if (i2c_transaction)
+		return FALSE;
+
+	i2c_transaction = t;
+	*(t->result) = I2C_IN_PROGRESS;
+
+	/* Paranoia in case we left things in a bad state */
+	IREG(I2CONCLR) = STOFLAG | STAFLAG;
+
+	/* Set it all going */
+	IREG(I2CONSET) = STAFLAG;
+
+	return TRUE;
+}
+
+void __attribute__((interrupt("IRQ"))) i2c_interrupt_handler(void)
+{
+	int stat = IREG(I2STAT);
+
+	if (!i2c_transaction) {
+		IREG(I2CONSET) = STOFLAG;
+		IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
+		interrupt_clear();
+		return;
+	}
+
+	switch (stat) {
+
+	case 0x08: /* START transmitted */
+	case 0x10: /* repeated START transmitted */
+		IREG(I2DAT) = i2c_transaction->address;
+		IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
+		i2c_bytes = 0;
+		break;
+	case 0x18: /* SA+W transmitted, ACK received */
+	case 0x28: /* data transmitted, ACK received */
+		if (i2c_bytes < i2c_transaction->bytes) {
+			IREG(I2DAT) = i2c_transaction->data[i2c_bytes++];
+			IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
+		} else {
+			*(i2c_transaction->result) = I2C_SUCCESS;
+			if (i2c_transaction->next) {
+				i2c_transaction = i2c_transaction->next;
+				i2c_bytes = 0;
+				IREG(I2CONSET) = STAFLAG;
+				IREG(I2CONCLR) = STOFLAG | AAFLAG | SIFLAG;
+			} else {
+				i2c_transaction = NULL;
+				IREG(I2CONSET) = STOFLAG;
+				IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
+				event_set(EVENT_I2C_COMPLETE);
+			}
+		}
+		break;
+
+	case 0x50: /* data received, ACK returned */
+		i2c_transaction->data[i2c_bytes++] = IREG(I2DAT);
+		/* fall through */
+
+	case 0x40: /* SA+R transmitted, ACK received */
+		if (i2c_bytes < (i2c_transaction->bytes-1)) {
+			IREG(I2CONSET) = AAFLAG;
+			IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
+		} else {
+			IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG 
+							   | AAFLAG;
+		}
+		break;
+
+	case 0x58: /* data received, NACK returned */
+		i2c_transaction->data[i2c_bytes] = IREG(I2DAT);
+		*(i2c_transaction->result) = I2C_SUCCESS;
+		if (i2c_transaction->next) {
+			i2c_transaction = i2c_transaction->next;
+			i2c_bytes = 0;
+			IREG(I2CONSET) = STAFLAG;
+			IREG(I2CONCLR) = STOFLAG | AAFLAG | SIFLAG;
+		} else {
+			i2c_transaction = NULL;
+			IREG(I2CONSET) = STOFLAG;
+			IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
+			event_set(EVENT_I2C_COMPLETE);
+		}
+		break;
+
+	case 0x20: /* SA+W transmitted, NACK received */
+	case 0x30: /* data transmitted, NACK received */
+	case 0x48: /* SA+R transmitted, NACK received */
+	case 0x38: /* arbitration lost during SA+W or data */
+	case 0x00: /* bus error */
+		*(i2c_transaction->result) = I2C_FAIL;
+		i2c_transaction = NULL;
+		IREG(I2CONSET) = STOFLAG;
+		IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
+		event_set(EVENT_I2C_COMPLETE);
+		break;
+
+	/* We don't handle slave mode */
+	}
+
+	interrupt_clear();
+}
+