i2c: Bus drivers return -Errno not -1

Tighten error paths used by various i2c adapters (mostly x86) so
they return real fault/errno codes instead of a "-1" (which is
most often interpreted as "-EPERM").  Build tested, with eyeball
review.

One minor initial goal is to have adapters consistently return
the code "-ENXIO" when addressing a device doesn't get an ACK
response, at least in the probe paths where they are already
good at stifling related logspam.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 26 insertions, 21 deletions

diff --git a/drivers/i2c/busses/i2c-sis630.c b/drivers/i2c/busses/i2c-sis630.c
index 3765dd7f450f..c4cc5eddf50d 100644
--- a/drivers/i2c/busses/i2c-sis630.c
+++ b/drivers/i2c/busses/i2c-sis630.c
@@ -134,7 +134,7 @@ static int sis630_transaction_start(struct i2c_adapter *adap, int size, u8 *oldc
 
                 if ((temp = sis630_read(SMB_CNT) & 0x03) != 0x00) {
                         dev_dbg(&adap->dev, "Failed! (%02x)\n", temp);
-                        return -1;
+                        return -EBUSY;
                 } else {
                         dev_dbg(&adap->dev, "Successful!\n");
                 }
@@ -177,17 +177,17 @@ static int sis630_transaction_wait(struct i2c_adapter *adap, int size)
         /* If the SMBus is still busy, we give up */
         if (timeout >= MAX_TIMEOUT) {
                 dev_dbg(&adap->dev, "SMBus Timeout!\n");
-                result = -1;
+                result = -ETIMEDOUT;
         }
 
         if (temp & 0x02) {
                 dev_dbg(&adap->dev, "Error: Failed bus transaction\n");
-                result = -1;
+                result = -ENXIO;
         }
 
         if (temp & 0x04) {
                 dev_err(&adap->dev, "Bus collision!\n");
-                result = -1;
+                result = -EIO;
                 /*
                   TBD: Datasheet say:
                   the software should clear this bit and restart SMBUS operation.
@@ -250,8 +250,10 @@ static int sis630_block_data(struct i2c_adapter *adap, union i2c_smbus_data *dat
                         if (i==8 || (len<8 && i==len)) {
                                 dev_dbg(&adap->dev, "start trans len=%d i=%d\n",len ,i);
                                 /* first transaction */
-                                if (sis630_transaction_start(adap, SIS630_BLOCK_DATA, &oldclock))
-                                        return -1;
+                                rc = sis630_transaction_start(adap,
+                                                SIS630_BLOCK_DATA, &oldclock);
+                                if (rc)
+                                        return rc;
                         }
                         else if ((i-1)%8 == 7 || i==len) {
                                 dev_dbg(&adap->dev, "trans_wait len=%d i=%d\n",len,i);
@@ -264,9 +266,10 @@ static int sis630_block_data(struct i2c_adapter *adap, union i2c_smbus_data *dat
                                         */
                                         sis630_write(SMB_STS,0x10);
                                 }
-                                if (sis630_transaction_wait(adap, SIS630_BLOCK_DATA)) {
+                                rc = sis630_transaction_wait(adap,
+                                                SIS630_BLOCK_DATA);
+                                if (rc) {
                                         dev_dbg(&adap->dev, "trans_wait failed\n");
-                                        rc = -1;
                                         break;
                                 }
                         }
@@ -275,13 +278,14 @@ static int sis630_block_data(struct i2c_adapter *adap, union i2c_smbus_data *dat
         else {
                 /* read request */
                 data->block[0] = len = 0;
-                if (sis630_transaction_start(adap, SIS630_BLOCK_DATA, &oldclock)) {
-                        return -1;
-                }
+                rc = sis630_transaction_start(adap,
+                                SIS630_BLOCK_DATA, &oldclock);
+                if (rc)
+                        return rc;
                 do {
-                        if (sis630_transaction_wait(adap, SIS630_BLOCK_DATA)) {
+                        rc = sis630_transaction_wait(adap, SIS630_BLOCK_DATA);
+                        if (rc) {
                                 dev_dbg(&adap->dev, "trans_wait failed\n");
-                                rc = -1;
                                 break;
                         }
                         /* if this first transaction then read byte count */
@@ -311,11 +315,13 @@ static int sis630_block_data(struct i2c_adapter *adap, union i2c_smbus_data *dat
         return rc;
 }
 
-/* Return -1 on error. */
+/* Return negative errno on error. */
 static s32 sis630_access(struct i2c_adapter *adap, u16 addr,
                          unsigned short flags, char read_write,
                          u8 command, int size, union i2c_smbus_data *data)
 {
+        int status;
+
         switch (size) {
                 case I2C_SMBUS_QUICK:
                         sis630_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
@@ -350,13 +356,13 @@ static s32 sis630_access(struct i2c_adapter *adap, u16 addr,
                         size = SIS630_BLOCK_DATA;
                         return sis630_block_data(adap, data, read_write);
                 default:
-                        printk("Unsupported I2C size\n");
-                        return -1;
-                        break;
+                        printk("Unsupported SMBus operation\n");
+                        return -EOPNOTSUPP;
         }
 
-        if (sis630_transaction(adap, size))
-                return -1;
+        status = sis630_transaction(adap, size);
+        if (status)
+                return status;
 
         if ((size != SIS630_PCALL) &&
                 ((read_write == I2C_SMBUS_WRITE) || (size == SIS630_QUICK))) {
@@ -373,8 +379,7 @@ static s32 sis630_access(struct i2c_adapter *adap, u16 addr,
                         data->word = sis630_read(SMB_BYTE) + (sis630_read(SMB_BYTE + 1) << 8);
                         break;
                 default:
-                        return -1;
-                        break;
+                        return -EOPNOTSUPP;
         }
 
         return 0;