IIC bitbang changes - prepare to make the bit delay configurable; debug print changes.

* Right now the delay is hard coded at 10uS. This is a bit long when doing lots
  of periodic i2c transactions. So create a 'udelay' parameter and initialise it
  to 10. This can be tuned later.

* Add a newline after a transaction finishes, so the debugging output isn't so
  horrible.

1 files changed, 42 insertions, 31 deletions

diff --git a/sys/dev/iicbus/iicbb.c b/sys/dev/iicbus/iicbb.c
index 2bc6321..a7eb2a0 100644
--- a/sys/dev/iicbus/iicbb.c
+++ b/sys/dev/iicbus/iicbb.c
@@ -61,6 +61,7 @@ __FBSDID("$FreeBSD$");
 
 struct iicbb_softc {
 	device_t iicbus;
+	int udelay;		/* signal toggle delay in usec */
 };
 
 static int iicbb_attach(device_t);
@@ -123,6 +124,7 @@ iicbb_attach(device_t dev)
 	sc->iicbus = device_add_child(dev, "iicbus", -1);
 	if (!sc->iicbus)
 		return (ENXIO);
+	sc->udelay = 10;		/* 10 uS default */
 	bus_generic_attach(dev);
 
 	return (0);
@@ -184,20 +186,18 @@ iicbb_print_child(device_t bus, device_t dev)
 	return (retval);
 }
 
-#define IIC_DELAY	10
-
-#define I2C_SETSDA(dev,val) do {			\
+#define I2C_SETSDA(sc,dev,val) do {			\
 	IICBB_SETSDA(device_get_parent(dev), val);	\
-	DELAY(IIC_DELAY);				\
+	DELAY(sc->udelay);				\
 	} while (0)
 
 #define I2C_SETSCL(dev,val) do {			\
 	iicbb_setscl(dev, val, 100);			\
 	} while (0)
 
-#define I2C_SET(dev,ctrl,data) do {			\
+#define I2C_SET(sc,dev,ctrl,data) do {			\
 	I2C_SETSCL(dev, ctrl);				\
-	I2C_SETSDA(dev, data);				\
+	I2C_SETSDA(sc, dev, data);			\
 	} while (0)
 
 #define I2C_GETSDA(dev) (IICBB_GETSDA(device_get_parent(dev)))
@@ -216,34 +216,39 @@ static int i2c_debug = 0;
 static void
 iicbb_setscl(device_t dev, int val, int timeout)
 {
+	struct iicbb_softc *sc = device_get_softc(dev);
 	int k = 0;
 
 	IICBB_SETSCL(device_get_parent(dev), val);
-	DELAY(IIC_DELAY);
+	DELAY(sc->udelay);
 
 	while (val && !I2C_GETSCL(dev) && k++ < timeout) {
 		IICBB_SETSCL(device_get_parent(dev), val);
-		DELAY(IIC_DELAY);
+		DELAY(sc->udelay);
 	}
-		
+
 	return;
 }
 
 static void
 iicbb_one(device_t dev, int timeout)
 {
-	I2C_SET(dev,0,1);
-	I2C_SET(dev,1,1);
-	I2C_SET(dev,0,1);
+	struct iicbb_softc *sc = device_get_softc(dev);
+
+	I2C_SET(sc,dev,0,1);
+	I2C_SET(sc,dev,1,1);
+	I2C_SET(sc,dev,0,1);
 	return;
 }
 
 static void
 iicbb_zero(device_t dev, int timeout)
 {
-	I2C_SET(dev,0,0);
-	I2C_SET(dev,1,0);
-	I2C_SET(dev,0,0);
+	struct iicbb_softc *sc = device_get_softc(dev);
+
+	I2C_SET(sc,dev,0,0);
+	I2C_SET(sc,dev,1,0);
+	I2C_SET(sc,dev,0,0);
 	return;
 }
 
@@ -264,20 +269,21 @@ iicbb_zero(device_t dev, int timeout)
 static int
 iicbb_ack(device_t dev, int timeout)
 {
+	struct iicbb_softc *sc = device_get_softc(dev);
 	int noack;
 	int k = 0;
-    
-	I2C_SET(dev,0,1);
-	I2C_SET(dev,1,1);
+
+	I2C_SET(sc,dev,0,1);
+	I2C_SET(sc,dev,1,1);
 	do {
 		noack = I2C_GETSDA(dev);
 		if (!noack)
 			break;
-		DELAY(10);
-		k += 10;
+		DELAY(1);
+		k++;
 	} while (k < timeout);
 
-	I2C_SET(dev,0,1);
+	I2C_SET(sc,dev,0,1);
 	I2C_DEBUG(printf("%c ",noack?'-':'+'));
 
 	return (noack);
@@ -302,16 +308,17 @@ iicbb_sendbyte(device_t dev, u_char data, int timeout)
 static u_char
 iicbb_readbyte(device_t dev, int last, int timeout)
 {
+	struct iicbb_softc *sc = device_get_softc(dev);
 	int i;
 	unsigned char data=0;
-    
-	I2C_SET(dev,0,1);
+
+	I2C_SET(sc,dev,0,1);
 	for (i=7; i>=0; i--) 
 	{
-		I2C_SET(dev,1,1);
+		I2C_SET(sc,dev,1,1);
 		if (I2C_GETSDA(dev))
 			data |= (1<<i);
-		I2C_SET(dev,0,1);
+		I2C_SET(sc,dev,0,1);
 	}
 	if (last) {
 		iicbb_one(dev, timeout);
@@ -337,13 +344,14 @@ iicbb_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
 static int
 iicbb_start(device_t dev, u_char slave, int timeout)
 {
+	struct iicbb_softc *sc = device_get_softc(dev);
 	int error;
 
 	I2C_DEBUG(printf("<"));
 
-	I2C_SET(dev,1,1);
-	I2C_SET(dev,1,0);
-	I2C_SET(dev,0,0);
+	I2C_SET(sc,dev,1,1);
+	I2C_SET(sc,dev,1,0);
+	I2C_SET(sc,dev,0,0);
 
 	/* send address */
 	iicbb_sendbyte(dev, slave, timeout);
@@ -364,10 +372,13 @@ error:
 static int
 iicbb_stop(device_t dev)
 {
-	I2C_SET(dev,0,0);
-	I2C_SET(dev,1,0);
-	I2C_SET(dev,1,1);
+	struct iicbb_softc *sc = device_get_softc(dev);
+
+	I2C_SET(sc,dev,0,0);
+	I2C_SET(sc,dev,1,0);
+	I2C_SET(sc,dev,1,1);
 	I2C_DEBUG(printf(">"));
+	I2C_DEBUG(printf("\n"));
 	return (0);
 }