ls2k i2c add bus conflict process.

Change-Id: Id490ff6587bfac147b922c40a4016e4f00a020cf
Signed-off-by: Chong Qiao <qiaochong@loongson.cn>

Targets/LS2K/dev/i2c.c

@@ -47,6 +47,12 @@ struct i2c_msg {
 
 #define ls2k_i2c_debug(fmt, args...)	//printf(fmt, ##args)
 #define pr_info printf
+static void ls2k_i2c_reinit()
+{
+        ls2k_i2c_writeb(0, LS2K_I2C_CTR_REG);
+        ls2k_i2c_writeb(0x80, LS2K_I2C_CTR_REG);
+	ls2k_i2c_writeb(CR_IACK, LS2K_I2C_CR_REG);
+}
 
 static void ls2k_i2c_stop(void)
 {
@@ -59,18 +65,24 @@ again:
 
 static int ls2k_i2c_start(int dev_addr, int flags)
 {
-	int retry = 5;
+	int retry = 5, sr;
 	unsigned char addr = (dev_addr & 0x7f) << 1;
 	addr |= (flags & I2C_M_RD)? 1:0;
 
 start:
+	delay(1000);
 	ls2k_i2c_writeb(addr, LS2K_I2C_TXR_REG);
 	ls2k_i2c_debug("%s <line%d>: i2c device address: 0x%x\n",
 			__func__, __LINE__, addr);
 	ls2k_i2c_writeb((CR_START | CR_WRITE), LS2K_I2C_CR_REG);
-	while (ls2k_i2c_readb(LS2K_I2C_SR_REG) & SR_TIP) ;
+	while (((sr = ls2k_i2c_readb(LS2K_I2C_SR_REG)) & (SR_TIP|SR_AL)) == SR_TIP);
+	if(sr & SR_AL) {
+		ls2k_i2c_reinit();
+		ls2k_i2c_stop();
+		goto start;
+	}
 
-	if (ls2k_i2c_readb(LS2K_I2C_SR_REG) & SR_NOACK) {
+	if (sr & SR_NOACK) {
 		ls2k_i2c_stop();
 		while (retry--)
 			goto start;
@@ -82,13 +94,17 @@ start:
 
 static int ls2k_i2c_read(unsigned char *buf, int count)
 {
-        int i;
+	int i, sr;
 
         for (i = 0; i < count; i++) {
                 ls2k_i2c_writeb((i == count - 1)?
 				(CR_READ | CR_ACK) : CR_READ,
 				LS2K_I2C_CR_REG);
-                while (ls2k_i2c_readb(LS2K_I2C_SR_REG) & SR_TIP) ;
+		while (((sr = ls2k_i2c_readb(LS2K_I2C_SR_REG)) & (SR_TIP|SR_AL)) == SR_TIP);
+		if(sr & SR_AL) {
+			ls2k_i2c_reinit();
+			break;
+		}
                 buf[i] = ls2k_i2c_readb(LS2K_I2C_RXR_REG);
 		ls2k_i2c_debug("%s <line%d>: read buf[%d] <= %02x\n",
 				__func__, __LINE__, i, buf[i]);
@@ -99,16 +115,20 @@ static int ls2k_i2c_read(unsigned char *buf, int count)
 
 static int ls2k_i2c_write(unsigned char *buf, int count)
 {
-        int i;
+        int i, sr;
 
         for (i = 0; i < count; i++) {
 		ls2k_i2c_writeb(buf[i], LS2K_I2C_TXR_REG);
 		ls2k_i2c_debug("%s <line%d>: write buf[%d] => %02x\n",
 				__func__, __LINE__, i, buf[i]);
 		ls2k_i2c_writeb(CR_WRITE, LS2K_I2C_CR_REG);
-		while (ls2k_i2c_readb(LS2K_I2C_SR_REG) & SR_TIP) ;
+		while (((sr = ls2k_i2c_readb(LS2K_I2C_SR_REG)) & (SR_TIP|SR_AL)) == SR_TIP);
+		if (sr & SR_AL) {
+			ls2k_i2c_reinit();
+			break;
+		}
 
-		if (ls2k_i2c_readb(LS2K_I2C_SR_REG) & SR_NOACK) {
+		if (sr & SR_NOACK) {
 			ls2k_i2c_debug("%s <line%d>: device no ack\n",
 					__func__, __LINE__);
 			ls2k_i2c_stop();