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, 10 insertions, 8 deletions

diff --git a/drivers/i2c/busses/i2c-amd756.c b/drivers/i2c/busses/i2c-amd756.c
index 43508d61eb7c..3d5bcb65e9e0 100644
--- a/drivers/i2c/busses/i2c-amd756.c
+++ b/drivers/i2c/busses/i2c-amd756.c
@@ -151,17 +151,17 @@ static int amd756_transaction(struct i2c_adapter *adap)
         }
 
         if (temp & GS_PRERR_STS) {
-                result = -1;
+                result = -ENXIO;
                 dev_dbg(&adap->dev, "SMBus Protocol error (no response)!\n");
         }
 
         if (temp & GS_COL_STS) {
-                result = -1;
+                result = -EIO;
                 dev_warn(&adap->dev, "SMBus collision!\n");
         }
 
         if (temp & GS_TO_STS) {
-                result = -1;
+                result = -ETIMEDOUT;
                 dev_dbg(&adap->dev, "SMBus protocol timeout!\n");
         }
 
@@ -189,22 +189,23 @@ static int amd756_transaction(struct i2c_adapter *adap)
         outw_p(inw(SMB_GLOBAL_ENABLE) | GE_ABORT, SMB_GLOBAL_ENABLE);
         msleep(100);
         outw_p(GS_CLEAR_STS, SMB_GLOBAL_STATUS);
-        return -1;
+        return -EIO;
 }
 
-/* Return -1 on error. */
+/* Return negative errno on error. */
 static s32 amd756_access(struct i2c_adapter * adap, u16 addr,
                   unsigned short flags, char read_write,
                   u8 command, int size, union i2c_smbus_data * data)
 {
         int i, len;
+        int status;
 
         /** TODO: Should I supporte the 10-bit transfers? */
         switch (size) {
         case I2C_SMBUS_PROC_CALL:
                 dev_dbg(&adap->dev, "I2C_SMBUS_PROC_CALL not supported!\n");
                 /* TODO: Well... It is supported, I'm just not sure what to do here... */
-                return -1;
+                return -EOPNOTSUPP;
         case I2C_SMBUS_QUICK:
                 outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                        SMB_HOST_ADDRESS);
@@ -256,8 +257,9 @@ static s32 amd756_access(struct i2c_adapter * adap, u16 addr,
         /* How about enabling interrupts... */
         outw_p(size & GE_CYC_TYPE_MASK, SMB_GLOBAL_ENABLE);
 
-        if (amd756_transaction(adap))   /* Error in transaction */
-                return -1;
+        status = amd756_transaction(adap);
+        if (status)
+                return status;
 
         if ((read_write == I2C_SMBUS_WRITE) || (size == AMD756_QUICK))
                 return 0;