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, 11 insertions, 9 deletions

diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index 77b13d027f86..7628fe8e0946 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -152,7 +152,7 @@ static int vt596_transaction(u8 size)
                 if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
                         dev_err(&vt596_adapter.dev, "SMBus reset failed! "
                                 "(0x%02x)\n", temp);
-                        return -1;
+                        return -EBUSY;
                 }
         }
 
@@ -167,24 +167,24 @@ static int vt596_transaction(u8 size)
 
         /* If the SMBus is still busy, we give up */
         if (timeout >= MAX_TIMEOUT) {
-                result = -1;
+                result = -ETIMEDOUT;
                 dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
         }
 
         if (temp & 0x10) {
-                result = -1;
+                result = -EIO;
                 dev_err(&vt596_adapter.dev, "Transaction failed (0x%02x)\n",
                         size);
         }
 
         if (temp & 0x08) {
-                result = -1;
+                result = -EIO;
                 dev_err(&vt596_adapter.dev, "SMBus collision!\n");
         }
 
         if (temp & 0x04) {
                 int read = inb_p(SMBHSTADD) & 0x01;
-                result = -1;
+                result = -ENXIO;
                 /* The quick and receive byte commands are used to probe
                    for chips, so errors are expected, and we don't want
                    to frighten the user. */
@@ -202,12 +202,13 @@ static int vt596_transaction(u8 size)
         return result;
 }
 
-/* Return -1 on error, 0 on success */
+/* Return negative errno on error, 0 on success */
 static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
                 unsigned short flags, char read_write, u8 command,
                 int size, union i2c_smbus_data *data)
 {
         int i;
+        int status;
 
         switch (size) {
         case I2C_SMBUS_QUICK:
@@ -258,8 +259,9 @@ static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
 
         outb_p(((addr & 0x7f) << 1) | read_write, SMBHSTADD);
 
-        if (vt596_transaction(size)) /* Error in transaction */
-                return -1;
+        status = vt596_transaction(size);
+        if (status)
+                return status;
 
         if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
                 return 0;
@@ -287,7 +289,7 @@ static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
 exit_unsupported:
         dev_warn(&vt596_adapter.dev, "Unsupported command invoked! (0x%02x)\n",
                  size);
-        return -1;
+        return -EOPNOTSUPP;
 }
 
 static u32 vt596_func(struct i2c_adapter *adapter)